New Feature : SharpSolve - SharpCap's new built-in plate solver

[OAVP6554084@]

Hello Robin, Hello All

First of all I would like to thanks and congrats Robin and his entire team for this Great New Feature which is working nicely and flawlessly with my setup.

Doing a very basic Test with my currently Astap in my Sharcap Tab Settings I found a small differences result doing Plate Solve Tool only and Deep Sky annotation.

For this test I use Sharcap Folder Monitor Camera in order to test the same image for both Plate Solver tools (SharcapSolve vs Astap). My camera is a PlayerOne Ares C-Pro with the IMX533 Chip which is a 11.31 mm x 11.31 mm format. According with Astronomy Tools de Field of View with my Sharpstar 94 ED 517 mm Focal Lenght APO Telescope refractor would be around 1.5 x 1.5 degrees.

Plate Solve Only Tool Results:
Astap:
Solution : RA=02:22:24,Dec=+89:16:19 (J2000)
Field of View : 1.2185x1.2194 degrees
Time : Thu, 23 Nov 2023 18:43:46 GMT
Orientation : up is 206.5 degrees E of N

SharcapSolve:
Solution : RA=02:22:22,Dec=+89:16:19 (J2000)
Field of View : 1.2183x1.2183 degrees
Time : Thu, 23 Nov 2023 17:56:39 GMT
Orientation : up is 206.3 degrees E of N

Being the IMX533 Chip with a square format, the SharcapSolve tool seems to measure the Field of View with a make sense result. I mean the Field of View measure result with SharcapSolve is for a totally square field of view.

Note there is a slightly difference in the RA solution value result too.

Deep Sky annotation:
If you see the image attached taken from Deep Sky annotation tool you can see both result, the one, with a difference position result on HIP 7283 was from the Astap. The Image from the SharcapSolve tool match great.

I am not want to conclude nothing with this basic test about which is best, just to share that the results I have with my Setup using SharpSolve tool is more accurate so I defenitily keep using SharpSolve as my Plate Solve tool.

Thanks again for this New Feature.

Orlando

Astap

Capture_00001_WithAnnotationsAstap.jpg (900.32 KiB) Viewed 35645 times

SharpSolve

Capture_00001_WithAnnotationsSharpSolve.jpg (755.58 KiB) Viewed 35645 times

[admin]

Hi Orlando,

glad to hear it is working nicely for you.

By testing near the North Celestial pole, you've highlighted a subtle diffence in the way that plate solving results from external plate solving tools (Astap, etc) differ from those provided by SharpSolve.

As well as reporting basic information like the position of the center of the image and the pixel size, plate solving tools report something called the 'CD transformation matrix', which allows the co-ordinates of any pixel in the image to be calculated (or, the pixel position of any co-ordinate - by working the maths in the other direction). This is used by SharpCap for annotation when using Astap, Astrotortilla, etc. Actually, the CD matrix is only an approximation - it assumes that RA and Dec change evenly across the image. This is fine away from the celestial poles, but near the poles where the lines of constant declination are curved and the RA lines converge to a point, it all goes rather wrong...

Fortunately in the case of SharpSolve, I was able to bypass the CD matrix approach and perform full calculations including the effects of spherical geometry, meaning that annotations on objects near the poles will be placed much more accurately when using SharpSolve. You will also find that the co-ordinate readout tool is more accurate for the same reasons.

cheers,

Robin

[Oberon510]

Corner case - planetary imaging suggestion.

I have a 2415mm Dall Kirkham reflector and when I use my ASI678MC (2mu) camera the platesolve has a lot of misses but with my ASI2600 (3.76mu) it works well. In the description notes on the tool it mentions that for >2000mm scopes the use of an APS-C level camera chip may be required.

That statement should be heeded and I do my initial platesolveing with the 2600 and switch to the 678 for actual planetary imaging work.

FYI and great tool Robin.
Ken

[RMSQueenMary]

I used the built-in plate solver. It goes really fast. It even gives you the focal length of the telescope. One thing, when using a long pass near infrared filter with the Apollo-M MAX Pro USB3.0 Mono Cooled Camera (IMX432), increase the exposure time to 2 seconds.

[admin]

@Oberon510 - I'm not surprised that your 678 has problems, since the calculated field of view is only .18 x 0.1 degrees with that camera on a 2400mm focal length. That's well below the 0.25x0.25 degrees minimum that is required for SharpSolve to work robustly. The larger sensor of the 2600 gives you a much nicer 0.56x0.37 degree field of view which should work well.

@RMSQueenMary - yes, that makes sense as it will all come down to detection of stars, and with less light going to the camera you need the longer exposures.

cheers,

Robin

[JALabrecque]

Robin,

Just wanted to say the new SharpCap plate solver is brilliant. Solves almost instantly and "unable to solve" messages are non existent!

Great job and thank you.

John Labrecque

[admin]

Hi John,

thanks for the positive feedback - good to hear it is working nicely!

Robin

[Jschultz]

Robin this is a great feature, I used the other add ins and found them to be hit and miss this works everytime.

[dlentz]

Hi, Robin
I recently downloaded SharpSolve, and got a chance to try it. My scope is a Celestron C6, FL (with reducer) 1100mm. The camera has an IMX533 sensor. Just some background:
I live 10 km from Philadelphia PA USA. Not 10 km from the border, the distance is to the center of the city. I never tried to plate solve here, assuming that it was hopeless.
My usual observing site is at a park at 50 km. I could plate solve with ASTAP through a finderscope but through the SCT? Hopeless.
I occasionally travel to a better site at 125 km. If I got a good night, plate solving through the C6 (ASTAP again) might work more than it didn't.

SharpSolve reliably worked with the above camera and tube from where I live! Officially Bortle 7, but I know the map uses old data and the sky here has not gotten any darker over the last 10 years.

SharpSolve is great. Thank you! I can see that I will be getting less sleep in the future.

[admin]

Hi,

glad to hear it works so well for you

The hard part with long focal lengths or light polluted skies (or both, like your case) is doing a good job of detecting stars in the image from the camera. If the detection isn't sensitive enough then you only get a handful of stars and plate solve fails. If it is too sensitive then it picks up noise in the image as stars - you get hundreds of stars, but most aren't real and the plate solve fails. Fortunately detecting stars is something that SharpCap has been doing for years for live stacking, polar alignment, focusing and a whole bunch of other tools, so I was able to use all of that experience when building SharpSolve...

It's not perfect mind you - I noticed the other day that having a very bright star in view tends to cause problems. In my case I have a long focal length telescope with spider vanes, and the diffraction spikes end up being large. I suspect that the large bright areas in the spikes are messing with the code that automatically tries to work out how sensitive the star detection should be... One to look into!

cheers,

Robin