Date   

Re: AP900GTO - DEC stiffness

tomb1818 <tomb1818@...>
 

"if it aint broken don't touch it!"
As to precision, you are right. I get +/- 4 arcsec without pem.

I'm gonna leave it alone.
Thanks

--- In ap-gto@..., "Howard" <howard@...> wrote:

Since the backlash you describe is in RA, it is not as critical to
remove it. The 600E mounts are a bit trickier to get a perfect gear
mesh, but they are still very high precision mounts. If you felt the
backlash in dec, I would say to go for it and try to remesh. As it is,
the question is "How much do you enjoy tinkering?"



Mag. 7 skies!



Howard Hedlund

Astro-Physics, Inc.

815-282-1513

________________________________

From: ap-gto@... [mailto:ap-gto@...] On Behalf
Of tomb1818
Sent: Sunday, March 21, 2010 4:39 PM
To: ap-gto@...
Subject: [ap-gto] Re: AP900GTO - DEC stiffness






Hi Howard,
Does the precision apply to mounts like the 600? I have a small amount
of backlash and was wondering if it would be useful to adjust it out( 2
mm at the end of the counterweight shaft.
Thanks

--- In ap-gto@... <mailto:ap-gto%40yahoogroups.com> ,
"Howard" <howard@> wrote:

Good Morning Stefano!



Are you using guiding software that employs the ASCOM driver? If so,
are you using the old driver from the ASCOM website - v. 4.1.25 - or
are
you using our new driver - v. 4.99.58 - available here:

http://www.gralak.com/apdriver <http://www.gralak.com/apdriver>

The reason I ask is that the old driver had a default backlash setting
that could be overriding whatever you might have set with the keypad.
I
can't count the number of times this has been an issue, and it almost
always presents itself as oscillations when guiding. Let's first
verify
that the backlash setting really and truly is at zero!



I would not loosen what sounds like an excellent gear mesh. Think of
it this way: If your car's right front wheel is out of alignment and
is
pulling the car to the right, you can correct this by lowering the
tire
pressure in the left front tire until the car tracks in a straight
line.
You may have made your car go straight, but this probably isn't the
best
solution. You will find that your 900GTO has enough mechanical
precision that the gear mesh can be adjusted to a level where backlash
is of little significance. Most of our most experienced AP family
members find that they simply don't need to use backlash compensation.



Mag. 7 skies!



Howard Hedlund

Astro-Physics, Inc.

815-282-1513

________________________________

From: ap-gto@... <mailto:ap-gto%40yahoogroups.com>
[mailto:ap-gto@... <mailto:ap-gto%40yahoogroups.com> ] On
Behalf
Of Stefano Cancelli
Sent: Friday, March 19, 2010 8:33 AM
To: ap-gto@... <mailto:ap-gto%40yahoogroups.com>
Subject: Re: [ap-gto] AP900GTO - DEC stiffness





Thanks, Rolando. I found the pdf's on the site that show the clutch
replacement procedure and the special extraction tool. This pretty
much
answers my question as it appears its not an uncommon problem and one
that
is easily remedied. I wasnt' sure if the stiffness was coming from the
clutches not being disengaged fully or if it was some other mechanical
binding problem from the axis itself.

Another imaging session last night and still the occasional ping pong
after
dithering guider move between exposures. Once it settles however, it
will
make dec correction happily for long exposures without oscillation.
I'm
wondering if perhaps the worm mesh in DEC might be a little too tight
as
there doesn't seem to be any backlash whatsover in DEC. I know it
might
seem
counterproductive to think a tiny bit of backlash is a good thing, but
its
fairly easy to handle.

Cheers,
Stef.

On Fri, Mar 19, 2010 at 4:06 AM, <chris1011@
<mailto:chris1011%40aol.com> > wrote:



In a message dated 3/18/2010 6:30:03 P.M. Central Daylight Time,
scancelli@ <mailto:scancelli%40treblestef.com> writes:

This kind of behaviour seems like stiction to me and I'm wondering
if
the
DEC stiffness is contributing to this.
Howard can answer you about the clutches being stiff and how to
remedy
that. However, be assured that this has nothing to do with your
guiding.
Whether the clutches are loose or fully locked has no effect
whatsoever on
guiding.

Rolando


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Re: Power connector on GOTOCP2?

tomb1818 <tomb1818@...>
 

looks like a good solution. I'll check it out.
Thanks

--- In ap-gto@..., "Barry Megdal" <bmegdal@...> wrote:

I got tired of wiring up the electronics (including DC power distribution)
each time I set up the mount, so I mounted all the parts semi-permanently on
a finished plywood board. The RigRunner distribution panel can be clearly
seen:



www.shbinstruments.com/MountElectronicsBoard.jpg



- Barry



Dr. Barry Megdal



Shb Instruments, Inc.

19215 Parthenia St., Suite A

Northridge, CA 91324

www.shbinstruments.com <http://www.shbinstruments.com/>

(818) 773-2000 (818) 773-2005 fax

bmegdal@...



Dept. of Electrical Engineering

California Institute of Technology

Pasadena, CA

bmegdal@... (use either email)





[Non-text portions of this message have been removed]


Re: USB to Serial adapters and Windows 7 for controlling AP1200

dannysperry
 

Hi James,

Looks like your problem is solved, but in case this comes up again, I just wanted to add another positive note for the FTDI-based adapters. After going through much of what you've gone through, I tried the FTDI chipset adapters and everything worked on Windows Vista and Windows 7 64-bit.

I went with this particular model:
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=768-1013-ND

It's worked on the CP3 interface, RoboFocus, and the TCF-S. Plus, the adapters maintain their comm port assignment regardless of which USB port you plug into, and no driver disk is needed on Win 7.

Best,
Danny
http://www.californiastars.net/

--- In ap-gto@..., "J M" <jsmiller58@...> wrote:

I was wondering if anyone on the list has a recommendation for a USB to Serial Adapter...

I have an AP1200GTO that I am trying to control from my new Windows 7 laptop, using apps such as TheSky 6 Pro and SkyTools 3.

My old laptop worked fine with my current adapter (I don't know the exact model, but I know that it has the Prolific Technology chipset in it). With XP I experienced no problems controlling the mount through the old and new series of ASCOM drivers, as well as with the built in control in TheSky 6 Pro.

With my new laptop, which is on Win 7, I cannot maintain a connection between the laptop and the mount for more than a minute. I will issue a go to command from TheSky and the mount will proceed to the target, but right afterwards (and often in the middle of the slew) I will get an error message that the communciation has been terminated. At first I thought that this might be a problem with Ray's new ASCOM driver, but I have the same problem when I use the built in control in the TheSky rather than the ASCOM driver. I also have the same problem if I try to control the mount from SkyTools (either directly talking to the ASCOM driver, or going through TheSky). In most (all?) cases when the communication goes away the application completely freezes up.

Anyway, my guess is that this is an incompatability between the serial to usb converter and the Win 7 OS. I have updated the driver from the Prolific web site (which I had to do in order to get ANY communication between the laptop and the mount).

Any recommendations would be greatly appreciated.

James


Re: USB to Serial adapters and Windows 7 for controlling AP1200

jsmiller58
 

I would like to thank everyone for your responses! While I am sad to see that so many others have had to deal with the same problem, at least it is good to hear that there are adapters that have been found to work.

I was looking at the Tripp Lite/Keyspan adapters assuming that the Prolific-based devices were to blame, so that is probably the way I will go.

James

--- In ap-gto@..., Thomas Billak <turkeybuzzard75@...> wrote:


The optec inc. serial to usb with the FTDI chipset always works for me.



Here is there web sit page: http://www.optecinc.com/optec_058.htm



Regards,



Tom





To: ap-gto@...
From: boschportell@...
Date: Mon, 22 Mar 2010 18:09:52 +0100
Subject: RE: [ap-gto] USB to Serial adapters and Windows 7 for controlling AP1200






I have the same problem and after a lot of test, I concluded taht the probles is the chipset of my adapters.

So, all adapters with the Prolific chipset (independently of the manufracturer: HAMA, Conceptronics, and others), don't work with Windows7 and my Labtop Acer Rave 3600, but all mi adapters with chipset made from FTDI, works well without any problem.

I report this problem in a little (but in spanish) Blogg: http://ager-allsky.blogspot.com/p/observatorio-joan-roget.html (see the charper: ┬┐Como se comporta Win7?)

(Sorry for my bad english)

To: ap-gto@...
From: salyer@...
Date: Mon, 22 Mar 2010 12:17:06 -0400
Subject: Re: [ap-gto] USB to Serial adapters and Windows 7 for controlling AP1200

I just went through a painful experience this
weekend with USB to serial adapters. After
updating my Vista system to Windows 7 I
discovered the serial interface to RoboFocus no
longer worked. Since I'd never had any problems
before I figured I just had a loose wire
somewhere or maybe the adapter gave out. After
all, if it work under Vista, it had to work under
Windows 7. No big deal. The interface is trivial
and there are plenty of cheap adapters. Since I
was about to add another RoboFocus and perhaps a
TAKpmoter (actually a third RoboFocus) I bought a
bunch of new adapters. What a nightmare. Out of 7
adapters, including 4 different brands, only one
adapter would work with RoboFocus while 3 worked
with my AP900 interface. After a lot of playing
around with windows and trying different things I
discovered that all the adapters, except one,
were really built by Prolific. Although I
downloaded several versions of the driver,
including the latest from the Prolific web site,
none of them worked. Several different failure
scenarios, but I concluded that the Prolific
design is junk. Several of the adapters worked
with the AP900 interface (not all), but not with
RoboFocus. There really isn't any way of knowing
if a particular brand is really built by Prolific
without viewing its driver information in Windows
so I'd be really afraid of buying any unknown
brand. Fortunately, I did have one adapter that
always seemed to work. It's a Keyspan model 19HS
built by Tripp Lite. It's a little fancier that
the others including a status LED. I checked the
AP web site and discovered that they recommend
Keyspan. Since I need more that a single
interface, I ordered a 4 port version from
Amazon. I expect to receive it this afternoon. Of
course that means I can't, right now tell you
that it works, but I do expect it will.

Greg

At 11:45 AM 3/22/2010, you wrote:


I was wondering if anyone on the list has a
recommendation for a USB to Serial Adapter...

I have an AP1200GTO that I am trying to control
from my new Windows 7 laptop, using apps such as TheSky 6 Pro and SkyTools 3.

My old laptop worked fine with my current
adapter (I don't know the exact model, but I
know that it has the Prolific Technology chipset
in it). With XP I experienced no problems
controlling the mount through the old and new
series of ASCOM drivers, as well as with the built in control in TheSky 6 Pro.

With my new laptop, which is on Win 7, I cannot
maintain a connection between the laptop and the
mount for more than a minute. I will issue a go
to command from TheSky and the mount will
proceed to the target, but right afterwards (and
often in the middle of the slew) I will get an
error message that the communciation has been
terminated. At first I thought that this might
be a problem with Ray's new ASCOM driver, but I
have the same problem when I use the built in
control in the TheSky rather than the ASCOM
driver. I also have the same problem if I try to
control the mount from SkyTools (either directly
talking to the ASCOM driver, or going through
TheSky). In most (all?) cases when the
communication goes away the application completely freezes up.

Anyway, my guess is that this is an
incompatability between the serial to usb
converter and the Win 7 OS. I have updated the
driver from the Prolific web site (which I had
to do in order to get ANY communication between the laptop and the mount).

Any recommendations would be greatly appreciated.

James


[Non-text portions of this message have been removed]



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Re: AP900GTO - DEC stiffness

CurtisC <calypte@...>
 

Some other himts: if you are using MaximDL, make sure you are always > using Dec value = 0 - do not use any other Dec value to modify the
guiding. Do your calibration once, near the celestial equator and use > that value everywhere in the sky - don't worry, it will work
perfectly even near the poles.
My new Mach1GTO is due here in two days. Looks like I have a lot to learn. I hope I get good results sooner than with my G-11! The people in the Losmandy group are upset over my parting comments yesterday.

WRT the above quoted statement -- OK, that's true for Maxim DL. What about CCDSoft? Not an A-P mount, of course, but I've found little benefit to setting the dec parameter to anything other than zero for autoguiding.


Re: USB to Serial adapters and Windows 7 for controlling AP1200

Salyer <salyer@...>
 

I downloaded new software from the Keyspan web
site. Everything works well. Their support
software lets you test the device and helps in
the mapping of ports into COM numbers (which can
be a pain with 4 ports and just the windows device manager)

Greg

At 01:06 PM 3/22/2010, you wrote:


Well USP delivered my new Keyspan 4 port USB to
serial adapter as I was typed my last post. I am
happy to report that the hardware works just
fine. Actually I only tested it with 2 RoboFocus
units. It's raining today so I can't check my
AP900 interface, but I wasn't having problems
with that. Although the hardware worked, there is
something wrong with the installation disk. It
created a directory for the new software but
didn't load anything. I had to manually install
the driver and 4 serial ports. I guess this is no
big thing, but I did need to find out what
happened (there is some support software that I would like to install).

Greg

At 12:17 PM 3/22/2010, you wrote:


I just went through a painful experience this
weekend with USB to serial adapters. After
updating my Vista system to Windows 7 I
discovered the serial interface to RoboFocus no
longer worked. Since I'd never had any problems
before I figured I just had a loose wire
somewhere or maybe the adapter gave out. After
all, if it work under Vista, it had to work under
Windows 7. No big deal. The interface is trivial
and there are plenty of cheap adapters. Since I
was about to add another RoboFocus and perhaps a
TAKpmoter (actually a third RoboFocus) I bought a
bunch of new adapters. What a nightmare. Out of 7
adapters, including 4 different brands, only one
adapter would work with RoboFocus while 3 worked
with my AP900 interface. After a lot of playing
around with windows and trying different things I
discovered that all the adapters, except one,
were really built by Prolific. Although I
downloaded several versions of the driver,
including the latest from the Prolific web site,
none of them worked. Several different failure
scenarios, but I concluded that the Prolific
design is junk. Several of the adapters worked
with the AP900 interface (not all), but not with
RoboFocus. There really isn't any way of knowing
if a particular brand is really built by Prolific
without viewing its driver information in Windows
so I'd be really afraid of buying any unknown
brand. Fortunately, I did have one adapter that
always seemed to work. It's a Keyspan model 19HS
built by Tripp Lite. It's a little fancier that
the others including a status LED. I checked the
AP web site and discovered that they recommend
Keyspan. Since I need more that a single
interface, I ordered a 4 port version from
Amazon. I expect to receive it this afternoon. Of
course that means I can't, right now tell you
that it works, but I do expect it will.

Greg

At 11:45 AM 3/22/2010, you wrote:


I was wondering if anyone on the list has a
recommendation for a USB to Serial Adapter...

I have an AP1200GTO that I am trying to control
from my new Windows 7 laptop, using apps such
as TheSky 6 Pro and SkyTools 3.

My old laptop worked fine with my current
adapter (I don't know the exact model, but I
know that it has the Prolific Technology chipset
in it). With XP I experienced no problems
controlling the mount through the old and new
series of ASCOM drivers, as well as with the
built in control in TheSky 6 Pro.

With my new laptop, which is on Win 7, I cannot
maintain a connection between the laptop and the
mount for more than a minute. I will issue a go
to command from TheSky and the mount will
proceed to the target, but right afterwards (and
often in the middle of the slew) I will get an
error message that the communciation has been
terminated. At first I thought that this might
be a problem with Ray's new ASCOM driver, but I
have the same problem when I use the built in
control in the TheSky rather than the ASCOM
driver. I also have the same problem if I try to
control the mount from SkyTools (either directly
talking to the ASCOM driver, or going through
TheSky). In most (all?) cases when the
communication goes away the application completely freezes up.

Anyway, my guess is that this is an
incompatability between the serial to usb
converter and the Win 7 OS. I have updated the
driver from the Prolific web site (which I had
to do in order to get ANY communication between the laptop and the mount).

Any recommendations would be greatly appreciated.

James




Re: USB to Serial adapters and Windows 7 for controlling AP1200

turkeybuzzard75
 

The optec inc. serial to usb with the FTDI chipset always works for me.



Here is there web sit page: http://www.optecinc.com/optec_058.htm



Regards,



Tom





To: ap-gto@...
From: boschportell@...
Date: Mon, 22 Mar 2010 18:09:52 +0100
Subject: RE: [ap-gto] USB to Serial adapters and Windows 7 for controlling AP1200






I have the same problem and after a lot of test, I concluded taht the probles is the chipset of my adapters.

So, all adapters with the Prolific chipset (independently of the manufracturer: HAMA, Conceptronics, and others), don't work with Windows7 and my Labtop Acer Rave 3600, but all mi adapters with chipset made from FTDI, works well without any problem.

I report this problem in a little (but in spanish) Blogg: http://ager-allsky.blogspot.com/p/observatorio-joan-roget.html (see the charper: ┐Como se comporta Win7?)

(Sorry for my bad english)

To: ap-gto@...
From: salyer@...
Date: Mon, 22 Mar 2010 12:17:06 -0400
Subject: Re: [ap-gto] USB to Serial adapters and Windows 7 for controlling AP1200

I just went through a painful experience this
weekend with USB to serial adapters. After
updating my Vista system to Windows 7 I
discovered the serial interface to RoboFocus no
longer worked. Since I'd never had any problems
before I figured I just had a loose wire
somewhere or maybe the adapter gave out. After
all, if it work under Vista, it had to work under
Windows 7. No big deal. The interface is trivial
and there are plenty of cheap adapters. Since I
was about to add another RoboFocus and perhaps a
TAKpmoter (actually a third RoboFocus) I bought a
bunch of new adapters. What a nightmare. Out of 7
adapters, including 4 different brands, only one
adapter would work with RoboFocus while 3 worked
with my AP900 interface. After a lot of playing
around with windows and trying different things I
discovered that all the adapters, except one,
were really built by Prolific. Although I
downloaded several versions of the driver,
including the latest from the Prolific web site,
none of them worked. Several different failure
scenarios, but I concluded that the Prolific
design is junk. Several of the adapters worked
with the AP900 interface (not all), but not with
RoboFocus. There really isn't any way of knowing
if a particular brand is really built by Prolific
without viewing its driver information in Windows
so I'd be really afraid of buying any unknown
brand. Fortunately, I did have one adapter that
always seemed to work. It's a Keyspan model 19HS
built by Tripp Lite. It's a little fancier that
the others including a status LED. I checked the
AP web site and discovered that they recommend
Keyspan. Since I need more that a single
interface, I ordered a 4 port version from
Amazon. I expect to receive it this afternoon. Of
course that means I can't, right now tell you
that it works, but I do expect it will.

Greg

At 11:45 AM 3/22/2010, you wrote:


I was wondering if anyone on the list has a
recommendation for a USB to Serial Adapter...

I have an AP1200GTO that I am trying to control
from my new Windows 7 laptop, using apps such as TheSky 6 Pro and SkyTools 3.

My old laptop worked fine with my current
adapter (I don't know the exact model, but I
know that it has the Prolific Technology chipset
in it). With XP I experienced no problems
controlling the mount through the old and new
series of ASCOM drivers, as well as with the built in control in TheSky 6 Pro.

With my new laptop, which is on Win 7, I cannot
maintain a connection between the laptop and the
mount for more than a minute. I will issue a go
to command from TheSky and the mount will
proceed to the target, but right afterwards (and
often in the middle of the slew) I will get an
error message that the communciation has been
terminated. At first I thought that this might
be a problem with Ray's new ASCOM driver, but I
have the same problem when I use the built in
control in the TheSky rather than the ASCOM
driver. I also have the same problem if I try to
control the mount from SkyTools (either directly
talking to the ASCOM driver, or going through
TheSky). In most (all?) cases when the
communication goes away the application completely freezes up.

Anyway, my guess is that this is an
incompatability between the serial to usb
converter and the Win 7 OS. I have updated the
driver from the Prolific web site (which I had
to do in order to get ANY communication between the laptop and the mount).

Any recommendations would be greatly appreciated.

James


[Non-text portions of this message have been removed]



------------------------------------

To UNSUBSCRIBE, or for general information on the ap-gto list
see http://groups.yahoo.com/group/ap-gtoYahoo! Groups Links



[Non-text portions of this message have been removed]





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Re: USB to Serial adapters and Windows 7 for controlling AP1200

daniel bosch portell <boschportell@...>
 

I have the same problem and after a lot of test, I concluded taht the probles is the chipset of my adapters.



So, all adapters with the Prolific chipset (independently of the manufracturer: HAMA, Conceptronics, and others), don't work with Windows7 and my Labtop Acer Rave 3600, but all mi adapters with chipset made from FTDI, works well without any problem.



I report this problem in a little (but in spanish) Blogg: http://ager-allsky.blogspot.com/p/observatorio-joan-roget.html (see the charper: ┬┐Como se comporta Win7?)



(Sorry for my bad english)




To: ap-gto@...
From: salyer@...
Date: Mon, 22 Mar 2010 12:17:06 -0400
Subject: Re: [ap-gto] USB to Serial adapters and Windows 7 for controlling AP1200

I just went through a painful experience this
weekend with USB to serial adapters. After
updating my Vista system to Windows 7 I
discovered the serial interface to RoboFocus no
longer worked. Since I'd never had any problems
before I figured I just had a loose wire
somewhere or maybe the adapter gave out. After
all, if it work under Vista, it had to work under
Windows 7. No big deal. The interface is trivial
and there are plenty of cheap adapters. Since I
was about to add another RoboFocus and perhaps a
TAKpmoter (actually a third RoboFocus) I bought a
bunch of new adapters. What a nightmare. Out of 7
adapters, including 4 different brands, only one
adapter would work with RoboFocus while 3 worked
with my AP900 interface. After a lot of playing
around with windows and trying different things I
discovered that all the adapters, except one,
were really built by Prolific. Although I
downloaded several versions of the driver,
including the latest from the Prolific web site,
none of them worked. Several different failure
scenarios, but I concluded that the Prolific
design is junk. Several of the adapters worked
with the AP900 interface (not all), but not with
RoboFocus. There really isn't any way of knowing
if a particular brand is really built by Prolific
without viewing its driver information in Windows
so I'd be really afraid of buying any unknown
brand. Fortunately, I did have one adapter that
always seemed to work. It's a Keyspan model 19HS
built by Tripp Lite. It's a little fancier that
the others including a status LED. I checked the
AP web site and discovered that they recommend
Keyspan. Since I need more that a single
interface, I ordered a 4 port version from
Amazon. I expect to receive it this afternoon. Of
course that means I can't, right now tell you
that it works, but I do expect it will.

Greg

At 11:45 AM 3/22/2010, you wrote:


I was wondering if anyone on the list has a
recommendation for a USB to Serial Adapter...

I have an AP1200GTO that I am trying to control
from my new Windows 7 laptop, using apps such as TheSky 6 Pro and SkyTools 3.

My old laptop worked fine with my current
adapter (I don't know the exact model, but I
know that it has the Prolific Technology chipset
in it). With XP I experienced no problems
controlling the mount through the old and new
series of ASCOM drivers, as well as with the built in control in TheSky 6 Pro.

With my new laptop, which is on Win 7, I cannot
maintain a connection between the laptop and the
mount for more than a minute. I will issue a go
to command from TheSky and the mount will
proceed to the target, but right afterwards (and
often in the middle of the slew) I will get an
error message that the communciation has been
terminated. At first I thought that this might
be a problem with Ray's new ASCOM driver, but I
have the same problem when I use the built in
control in the TheSky rather than the ASCOM
driver. I also have the same problem if I try to
control the mount from SkyTools (either directly
talking to the ASCOM driver, or going through
TheSky). In most (all?) cases when the
communication goes away the application completely freezes up.

Anyway, my guess is that this is an
incompatability between the serial to usb
converter and the Win 7 OS. I have updated the
driver from the Prolific web site (which I had
to do in order to get ANY communication between the laptop and the mount).

Any recommendations would be greatly appreciated.

James






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To UNSUBSCRIBE, or for general information on the ap-gto list
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[Non-text portions of this message have been removed]


Re: USB to Serial adapters and Windows 7 for controlling AP1200

Salyer <salyer@...>
 

Well USP delivered my new Keyspan 4 port USB to
serial adapter as I was typed my last post. I am
happy to report that the hardware works just
fine. Actually I only tested it with 2 RoboFocus
units. It's raining today so I can't check my
AP900 interface, but I wasn't having problems
with that. Although the hardware worked, there is
something wrong with the installation disk. It
created a directory for the new software but
didn't load anything. I had to manually install
the driver and 4 serial ports. I guess this is no
big thing, but I did need to find out what
happened (there is some support software that I would like to install).

Greg

At 12:17 PM 3/22/2010, you wrote:


I just went through a painful experience this
weekend with USB to serial adapters. After
updating my Vista system to Windows 7 I
discovered the serial interface to RoboFocus no
longer worked. Since I'd never had any problems
before I figured I just had a loose wire
somewhere or maybe the adapter gave out. After
all, if it work under Vista, it had to work under
Windows 7. No big deal. The interface is trivial
and there are plenty of cheap adapters. Since I
was about to add another RoboFocus and perhaps a
TAKpmoter (actually a third RoboFocus) I bought a
bunch of new adapters. What a nightmare. Out of 7
adapters, including 4 different brands, only one
adapter would work with RoboFocus while 3 worked
with my AP900 interface. After a lot of playing
around with windows and trying different things I
discovered that all the adapters, except one,
were really built by Prolific. Although I
downloaded several versions of the driver,
including the latest from the Prolific web site,
none of them worked. Several different failure
scenarios, but I concluded that the Prolific
design is junk. Several of the adapters worked
with the AP900 interface (not all), but not with
RoboFocus. There really isn't any way of knowing
if a particular brand is really built by Prolific
without viewing its driver information in Windows
so I'd be really afraid of buying any unknown
brand. Fortunately, I did have one adapter that
always seemed to work. It's a Keyspan model 19HS
built by Tripp Lite. It's a little fancier that
the others including a status LED. I checked the
AP web site and discovered that they recommend
Keyspan. Since I need more that a single
interface, I ordered a 4 port version from
Amazon. I expect to receive it this afternoon. Of
course that means I can't, right now tell you
that it works, but I do expect it will.

Greg

At 11:45 AM 3/22/2010, you wrote:


I was wondering if anyone on the list has a
recommendation for a USB to Serial Adapter...

I have an AP1200GTO that I am trying to control
from my new Windows 7 laptop, using apps such
as TheSky 6 Pro and SkyTools 3.

My old laptop worked fine with my current
adapter (I don't know the exact model, but I
know that it has the Prolific Technology chipset
in it). With XP I experienced no problems
controlling the mount through the old and new
series of ASCOM drivers, as well as with the
built in control in TheSky 6 Pro.

With my new laptop, which is on Win 7, I cannot
maintain a connection between the laptop and the
mount for more than a minute. I will issue a go
to command from TheSky and the mount will
proceed to the target, but right afterwards (and
often in the middle of the slew) I will get an
error message that the communciation has been
terminated. At first I thought that this might
be a problem with Ray's new ASCOM driver, but I
have the same problem when I use the built in
control in the TheSky rather than the ASCOM
driver. I also have the same problem if I try to
control the mount from SkyTools (either directly
talking to the ASCOM driver, or going through
TheSky). In most (all?) cases when the
communication goes away the application completely freezes up.

Anyway, my guess is that this is an
incompatability between the serial to usb
converter and the Win 7 OS. I have updated the
driver from the Prolific web site (which I had
to do in order to get ANY communication between the laptop and the mount).

Any recommendations would be greatly appreciated.

James

[Non-text portions of this message have been removed]


Re: USB to Serial adapters and Windows 7 for controlling AP1200

Salyer <salyer@...>
 

I just went through a painful experience this
weekend with USB to serial adapters. After
updating my Vista system to Windows 7 I
discovered the serial interface to RoboFocus no
longer worked. Since I'd never had any problems
before I figured I just had a loose wire
somewhere or maybe the adapter gave out. After
all, if it work under Vista, it had to work under
Windows 7. No big deal. The interface is trivial
and there are plenty of cheap adapters. Since I
was about to add another RoboFocus and perhaps a
TAKpmoter (actually a third RoboFocus) I bought a
bunch of new adapters. What a nightmare. Out of 7
adapters, including 4 different brands, only one
adapter would work with RoboFocus while 3 worked
with my AP900 interface. After a lot of playing
around with windows and trying different things I
discovered that all the adapters, except one,
were really built by Prolific. Although I
downloaded several versions of the driver,
including the latest from the Prolific web site,
none of them worked. Several different failure
scenarios, but I concluded that the Prolific
design is junk. Several of the adapters worked
with the AP900 interface (not all), but not with
RoboFocus. There really isn't any way of knowing
if a particular brand is really built by Prolific
without viewing its driver information in Windows
so I'd be really afraid of buying any unknown
brand. Fortunately, I did have one adapter that
always seemed to work. It's a Keyspan model 19HS
built by Tripp Lite. It's a little fancier that
the others including a status LED. I checked the
AP web site and discovered that they recommend
Keyspan. Since I need more that a single
interface, I ordered a 4 port version from
Amazon. I expect to receive it this afternoon. Of
course that means I can't, right now tell you
that it works, but I do expect it will.

Greg

At 11:45 AM 3/22/2010, you wrote:


I was wondering if anyone on the list has a
recommendation for a USB to Serial Adapter...

I have an AP1200GTO that I am trying to control
from my new Windows 7 laptop, using apps such as TheSky 6 Pro and SkyTools 3.

My old laptop worked fine with my current
adapter (I don't know the exact model, but I
know that it has the Prolific Technology chipset
in it). With XP I experienced no problems
controlling the mount through the old and new
series of ASCOM drivers, as well as with the built in control in TheSky 6 Pro.

With my new laptop, which is on Win 7, I cannot
maintain a connection between the laptop and the
mount for more than a minute. I will issue a go
to command from TheSky and the mount will
proceed to the target, but right afterwards (and
often in the middle of the slew) I will get an
error message that the communciation has been
terminated. At first I thought that this might
be a problem with Ray's new ASCOM driver, but I
have the same problem when I use the built in
control in the TheSky rather than the ASCOM
driver. I also have the same problem if I try to
control the mount from SkyTools (either directly
talking to the ASCOM driver, or going through
TheSky). In most (all?) cases when the
communication goes away the application completely freezes up.

Anyway, my guess is that this is an
incompatability between the serial to usb
converter and the Win 7 OS. I have updated the
driver from the Prolific web site (which I had
to do in order to get ANY communication between the laptop and the mount).

Any recommendations would be greatly appreciated.

James


[Non-text portions of this message have been removed]


Re: USB to Serial adapters and Windows 7 for controlling AP1200

Kent Kirkley
 

On Mar 22, 2010, at 10:45:34 AM, "J M" <jsmiller58@...> wrote:

I was wondering if anyone on the list has a recommendation for a USB to Serial Adapter... 

Concerning my previous reply about Edgeport Serial to USB adapters.....I use Windows XP and not Windows 7......so I don't know if they work with Windows 7.

Also, while there are single port Edgeport's available, the additional ports come in handy for other serial based accessories like focusers, rotators, Robofocus, etc.

Kent Kirkley


[Non-text portions of this message have been removed]


Re: USB to Serial adapters and Windows 7 for controlling AP1200

Kent Kirkley
 

On Mar 22, 2010, at 10:45:34 AM, "J M" <jsmiller58@...> wrote:

I was wondering if anyone on the list has a recommendation for a USB to Serial Adapter... 

I use an Edgeport 4-Port, Serial to USB adapter and have done so for a number of years.

They are available used on ebay in the $ 30-$50 range, just do a search for 'Edgeport'.
(there are also 8 port units for a little more)

You will also find the exact same units for hundreds of dollars but don't be tempted....the $30-$50 ones are just fine.

It seems that these are surplus from large companies who have upgraded their gear and don't need Serial to USB adapters.

Kent Kirkley


[Non-text portions of this message have been removed]


USB to Serial adapters and Windows 7 for controlling AP1200

jsmiller58
 

I was wondering if anyone on the list has a recommendation for a USB to Serial Adapter...

I have an AP1200GTO that I am trying to control from my new Windows 7 laptop, using apps such as TheSky 6 Pro and SkyTools 3.

My old laptop worked fine with my current adapter (I don't know the exact model, but I know that it has the Prolific Technology chipset in it). With XP I experienced no problems controlling the mount through the old and new series of ASCOM drivers, as well as with the built in control in TheSky 6 Pro.

With my new laptop, which is on Win 7, I cannot maintain a connection between the laptop and the mount for more than a minute. I will issue a go to command from TheSky and the mount will proceed to the target, but right afterwards (and often in the middle of the slew) I will get an error message that the communciation has been terminated. At first I thought that this might be a problem with Ray's new ASCOM driver, but I have the same problem when I use the built in control in the TheSky rather than the ASCOM driver. I also have the same problem if I try to control the mount from SkyTools (either directly talking to the ASCOM driver, or going through TheSky). In most (all?) cases when the communication goes away the application completely freezes up.

Anyway, my guess is that this is an incompatability between the serial to usb converter and the Win 7 OS. I have updated the driver from the Prolific web site (which I had to do in order to get ANY communication between the laptop and the mount).

Any recommendations would be greatly appreciated.

James


Re: AP900GTO - DEC stiffness

Stef Cancelli
 

Ok.. .this is interesting. So even at longer FL with under arcsec resolution
of the main camera? I'm shooting at 1800 mm and .78asp. I was under the
impression that smaller, more gentle nudges were better.

Cheers,
Stef.

On Mon, Mar 22, 2010 at 10:57 AM, Howard <howard@...> wrote:

I will second this. Please calibrate and guide at 1x.



Mag. 7 skies!



Howard Hedlund

Astro-Physics, Inc.

815-282-1513

________________________________

From: ap-gto@... [mailto:ap-gto@...] On Behalf
Of chris provost
Sent: Sunday, March 21, 2010 8:57 PM
To: ap-gto@...
Subject: Re: [ap-gto] AP900GTO - DEC stiffness





Roland has always said it is best to use 1x gor an ag rate. I can't
remember why but I had a similar issue as you and once i switched to 1X
guiding is perfect in dec.

Chris

--- On Sun, 3/21/10, Stefano Cancelli <scancelli@...
<mailto:scancelli%40treblestef.com <scancelli%2540treblestef.com>> >
wrote:

From: Stefano Cancelli <scancelli@...
<mailto:scancelli%40treblestef.com <scancelli%2540treblestef.com>> >
Subject: Re: [ap-gto] AP900GTO - DEC stiffness
To: ap-gto@... <mailto:ap-gto%40yahoogroups.com<ap-gto%2540yahoogroups.com>
Date: Sunday, March 21, 2010, 8:47 PM



Howard and Rick,

Thanks for the information. I'm pretty sure backlash really is set to 0,
I'm
using Ray's latest ascom driver. I'll keep working on it but for now, if
I
keep aggresiveness really low.. around the 2 range in MaxIm DL and guide
speed at .5x it's manageable. My max move is set to .3 secs and the dead
zone is currently set to .02 secs. It takes a while for the guide star
to
center after a dec dither at these low aggressiveness values, but its
not
that big a deal since CCDAP does all the heavy lifting :)

Rick, yes dithering moves the guide star between exposures randomly
within a
user defined box. CCDAP has an enhanced dithering pattern rather than
random
that works great even if you have just a few exposures. Dithering makes
a
huge difference when combining since the rejection algorithms have no
problem identifying outliers and eliminating them. The results are much
smoother and less noisy stacked images.

Cheers,
Stef.

On Fri, Mar 19, 2010 at 10:17 AM, Howard <howard@astro- physics.com>
wrote:

Good Morning Stefano!



Are you using guiding software that employs the ASCOM driver? If so,
are you using the old driver from the ASCOM website - v. 4.1.25 - or
are
you using our new driver - v. 4.99.58 - available here:

http://www.gralak. com/apdriver

The reason I ask is that the old driver had a default backlash setting
that could be overriding whatever you might have set with the keypad.
I
can't count the number of times this has been an issue, and it almost
always presents itself as oscillations when guiding. Let's first
verify
that the backlash setting really and truly is at zero!



I would not loosen what sounds like an excellent gear mesh. Think of
it this way: If your car's right front wheel is out of alignment and
is
pulling the car to the right, you can correct this by lowering the
tire
pressure in the left front tire until the car tracks in a straight
line.
You may have made your car go straight, but this probably isn't the
best
solution. You will find that your 900GTO has enough mechanical
precision that the gear mesh can be adjusted to a level where backlash
is of little significance. Most of our most experienced AP family
members find that they simply don't need to use backlash compensation.



Mag. 7 skies!



Howard Hedlund

Astro-Physics, Inc.

815-282-1513

____________ _________ _________ __

From: ap-gto@yahoogroups. com [mailto:ap-gto@yahoogroups. com] On
Behalf
Of Stefano Cancelli
Sent: Friday, March 19, 2010 8:33 AM
To: ap-gto@yahoogroups. com
> Subject: Re: [ap-gto] AP900GTO - DEC stiffness





Thanks, Rolando. I found the pdf's on the site that show the clutch
replacement procedure and the special extraction tool. This pretty
much
answers my question as it appears its not an uncommon problem and one
that
is easily remedied. I wasnt' sure if the stiffness was coming from the
clutches not being disengaged fully or if it was some other mechanical
binding problem from the axis itself.

Another imaging session last night and still the occasional ping pong
after
dithering guider move between exposures. Once it settles however, it
will
make dec correction happily for long exposures without oscillation.
I'm
wondering if perhaps the worm mesh in DEC might be a little too tight
as
there doesn't seem to be any backlash whatsover in DEC. I know it
might
seem
counterproductive to think a tiny bit of backlash is a good thing, but
its
fairly easy to handle.

Cheers,
Stef.

On Fri, Mar 19, 2010 at 4:06 AM, <chris1011@aol. com
<mailto:chris1011% <chris1011%25> 40aol.com <chris1011%2540aol. com>> >
wrote:



In a message dated 3/18/2010 6:30:03 P.M. Central Daylight Time,
> > scancelli@trebleste f.com <mailto:scancelli% <scancelli%25>40treblestef.
com<scancelli% 2540treblestef. com>>
writes:

This kind of behaviour seems like stiction to me and I'm wondering
if
the
DEC stiffness is contributing to this.
Howard can answer you about the clutches being stiff and how to
remedy
that. However, be assured that this has nothing to do with your
guiding.
Whether the clutches are loose or fully locked has no effect
whatsoever on
guiding.

Rolando






------------ --------- --------- ------

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see http://groups. yahoo.com/ group/ap- gtoYahoo
<http://groups. yahoo.com/ group/ap- gtoYahoo> ! Groups Links













------------ --------- --------- ------
>
To UNSUBSCRIBE, or for general information on the ap-gto list
see http://groups. yahoo.com/ group/ap- gtoYahoo! Groups Links















------------------------------------

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see http://groups.yahoo.com/group/ap-gtoYahoo! Groups Links




Re: transporting Mach1/puklse guide

Howard Hedlund
 

Hi Suresh,



The clutches in the Mach1GTO are different from those in the 900 or 1200
series mounts. There are no clutch plugs to deform in the Mach1GTO.
Therefore, clutch tightness is not a critical issue for transport or
storage. For practical reasons, I handle it much like Rick. I don't
want the clutches loose enough that the mount can move unexpectedly as I
am handling it, but I want to be able to move the axes if I need to. I
know that I over-use this term, but "snug" just seems to fit.



PulseGuide has documentation on the CD. You can also find the
documentation on www.pulseguide.com <http://www.pulseguide.com/> .
Don't confuse PulseGuide, PEMPro and SmartGuide. PulseGuide is a
complete mount control utility. It can be used to do virtually anything
that the keypad does in terms of controlling the mount. The only thing
it lacks in comparison to the keypad is the object database.
PulseGuide is named for its feature of pulsed guiding that allows you to
track objects at a non-sidereal rate or that have some motion in
declination. SmartGuide is a "light" version of this pulsed guiding
that is contained in the keypad. It is adequate if you are observing
without a PC in the mix, but PulseGuide will give much better results on
such moving targets.



PEMPro is for measuring, analyzing and recording periodic error (among
other things). Once a PE curve is loaded into the servo, PEMPro no
longer needs to be running to use the PE correction. You simply turn
the correction on or off with the keypad, or PulseGuide, or the V2 ASCOM
driver. Just be sure that you don't tell the mount to record a new PE
curve unless you really intend to do so! Your Mach1GTO will arrive
with a PE curve loaded into the servo that was generated by PEMPro
during our testing of the mount. If you turn PEM on in the keypad, it
is this curve that will be used to correct periodic error.



PEMPro, PulseGuide and the new V2 ASCOM driver are all the
brain-children of Ray Gralak. PulseGuide and the ASCOM driver are
free. Your mount will have a CD with PulseGuide and the necessary links
for the ASCOM driver. PEMPro is not included with the Mach1GTO, but
can be purchased from our website or from CCDWare.



Mag. 7 skies!



Howard Hedlund

Astro-Physics, Inc.

815-282-1513

________________________________

From: ap-gto@... [mailto:ap-gto@...] On Behalf
Of Suresh Mohan
Sent: Sunday, March 21, 2010 10:25 PM
To: ap-gto@...
Subject: RE: [ap-gto] Re: transporting Mach1/puklse guide





Thanks Ray and Rick,

At present im keeping my (orion atlas)clutches
quite loose, the las t 15 miles of my trip is dirt road(aka Paris Dakar
Rally).

There is very little detail in the Manual on using
Pulse guide and PC; probably smart guide is the same thing?

I assumed Ray s software is already pre sent in a
preloaded curve but I cant seem to find the option in the HC( manual) to
activate that, I only see PEM and like in LX 200 record the star
motion/correction for 8 minutes.Any help in this regard will be
appreciated.

Suresh

_____

From: ap-gto@... <mailto:ap-gto%40yahoogroups.com>
[mailto:ap-gto@... <mailto:ap-gto%40yahoogroups.com> ] On
Behalf Of
observe_m13
Sent: Sunday, March 21, 2010 11:07 PM
To: ap-gto@... <mailto:ap-gto%40yahoogroups.com>
Subject: [ap-gto] Re: transporting Mach1

I loosen the clutches but do this so that I can rotate the mount into
the
smallest possible package for transporting in a Pelican case. Every so
often, when I was taking the mount out, I forgot the clutches were loose
and
the mount suddenly flipped in my hands giving me a sudden case of heart
failure/adrenaline rush as I rapidly re-position my hands to catch what
feels like a mount falling from my grasp. I have now come to finger
tighten
the clutches just enough to stop the mount from turning/twisting in my
grasp
as I move it to/from the case. It is still loose enough that if there
were
to be a sudden shock during transport the head would rotate instead of
hammering the gears. I have no idea if it is necessary as it is fairly
well
protected inside the case, just something I do.
Rick.

--- In ap-gto@yahoogroups. <mailto:ap-gto%40yahoogroups.com> com, Suresh
Mohan <swashya@...> wrote:

Hi,

Im likely to receive the mount by this month end, I Image from
a farm 50 miles from from my home in Chennai ,India. I was reading the
manual and came to understand that the clutch would be locked when I
receive
it which meant the company intended that while transportation.

Is it best to lock clutch while transporting in a car or leave
the clutch disengaged?

Suresh





_____





Re: AP900GTO - DEC stiffness

Roland Christen
 

In a message dated 3/22/2010 1:05:23 PM Central Daylight Time,
calypte@... writes:


WRT the above quoted statement -- OK, that's true for Maxim DL. What
about CCDSoft? Not an A-P mount, of course, but I've found little benefit to
setting the dec parameter to anything other than zero for autoguiding.
Always set the Dec to zero, otherwise you are courting potential
instability due to higher loop gain. You always want the loop gain to be 100% or
lower. Loop gain over 100% means that the correction signal sent to the mount
will be larger than the error it is trying to correct. That will cause the
mount to overshoot and begin limit cycling, hunting or oscillating.

Rolando


Re: AP900GTO - DEC stiffness

Howard Hedlund
 

I will second this. Please calibrate and guide at 1x.



Mag. 7 skies!



Howard Hedlund

Astro-Physics, Inc.

815-282-1513

________________________________

From: ap-gto@... [mailto:ap-gto@...] On Behalf
Of chris provost
Sent: Sunday, March 21, 2010 8:57 PM
To: ap-gto@...
Subject: Re: [ap-gto] AP900GTO - DEC stiffness





Roland has always said it is best to use 1x gor an ag rate. I can't
remember why but I had a similar issue as you and once i switched to 1X
guiding is perfect in dec.

Chris

--- On Sun, 3/21/10, Stefano Cancelli <scancelli@...
<mailto:scancelli%40treblestef.com> > wrote:

From: Stefano Cancelli <scancelli@...
<mailto:scancelli%40treblestef.com> >
Subject: Re: [ap-gto] AP900GTO - DEC stiffness
To: ap-gto@... <mailto:ap-gto%40yahoogroups.com>
Date: Sunday, March 21, 2010, 8:47 PM



Howard and Rick,

Thanks for the information. I'm pretty sure backlash really is set to 0,
I'm
using Ray's latest ascom driver. I'll keep working on it but for now, if
I
keep aggresiveness really low.. around the 2 range in MaxIm DL and guide
speed at .5x it's manageable. My max move is set to .3 secs and the dead
zone is currently set to .02 secs. It takes a while for the guide star
to
center after a dec dither at these low aggressiveness values, but its
not
that big a deal since CCDAP does all the heavy lifting :)

Rick, yes dithering moves the guide star between exposures randomly
within a
user defined box. CCDAP has an enhanced dithering pattern rather than
random
that works great even if you have just a few exposures. Dithering makes
a
huge difference when combining since the rejection algorithms have no
problem identifying outliers and eliminating them. The results are much
smoother and less noisy stacked images.

Cheers,
Stef.

On Fri, Mar 19, 2010 at 10:17 AM, Howard <howard@astro- physics.com>
wrote:

Good Morning Stefano!



Are you using guiding software that employs the ASCOM driver? If so,
are you using the old driver from the ASCOM website - v. 4.1.25 - or
are
you using our new driver - v. 4.99.58 - available here:

http://www.gralak. com/apdriver

The reason I ask is that the old driver had a default backlash setting
that could be overriding whatever you might have set with the keypad.
I
can't count the number of times this has been an issue, and it almost
always presents itself as oscillations when guiding. Let's first
verify
that the backlash setting really and truly is at zero!



I would not loosen what sounds like an excellent gear mesh. Think of
it this way: If your car's right front wheel is out of alignment and
is
pulling the car to the right, you can correct this by lowering the
tire
pressure in the left front tire until the car tracks in a straight
line.
You may have made your car go straight, but this probably isn't the
best
solution. You will find that your 900GTO has enough mechanical
precision that the gear mesh can be adjusted to a level where backlash
is of little significance. Most of our most experienced AP family
members find that they simply don't need to use backlash compensation.



Mag. 7 skies!



Howard Hedlund

Astro-Physics, Inc.

815-282-1513

____________ _________ _________ __

From: ap-gto@yahoogroups. com [mailto:ap-gto@yahoogroups. com] On
Behalf
Of Stefano Cancelli
Sent: Friday, March 19, 2010 8:33 AM
To: ap-gto@yahoogroups. com
Subject: Re: [ap-gto] AP900GTO - DEC stiffness





Thanks, Rolando. I found the pdf's on the site that show the clutch
replacement procedure and the special extraction tool. This pretty
much
answers my question as it appears its not an uncommon problem and one
that
is easily remedied. I wasnt' sure if the stiffness was coming from the
clutches not being disengaged fully or if it was some other mechanical
binding problem from the axis itself.

Another imaging session last night and still the occasional ping pong
after
dithering guider move between exposures. Once it settles however, it
will
make dec correction happily for long exposures without oscillation.
I'm
wondering if perhaps the worm mesh in DEC might be a little too tight
as
there doesn't seem to be any backlash whatsover in DEC. I know it
might
seem
counterproductive to think a tiny bit of backlash is a good thing, but
its
fairly easy to handle.

Cheers,
Stef.

On Fri, Mar 19, 2010 at 4:06 AM, <chris1011@aol. com
<mailto:chris1011% 40aol.com <chris1011%2540aol. com>> > wrote:



In a message dated 3/18/2010 6:30:03 P.M. Central Daylight Time,
scancelli@trebleste f.com <mailto:scancelli% 40treblestef.
com<scancelli% 2540treblestef. com>>
writes:

This kind of behaviour seems like stiction to me and I'm wondering
if
the
DEC stiffness is contributing to this.
Howard can answer you about the clutches being stiff and how to
remedy
that. However, be assured that this has nothing to do with your
guiding.
Whether the clutches are loose or fully locked has no effect
whatsoever on
guiding.

Rolando






------------ --------- --------- ------

To UNSUBSCRIBE, or for general information on the ap-gto list
see http://groups. yahoo.com/ group/ap- gtoYahoo
<http://groups. yahoo.com/ group/ap- gtoYahoo> ! Groups Links













------------ --------- --------- ------

To UNSUBSCRIBE, or for general information on the ap-gto list
see http://groups. yahoo.com/ group/ap- gtoYahoo! Groups Links




Re: AP900GTO - DEC stiffness

Howard Hedlund
 

Since the backlash you describe is in RA, it is not as critical to
remove it. The 600E mounts are a bit trickier to get a perfect gear
mesh, but they are still very high precision mounts. If you felt the
backlash in dec, I would say to go for it and try to remesh. As it is,
the question is "How much do you enjoy tinkering?"



Mag. 7 skies!



Howard Hedlund

Astro-Physics, Inc.

815-282-1513

________________________________

From: ap-gto@... [mailto:ap-gto@...] On Behalf
Of tomb1818
Sent: Sunday, March 21, 2010 4:39 PM
To: ap-gto@...
Subject: [ap-gto] Re: AP900GTO - DEC stiffness






Hi Howard,
Does the precision apply to mounts like the 600? I have a small amount
of backlash and was wondering if it would be useful to adjust it out( 2
mm at the end of the counterweight shaft.
Thanks

--- In ap-gto@... <mailto:ap-gto%40yahoogroups.com> ,
"Howard" <howard@...> wrote:

Good Morning Stefano!



Are you using guiding software that employs the ASCOM driver? If so,
are you using the old driver from the ASCOM website - v. 4.1.25 - or
are
you using our new driver - v. 4.99.58 - available here:

http://www.gralak.com/apdriver <http://www.gralak.com/apdriver>

The reason I ask is that the old driver had a default backlash setting
that could be overriding whatever you might have set with the keypad.
I
can't count the number of times this has been an issue, and it almost
always presents itself as oscillations when guiding. Let's first
verify
that the backlash setting really and truly is at zero!



I would not loosen what sounds like an excellent gear mesh. Think of
it this way: If your car's right front wheel is out of alignment and
is
pulling the car to the right, you can correct this by lowering the
tire
pressure in the left front tire until the car tracks in a straight
line.
You may have made your car go straight, but this probably isn't the
best
solution. You will find that your 900GTO has enough mechanical
precision that the gear mesh can be adjusted to a level where backlash
is of little significance. Most of our most experienced AP family
members find that they simply don't need to use backlash compensation.



Mag. 7 skies!



Howard Hedlund

Astro-Physics, Inc.

815-282-1513

________________________________

From: ap-gto@... <mailto:ap-gto%40yahoogroups.com>
[mailto:ap-gto@... <mailto:ap-gto%40yahoogroups.com> ] On
Behalf
Of Stefano Cancelli
Sent: Friday, March 19, 2010 8:33 AM
To: ap-gto@... <mailto:ap-gto%40yahoogroups.com>
Subject: Re: [ap-gto] AP900GTO - DEC stiffness





Thanks, Rolando. I found the pdf's on the site that show the clutch
replacement procedure and the special extraction tool. This pretty
much
answers my question as it appears its not an uncommon problem and one
that
is easily remedied. I wasnt' sure if the stiffness was coming from the
clutches not being disengaged fully or if it was some other mechanical
binding problem from the axis itself.

Another imaging session last night and still the occasional ping pong
after
dithering guider move between exposures. Once it settles however, it
will
make dec correction happily for long exposures without oscillation.
I'm
wondering if perhaps the worm mesh in DEC might be a little too tight
as
there doesn't seem to be any backlash whatsover in DEC. I know it
might
seem
counterproductive to think a tiny bit of backlash is a good thing, but
its
fairly easy to handle.

Cheers,
Stef.

On Fri, Mar 19, 2010 at 4:06 AM, <chris1011@...
<mailto:chris1011%40aol.com> > wrote:



In a message dated 3/18/2010 6:30:03 P.M. Central Daylight Time,
scancelli@... <mailto:scancelli%40treblestef.com> writes:

This kind of behaviour seems like stiction to me and I'm wondering
if
the
DEC stiffness is contributing to this.
Howard can answer you about the clutches being stiff and how to
remedy
that. However, be assured that this has nothing to do with your
guiding.
Whether the clutches are loose or fully locked has no effect
whatsoever on
guiding.

Rolando






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Re: DOVELM2 Thumbscrew Thread Type

Howard Hedlund
 

Hi Robert,



It's 3/8" x 24 tpi.



Mag. 7 skies!



Howard Hedlund

Astro-Physics, Inc.

815-282-1513

________________________________

From: ap-gto@... [mailto:ap-gto@...] On Behalf
Of gnilsch
Sent: Sunday, March 21, 2010 1:08 PM
To: ap-gto@...
Subject: [ap-gto] DOVELM2 Thumbscrew Thread Type





Hi all,

I want to use the third spare threaded hole on the Dovelm2 mounting
plate(for the thumbscrew) for another purpose. Does anybody (Howard?)
know what the thread type and dia is? From looking at it it seems to be
a fine thread, maybe UNF. All the screws I had lying around have too
small a dia for me to even try.

Thanks

Robert


Re: AP900GTO - DEC stiffness

Roland Christen
 

In a message dated 3/22/2010 10:36:28 AM Central Daylight Time,
scancelli@... writes:


Another imaging session last night and still the occasional ping pong
after
dithering guider move between exposures. Once it settles however, it
will
make dec correction happily for long exposures without oscillation.
Just one more thought about this oscillation. In almost all cases,
oscillation is the result of improper calibration, which results in loop gain larger
than 100%. During calibration procedure, the mount is asked to move in RA
and Dec for a certain number of seconds so that the guiding software can
figure out how many seconds it takes to move a certain number of pixels (Pixels
per second). Because of inevitable delay in reversing Dec (RA does not have
this delay), there is always an undercount of the time it takes to move a
certain distance. Normally that delay is on the order of 0.5 seconds, but if
the geartrain in Dec is not fully meshed, it could be as long as 2 seconds at
1x, 4 seconds at 0.5x and 8 seconds at 0.25x! So you can see that if you
try to calibrate at 0.5x or even at 0.25x, you will undercount the time.

Now on top of that, if you calibrate for only 5 seconds, you will never get
any movement in the reverse direction in Dec, and the resulting parameter
numbers in your guiding software will be way off (too low by an order of
magnitude).

So, to make matters really bad, if you do 3 things wrong: use less than 1x
guide rate to calibrate and guide, have some significant de-mesh in the worm
gears, and calibrate for less than 10 seconds - then you will indeed end up
with bad parameter numbers and will likely see oscillations during guiding.


Therefore, you must do the opposite: use 1x guide rate to calibrate, make
sure you have good worm mesh, calibrate for at least 10 seconds time period.

Some other himts: if you are using MaximDL, make sure you are always using
Dec value = 0 - do not use any other Dec value to modify the guiding. Do
your calibration once, near the celestial equator and use that value everywhere
in the sky - don't worry, it will work perfectly even near the poles. Also,
please check your parameter numbers after calibration to make sure they
make sense. What is a parameter number? That is the number of pixels per second
in both RA and Dec that the guide program has calculated from your
calibration routine. These numbers should be nearly equal or at least close in value
for both RA and Dec when you calibrate near the celestial equator. If they
are quite different (by more than 10%) then that is a very good indication
that you have a bad calibration result.

An example of parameter numbers: if your pixel scale is 1 arc sec per
pixel, then the proper parmater numbers that shoudl show up each time you
calibrate will be 15 in RA and 15 in Dec. 15 is the number of arc seconds per
second that the mount moves at 1x sidereal rate. If your resultant parameter
numbers are 15 in RA and 7 in Dec, then you have a bad calibration (excessive
backlas due to poor mesh, or not enough cal time, etc). Bad calibration will
result in loop gain larger than 100%, which will result in oscillation or
hunting, as the mount is consistently given too large a correction signal for
the star's position error, and the guide star will seem to bobble back and
forth.

Good luck and good hunting, er, guiding.

Rolando