I am using plate solve and resync to get really accurate gotos for visual astronomy using a Celestron AstroFi Alt-AZ mount.
I am using an Orion 30mm guide scope and an ASI120mm mini in place of a finder scope.
I do a north-level alignment and use plate solve and resync to refine the gotos. After the first solve and sync, the gotos become accurate. If a goto is off, I can just solve and resync again.
However, invariably CPWI will get disconnected at some point, and I need to re-do the north-level alignment. I am prone to rush it at this point.
If I don't do the north-level carefully enough, then I find myself in a situation where blind solve works, but solve and resync does not, I think because my north level was not good enough.
I really wish there were a way to do a solve and resync using a blind solve if the mount is too far off to use the current solve and resync method.
Blind Solve and Resync
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Re: Blind Solve and Resync
Hi,
the current distance limit for solve+sync is 15 degrees - ie the real position of the telescope must be within 15 degrees distance of the position reported by the mount.
There is no way of changing this limit at the moment. However there are a couple of options
* Use the very latest version of SharpCap and use the built in 'SharpSolve' plate solving engine. Because of the way the engine works, it tends to search a bit further away from the start point than requested, so if given a 15 degree limit, it will end up searchout to 20 or so degrees - that might help
* Use the sequencer - the sequence shown below will do a full sky solve and then sync the mount to the solved position (note: some mount ASCOM drivers will reject a sync command if they think it is too far from the current position - not sure about CPWI in this regard)
cheers,
Robin
the current distance limit for solve+sync is 15 degrees - ie the real position of the telescope must be within 15 degrees distance of the position reported by the mount.
There is no way of changing this limit at the moment. However there are a couple of options
* Use the very latest version of SharpCap and use the built in 'SharpSolve' plate solving engine. Because of the way the engine works, it tends to search a bit further away from the start point than requested, so if given a 15 degree limit, it will end up searchout to 20 or so degrees - that might help
* Use the sequencer - the sequence shown below will do a full sky solve and then sync the mount to the solved position (note: some mount ASCOM drivers will reject a sync command if they think it is too far from the current position - not sure about CPWI in this regard)
- Capture.JPG (88.62 KiB) Viewed 5767 times
Robin
Re: Blind Solve and Resync
I installed the latest version with SharpSolve yesterday.
I really like SharpSolve. Thanks for creating it.
I got disconnected last night. I re-did the north-level alignment, and even though both Astap (my previous favorite) and ASPS failed on plate solve and resync, SharpSolve worked!
I didn't need to use the sequence, but thanks for that too. I'll try it next time I can't make plate solve and resync work but blind solve works.
Another issue I run into with plate solving from time to time is not enough stars detected. Sometimes I have to slew to a nearby location with more stars for it to work.
It would be great for me if not only were the cone adjustable but also the minimum number of stars needed and/or the required confidence level for a plate solve to succeed.
I really like SharpSolve. Thanks for creating it.
I got disconnected last night. I re-did the north-level alignment, and even though both Astap (my previous favorite) and ASPS failed on plate solve and resync, SharpSolve worked!
I didn't need to use the sequence, but thanks for that too. I'll try it next time I can't make plate solve and resync work but blind solve works.
Another issue I run into with plate solving from time to time is not enough stars detected. Sometimes I have to slew to a nearby location with more stars for it to work.
It would be great for me if not only were the cone adjustable but also the minimum number of stars needed and/or the required confidence level for a plate solve to succeed.
-
admin
- Site Admin
- Posts: 13350
- Joined: Sat Feb 11, 2017 3:52 pm
- Location: Vale of the White Horse, UK
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Re: Blind Solve and Resync
Hi,
my testing has indicated that solving with the star number between 12 and 25 is possible, but not to be relied on. As the star number increases from 25 to about 70 it goes from fairly reliable to very reliable. Above 70 there seems to be little further improvement.
SharpSolve looks for up to 100 stars - they may not all get used in the end as it picks to use in a fairly even manner across the image rather than simply starting with the brightest.
I will have a look at allowing the radius of search to be adjusted.
cheers,
Robin
my testing has indicated that solving with the star number between 12 and 25 is possible, but not to be relied on. As the star number increases from 25 to about 70 it goes from fairly reliable to very reliable. Above 70 there seems to be little further improvement.
SharpSolve looks for up to 100 stars - they may not all get used in the end as it picks to use in a fairly even manner across the image rather than simply starting with the brightest.
I will have a look at allowing the radius of search to be adjusted.
cheers,
Robin