Using APCC to guide on a sunspot


Eric Coles
 

I am trying out APCC to guide on sunspots for my solar imaging. Up to now, I just used polar alignment and GOTO to find the sun and the ASCOM controller to navigate. Once on a sunspot, I again use the ASCOM interface to keep it steady. Even with good polar alignment, the position of the sunspots moves in the frame and requires frequent repositioning.

It was suggested that I use APCC and the Horizon ephemerides as a guiding tool instead. I got the trial license and set it up as best I could with guidance from George. I downloaded the ephemerides for a day from JPL, loaded it into Horizons and set it to track. Even then, it doesn't seem to track any better than just polar alignment. I assume I am doing something wrong.

Does anyone have specific experience in using APCC to track the sun, and specifically sunspots. I am using a 5 M folded refractor with either a QHY 178 or QHY 174 camera.

Any help would be appreciated.

Eric


 

Hi Eric

not directly related to APCC, but I was just looking at this thread on Sharpcap last night regarding tracking sunspots




On Tue, Aug 9, 2022 at 9:03 AM Eric Coles <eric@...> wrote:
I am trying out APCC to guide on sunspots for my solar imaging. Up to now, I just used polar alignment and GOTO to find the sun and the ASCOM controller to navigate. Once on a sunspot, I again use the ASCOM interface to keep it steady. Even with good polar alignment, the position of the sunspots moves in the frame and requires frequent repositioning.

It was suggested that I use APCC and the Horizon ephemerides as a guiding tool instead. I got the trial license and set it up as best I could with guidance from George. I downloaded the ephemerides for a day from JPL, loaded it into Horizons and set it to track. Even then, it doesn't seem to track any better than just polar alignment. I assume I am doing something wrong.

Does anyone have specific experience in using APCC to track the sun, and specifically sunspots. I am using a 5 M folded refractor with either a QHY 178 or QHY 174 camera.

Any help would be appreciated.

Eric




Eric Coles
 

Brian,

I read through the entire  post. In the end it didn't work well or at all. And that is with mostly a full disk image. With the 5 M scope, you have only a small fraction of the sun's surface. but it was a good suggestion. I have seen that feature on Sharpcap before, but never got it to work.

Back to getting APCC to do its job.

Eric


Howard Hedlund
 

Wow!  At 5000 mm focal length, you must just about be able to see the sunspots move as the sun rotates!  (OK, not sure about that, but that's still a lot of focal length.  I'm glad it's folded.

 


Howard Hedlund
 

What you are asking is a lot for a non-encoder mount, especially one with an older GTOCP3.
As I'm sure you are well aware, everything is more difficult at such a long focal length.
  • Polar alignment errors will be more evident.
  • Balance needs to be near perfect.
  • Moment arm should be reduced as much as possible.
  • The possibilities for flexure are endless.
  • APCC Pro modeling could be extremely helpful since the Horizons program will work with APCC.
You've created an interesting challenge for yourself.  We are all looking forward to seeing some cool stuff!


Eric Coles
 

Yes we can. You can see the rotation of the sun over a day's imaging. I have done that kind of animation before.


Eric Coles
 

It is an 1100 mount with a CP4 controller. And it does not have encoders. I do my best with polar alignment, balancing and levelling of the mount.

I was given the impression that APCC with the JPL ephemerides would give me precise guiding.  But that has turned out not to be the case. So I was wondering if there was something wrong with my setup. that is what the post is about.


Worsel
 

Eric

With the likely image scale on a 5m scope, I think 'precise guiding' is open to interpretation.

Bryan


Daniel Marcus
 

I have guided on the sun with LuSol - and firecapture. You don't need to be perfect like you do for deep sky. Having the image move around a little is not an issue, I usually keep the guiding to 10 pixels when I do time laps sequences of the Sun in Ha - take 1000 frames every 2.5 minutes and make a time lapse move from them. But then I am only using a 400mm focal length and a 3X barlow with a DMK445 camera. I currently use SiTech controller on an old mountain instruments mount - firecapture will autoguide that mount and take 1000 frames every 2 minutes automatically. I too am looking for how to get firecapture to autoguide using the apV2 driver. My understanding is we need to use ACPP to get firecapture to properly autoguide the mount?? Have not had time to test out firecapture with the clubs AP1200 mount to see how it works on the Moon or the Sun. If anyone has done this I'd like to know how you do it.
Dan Marcus.

From: main@ap-gto.groups.io <main@ap-gto.groups.io> on behalf of Worsel via groups.io <bryancashion@...>
Sent: Tuesday, August 9, 2022 7:32 PM
To: main@ap-gto.groups.io <main@ap-gto.groups.io>
Subject: Re: [ap-gto] Using APCC to guide on a sunspot
 
Eric

With the likely image scale on a 5m scope, I think 'precise guiding' is open to interpretation.

Bryan


Andrew J
 

On Tue, Aug 9, 2022 at 09:03 AM, Eric Coles wrote:
It was suggested that I use APCC and the Horizon ephemerides as a guiding tool instead. I got the trial license and set it up as best I could with guidance from George. I downloaded the ephemerides for a day from JPL, loaded it into Horizons and set it to track.

I didn't even know this was an option. I thought Horizons was only used for tracking comets or satellites. Are you saying this would work even if the mount is not polar aligned? This is very intriguing. Where can I find more details on how to set this up?


George
 

The more accurate the polar alignment, the more accurate the results.    Horizons is found under Tools in the APCC menu.     Clicking the “?” will explain how it works.     Remember, “?” help can be found throughout APCC and the V2 driver.

 

Regards,

 

George

 

George Whitney

Astro-Physics, Inc.

Phone:  815-222-6538 (direct line)

Phone:  815-282-1513 (office)

Email:  george@...

Video Tutorials: https://www.youtube.com/astrophysicscorp 

 

From: main@ap-gto.groups.io <main@ap-gto.groups.io> On Behalf Of Andrew J
Sent: Wednesday, August 10, 2022 9:56 AM
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] Using APCC to guide on a sunspot

 

On Tue, Aug 9, 2022 at 09:03 AM, Eric Coles wrote:

It was suggested that I use APCC and the Horizon ephemerides as a guiding tool instead. I got the trial license and set it up as best I could with guidance from George. I downloaded the ephemerides for a day from JPL, loaded it into Horizons and set it to track.

I didn't even know this was an option. I thought Horizons was only used for tracking comets or satellites. Are you saying this would work even if the mount is not polar aligned? This is very intriguing. Where can I find more details on how to set this up?