All Sky Plate Solver question

Discussion of using SharpCap for Deep Sky Imaging
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kongpup
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All Sky Plate Solver question

#1

Post by kongpup »

Having spent some time in film astrophotography decades ago, I've re-entered into the digital age about a year ago. Learned how to control the Stellarvue scope and Heq5 mount using ASCOM, Cartes du Ciel, PHD guider and run the ZWO 294 pro using SharpCap. Just getting started with plate solving and tried AstroTortilla - it didn't work, so I switched to All Sky, which did. According to SharpCap, their program uses it's own tested settings rather than those in the All Sky program. That said, can anyone tell me just what it is that the All Sky program does (ie. where/how does it fit into the equation)?
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Re: All Sky Plate Solver question

#2

Post by admin »

Hi,

A plate solving application can work out where in the sky a particular image is from by looking at the pattern of stars in the image and recognising that pattern against a database stored on the computer. The usual use for this is to to correct where the telescope is pointing after moving it to a new target – often the move is slightly inaccurate, but the use of the plate solving application allows the software (like SharpCap) to work out what the inaccuracies and correct for it.

Hope this helps, Robin
kongpup
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Re: All Sky Plate Solver question

#3

Post by kongpup »

Thanks, Robin. As far as the basic idea of plate solving, I get it - I'm more curious of the role that ASPS plays in it. Since, SharpCap uses it's own settings does ASPS simply act as a gateway to the Astrometry.net files?
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Re: All Sky Plate Solver question

#4

Post by admin »

Hi,

Yes, pretty much – actually ASPS acts as a convenient way to get the astrometry.net files installed on your machine. Once the solving engine and indexes are installed, SharpCap goes directly to those and bypasses the ASPS settings and UI entirely.

Cheers, Robin
kongpup
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Re: All Sky Plate Solver question

#5

Post by kongpup »

Very good - thanks again, Robin.
kongpup
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Re: All Sky Plate Solver question

#6

Post by kongpup »

Very sorry - still struggling with this. Originally downloaded AstroTortilla for plate solving with SharpCap, but it didn't work. I then read something about the AT/Cygwin/Astrometry links being too old, so I tried ASPS which apparently successfully solved with SC, but won't exactly center the image. Tried "in office" experimenting with AT "file open dialogue" & "go to image" using FITS files taken with SC (and solved at nova.astrometerics) - nothing. More online searchs mentioned a file named "cygwin_ ansvr" as part of a needed file path. This file does not exist on my computer - I'm pretty sure that I have the correct cygwin and astrometry.net files, but honestly I've become so spun around that I'm no longer sure how I came by them (something about a "mirror' at hoobly.com?). At this point, don't know if I'm coming or going - obviously I'm nothing close to a computer whiz and may simply be in over my head (I can always stick to grossly overexposing my first shot in order to see where I'm at).
chongo228
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Re: All Sky Plate Solver question

#7

Post by chongo228 »

kongpup wrote: Fri Dec 20, 2019 11:22 pm Very sorry - still struggling with this. Originally downloaded AstroTortilla for plate solving with SharpCap, but it didn't work. I then read something about the AT/Cygwin/Astrometry links being too old, so I tried ASPS which apparently successfully solved with SC, but won't exactly center the image. Tried "in office" experimenting with AT "file open dialogue" & "go to image" using FITS files taken with SC (and solved at nova.astrometerics) - nothing. More online searchs mentioned a file named "cygwin_ ansvr" as part of a needed file path. This file does not exist on my computer - I'm pretty sure that I have the correct cygwin and astrometry.net files, but honestly I've become so spun around that I'm no longer sure how I came by them (something about a "mirror' at hoobly.com?). At this point, don't know if I'm coming or going - obviously I'm nothing close to a computer whiz and may simply be in over my head (I can always stick to grossly overexposing my first shot in order to see where I'm at).
So it plate solves but then doesn't move the mount to the correct position? In settings you can tell SC to plate solve and center or plate solve and sync RA/DEC. Maybe this would be a better option for you? I don't use plate solving to frame targets. To me it's more of a tool for consistency. Especially when imaging multiple nights. I'm a little confused by your post but I think ASPS is working correctly but you're trying to use it wrong.

To frame a target I usually slew to a target and plate solve to sync everything up. Then I judge how I want to frame the image. For example if you slew to M42 it will be centered but the running man nebula will be half out of the frame. Let's say I need to bump the mount left a bit to center M42 and the running man. I select a star or cataloged object slightly left in CDC and tell it to slew to it. If I'm imaging over multiple nights I'll just tell CDC to swing back to that star and plate solve to line everything up the next night.

Look at this persons photo of M42. https://www.astrobin.com/58645/?page=11&nc=user ----Hold your cursor over the image and you will see all the catalog numbers pop up. You can center on any of those to center the image to your liking.


Hope that makes sense- another example would be the Rossette nebula. It would be centered if you slewed to NGC2244. If you wanted to frame it slightly different you could slew to NGC 2236, 2237, 2246, 2244, or 2252. All of those are inside the nebula but just off to the side and might help frame it.

CDC also has a slew to cursor position. Only problem is you can't recreate that the next night unless you write down the RA/DEC. I find zooming way in a picking a star to be the easiest.
kongpup
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Re: All Sky Plate Solver question

#8

Post by kongpup »

Chongo228,
After alignment with CdC, I sent the scope to IC1805(Heart nebula) which is pretty much invisible for me until photo development. The CdC goto brings the central star cluster into the field of view but, of course, not exactly centered. Then using ASPS, after a successful solve, it would then move the scope so the cluster would be further from the center rather than closer. I have the "sync & re-center" checked in the SC settings. I hear what you're saying about using the designation of the cluster itself rather than the more diffuse nebula and will give that a try. That said, however, I did try solving an alignment star that CdC did put dead center of the frame and that ended up being moved out of center also. Thank you for taking the time to respond - much appreciated!
BlackWikkett
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Re: All Sky Plate Solver question

#9

Post by BlackWikkett »

I don't use ASPS but have been using Astrotortilla successfully for plate solving with SharpCap for over a year now. Sounds like you've got ASPS actually reading your star field and generating a solution that it then send the mount to slew to. You're reporting the slew are still off. Every time I've seen this issue with plate solving the problem has been the plate solver and mount using different epochs. Have a look what you mount and ASPS are set for. One may be JNOW and the other J2000. Set them to the same epoch and this should fix the issue.

-Chris
ippiu
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Re: All Sky Plate Solver question

#10

Post by ippiu »

BlackWikkett wrote: Sun Dec 22, 2019 3:15 pm I don't use ASPS but have been using Astrotortilla successfully for plate solving with SharpCap for over a year now. Sounds like you've got ASPS actually reading your star field and generating a solution that it then send the mount to slew to. You're reporting the slew are still off. Every time I've seen this issue with plate solving the problem has been the plate solver and mount using different epochs. Have a look what you mount and ASPS are set for. One may be JNOW and the other J2000. Set them to the same epoch and this should fix the issue.

-Chris
viewtopic.php?f=23&t=2206
Probably it's my problem, as i suspected.
But i can't find anywhere in autostar where should be the coordinate settings. Neither in meade ascom driver..
IOptron Cem40 + Apo 115 f7 + Asi533 Pro + Asiair Pro + Optolong L-eNhance + L-Pro 2"
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