Autoguider correction frequency


Roland Christen
 

In a message dated 3/27/2008 3:19:06 PM Central Daylight Time,
mphammick@... writes:


Has anyone else tried this system and if yes, what frequency setting
do they have for the corrections. I have a friend with a Paramount ME
who says his guider corrects 10 times a second; this seems rather high
to me. Does anyone have strong views as to how often the guider should
correct a reasonable AP900 ?

Murray
10 times a second is quite fast and is usually associated with the AO7 or AO8
device. You can correct the mount this fast, but normally the correction
rates are anywhere from 1-2 seconds to 10-15 seconds, depending on how well your
mount is polar aligned, the amount of drift you get, and the focal length and
pixel scale that you're working with.

Rolando


**************
Create a Home Theater Like the Pros. Watch the video on
AOL Home.
(http://home.aol.com/diy/home-improvement-eric-stromer?video=15&;
ncid=aolhom00030000000001)


Woodwind
 

I have just bought the Orion Starshoot autoguider camera and have got
some very sharp images with a TAK scope on an AP900 mount.

Has anyone else tried this system and if yes, what frequency setting
do they have for the corrections. I have a friend with a Paramount ME
who says his guider corrects 10 times a second; this seems rather high
to me. Does anyone have strong views as to how often the guider should
correct a reasonable AP900 ?

Murray


Kent Kirkley
 

In a message dated 03/27/08 15:19:06 Central Daylight Time, mphammick@... writes:
I have just bought the Orion Starshoot autoguider camera and have got
some very sharp images with a TAK scope on an AP900 mount.

Has anyone else tried this system and if yes, what frequency setting
do they have for the corrections. I have a friend with a Paramount ME
who says his guider corrects 10 times a second; this seems rather high
to me. Does anyone have strong views as to how often the guider should
correct a reasonable AP900 ?

Murray


Murray:
That is strange.
What guider exposure would he be using....1/10 sec.???
That might only work on a very bright star.

Generally, I use 1 sec. guider exposures and have corrections made anywhere from 1 to 6 seconds.
(SBIG remote guide head-STL-11000)
If guider exposures and corrections are too fast, they can be 'chasing the seeing'.

Kent Kirkley


hewholooks
 

I believe that the Orion guider is packaged with PHD guiding, which I
have used for over a year with my Atlas EQ-G and plan to _try_ to use
with an AP mount. It allows setting of RA aggressiveness from 1 to
over 120, hysteresis settings, dec guide mode off/auto/north/south,
dec algorithm either resist switching or low pass filter, calibration
step setting to allow calibrating at high latitudes if desired,
minimum motion, search box size, noise reduction, etc. Exposures can
be set from 0.05 seconds to 10 seconds. There is an adjustable real
time guiding graph. There are multiple template grids available
(crosshair, grid, bullseye).

It's ascom compliant and supports many cameras.

All in all, it has been a good guiding program - and it's freeware.

Here's a screenshot of PHD with the menu open:
http://hwilson.zenfolio.com/img/v1/p906662519-5.jpg

Here it is while guiding a 10 minute exposure with DSLRFocus:
http://hwilson.zenfolio.com/img/v1/p115148958-5.jpg

I am not promoting it, but just lending my experience with it.

Hunter

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

In a message dated 3/27/2008 3:19:06 PM Central Daylight Time,
mphammick@... writes:


Has anyone else tried this system and if yes, what frequency
setting
do they have for the corrections. I have a friend with a
Paramount ME
who says his guider corrects 10 times a second; this seems rather
high
to me. Does anyone have strong views as to how often the guider
should
correct a reasonable AP900 ?

Murray
10 times a second is quite fast and is usually associated with the
AO7 or AO8
device. You can correct the mount this fast, but normally the
correction
rates are anywhere from 1-2 seconds to 10-15 seconds, depending on
how well your
mount is polar aligned, the amount of drift you get, and the focal
length and
pixel scale that you're working with.

Rolando


**************
Create a Home Theater Like the Pros. Watch the video on
AOL Home.
(http://home.aol.com/diy/home-improvement-eric-stromer?
video=15&
ncid=aolhom00030000000001)


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


Woodwind
 

Rolando et-al,

Thanks for all your responses.

The software packaged with the Orion guider allows for .05 sec exposures - so I assume that guidance data is sent out from each exposure - that is to say, up to 20 times per second.

I seem to get good results from half second or one second exposures. Intuitively, it seems that it is better to correct after a shorter time to minimise any inherent mis-alignment - as long as the software and drive motors can cope with such fine adjustments and you are not setting up a feedback loop with a resonant frequency in it which bounces the mount (sorry - I was in tanks and that is tank gunnery talk - I am sure there is a more astro-related expression for what I am trying to say).

Otherwise - I will try Rolando's suggested times and see what comes out on the photos.

Murray



hewholooks <hewholooks@...> wrote: I believe that the Orion guider is packaged with PHD guiding, which I
have used for over a year with my Atlas EQ-G and plan to _try_ to use
with an AP mount. It allows setting of RA aggressiveness from 1 to
over 120, hysteresis settings, dec guide mode off/auto/north/south,
dec algorithm either resist switching or low pass filter, calibration
step setting to allow calibrating at high latitudes if desired,
minimum motion, search box size, noise reduction, etc. Exposures can
be set from 0.05 seconds to 10 seconds. There is an adjustable real
time guiding graph. There are multiple template grids available
(crosshair, grid, bullseye).

It's ascom compliant and supports many cameras.

All in all, it has been a good guiding program - and it's freeware.

Here's a screenshot of PHD with the menu open:
http://hwilson.zenfolio.com/img/v1/p906662519-5.jpg

Here it is while guiding a 10 minute exposure with DSLRFocus:
http://hwilson.zenfolio.com/img/v1/p115148958-5.jpg

I am not promoting it, but just lending my experience with it.

Hunter

--- In ap-gto@..., chris1011@... wrote:
>
> In a message dated 3/27/2008 3:19:06 PM Central Daylight Time,
> mphammick@... writes:
>
>
> > Has anyone else tried this system and if yes, what frequency
setting
> > do they have for the corrections. I have a friend with a
Paramount ME
> > who says his guider corrects 10 times a second; this seems rather
high
> > to me. Does anyone have strong views as to how often the guider
should
> > correct a reasonable AP900 ?
> >
> > Murray
> >
>
> 10 times a second is quite fast and is usually associated with the
AO7 or AO8
> device. You can correct the mount this fast, but normally the
correction
> rates are anywhere from 1-2 seconds to 10-15 seconds, depending on
how well your
> mount is polar aligned, the amount of drift you get, and the focal
length and
> pixel scale that you're working with.
>
> Rolando
>
>
> **************
> Create a Home Theater Like the Pros. Watch the video on
> AOL Home.
> (http://home.aol.com/diy/home-improvement-eric-stromer?
video=15&amp;
> ncid=aolhom00030000000001)
>
>
>
>


Gedas
 

Murray, I use a 900GTO and the Orion guider along with PHD. Last week I tried the guider for the first time and found that for my rough polar alignment and available stars, 2 second exposures provided me with perfect round stars for my 15 minute test frame. I'm sure I could have gone longer between exposures but since it worked I didn't mess with the settings after that. One note, I did have to reduce the ms step size from (I think the default was 1000ms) to like 100ms. By default, the cal star would quickly leave the cal box if left alone. Once I changed it to 100ms, this reduced how far the mount would move and I had solid guiding.

Gedas
http://gedas.cc
http://www.w8bya.com

----- Original Message -----
From: "mphammick" <mphammick@...>
To: <ap-gto@...>
Sent: Thursday, March 27, 2008 4:18 PM
Subject: [ap-gto] Autoguider correction frequency


I have just bought the Orion Starshoot autoguider camera and have got
some very sharp images with a TAK scope on an AP900 mount.

Has anyone else tried this system and if yes, what frequency setting
do they have for the corrections. I have a friend with a Paramount ME
who says his guider corrects 10 times a second; this seems rather high
to me. Does anyone have strong views as to how often the guider should
correct a reasonable AP900 ?

Murray


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drgert1
 

Hi All,

Guiding corrections are made for different reasong at different speeds.

#1 Changes in refraction, air pressure, humidity, temperature on the
order of minutes to hrs.
#2 Mount drive train mechanic tolerances on the order of seconds (good
mounts longer bad ones shorter).
#3 Seeing motions of the star on the order of 1/10seconds and shorter.

There are systems that correct tracking errors of the above by
different means. If your time constant gets shorter the mechanical
inertia of the telescope becomes a problem as well as collecting
enough signal (photons) from a reference star.

The domain of the commercial amateur AO system is a mix of #2 & #3 and
a far cry from what large observatory opticians consider 'adaptive'.

But it's helpful for amateurs. A well aligned mount can track
exposures ~ 1hrs at 2m FL by just using i.e. an SBIG AO. Leaving the
mount free running very much reduces cabling between mount, camera,
laptop!.

Clear Skies,

Gert

--- In ap-gto@..., "KG KIRKLEY" <kgkirkley@...> wrote:





In a message dated 03/27/08 15:19:06 Central Daylight Time,
mphammick@... writes:
I have just bought the Orion Starshoot autoguider camera and have got
some very sharp images with a TAK scope on an AP900 mount.

Has anyone else tried this system and if yes, what frequency setting
do they have for the corrections. I have a friend with a Paramount ME
who says his guider corrects 10 times a second; this seems rather high
to me. Does anyone have strong views as to how often the guider should
correct a reasonable AP900 ?

Murray


Murray:
That is strange.
What guider exposure would he be using....1/10 sec.???
That might only work on a very bright star.

Generally, I use 1 sec. guider exposures and have corrections made
anywhere from 1 to 6 seconds.
(SBIG remote guide head-STL-11000)
If guider exposures and corrections are too fast, they can be
'chasing the seeing'.

Kent Kirkley


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


hewholooks
 

Gedas,

What guiding rate did you set the AP ASCOM driver to (on the ASCOM
panel - NOT the PHD settings) when you used PHD - I believe it has
1x, 0.5x, and 0.25x as choices. I was wondering which to use when I
give it a try. Also, while I'm asking, what RA aggressiveness did
you select.

Hunter

--- In ap-gto@..., "Gedas" <w8bya@...> wrote:

Murray, I use a 900GTO and the Orion guider along with PHD. Last
week I
tried the guider for the first time and found that for my rough
polar
alignment and available stars, 2 second exposures provided me with
perfect
round stars for my 15 minute test frame. I'm sure I could have
gone longer
between exposures but since it worked I didn't mess with the
settings after
that. One note, I did have to reduce the ms step size from (I
think the
default was 1000ms) to like 100ms. By default, the cal star would
quickly
leave the cal box if left alone. Once I changed it to 100ms, this
reduced
how far the mount would move and I had solid guiding.

Gedas
http://gedas.cc
http://www.w8bya.com



----- Original Message -----
From: "mphammick" <mphammick@...>
To: <ap-gto@...>
Sent: Thursday, March 27, 2008 4:18 PM
Subject: [ap-gto] Autoguider correction frequency


I have just bought the Orion Starshoot autoguider camera and have
got
some very sharp images with a TAK scope on an AP900 mount.

Has anyone else tried this system and if yes, what frequency
setting
do they have for the corrections. I have a friend with a
Paramount ME
who says his guider corrects 10 times a second; this seems rather
high
to me. Does anyone have strong views as to how often the guider
should
correct a reasonable AP900 ?

Murray


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

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



Gedas
 

That's a good question Hunter. As far as I know I have not loaded ASCOM onto this newly populated pc yet so I did not even access the panel you mention. I just selected on-camera for mount type in PHD. I should have double checked the guide rate on the AP hand controller however. The last time I tried AG it was set to 1x and assumed it did not change, that's a poor assumption on my part, I should have looked.

Gedas
http://gedas.cc
http://www.w8bya.com

----- Original Message -----
From: "hewholooks" <hewholooks@...>
To: <ap-gto@...>
Sent: Friday, March 28, 2008 11:04 AM
Subject: [ap-gto] Re: Autoguider correction frequency


Gedas,

What guiding rate did you set the AP ASCOM driver to (on the ASCOM
panel - NOT the PHD settings) when you used PHD - I believe it has
1x, 0.5x, and 0.25x as choices. I was wondering which to use when I
give it a try. Also, while I'm asking, what RA aggressiveness did
you select.

Hunter

--- In ap-gto@..., "Gedas" <w8bya@...> wrote:

Murray, I use a 900GTO and the Orion guider along with PHD. Last
week I
tried the guider for the first time and found that for my rough
polar
alignment and available stars, 2 second exposures provided me with
perfect
round stars for my 15 minute test frame. I'm sure I could have
gone longer
between exposures but since it worked I didn't mess with the
settings after
that. One note, I did have to reduce the ms step size from (I
think the
default was 1000ms) to like 100ms. By default, the cal star would
quickly
leave the cal box if left alone. Once I changed it to 100ms, this
reduced
how far the mount would move and I had solid guiding.

Gedas
http://gedas.cc
http://www.w8bya.com



----- Original Message -----
From: "mphammick" <mphammick@...>
To: <ap-gto@...>
Sent: Thursday, March 27, 2008 4:18 PM
Subject: [ap-gto] Autoguider correction frequency


I have just bought the Orion Starshoot autoguider camera and have
got
some very sharp images with a TAK scope on an AP900 mount.

Has anyone else tried this system and if yes, what frequency
setting
do they have for the corrections. I have a friend with a
Paramount ME
who says his guider corrects 10 times a second; this seems rather
high
to me. Does anyone have strong views as to how often the guider
should
correct a reasonable AP900 ?

Murray


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

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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hewholooks
 

So you are using your "on camera" guider and not something like a DSI
or independant webcam to guide with.

Thanks,

Hunter

--- In ap-gto@..., "Gedas" <w8bya@...> wrote:

That's a good question Hunter. As far as I know I have not loaded
ASCOM
onto this newly populated pc yet so I did not even access the panel
you
mention. I just selected on-camera for mount type in PHD. I
should have
double checked the guide rate on the AP hand controller however.
The last
time I tried AG it was set to 1x and assumed it did not change,
that's a
poor assumption on my part, I should have looked.

Gedas
http://gedas.cc
http://www.w8bya.com



----- Original Message -----
From: "hewholooks" <hewholooks@...>
To: <ap-gto@...>
Sent: Friday, March 28, 2008 11:04 AM
Subject: [ap-gto] Re: Autoguider correction frequency


Gedas,

What guiding rate did you set the AP ASCOM driver to (on the ASCOM
panel - NOT the PHD settings) when you used PHD - I believe it has
1x, 0.5x, and 0.25x as choices. I was wondering which to use
when I
give it a try. Also, while I'm asking, what RA aggressiveness did
you select.

Hunter

--- In ap-gto@..., "Gedas" <w8bya@> wrote:

Murray, I use a 900GTO and the Orion guider along with PHD. Last
week I
tried the guider for the first time and found that for my rough
polar
alignment and available stars, 2 second exposures provided me
with
perfect
round stars for my 15 minute test frame. I'm sure I could have
gone longer
between exposures but since it worked I didn't mess with the
settings after
that. One note, I did have to reduce the ms step size from (I
think the
default was 1000ms) to like 100ms. By default, the cal star
would
quickly
leave the cal box if left alone. Once I changed it to 100ms,
this
reduced
how far the mount would move and I had solid guiding.

Gedas
http://gedas.cc
http://www.w8bya.com



----- Original Message -----
From: "mphammick" <mphammick@>
To: <ap-gto@...>
Sent: Thursday, March 27, 2008 4:18 PM
Subject: [ap-gto] Autoguider correction frequency


I have just bought the Orion Starshoot autoguider camera and
have
got
some very sharp images with a TAK scope on an AP900 mount.

Has anyone else tried this system and if yes, what frequency
setting
do they have for the corrections. I have a friend with a
Paramount ME
who says his guider corrects 10 times a second; this seems
rather
high
to me. Does anyone have strong views as to how often the guider
should
correct a reasonable AP900 ?

Murray


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

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




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Gedas
 

Correct, it's the orion AG'er.

Gedas
http://gedas.cc
http://www.w8bya.com

----- Original Message -----
From: "hewholooks" <hewholooks@...>
To: <ap-gto@...>
Sent: Friday, March 28, 2008 11:53 AM
Subject: [ap-gto] Re: Autoguider correction frequency


So you are using your "on camera" guider and not something like a DSI or independant webcam to guide with.
Thanks,
Hunter
--- In ap-gto@..., "Gedas" <w8bya@...> wrote:

That's a good question Hunter. As far as I know I have not loaded
ASCOM
onto this newly populated pc yet so I did not even access the panel
you
mention. I just selected on-camera for mount type in PHD. I
should have
double checked the guide rate on the AP hand controller however.
The last
time I tried AG it was set to 1x and assumed it did not change,
that's a
poor assumption on my part, I should have looked.
Gedas
http://gedas.cc
http://www.w8bya.com
----- Original Message -----
From: "hewholooks" <hewholooks@...>
To: <ap-gto@...>
Sent: Friday, March 28, 2008 11:04 AM
Subject: [ap-gto] Re: Autoguider correction frequency

Gedas,

What guiding rate did you set the AP ASCOM driver to (on the ASCOM
panel - NOT the PHD settings) when you used PHD - I believe it has
1x, 0.5x, and 0.25x as choices. I was wondering which to use
when I
give it a try. Also, while I'm asking, what RA aggressiveness did
you select.

Hunter

--- In ap-gto@..., "Gedas" <w8bya@> wrote:

Murray, I use a 900GTO and the Orion guider along with PHD. Last
week I
tried the guider for the first time and found that for my rough
polar
alignment and available stars, 2 second exposures provided me
with
perfect
round stars for my 15 minute test frame. I'm sure I could have
gone longer
between exposures but since it worked I didn't mess with the
settings after
that. One note, I did have to reduce the ms step size from (I
think the
default was 1000ms) to like 100ms. By default, the cal star
would
quickly
leave the cal box if left alone. Once I changed it to 100ms,
this
reduced
how far the mount would move and I had solid guiding.

Gedas
http://gedas.cc
http://www.w8bya.com



----- Original Message -----
From: "mphammick" <mphammick@>
To: <ap-gto@...>
Sent: Thursday, March 27, 2008 4:18 PM
Subject: [ap-gto] Autoguider correction frequency


I have just bought the Orion Starshoot autoguider camera and
have
got
some very sharp images with a TAK scope on an AP900 mount.

Has anyone else tried this system and if yes, what frequency
setting
do they have for the corrections. I have a friend with a
Paramount ME
who says his guider corrects 10 times a second; this seems
rather
high
to me. Does anyone have strong views as to how often the guider
should
correct a reasonable AP900 ?

Murray


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

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




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

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Woodwind
 

I use the Orion SSAG with an AT 66ED and AP900 using the on-camera setting and a refresh rate of .5 sec. Seems to work well - but will try it at one and five seconds this weekend.

With very low settings for aggressivenss and high averaging, the shorter exposure times seemed more rational - but per the above I iwll try it on much slower settings

Murray




Gedas <w8bya@...> wrote:
Correct, it's the orion AG'er.

Gedas
http://gedas.cc
http://www.w8bya.com

----- Original Message -----
From: "hewholooks" <hewholooks@...>
To: <ap-gto@...>
Sent: Friday, March 28, 2008 11:53 AM
Subject: [ap-gto] Re: Autoguider correction frequency

So you are using your "on camera" guider and not something like a DSI
or independant webcam to guide with.

Thanks,

Hunter

--- In ap-gto@..., "Gedas" <w8bya@...> wrote:

That's a good question Hunter. As far as I know I have not loaded
ASCOM
onto this newly populated pc yet so I did not even access the panel
you
mention. I just selected on-camera for mount type in PHD. I
should have
double checked the guide rate on the AP hand controller however.
The last
time I tried AG it was set to 1x and assumed it did not change,
that's a
poor assumption on my part, I should have looked.

Gedas
http://gedas.cc
http://www.w8bya.com



----- Original Message -----
From: "hewholooks" <hewholooks@...>
To: <ap-gto@...>
Sent: Friday, March 28, 2008 11:04 AM
Subject: [ap-gto] Re: Autoguider correction frequency


Gedas,

What guiding rate did you set the AP ASCOM driver to (on the ASCOM
panel - NOT the PHD settings) when you used PHD - I believe it has
1x, 0.5x, and 0.25x as choices. I was wondering which to use
when I
give it a try. Also, while I'm asking, what RA aggressiveness did
you select.

Hunter

--- In ap-gto@..., "Gedas" <w8bya@> wrote:

Murray, I use a 900GTO and the Orion guider along with PHD. Last
week I
tried the guider for the first time and found that for my rough
polar
alignment and available stars, 2 second exposures provided me
with
perfect
round stars for my 15 minute test frame. I'm sure I could have
gone longer
between exposures but since it worked I didn't mess with the
settings after
that. One note, I did have to reduce the ms step size from (I
think the
default was 1000ms) to like 100ms. By default, the cal star
would
quickly
leave the cal box if left alone. Once I changed it to 100ms,
this
reduced
how far the mount would move and I had solid guiding.

Gedas
http://gedas.cc
http://www.w8bya.com



----- Original Message -----
From: "mphammick" <mphammick@>
To: <ap-gto@...>
Sent: Thursday, March 27, 2008 4:18 PM
Subject: [ap-gto] Autoguider correction frequency


I have just bought the Orion Starshoot autoguider camera and
have
got
some very sharp images with a TAK scope on an AP900 mount.

Has anyone else tried this system and if yes, what frequency
setting
do they have for the corrections. I have a friend with a
Paramount ME
who says his guider corrects 10 times a second; this seems
rather
high
to me. Does anyone have strong views as to how often the guider
should
correct a reasonable AP900 ?

Murray


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

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




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

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




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hewholooks
 

Gedas,

Right now, as I write, I am guiding with my new Mach1 (Thank you
Roland - you are my hero) using PHD. I have guide rate on the mount
set to 0.5 and PHD RA agress set to 60. I have never seen anything
like this. PHD is on vacation - maybe, MAYBE one correction every 5
or 10 minutes and that's only 0.3 pixels (1.3 arcsec).

I am in awe. I can't wait to image at 1500mm (tonight it's at 780
with the 130 refractor).

The Mach1 is everything they say it is.

Hunter

--- In ap-gto@..., "Gedas" <w8bya@...> wrote:

Correct, it's the orion AG'er.

Gedas
http://gedas.cc
http://www.w8bya.com



----- Original Message -----
From: "hewholooks" <hewholooks@...>
To: <ap-gto@...>
Sent: Friday, March 28, 2008 11:53 AM
Subject: [ap-gto] Re: Autoguider correction frequency


So you are using your "on camera" guider and not something like a
DSI
or independant webcam to guide with.

Thanks,

Hunter

--- In ap-gto@..., "Gedas" <w8bya@> wrote:

That's a good question Hunter. As far as I know I have not
loaded
ASCOM
onto this newly populated pc yet so I did not even access the
panel
you
mention. I just selected on-camera for mount type in PHD. I
should have
double checked the guide rate on the AP hand controller
however.
The last
time I tried AG it was set to 1x and assumed it did not change,
that's a
poor assumption on my part, I should have looked.

Gedas
http://gedas.cc
http://www.w8bya.com



----- Original Message -----
From: "hewholooks" <hewholooks@>
To: <ap-gto@...>
Sent: Friday, March 28, 2008 11:04 AM
Subject: [ap-gto] Re: Autoguider correction frequency


Gedas,

What guiding rate did you set the AP ASCOM driver to (on the
ASCOM
panel - NOT the PHD settings) when you used PHD - I believe it
has
1x, 0.5x, and 0.25x as choices. I was wondering which to use
when I
give it a try. Also, while I'm asking, what RA aggressiveness
did
you select.

Hunter

--- In ap-gto@..., "Gedas" <w8bya@> wrote:

Murray, I use a 900GTO and the Orion guider along with PHD.
Last
week I
tried the guider for the first time and found that for my
rough
polar
alignment and available stars, 2 second exposures provided me
with
perfect
round stars for my 15 minute test frame. I'm sure I could
have
gone longer
between exposures but since it worked I didn't mess with the
settings after
that. One note, I did have to reduce the ms step size from (I
think the
default was 1000ms) to like 100ms. By default, the cal star
would
quickly
leave the cal box if left alone. Once I changed it to 100ms,
this
reduced
how far the mount would move and I had solid guiding.

Gedas
http://gedas.cc
http://www.w8bya.com



----- Original Message -----
From: "mphammick" <mphammick@>
To: <ap-gto@...>
Sent: Thursday, March 27, 2008 4:18 PM
Subject: [ap-gto] Autoguider correction frequency


I have just bought the Orion Starshoot autoguider camera and
have
got
some very sharp images with a TAK scope on an AP900 mount.

Has anyone else tried this system and if yes, what frequency
setting
do they have for the corrections. I have a friend with a
Paramount ME
who says his guider corrects 10 times a second; this seems
rather
high
to me. Does anyone have strong views as to how often the
guider
should
correct a reasonable AP900 ?

Murray


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

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roy uyematsu <roystarman@...>
 

I am very late to this discussion but from what Iíve read, I think you maybe
making an assumption that is not true. That is Autoguiding can help to
overcome polar alignment issues and mount problems. To some extent this is
true but the real reason for autoguiding is to correct errors in the RA
drive periodic error and others. If you are having to make regular and large
declination corrections then you have either a polar alignment issue or a
backlash issue. You should be working to minimize the number of corrections
required, not trying to determine the fastest rate you can put them in. As
you have stated each time the mount moves there is settling and other
issues. So it seems very reasonable that you want to minimize the movements.
Try get to a regime of 5 second as a minimum and probably more like 10 to
15. If you use narrow band filters you will probably need 20 to 30 seconds
perhaps more to find a good guide star.



Roy Uyematsu



roystarman@...



_____

From: ap-gto@... [mailto:ap-gto@...] On Behalf Of
Murray Hammick
Sent: Friday, March 28, 2008 12:25 PM
To: ap-gto@...
Subject: Re: [ap-gto] Re: Autoguider correction frequency



I use the Orion SSAG with an AT 66ED and AP900 using the on-camera setting
and a refresh rate of .5 sec. Seems to work well - but will try it at one
and five seconds this weekend.

With very low settings for aggressivenss and high averaging, the shorter
exposure times seemed more rational - but per the above I iwll try it on
much slower settings

Murray




Gedas <HYPERLINK "mailto:w8bya%40mchsi.com"w8bya@...> wrote:
Correct, it's the orion AG'er.

Gedas
HYPERLINK "http://gedas.cc"http://gedas.-cc
HYPERLINK "http://www.w8bya.com"http://www.w8bya.-com

----- Original Message -----
From: "hewholooks" <HYPERLINK
"mailto:hewholooks%40yahoo.com"hewholooks@...>
To: <HYPERLINK "mailto:ap-gto%40yahoogroups.com"ap-gto@...>
Sent: Friday, March 28, 2008 11:53 AM
Subject: [ap-gto] Re: Autoguider correction frequency

So you are using your "on camera" guider and not something like a DSI
or independant webcam to guide with.

Thanks,

Hunter

--- In HYPERLINK "mailto:ap-gto%40yahoogroups.com"ap-gto@...,
"Gedas" <w8bya@...> wrote:

That's a good question Hunter. As far as I know I have not loaded
ASCOM
onto this newly populated pc yet so I did not even access the panel
you
mention. I just selected on-camera for mount type in PHD. I
should have
double checked the guide rate on the AP hand controller however.
The last
time I tried AG it was set to 1x and assumed it did not change,
that's a
poor assumption on my part, I should have looked.

Gedas
HYPERLINK "http://gedas.cc"http://gedas.-cc
HYPERLINK "http://www.w8bya.com"http://www.w8bya.-com



----- Original Message -----
From: "hewholooks" <hewholooks@-...>
To: <HYPERLINK "mailto:ap-gto%40yahoogroups.com"ap-gto@...>
Sent: Friday, March 28, 2008 11:04 AM
Subject: [ap-gto] Re: Autoguider correction frequency


Gedas,

What guiding rate did you set the AP ASCOM driver to (on the ASCOM
panel - NOT the PHD settings) when you used PHD - I believe it has
1x, 0.5x, and 0.25x as choices. I was wondering which to use
when I
give it a try. Also, while I'm asking, what RA aggressiveness did
you select.

Hunter

--- In HYPERLINK
"mailto:ap-gto%40yahoogroups.com"ap-gto@..., "Gedas" <w8bya@>
wrote:

Murray, I use a 900GTO and the Orion guider along with PHD. Last
week I
tried the guider for the first time and found that for my rough
polar
alignment and available stars, 2 second exposures provided me
with
perfect
round stars for my 15 minute test frame. I'm sure I could have
gone longer
between exposures but since it worked I didn't mess with the
settings after
that. One note, I did have to reduce the ms step size from (I
think the
default was 1000ms) to like 100ms. By default, the cal star
would
quickly
leave the cal box if left alone. Once I changed it to 100ms,
this
reduced
how far the mount would move and I had solid guiding.

Gedas
HYPERLINK "http://gedas.cc"http://gedas.-cc
HYPERLINK "http://www.w8bya.com"http://www.w8bya.-com



----- Original Message -----
From: "mphammick" <mphammick@>
To: <HYPERLINK
"mailto:ap-gto%40yahoogroups.com"ap-gto@...>
Sent: Thursday, March 27, 2008 4:18 PM
Subject: [ap-gto] Autoguider correction frequency


I have just bought the Orion Starshoot autoguider camera and
have
got
some very sharp images with a TAK scope on an AP900 mount.

Has anyone else tried this system and if yes, what frequency
setting
do they have for the corrections. I have a friend with a
Paramount ME
who says his guider corrects 10 times a second; this seems
rather
high
to me. Does anyone have strong views as to how often the guider
should
correct a reasonable AP900 ?

Murray


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

To UNSUBSCRIBE, or for general information on the ap-gto list
see HYPERLINK
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p--gtoYahoo! Groups Links




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

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




No virus found in this incoming message.
Checked by AVG.
Version: 7.5.519 / Virus Database: 269.22.1/1348 - Release Date: 3/28/2008
10:58 AM



No virus found in this outgoing message.
Checked by AVG.
Version: 7.5.519 / Virus Database: 269.22.1/1348 - Release Date: 3/28/2008
10:58 AM



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


gilovision2@...
 

Dans un e-mail daté du 29/03/2008 17:40:55 Paris, Madrid,
JunkMailGoesHere@... a écrit :

Absolutely true. There is no substitute for a good if not excellent
polar alignment.


Yes, I totally agree too ;-))

Gilles


Gedas
 

Congrats Hunter ! You will absolutely love your new toy. This is one of those investments that you will never regret and always appreciate. I love my AP mount more each and every time I use it. Have fun !

Gedas
http://gedas.cc
http://www.w8bya.com

----- Original Message -----
From: "hewholooks" <hewholooks@...>
To: <ap-gto@...>
Sent: Saturday, March 29, 2008 1:57 AM
Subject: [ap-gto] Re: Autoguider correction frequency


Gedas,

Right now, as I write, I am guiding with my new Mach1 (Thank you
Roland - you are my hero) using PHD. I have guide rate on the mount
set to 0.5 and PHD RA agress set to 60. I have never seen anything
like this. PHD is on vacation - maybe, MAYBE one correction every 5
or 10 minutes and that's only 0.3 pixels (1.3 arcsec).

I am in awe. I can't wait to image at 1500mm (tonight it's at 780
with the 130 refractor).

The Mach1 is everything they say it is.

Hunter

--- In ap-gto@..., "Gedas" <w8bya@...> wrote:

Correct, it's the orion AG'er.

Gedas
http://gedas.cc
http://www.w8bya.com



----- Original Message -----
From: "hewholooks" <hewholooks@...>
To: <ap-gto@...>
Sent: Friday, March 28, 2008 11:53 AM
Subject: [ap-gto] Re: Autoguider correction frequency


So you are using your "on camera" guider and not something like a
DSI
or independant webcam to guide with.

Thanks,

Hunter

--- In ap-gto@..., "Gedas" <w8bya@> wrote:

That's a good question Hunter. As far as I know I have not
loaded
ASCOM
onto this newly populated pc yet so I did not even access the
panel
you
mention. I just selected on-camera for mount type in PHD. I
should have
double checked the guide rate on the AP hand controller
however.
The last
time I tried AG it was set to 1x and assumed it did not change,
that's a
poor assumption on my part, I should have looked.

Gedas
http://gedas.cc
http://www.w8bya.com



----- Original Message -----
From: "hewholooks" <hewholooks@>
To: <ap-gto@...>
Sent: Friday, March 28, 2008 11:04 AM
Subject: [ap-gto] Re: Autoguider correction frequency


Gedas,

What guiding rate did you set the AP ASCOM driver to (on the
ASCOM
panel - NOT the PHD settings) when you used PHD - I believe it
has
1x, 0.5x, and 0.25x as choices. I was wondering which to use
when I
give it a try. Also, while I'm asking, what RA aggressiveness
did
you select.

Hunter

--- In ap-gto@..., "Gedas" <w8bya@> wrote:

Murray, I use a 900GTO and the Orion guider along with PHD.
Last
week I
tried the guider for the first time and found that for my
rough
polar
alignment and available stars, 2 second exposures provided me
with
perfect
round stars for my 15 minute test frame. I'm sure I could
have
gone longer
between exposures but since it worked I didn't mess with the
settings after
that. One note, I did have to reduce the ms step size from (I
think the
default was 1000ms) to like 100ms. By default, the cal star
would
quickly
leave the cal box if left alone. Once I changed it to 100ms,
this
reduced
how far the mount would move and I had solid guiding.

Gedas
http://gedas.cc
http://www.w8bya.com



----- Original Message -----
From: "mphammick" <mphammick@>
To: <ap-gto@...>
Sent: Thursday, March 27, 2008 4:18 PM
Subject: [ap-gto] Autoguider correction frequency


I have just bought the Orion Starshoot autoguider camera and
have
got
some very sharp images with a TAK scope on an AP900 mount.

Has anyone else tried this system and if yes, what frequency
setting
do they have for the corrections. I have a friend with a
Paramount ME
who says his guider corrects 10 times a second; this seems
rather
high
to me. Does anyone have strong views as to how often the
guider
should
correct a reasonable AP900 ?

Murray


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

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




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

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

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observe_m13
 

Absolutely true. There is no substitute for a good if not excellent
polar alignment. With the increased size of imaging detectors, it
becomes more and more crucial to have a proper polar alignment for
long duration exposures. Field rotation results if polar alignment is
off and while it is negligible at or at close to 0 Dec, it becomes
pronounced and impossible to deal with in virtually any other manner
if one is imaging above/below +/-60 Dec and the closer one is imaging
to +/-90 Dec the worse it gets depending on the polar misalignment.

I have several useless large format images to prove the point after I
managed to trip over a leg and thought that I didn't move the mount.

Guiding is for correcting the inherent drive errors in the mount and
can be useful to help overcome atmospheric refraction somewhat in a
series of long exposures, not for correcting poor mount alignment.

Rick.


--- In ap-gto@..., "roy uyematsu" <roystarman@...> wrote:

I am very late to this discussion but from what I've read, I think
you maybe
making an assumption that is not true. That is Autoguiding can help to
overcome polar alignment issues and mount problems. To some extent
this is
true but the real reason for autoguiding is to correct errors in the RA
drive periodic error and others. If you are having to make regular
and large
declination corrections then you have either a polar alignment issue
or a
backlash issue. You should be working to minimize the number of
corrections
required, not trying to determine the fastest rate you can put them
in. As
you have stated each time the mount moves there is settling and other
issues. So it seems very reasonable that you want to minimize the
movements.
Try get to a regime of 5 second as a minimum and probably more like
10 to
15. If you use narrow band filters you will probably need 20 to 30
seconds
perhaps more to find a good guide star.



Roy Uyematsu



roystarman@...



_____

From: ap-gto@... [mailto:ap-gto@...] On
Behalf Of
Murray Hammick
Sent: Friday, March 28, 2008 12:25 PM
To: ap-gto@...
Subject: Re: [ap-gto] Re: Autoguider correction frequency



I use the Orion SSAG with an AT 66ED and AP900 using the on-camera
setting
and a refresh rate of .5 sec. Seems to work well - but will try it
at one
and five seconds this weekend.

With very low settings for aggressivenss and high averaging, the shorter
exposure times seemed more rational - but per the above I iwll try it on
much slower settings

Murray




Gedas <HYPERLINK "mailto:w8bya%40mchsi.com"w8bya@...> wrote:
Correct, it's the orion AG'er.

Gedas
HYPERLINK "http://gedas.cc"http://gedas.-cc
HYPERLINK "http://www.w8bya.com"http://www.w8bya.-com

----- Original Message -----
From: "hewholooks" <HYPERLINK
"mailto:hewholooks%40yahoo.com"hewholooks@...>
To: <HYPERLINK "mailto:ap-gto%40yahoogroups.com"ap-gto@...>
Sent: Friday, March 28, 2008 11:53 AM
Subject: [ap-gto] Re: Autoguider correction frequency

So you are using your "on camera" guider and not something like a DSI
or independant webcam to guide with.

Thanks,

Hunter

--- In HYPERLINK "mailto:ap-gto%40yahoogroups.com"ap-gto@...,
"Gedas" <w8bya@> wrote:

That's a good question Hunter. As far as I know I have not loaded
ASCOM
onto this newly populated pc yet so I did not even access the panel
you
mention. I just selected on-camera for mount type in PHD. I
should have
double checked the guide rate on the AP hand controller however.
The last
time I tried AG it was set to 1x and assumed it did not change,
that's a
poor assumption on my part, I should have looked.

Gedas
HYPERLINK "http://gedas.cc"http://gedas.-cc
HYPERLINK "http://www.w8bya.com"http://www.w8bya.-com



----- Original Message -----
From: "hewholooks" <hewholooks@>
To: <HYPERLINK "mailto:ap-gto%40yahoogroups.com"ap-gto@...>
Sent: Friday, March 28, 2008 11:04 AM
Subject: [ap-gto] Re: Autoguider correction frequency


Gedas,

What guiding rate did you set the AP ASCOM driver to (on the ASCOM
panel - NOT the PHD settings) when you used PHD - I believe it has
1x, 0.5x, and 0.25x as choices. I was wondering which to use
when I
give it a try. Also, while I'm asking, what RA aggressiveness did
you select.

Hunter

--- In HYPERLINK
"mailto:ap-gto%40yahoogroups.com"ap-gto@..., "Gedas" <w8bya@>
wrote:

Murray, I use a 900GTO and the Orion guider along with PHD. Last
week I
tried the guider for the first time and found that for my rough
polar
alignment and available stars, 2 second exposures provided me
with
perfect
round stars for my 15 minute test frame. I'm sure I could have
gone longer
between exposures but since it worked I didn't mess with the
settings after
that. One note, I did have to reduce the ms step size from (I
think the
default was 1000ms) to like 100ms. By default, the cal star
would
quickly
leave the cal box if left alone. Once I changed it to 100ms,
this
reduced
how far the mount would move and I had solid guiding.

Gedas
HYPERLINK "http://gedas.cc"http://gedas.-cc
HYPERLINK "http://www.w8bya.com"http://www.w8bya.-com



----- Original Message -----
From: "mphammick" <mphammick@>
To: <HYPERLINK
"mailto:ap-gto%40yahoogroups.com"ap-gto@...>
Sent: Thursday, March 27, 2008 4:18 PM
Subject: [ap-gto] Autoguider correction frequency


I have just bought the Orion Starshoot autoguider camera and
have
got
some very sharp images with a TAK scope on an AP900 mount.

Has anyone else tried this system and if yes, what frequency
setting
do they have for the corrections. I have a friend with a
Paramount ME
who says his guider corrects 10 times a second; this seems
rather
high
to me. Does anyone have strong views as to how often the guider
should
correct a reasonable AP900 ?

Murray


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

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




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

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p--gtoYahoo! Groups Links




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

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


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




No virus found in this incoming message.
Checked by AVG.
Version: 7.5.519 / Virus Database: 269.22.1/1348 - Release Date:
3/28/2008
10:58 AM



No virus found in this outgoing message.
Checked by AVG.
Version: 7.5.519 / Virus Database: 269.22.1/1348 - Release Date:
3/28/2008
10:58 AM



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


Roland Christen
 

In a message dated 3/29/2008 1:12:28 PM Central Daylight Time,
mphammick@... writes:


I have a friend with a Paramount ME who says that that system corrects up
to 10 times a second.
Not sure what this means. I don't think your friend does either. A mount
system (mount servo) does nothing by itself - it does not do any correcting by
itself. It simply goes at a steady sidereal rate until you command it to change
that rate by an outside software command (or guider command).

Of course the mount will respond to move inputs as short as 10 milliseconds,
and probably even shorter. The question would be, what are the fastest
repetition rates that a mount should be commanded at? I would think that 10 times per
second is not ideal, and that this would simply chase the seeing. The motors
can certainly respond that fast, but the mass of the mount head and telescope
along with the moment arm would prevent the optical axis from actually
accelerating and decelerating at that rate and follow the commanded trajectory
faithfully. The optical axis will probably always be behind in actual position.

Rolando


**************
Create a Home Theater Like the Pros. Watch the video on
AOL Home.
(http://home.aol.com/diy/home-improvement-eric-stromer?video=15&;
ncid=aolhom00030000000001)


Woodwind
 

Roy,

I started the thread and I was not specifically talking about the issues you raise. I might have missed some posts - but the main theme was whether to use low aggressiveness levels and plenty of feedback from previous readings and then correct more quickly to minimise actual movements - or to allow the mount more time.

I have a friend with a Paramount ME who says that that system corrects up to 10 times a second.

I was assuming good polar alignment was taken as read.

Not sure if this alters the price of fish- but it might clarify some of the background to the thread. On the basis of yours and other comments, I am certainly going to try a longer exposure setting this week-end - weather permitting.

Murray





roy uyematsu <roystarman@...> wrote: I am very late to this discussion but from what I’ve read, I think you maybe
making an assumption that is not true. That is Autoguiding can help to
overcome polar alignment issues and mount problems. To some extent this is
true but the real reason for autoguiding is to correct errors in the RA
drive periodic error and others. If you are having to make regular and large
declination corrections then you have either a polar alignment issue or a
backlash issue. You should be working to minimize the number of corrections
required, not trying to determine the fastest rate you can put them in. As
you have stated each time the mount moves there is settling and other
issues. So it seems very reasonable that you want to minimize the movements.
Try get to a regime of 5 second as a minimum and probably more like 10 to
15. If you use narrow band filters you will probably need 20 to 30 seconds
perhaps more to find a good guide star.



Roy Uyematsu



roystarman@...



_____

From: ap-gto@... [mailto:ap-gto@...] On Behalf Of
Murray Hammick
Sent: Friday, March 28, 2008 12:25 PM
To: ap-gto@...
Subject: Re: [ap-gto] Re: Autoguider correction frequency



I use the Orion SSAG with an AT 66ED and AP900 using the on-camera setting
and a refresh rate of .5 sec. Seems to work well - but will try it at one
and five seconds this weekend.

With very low settings for aggressivenss and high averaging, the shorter
exposure times seemed more rational - but per the above I iwll try it on
much slower settings

Murray




Gedas wrote:
Correct, it's the orion AG'er.

Gedas
HYPERLINK "http://gedas.cc"http://gedas.-cc
HYPERLINK "http://www.w8bya.com"http://www.w8bya.-com

----- Original Message -----
From: "hewholooks"
"mailto:hewholooks%40yahoo.com"hewholooks@...>
To:
Sent: Friday, March 28, 2008 11:53 AM
Subject: [ap-gto] Re: Autoguider correction frequency

So you are using your "on camera" guider and not something like a DSI
or independant webcam to guide with.

Thanks,

Hunter

--- In HYPERLINK "mailto:ap-gto%40yahoogroups.com"ap-gto@...,
"Gedas" wrote:

That's a good question Hunter. As far as I know I have not loaded
ASCOM
onto this newly populated pc yet so I did not even access the panel
you
mention. I just selected on-camera for mount type in PHD. I
should have
double checked the guide rate on the AP hand controller however.
The last
time I tried AG it was set to 1x and assumed it did not change,
that's a
poor assumption on my part, I should have looked.

Gedas
HYPERLINK "http://gedas.cc"http://gedas.-cc
HYPERLINK "http://www.w8bya.com"http://www.w8bya.-com



----- Original Message -----
From: "hewholooks"
To:
Sent: Friday, March 28, 2008 11:04 AM
Subject: [ap-gto] Re: Autoguider correction frequency


Gedas,

What guiding rate did you set the AP ASCOM driver to (on the ASCOM
panel - NOT the PHD settings) when you used PHD - I believe it has
1x, 0.5x, and 0.25x as choices. I was wondering which to use
when I
give it a try. Also, while I'm asking, what RA aggressiveness did
you select.

Hunter

--- In HYPERLINK
"mailto:ap-gto%40yahoogroups.com"ap-gto@..., "Gedas"
wrote:

Murray, I use a 900GTO and the Orion guider along with PHD. Last
week I
tried the guider for the first time and found that for my rough
polar
alignment and available stars, 2 second exposures provided me
with
perfect
round stars for my 15 minute test frame. I'm sure I could have
gone longer
between exposures but since it worked I didn't mess with the
settings after
that. One note, I did have to reduce the ms step size from (I
think the
default was 1000ms) to like 100ms. By default, the cal star
would
quickly
leave the cal box if left alone. Once I changed it to 100ms,
this
reduced
how far the mount would move and I had solid guiding.

Gedas
HYPERLINK "http://gedas.cc"http://gedas.-cc
HYPERLINK "http://www.w8bya.com"http://www.w8bya.-com



----- Original Message -----
From: "mphammick"
To:
"mailto:ap-gto%40yahoogroups.com"ap-gto@...>
Sent: Thursday, March 27, 2008 4:18 PM
Subject: [ap-gto] Autoguider correction frequency


I have just bought the Orion Starshoot autoguider camera and
have
got
some very sharp images with a TAK scope on an AP900 mount.

Has anyone else tried this system and if yes, what frequency
setting
do they have for the corrections. I have a friend with a
Paramount ME
who says his guider corrects 10 times a second; this seems
rather
high
to me. Does anyone have strong views as to how often the guider
should
correct a reasonable AP900 ?

Murray


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Dr. David Toth
 

At 06:08 PM 3/29/2008, chris1011@... wrote:
In a message dated 3/29/2008 1:12:28 PM Central Daylight Time,
mphammick@... writes:


I have a friend with a Paramount ME who says that that system corrects up
to 10 times a second.
Not sure what this means. I don't think your friend does either. A mount
system (mount servo) does nothing by itself - it does not do any correcting by
itself. It simply goes at a steady sidereal rate until you command it to change
that rate by an outside software command (or guider command).
Roland; you posted exactly what I was going to say .... I have AP mounts and I have a Paramount,
and I have never heard those figures quoted .... As you suggest, the servo system is busy sensing
thousands of times per second, but the only corrections, as you say, come from guider instructions.

Even IF a system could respond to 10 guider corrections per second, why would you?
You would just be chasing the seeing ....

I try for the best polar alignment possible, and try to do as FEW corrections as possible ...

I don't think you can get the same "adaptic-optics" effect from guiding rapidly.

Just my $0.02 worth ....

Dave