All sky findescope for manual mounts

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JSolaz
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Joined: Sat Mar 02, 2019 6:37 am

All sky findescope for manual mounts

Post by JSolaz » Sat Mar 02, 2019 7:11 am

Hi
I don’t know if my proposal has already been proposed before.

The request would be to use the similar functionality of polar alignment (which I love it so much!) as a powerful finderscope for all sky pointing manual mounts (no-goto).

Points of consideration:
• Sharpcap should have a whole sky star database, although small in size to ease the random position plate solving.
• I assume the user has no goto mount.

Procedure:
1.) Inputting RA and DEC (or object name) numerical input
2.) The user points manually the telescope to the rough position of the target, usually inside the constellation, although not strictly necessary.
3.) Sharpcap takes a picture through guide scope and analyzes it. Plate solving it could take long time maybe 1-2 minutes. No problem.
4.) Sharpcap solves it and shows the center coordinates of the pointing and displays an arrow on the picture pointing to the target direction, indicating distance remaining to the target.
5.) Now with the accurate position knowledge, the star database could be sorted out to be small like the one that is already existing for polar alignment (I think 5 degrees). This would be database focus.
6.) After step 5, now would be easy to unlock the scope and steer it manually to the target position while seeing realtime stars and pointings on screen.

Do you think this functionality would be implemented?
Greeting

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admin
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Re: All sky findescope for manual mounts

Post by admin » Sat Mar 02, 2019 8:27 pm

Hi,

I'm afraid there's no such thing as a small database for plate solving – depending on the size of the field of view you want to cope with the size of the database can run to many hundreds of megabytes or even gigabytes for a full sky database stop this is why the various plate solving programs like Astro tortilla install the databases separately after the main program is installed.

SharpCap can get away with using a simplified algorithm and a small database for polar alignment because the code only tries to solve for positions within a few degrees of the celestial pole. Trying to use the same algorithm for the whole sky would almost certainly lead to poor results

Sorry, Robin

JSolaz
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Joined: Sat Mar 02, 2019 6:37 am

Re: All sky findescope for manual mounts

Post by JSolaz » Sun Mar 03, 2019 5:49 am

Thanks for your answer Robin,

I fully agree with you, but my intention was to create an all sky star database with the same star density currently used by Sharpcap polar align function. This way we dramatically reduce database size and processing time.

Images for solving the field would typically be done with small guidescope, a guiding camera and short exposure time. For example, in my case, I would use a kepler 60mm/F240mm guidescope and a ZWO ASI224, with 0.2s-0.5s exposures.

Additionally for faster processing time and to give more constrain, we could consider this function to be available, at least if the user points the telescope at least, lets say, within 10 degrees of the intended target position.

Do you think, I would be possible with these conditions?

JSolaz
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Joined: Sat Mar 02, 2019 6:37 am

Re: All sky findescope for manual mounts

Post by JSolaz » Sun Mar 03, 2019 6:16 am

Hi Robin again,

Put in another way, the process would be like this:

1.- The user selects a target position in the sky by RA & DEC or by target name.
2.- Sharpcap sorts out a very simplified star database centered in the target position with a radius of 10 degrees (for example)
3.- The user manually points the telescope within 10 degrees of target position.
4.- guidescope camera is taking short exposures (example 0.2-0.5s) in realtime.
5.- In realtime, the plate is solved only if within 10 degrees of target. Otherwise is out of the simplified starmap database. Sharpcap draws in realtime an arrow indicator where to steer manually the scope in order to reach the target.

Essentially, this method is the same that has been implemented for polar alignment, with the exception that the database is custom made on request, and the scope movements are done manually with the RA and DEC knobs instead of the polar orientation screws.

The benefits of this function, in my case are very clear. I don’t have goto function in my old Losmandy mount. Second, I live in a light polluted sky area, and with the standard findescope it’s quite difficult to point to deep sky objects away from bright stars. This request idea came to me when I first saw the amazing polar align function of Sharpcap. Just finding few stars in the finderscope and in REALTIME! It can quickly and precisely locate the true north celestial pole.

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Re: All sky findescope for manual mounts

Post by admin » Sun Mar 03, 2019 7:03 pm

Hi,

Yes, I think I understand the idea that you are trying to suggest however I think the implementation would be quite complicated and at the moment I have no intention of taking SharpCap in that direction, sorry.

Cheers, Robin

JSolaz
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Re: All sky findescope for manual mounts

Post by JSolaz » Sun Mar 03, 2019 7:06 pm

Ok, thnaks for your undestanding
Cheers

SteveInNZ
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Re: All sky findescope for manual mounts

Post by SteveInNZ » Mon Mar 04, 2019 9:52 am

I'm pretty sure that you can do what the OP is trying to achieve already by using the ASCOM simulated telescope.
With Carte du Ciel, you'd tell the simulated telescope to go to say, M42 by putting a (red) finderscope at the location and telling it to slew there.
Manually point your scope to the same region and have SharpCap do a plate solve & sync.
The sync will place a white finder circle at the plate solved location.
You can use the ruler tool to measure the difference. If you set the finderscope field up to match your field of view and you can just eyeball it. eg. Move the scope up by half a frame.

Or if you're really nostalgic, just do a plate solve, get the RA & Dec and look them up on your paper atlas.

Steve.

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