Plate Solving with Telescope GoTo hand controller

Discussion of using SharpCap for Deep Sky Imaging
FDNF
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Plate Solving with Telescope GoTo hand controller

#1

Post by FDNF »

Hello There,

I am new to the Sharpcap forum, and also on using the SharpCap Plate Solving.

I have everything setup and understand how to use it.

I just have one question, I have a older model Meade LX90 8" telescope with the Autostar GoTo hand controller.

So I do an alignment using the hand controller, and than use SC's plate solver to confirm its aligned with the proper star.

Does SC's Plate Solver read the coordinates from the hand controller? than use the image to plate solve? Or is SC just solving the plating by looking at
the image it has taken?

Thanks

Curtis
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Menno555
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Re: Plate Solving with Telescope GoTo hand controller

#2

Post by Menno555 »

Hi and welcome Curtis

SC is indeed solving the capture you made. It compares it with astrometric data from the plate solver and then tells you where you are in the sky.

Menno
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Re: Plate Solving with Telescope GoTo hand controller

#3

Post by admin »

Hi Curtis,

the answer is, it depends...

Assuming you are running SharpCap 4.0,

* Tools menu 'Plate solve and resync' and the 'Locate me' button in the telescope control take the co-ordinates from the handset (via the ASCOM driver), then use those co-ordinates as a hint to the plate solving program. The plate solving program finds the exact co-ordinates from the image, but uses the handset co-ordinates to start the search in the right place, so it finishes quickly.

* Tools menu 'Plate Solve (solve only)' - this only works from the image, so it may be much slower as it has to search the whole sky

cheers,

Robin
FDNF
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Re: Plate Solving with Telescope GoTo hand controller

#4

Post by FDNF »

Menno, Robin...... Thank you for the information, that clears up a lot for my self!


Robin, your information helped confirm what I was thinkng. In the past, when I have used Stellarium, connected to my Autostar 497, to slew to areas, or objects in the sky, the mount would slew the scope to that area, or object. But the Autostar hand controller would not update to the area, or object, and would remain on the previous area, or object is was on.

This is telling me, that I have to use the hand controller to slew to an object, or area in order to use the "Plate solve and resync" along with the "locate me" button.

Does this sound correct to everyone :?: :?:

Cheers

Curtis
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Re: Plate Solving with Telescope GoTo hand controller

#5

Post by admin »

Hi Curtis,

I think you need to watch the co-ordinates showing in SharpCap's mount control area - if those move to the correct target when you slew using Stellarium then it would indicate that all the computer side software is working correctly and it all agrees on the place that the mount is pointing to, maybe just the Autostar handset is not updating.

If the co-ordinates in SharpCap do *not* update then maybe your handset idea is sensible - alternatively you could try to dig into *why* things are not updating in SharpCap as they should.

cheers,

Robin
FDNF
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Re: Plate Solving with Telescope GoTo hand controller

#6

Post by FDNF »

Robin,

Thank You, I will keep an eye on it next time I get to use the scope!

Cheers
Curtis
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Re: Plate Solving with Telescope GoTo hand controller

#7

Post by FDNF »

I got to play a little bit tonight with my setup

I got both Stellarium and Sharpcap to connect to my setup at once! Thanks Robin (Admin)

Sharpcap's mount control coordinates change when I slew the mount through Stellarium and I get the same coordinate readings on all 3 systems. (Stellarium, Sharpcap, AutoStar HC)

I have everything downloaded and setup for Sharpcap Plate Solver to work.

My question is, Is my Meade 8" telescope too big to plate solve?

I could not get SC to plate solve at all. I had Polaris in my FOV, but not centered, I wanted to see SC center it after solving.

Is there a basic guide line of settings, to start off with?

I played around with Colour Space, Gain, and Exposure for a couple of hours but could not get it to solve.

Thanks

Curtis
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Re: Plate Solving with Telescope GoTo hand controller

#8

Post by admin »

Hi Curtis,

it all comes down to field of view - the long focal length of your SCT tends to lead to a small field of view. If it's combined with a camera with a small sensor then the field of view will be *very* small, which makes plate solving slow/hard/possibly impossible.

You can use a web site like this one - https://astronomy.tools/calculators/field_of_view/ - to work out the field of view of your telescope/camera combination. You then need to check that you have the right plate solving index data installed so that plate solving will work with your field of view - for instance for Astap there is a guide here : http://www.hnsky.org/astap.htm#database_usability . If you don't have a detailed enough database installed and have a small field of view then there simply won't be enough stars in the database within your field of view for it to work.

Perhaps you could share a SharpCap log from one of your plate solving attempts and a sample captured image that is failing to solve - that would help let us give more specific advice.

cheers,

Robin
FDNF
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Re: Plate Solving with Telescope GoTo hand controller

#9

Post by FDNF »

Robin,

I am thinking my FOV is too small with my telescope and camera.

I have done both those steps in your above post.

I have the proper indexes downloaded and installed.

I have a spotting scope and spare camera on the shelf, I will install it today, and download the proper indexes for that setup and give it another try when the weather allows.

Thanks for your info. on this!

Curtis
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Menno555
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Re: Plate Solving with Telescope GoTo hand controller

#10

Post by Menno555 »

Hi Curtis

What camera do you have?
I have an 8" Meade too (LX200 f/10 ACF) and plate solving does work on it. With my Zwo ASI071MC Pro it works all the time because with this camera there is a bigger FOV. Most of the times 2 second exposures with a a midrange gain works just fine.
But with my Zwo ASI385MC it gets more trickier because the FOV is smaller. So with this camera it works only when there enough stars in the FOV. And then with exposures of 4 to 6 seconds with a bit higher gain.

Menno
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