Topics

Multi-star guiding


Roland Christen
 

Hello fellow Astronuts,

I've been meaning to try something new (for me) in my guided imaging. My setup consists of a 160EDF refractor on a mach2 encoder mount, a QSI-683WSG camera with off-axis pickup, and a Lodestar guide camera. I do all of my imaging with MaximDL Pro6 which has a multi star guiding function. Up to now I have used single star guiding and so i have to pick a guide star and let the guider do its thing. That's an extra step, and since I'm lazy I decided to let the program guide on the whole enchilada using the multi star guide method. So, how did that work out for a 20 minute exposure? Well see below:

Rolando
Notes:
The guiding was effortless, extremely accurate (partly thanks to the precision movements of the Mach2 mount), and required no thinking on my part. The Lodestar guide camera is really tops in my book. It picks up stars in every part of the sky, even in star-poor regions. My guide exposures are 5 seconds with 1 second delay between exposures. My Min Move for both axes was set to 0.02 seconds (which is 0.3 arc sec), and the aggressiveness was set to 8 out of 10 since the seeing was quite good. Outside temperature last night was 25 degrees F. The peak values reflect the dither moves between exposures in case you're wondering.

The California Nebula did not fit into my camera's field of view, oh well. Thus I'm in the market for a larger chip camera for Christmas Smile




--
Roland Christen
Astro-Physics


Michael Hamburg
 

That tracking error graph is something to really envy! Congratulations!

Best wishes, Michael


On Thursday, December 3, 2020, 12:06:16 PM EST, Roland Christen via groups.io <chris1011@...> wrote:


Hello fellow Astronuts,

I've been meaning to try something new (for me) in my guided imaging. My setup consists of a 160EDF refractor on a mach2 encoder mount, a QSI-683WSG camera with off-axis pickup, and a Lodestar guide camera. I do all of my imaging with MaximDL Pro6 which has a multi star guiding function. Up to now I have used single star guiding and so i have to pick a guide star and let the guider do its thing. That's an extra step, and since I'm lazy I decided to let the program guide on the whole enchilada using the multi star guide method. So, how did that work out for a 20 minute exposure? Well see below:

Rolando
Notes:
The guiding was effortless, extremely accurate (partly thanks to the precision movements of the Mach2 mount), and required no thinking on my part. The Lodestar guide camera is really tops in my book. It picks up stars in every part of the sky, even in star-poor regions. My guide exposures are 5 seconds with 1 second delay between exposures. My Min Move for both axes was set to 0.02 seconds (which is 0.3 arc sec), and the aggressiveness was set to 8 out of 10 since the seeing was quite good. Outside temperature last night was 25 degrees F. The peak values reflect the dither moves between exposures in case you're wondering.

The California Nebula did not fit into my camera's field of view, oh well. Thus I'm in the market for a larger chip camera for Christmas Smile




--
Roland Christen
Astro-Physics


Joel Short
 

Interestingly I just learned today that PHD2 now has multi-star guiding.  The results by other users look promising, and I'm hoping to try it tonight with my AP1100.  Looks to be clear in northern Indiana, but the seeing conditions don't look great.  With my "glass half full" outlook, that means it should be a good test for the new multi-star guiding!  :)
joel


 

indeed it should be a good test!

as I mentioned before (and i just saw a few more confirmations of this) it looks like a 10-15% improvement in guiding accuracy (i'm talking PHD2 multi-star specifically)

On Thu, Dec 3, 2020 at 1:12 PM Joel Short <buckeyestargazer@...> wrote:
Interestingly I just learned today that PHD2 now has multi-star guiding.  The results by other users look promising, and I'm hoping to try it tonight with my AP1100.  Looks to be clear in northern Indiana, but the seeing conditions don't look great.  With my "glass half full" outlook, that means it should be a good test for the new multi-star guiding!  :)
joel



--
Brian 



Brian Valente


Calypte
 

I have the Superstar guider, which I chose for its pixels being smaller than those of the Lodestar.  When using the QSI's OAG, I have had instances where there were no usable guide stars within the parameters I set in CCD Commander (which selects the guide star automatically).  A specific object where I had this problem was M64.  The scope is a TEC140ED, 1030 mm FL with the flattener.  


Worsel
 

Roland

MaximDL does have a Mosaic function, as an alternative to a whole new camera!  But then it is Christmas!

Bryan


Terri Zittritsch
 

Your skies must be way better than mine, or the multi-star aspect of the Maxim guiding somehow average out the seeing across  the three stars for you.    I need to read up on this to understand how it takes advantage of the multiple stars and my guess is some kind of averaging which can filter out seeing to some extent. 
I just picked up a full frame 60mp ASI camera with filterwheel and OAG.    I plan to try the OAG but have had limited success in the past.  I do have a lodestar which is the guide camera I'd use with this kind of setup due to its sensitivity.     I really enjoy the flexibility and FOV fo the guidescope, but maybe I have some amount of error as a result of the differential flex.    The precision movement of the mach2 makes it a joy to use.


Terri


M Hambrick
 

Hi Roland

This looks interesting. When you do the multi-star guiding does MaxIm allow you to select which stars to guide on ?

I am trying to get a grasp on what benefits can be gained by multi-star guiding. I don't think that you can compensate for field rotation with multi star guiding, but Terri's comment about averaging out the seeing makes sense.


Roland Christen
 

I don't choose the stars when doing multi-star guiding. maxim looks at the entire frame and guides on all the bright stars in the frame. Other than that, I really don't know what their criteria are for which stars to guide on.

The only benefit that I see is during poor seeing when a single guide star is jumping around but an average of multiple stars seems to lead to a smoother guide graph. During good seeing I can't see any difference.

Roland



-----Original Message-----
From: M Hambrick <mhambrick563@...>
To: main@ap-gto.groups.io
Sent: Fri, Dec 11, 2020 7:31 am
Subject: Re: [ap-gto] Multi-star guiding

Hi Roland

This looks interesting. When you do the multi-star guiding does MaxIm allow you to select which stars to guide on ?

I am trying to get a grasp on what benefits can be gained by multi-star guiding. I don't think that you can compensate for field rotation with multi star guiding, but Terri's comment about averaging out the seeing makes sense.

--
Roland Christen
Astro-Physics


Michael 'Mikey' Mangieri
 

I just started experimenting with PHD2 new dev release which has multi star guiding. I can attest that in poor seeing there is noticeable improvement in guiding. This was with my EdgeHD 11 on AP1100 with OAG guiding. 


On Dec 11, 2020, at 11:13 AM, Roland Christen via groups.io <chris1011@...> wrote:


I don't choose the stars when doing multi-star guiding. maxim looks at the entire frame and guides on all the bright stars in the frame. Other than that, I really don't know what their criteria are for which stars to guide on.

The only benefit that I see is during poor seeing when a single guide star is jumping around but an average of multiple stars seems to lead to a smoother guide graph. During good seeing I can't see any difference.

Roland



-----Original Message-----
From: M Hambrick <mhambrick563@...>
To: main@ap-gto.groups.io
Sent: Fri, Dec 11, 2020 7:31 am
Subject: Re: [ap-gto] Multi-star guiding

Hi Roland

This looks interesting. When you do the multi-star guiding does MaxIm allow you to select which stars to guide on ?

I am trying to get a grasp on what benefits can be gained by multi-star guiding. I don't think that you can compensate for field rotation with multi star guiding, but Terri's comment about averaging out the seeing makes sense.

--
Roland Christen
Astro-Physics


 

wow that's interesting!

I hope you'll share the details of your setup and results either here or over at PHD

Generally we (over at PHD forums) have seen the smaller the image scale, the less impact multi-star has, but i haven't yet heard anyone with the combo of long focal length/oag and poor seeing talk about their results and details

On Fri, Dec 11, 2020 at 8:49 AM Michael 'Mikey' Mangieri <mjmangieri@...> wrote:
I just started experimenting with PHD2 new dev release which has multi star guiding. I can attest that in poor seeing there is noticeable improvement in guiding. This was with my EdgeHD 11 on AP1100 with OAG guiding. 


On Dec 11, 2020, at 11:13 AM, Roland Christen via groups.io <chris1011=aol.com@groups.io> wrote:


I don't choose the stars when doing multi-star guiding. maxim looks at the entire frame and guides on all the bright stars in the frame. Other than that, I really don't know what their criteria are for which stars to guide on.

The only benefit that I see is during poor seeing when a single guide star is jumping around but an average of multiple stars seems to lead to a smoother guide graph. During good seeing I can't see any difference.

Roland



-----Original Message-----
From: M Hambrick <mhambrick563@...>
To: main@ap-gto.groups.io
Sent: Fri, Dec 11, 2020 7:31 am
Subject: Re: [ap-gto] Multi-star guiding

Hi Roland

This looks interesting. When you do the multi-star guiding does MaxIm allow you to select which stars to guide on ?

I am trying to get a grasp on what benefits can be gained by multi-star guiding. I don't think that you can compensate for field rotation with multi star guiding, but Terri's comment about averaging out the seeing makes sense.

--
Roland Christen
Astro-Physics



--
Brian 



Brian Valente


Bill Long
 

I tested out PHD2's new multi star guiding and it worked great. Seeing was decent and I was at a dark site though.


From: main@ap-gto.groups.io <main@ap-gto.groups.io> on behalf of Roland Christen via groups.io <chris1011@...>
Sent: Friday, December 11, 2020 8:13 AM
To: main@ap-gto.groups.io <main@ap-gto.groups.io>
Subject: Re: [ap-gto] Multi-star guiding
 
I don't choose the stars when doing multi-star guiding. maxim looks at the entire frame and guides on all the bright stars in the frame. Other than that, I really don't know what their criteria are for which stars to guide on.

The only benefit that I see is during poor seeing when a single guide star is jumping around but an average of multiple stars seems to lead to a smoother guide graph. During good seeing I can't see any difference.

Roland



-----Original Message-----
From: M Hambrick <mhambrick563@...>
To: main@ap-gto.groups.io
Sent: Fri, Dec 11, 2020 7:31 am
Subject: Re: [ap-gto] Multi-star guiding

Hi Roland

This looks interesting. When you do the multi-star guiding does MaxIm allow you to select which stars to guide on ?

I am trying to get a grasp on what benefits can be gained by multi-star guiding. I don't think that you can compensate for field rotation with multi star guiding, but Terri's comment about averaging out the seeing makes sense.

--
Roland Christen
Astro-Physics


Brian ORourke
 

I believe with MaxIm you can select what stars are used by reducing the image field. If you drag your mouse to create a smaller field you can eliminate a problem source, ( a galaxy core perhaps), but you are still dealing with the whole of the new field. So a weak star with a poor s/n ratio would be included.


On Fri., Dec. 11, 2020, 11:52 a.m. Bill Long, <bill@...> wrote:
I tested out PHD2's new multi star guiding and it worked great. Seeing was decent and I was at a dark site though.


From: main@ap-gto.groups.io <main@ap-gto.groups.io> on behalf of Roland Christen via groups.io <chris1011=aol.com@groups.io>
Sent: Friday, December 11, 2020 8:13 AM
To: main@ap-gto.groups.io <main@ap-gto.groups.io>
Subject: Re: [ap-gto] Multi-star guiding
 
I don't choose the stars when doing multi-star guiding. maxim looks at the entire frame and guides on all the bright stars in the frame. Other than that, I really don't know what their criteria are for which stars to guide on.

The only benefit that I see is during poor seeing when a single guide star is jumping around but an average of multiple stars seems to lead to a smoother guide graph. During good seeing I can't see any difference.

Roland



-----Original Message-----
From: M Hambrick <mhambrick563@...>
To: main@ap-gto.groups.io
Sent: Fri, Dec 11, 2020 7:31 am
Subject: Re: [ap-gto] Multi-star guiding

Hi Roland

This looks interesting. When you do the multi-star guiding does MaxIm allow you to select which stars to guide on ?

I am trying to get a grasp on what benefits can be gained by multi-star guiding. I don't think that you can compensate for field rotation with multi star guiding, but Terri's comment about averaging out the seeing makes sense.

--
Roland Christen
Astro-Physics