Date   

Re: Mount is tracking fast

William Rison <werison@...>
 

--- In ap-gto@..., chris1011@... wrote:

In a message dated 11/2/2007 7:44:55 AM Central Daylight Time,
werison@... writes:


I have an AP900 with GTOCP2 microcode D Keypad 4.12.
The mount is in an observatory and I have done a star drift polar
alignment but still have a problem with tracking. The mount is
tracking fast when set to sidereal rate. I can see movement is 30
second exposures in RA. The drift is always to the East in RA, it
does not matter where I am pointed. I.E. at DEC + 50 and and DEC + 0
the star only drifts in RA to the East (tracking too fast?). The
balance of the ota is fine and the goto functions work great on both
sides of the mount. Also checked PE and the star just keeps moving
East even after the 8 minutes of the PE cycle. Any ideas on what I
can check?
How long have you had this mount? Is it a used mount, new to you?

Normally you have to offset the Alt axis from the true pole to the
refracted
pole in order to zero out the RA drift. I would suggest pointing
your scope to
a star near the celestial equator and meridian line and then
adjusting the
height of the altitude axis until the drift is zeroed out. There
will always be
drift elsewhere in the sky because of atmospheric refraction. You
cannot
eliminate drift entirely over the whole sky with the sidereal rate
because of the
variability of refraction.

By the way, the classic drift alignment procedure that you probably
used does
not eliminate RA drift because it results in the polar axis being
pointed at
the true north pole rather than the refracted pole.

Rolando
Rolando,

The mount was purchased in November 2006 used. I am told it is a 2003
model and the serial number is 900395.

Since refraction plays a part in all of this I think the fact that the
mount is on a Pier-Tech II movable pier may also be causing a problem.
I am going to adjust the Pier-Tech to a set position and level it then
do the drift alignment again and then the adjustment to the refraction
pole. I know when I move the Pier-Tech up and down the star move a
little in the field of view.

Thanks Rolando,
William


Re: Mount is tracking fast

Ray Gralak <rgr@...>
 

Hi William,

Have you confirmed that you are tracking in sidereal and not lunar or solar?

-Ray

-----Original Message-----
From: ap-gto@... [mailto:ap-gto@...]
On Behalf Of William Rison
Sent: Friday, November 02, 2007 10:35 AM
To: ap-gto@...
Subject: [ap-gto] Re: Mount is tracking fast

Hello John,

The mount has always been in the observatory and the mount has never
tracked without some drift but before I did this last polar alignment
the drift was in DEC and the RA looked fine. Now the DEC does not
drift but the RA drifts West. The drift polar alignment I did has
made thing much better as far as pointing goes but tracking is off. I
would figure if the polar alignment is off there would be DEC drift in
one of the two alignment stars, either the one near 0 DEC on the
meridian or the one 20 degrees above the eastern horizon near 0 DEC.
I know for sure the one above the eastern horizon only drifts in RA
and will make sure the one on the meridian does the same tonight.

The drift is very small about 30 arc seconds in 10 minutes.
It's not caused by periodic error, the star only drifts east just as
if the drive is running too fast.

Do you know of anything else that will only cause an drift in RA and
no drift in DEC when doing the drift polar alignment? I have done
these on other mounts in the past so this is not my first
time doing one.

Thanks,
William

--- In ap-gto@...
<mailto:ap-gto%40yahoogroups.com> , "John Winfield"
<winfij@...> wrote:

Hi William,

Was your mount tracking OK before, or is this the first time you've
used it in the obs?

You say you managed to do a drift alignment - how sure are
you it was
good, if the stars continue to drift after doing it?
If the mount motor was indeed running fast, I don't think you'd be
able to successfully complete the drift align, i.e. get the drift to
zero in south and east.

I'd suggest redoing the polar align to check.

btw, what rate are the stars appearing to drift at?

John


--- In ap-gto@...
<mailto:ap-gto%40yahoogroups.com> , "William Rison" <werison@> wrote:

Joe,
It's set to sidereal rate, I stated this in the post.
That was the first thing I checked.

William

--- In ap-gto@...
<mailto:ap-gto%40yahoogroups.com> , "Joseph Zeglinski" <J.Zeglinski@>
wrote:

William,
Your CP2 is probably set to Lunar tracking rate - change it.

Joe

----- Original Message -----
From: "William Rison" <werison@>
To: <ap-gto@... <mailto:ap-gto%40yahoogroups.com> >
Sent: Friday, November 02, 2007 8:43 AM
Subject: [ap-gto] Mount is tracking fast


Hello Everyone,

I have an AP900 with GTOCP2 microcode D Keypad 4.12.
The mount is in an observatory and I have done a star
drift polar
alignment but still have a problem with tracking. The mount is
tracking fast when set to sidereal rate. I can see
movement is 30
second exposures in RA. The drift is always to the
East in RA, it
does not matter where I am pointed. I.E. at DEC + 50 and and
DEC + 0
the star only drifts in RA to the East (tracking too
fast?). The
balance of the ota is fine and the goto functions work great
on both
sides of the mount. Also checked PE and the star just keeps
moving
East even after the 8 minutes of the PE cycle. Any ideas on
what I
can check?

Thanks,
William Rison



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Re: Mount is tracking fast

William Rison <werison@...>
 

Hello John,

The mount has always been in the observatory and the mount has never
tracked without some drift but before I did this last polar alignment
the drift was in DEC and the RA looked fine. Now the DEC does not
drift but the RA drifts West. The drift polar alignment I did has
made thing much better as far as pointing goes but tracking is off. I
would figure if the polar alignment is off there would be DEC drift in
one of the two alignment stars, either the one near 0 DEC on the
meridian or the one 20 degrees above the eastern horizon near 0 DEC.
I know for sure the one above the eastern horizon only drifts in RA
and will make sure the one on the meridian does the same tonight.

The drift is very small about 30 arc seconds in 10 minutes.
It's not caused by periodic error, the star only drifts east just as
if the drive is running too fast.

Do you know of anything else that will only cause an drift in RA and
no drift in DEC when doing the drift polar alignment? I have done
these on other mounts in the past so this is not my first time doing one.

Thanks,
William



--- In ap-gto@..., "John Winfield" <winfij@...> wrote:

Hi William,

Was your mount tracking OK before, or is this the first time you've
used it in the obs?

You say you managed to do a drift alignment - how sure are you it was
good, if the stars continue to drift after doing it?
If the mount motor was indeed running fast, I don't think you'd be
able to successfully complete the drift align, i.e. get the drift to
zero in south and east.

I'd suggest redoing the polar align to check.

btw, what rate are the stars appearing to drift at?

John


--- In ap-gto@..., "William Rison" <werison@> wrote:

Joe,
It's set to sidereal rate, I stated this in the post.
That was the first thing I checked.

William

--- In ap-gto@..., "Joseph Zeglinski" <J.Zeglinski@>
wrote:

William,
Your CP2 is probably set to Lunar tracking rate - change it.

Joe

----- Original Message -----
From: "William Rison" <werison@>
To: <ap-gto@...>
Sent: Friday, November 02, 2007 8:43 AM
Subject: [ap-gto] Mount is tracking fast


Hello Everyone,

I have an AP900 with GTOCP2 microcode D Keypad 4.12.
The mount is in an observatory and I have done a star drift polar
alignment but still have a problem with tracking. The mount is
tracking fast when set to sidereal rate. I can see movement is 30
second exposures in RA. The drift is always to the East in RA, it
does not matter where I am pointed. I.E. at DEC + 50 and and
DEC + 0
the star only drifts in RA to the East (tracking too fast?). The
balance of the ota is fine and the goto functions work great
on both
sides of the mount. Also checked PE and the star just keeps
moving
East even after the 8 minutes of the PE cycle. Any ideas on
what I
can check?

Thanks,
William Rison



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Re: Mount is tracking fast

John Winfield
 

Hi William,

Was your mount tracking OK before, or is this the first time you've
used it in the obs?

You say you managed to do a drift alignment - how sure are you it was
good, if the stars continue to drift after doing it?
If the mount motor was indeed running fast, I don't think you'd be
able to successfully complete the drift align, i.e. get the drift to
zero in south and east.

I'd suggest redoing the polar align to check.

btw, what rate are the stars appearing to drift at?

John


--- In ap-gto@..., "William Rison" <werison@...> wrote:

Joe,
It's set to sidereal rate, I stated this in the post.
That was the first thing I checked.

William

--- In ap-gto@..., "Joseph Zeglinski" <J.Zeglinski@> wrote:

William,
Your CP2 is probably set to Lunar tracking rate - change it.

Joe

----- Original Message -----
From: "William Rison" <werison@>
To: <ap-gto@...>
Sent: Friday, November 02, 2007 8:43 AM
Subject: [ap-gto] Mount is tracking fast


Hello Everyone,

I have an AP900 with GTOCP2 microcode D Keypad 4.12.
The mount is in an observatory and I have done a star drift polar
alignment but still have a problem with tracking. The mount is
tracking fast when set to sidereal rate. I can see movement is 30
second exposures in RA. The drift is always to the East in RA, it
does not matter where I am pointed. I.E. at DEC + 50 and and
DEC + 0
the star only drifts in RA to the East (tracking too fast?). The
balance of the ota is fine and the goto functions work great on both
sides of the mount. Also checked PE and the star just keeps moving
East even after the 8 minutes of the PE cycle. Any ideas on what I
can check?

Thanks,
William Rison



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Re: Mach1 critique in S&T Dec 2007

Wiggins, Rick
 

Hi,
Is it true that Britney Spears is secretely testing a new AP 4800
Fork Mount? Wait til this hits the tabloids!
Couldn't resist.
Thanks, Rick

--- In ap-gto@..., "Joseph Zeglinski" <J.Zeglinski@...>
wrote:

William,

My point was, I expect "news people" to be on top of stories
in their
industry, that is what I PAY them for, or I would just subscribe
to the
internet. They should have been prep'd, with a story to go out
with the issue.
What ... they just sit there in their office and wait for this
group, or what
pops up at a conference? The Mach1 review took long enough, so I
suppose S&T
will report further on the AP3600 - "in the fullness of time ...
next spring.

Sheesh indeed,
Joe

----- Original Message -----
From: "William R. Mattil" <wrmattil@...>
To: <ap-gto@...>
Sent: Thursday, November 01, 2007 2:30 PM
Subject: Re: [ap-gto] Re: Mach1 critique in S&T Dec 2007


Joseph Zeglinski wrote:

Back to topic - I am surprised that S&T didn't scoop the
astro
publishing
world with such a major announcement review (prepared in
advanced) of the
AP3600 - somebody there, in the new management, asleep at the
wheel - (they
probably aren't astro literate) ?
How could S&T make this announcement if they were not aware of
it ?
Sheesh. There are plenty of things to flame them for so that we
need not
resort to making things up.


Bill


--

William R. Mattil : http://www.celestial-images.com



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Re: Effect of temperature on backlash

Roland Christen
 

In a message dated 11/2/2007 2:34:57 PM Central Daylight Time,
reseavey@... writes:


The following, winter when the temperature was about 5F, the engagement of
the RA worm and worm wheel seemed to be much tighter; in fact I had to
re-adjust the worm mesh so that the RA motor wouldn't make strange noises
while slewing.
I think you might have seen the effect of thickening of the grease, not worm
mesh.

Rolando


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Re: software for orthogonality problem - solution

gjsalyer <salyer@...>
 

Well Rolando was right. My flip problem was caused by mirror shift. I
had a 21' error in dec after a flip in a 20'x30' image. But, I also
fould an error in my focal length setting in one program. After
fixing this, Pinpoint finds the correct position after a flip so my
problem is FIXED. (well as much as any mirror shift can be "fixed" in
software).

Greg

--- In ap-gto@..., chris1011@... wrote:

In a message dated 10/22/2007 8:08:44 AM Central Daylight Time,
salyer@... writes:


Jeff, thanks for the info. I hadn't thought of using the feeler
gauge
fix. I really need to check out the exact amount of offset. It's
possible something else is wrong. Last night I did a quick check
and
I thought the error was in the dec axis rather than RA as
expected. I
then used FocusMax to get my alignment error much less than a
minute
but I was still getting a large error after the flip. If the
weather
holds, I'll spend this evening looking more carefully at the
problem.

Are you sure you are not getting mirror shift?

Rolando


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Re: Mount is tracking fast

William Rison <werison@...>
 

Joe,
It's set to sidereal rate, I stated this in the post.
That was the first thing I checked.

William

--- In ap-gto@..., "Joseph Zeglinski" <J.Zeglinski@...> wrote:

William,
Your CP2 is probably set to Lunar tracking rate - change it.

Joe

----- Original Message -----
From: "William Rison" <werison@...>
To: <ap-gto@...>
Sent: Friday, November 02, 2007 8:43 AM
Subject: [ap-gto] Mount is tracking fast


Hello Everyone,

I have an AP900 with GTOCP2 microcode D Keypad 4.12.
The mount is in an observatory and I have done a star drift polar
alignment but still have a problem with tracking. The mount is
tracking fast when set to sidereal rate. I can see movement is 30
second exposures in RA. The drift is always to the East in RA, it
does not matter where I am pointed. I.E. at DEC + 50 and and DEC + 0
the star only drifts in RA to the East (tracking too fast?). The
balance of the ota is fine and the goto functions work great on both
sides of the mount. Also checked PE and the star just keeps moving
East even after the 8 minutes of the PE cycle. Any ideas on what I
can check?

Thanks,
William Rison



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Re: Mount is tracking fast

Roland Christen
 

In a message dated 11/2/2007 1:53:41 PM Central Daylight Time,
alanv12952@... writes:


Will the 'King' or 'Adaptive King' tracking rate minimize that? It's what I
had my Gemini
unit set to...

Alan
The King rate does not eliminate drift. The only way to eliminate drift
everywhere is to have a variable rate, which the CP3 controller has. The software
to set the rate is being developed at this time and will be available in the
new computer interface program.

Rolando


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Re: Mount is tracking fast

Joe Zeglinski
 

William,
Your CP2 is probably set to Lunar tracking rate - change it.

Joe

----- Original Message -----
From: "William Rison" <werison@...>
To: <ap-gto@...>
Sent: Friday, November 02, 2007 8:43 AM
Subject: [ap-gto] Mount is tracking fast


Hello Everyone,

I have an AP900 with GTOCP2 microcode D Keypad 4.12.
The mount is in an observatory and I have done a star drift polar
alignment but still have a problem with tracking. The mount is
tracking fast when set to sidereal rate. I can see movement is 30
second exposures in RA. The drift is always to the East in RA, it
does not matter where I am pointed. I.E. at DEC + 50 and and DEC + 0
the star only drifts in RA to the East (tracking too fast?). The
balance of the ota is fine and the goto functions work great on both
sides of the mount. Also checked PE and the star just keeps moving
East even after the 8 minutes of the PE cycle. Any ideas on what I
can check?

Thanks,
William Rison



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Re: Effect of temperature on backlash

Roland Christen
 

In a message dated 10/26/2007 1:23:41 PM Central Daylight Time,
richard.kinsey@... writes:


I can detect a small amount of backlash in both the RA and Dec axis of
my recently received AP1200. I am wondering whether this could be
caused by a change in temperature from the factory to the mount's
present location in my observatory where it is presently around 10
degrees C. If such a change of temperature explains the slight backlash
I can feel, perhaps I should leave it in readiness for warmer days. Any
advice would be gratefully received. Richard
Change in temperature will not cause a change in backlash. Adjust it and the
mount should work at all temperatures.

Rolando


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Re: PDI (Stokes technique applied to comet) was Re: Comet 17P Holmes...

Roland Christen
 

In a message dated 10/29/2007 9:20:34 AM Central Daylight Time,
rdcrisp@... writes:


http://www.narrowbandimaging.com/comet_17_p_holmes_stokes_page.htm

read down the page a bit and you will see an abstract from a refereed
journal speaking to use of polarization studies on comets.
Very interesting images. Thanks,

Roland


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Re: 1200gto losing time base

Roland Christen
 

In a message dated 10/29/2007 12:14:36 PM Central Daylight Time,
mizzou156@... writes:


Hello,
New to astronomy and my 1200 gto seems to have developed a
peculiar problem. If I use the keypad to initialize contact with the
mount and then switch over to external control via a windows 2000 xp os
computer, the pointing and time base gets screwed up. the computer goes
into hibernate (resting) mode after one hour of inactivity. (This is
per the windows power management system and that can be changed.)
After I reactivate the computer, it seems that the time base for the
keypad is way off from the time base of the computer. I have use the
keypad feature for getting the time/ location from the mount, when I
initiate connection with the computer.
If you use the keypad to initialize the mount, there is never a reason to
switch over to an external time base in order to control the mount from an
external program. Don't set the keypad to EXT unless you absolutely know why you are
doing this and how to do it properly. Normally the keypad should be left on
Autostart "YES" so that the servo can start up automatically at power up. Then
just link to your favorite planetarium program and do your GoTo with that
program. No need to ever place the keypad in "EXT" mode just to use an external
program.

Rolando


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Re: Interim Daylight Savings Settings (Remote Setup) - How To ??

Roland Christen
 

In a message dated 10/29/2007 11:02:55 AM Central Daylight Time,
rickwiggins@... writes:


Hi Members and Roland,
I want to know how to set up my system over the next week to deal
with the various DST issues.
I have an AP 1200 mount that is set to "Ext".
The keypad was used to turn DST "On" last spring and it is now
unplugged.
I never change my keypad settings, so I don't care if it is daylight savings
or not. I always use the keypad for startup and shut down. If you are using
external time settings from your laptop, I suggest that you use Pulse Guide for
now. It will be correct regardless of the change in date for daylight savings.
In the future we will make available a new control program for your laptop
computers that you can use as a "gateway" to the mount from any program. The
program will clean up and fix any and all errors from other programs before
sending the info to the servo.

Rolando



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Re: Mount is tracking fast

Roland Christen
 

In a message dated 11/2/2007 12:39:28 PM Central Daylight Time,
werison@... writes:


Do you know of anything else that will only cause an drift in RA and
no drift in DEC when doing the drift polar alignment?
If you are pointing to the true north pole you will have RA drift. You need
to point to the refracted pole to minimize drift. With a fixed sidereal drive
rate, you will never have zero drift in RA everywhere in the sky, just at the
zenith.

Rolando


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Re: Mount is tracking fast

Roland Christen
 

In a message dated 11/2/2007 7:44:55 AM Central Daylight Time,
werison@... writes:


I have an AP900 with GTOCP2 microcode D Keypad 4.12.
The mount is in an observatory and I have done a star drift polar
alignment but still have a problem with tracking. The mount is
tracking fast when set to sidereal rate. I can see movement is 30
second exposures in RA. The drift is always to the East in RA, it
does not matter where I am pointed. I.E. at DEC + 50 and and DEC + 0
the star only drifts in RA to the East (tracking too fast?). The
balance of the ota is fine and the goto functions work great on both
sides of the mount. Also checked PE and the star just keeps moving
East even after the 8 minutes of the PE cycle. Any ideas on what I
can check?
How long have you had this mount? Is it a used mount, new to you?

Normally you have to offset the Alt axis from the true pole to the refracted
pole in order to zero out the RA drift. I would suggest pointing your scope to
a star near the celestial equator and meridian line and then adjusting the
height of the altitude axis until the drift is zeroed out. There will always be
drift elsewhere in the sky because of atmospheric refraction. You cannot
eliminate drift entirely over the whole sky with the sidereal rate because of the
variability of refraction.

By the way, the classic drift alignment procedure that you probably used does
not eliminate RA drift because it results in the polar axis being pointed at
the true north pole rather than the refracted pole.

Rolando


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Mount is tracking fast

William Rison <werison@...>
 

Hello Everyone,

I have an AP900 with GTOCP2 microcode D Keypad 4.12.
The mount is in an observatory and I have done a star drift polar
alignment but still have a problem with tracking. The mount is
tracking fast when set to sidereal rate. I can see movement is 30
second exposures in RA. The drift is always to the East in RA, it
does not matter where I am pointed. I.E. at DEC + 50 and and DEC + 0
the star only drifts in RA to the East (tracking too fast?). The
balance of the ota is fine and the goto functions work great on both
sides of the mount. Also checked PE and the star just keeps moving
East even after the 8 minutes of the PE cycle. Any ideas on what I
can check?

Thanks,
William Rison


Re: TEC 140 + 14" LX200R on an AP1200

Gavin Bray
 

Thanks Bill and Jeff.

--- In ap-gto@..., "Jeff Young" <jey@...> wrote:

Gavin --

I have a Losmandy dovetail attached to the top of my Parallax rings
holding a Meade 16" LX200GPS OTA. On the rail rides a Tak FC-100.

The FC-100 is a doublet, and considerably smaller than 140mm, so it
probably weighs about 1/2 what the TEC does. Then agian, the 16"
OTA is
about twice the weight of the 14", and leaves the Tak's weight on a
slightly longer moment arm.

Seems to work fine. The mirror flop is enough in the SCT that you
can't
get both scopes to point to the same spot all over the sky, but the
refractors have a big enough field to mostly make up for that.

-- Jeff.


________________________________

From: ap-gto@... [mailto:ap-gto@...]
On
Behalf Of Gavin Bray
Sent: Thursday, November 01, 2007 12:28 PM
To: ap-gto@...
Subject: [ap-gto] TEC 140 + 14" LX200R on an AP1200



Hello

I have a 14" LX200R attached to an AP1200 using a set of
Parallax
Instruments rings. The setup is housed in my observatory and
I'm
very
happy with it.

I was wondering whether I could attach a dovetail plate to the
top of
the parallax rings (above the 14") and attach something like a
TEC 140
to that.

Is it feasible to mount something like a TEC 140 on top of the
14"?

Is there a better option I should be considering?

Thanks
Gavin







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


Re: portable pier height for 1200GTO

Dean S
 

Thanks all for the opinions on the pier heights. I talked with Howard and
them may be able to make one for me from a 42" tube.

Thanks,
Dean S

----- Original Message -----
From: "Louis Marchesi" <lmarchesi@...>
To: <ap-gto@...>
Sent: Thursday, November 01, 2007 6:57 PM
Subject: [ap-gto] Re: portable pier height for 1200GTO


Dean,

I opted for the 48-inch pier. I usually set the pier base on some
pavers (for leveling), so that adds a couple of inches. I need to use
a small step (about a foot tall) to get my 6-inch refractor into the
saddle. I'm vertically challenged as well, but since I do both visual
and imaging I didn't want the EP height to be too low when viewing
near the zenith.

Regards,
Lou Marchesi




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Re: portable pier height for 1200GTO

primeclash
 

Dean,

I opted for the 48-inch pier. I usually set the pier base on some
pavers (for leveling), so that adds a couple of inches. I need to use
a small step (about a foot tall) to get my 6-inch refractor into the
saddle. I'm vertically challenged as well, but since I do both visual
and imaging I didn't want the EP height to be too low when viewing
near the zenith.

Regards,
Lou Marchesi