Plate solving question.

Karen F

I have lots of data.  Most of the time I get an astrometric solution.  I have one set of data which was collected under poor conditions but I looked at the files and I believed PixInsight could plate solve.  I can see a dozen stars so why does it fail?    This set of data was small and noisy.   If you have time, would you look at the three files I have shared.   I also shared the process log, which tells me " If the image has extreme noise levels, bad tracking, or is poorly focused, you may need to adjust some star detection parameters."    I am sure I have the star catalogs installed, I am sure of the focal length 450 mm and pixel size 1.33.      I included a reference image, debayed image and the  cropped image out of WBPP.   Here are the links to these shared files on my google drive.  Is this data just too noisy?        process log(word doc) + 3 files :           

https://docs.google.com/document/d/1SDSnbxjBmcqWqjP5AJdEvdIsUrgSW8aI/edit?usp=drive_link&ouid=100118396449191559397&rtpof=true&sd=true

https://drive.google.com/file/d/1mutjvhxBGEDZZXSMbYRaNjTNeHR39LfU/view?usp=drive_link

https://drive.google.com/file/d/1YKW1uUl7bGjbdBT9SwuROtb81BJzjmQG/view?usp=drive_link

https://drive.google.com/file/d/1GFFH158d4_qp9PLE3CGI9PPMVQCxfb81/view?usp=drive_link

HERE 

Karen F

Yeah, you need to know what this is.... It's the Crab Nebula, Messier 1

BlockHead

Karen,

It does not fail.

Your first file above is the LN reference. (which is better than the masterLight).

It solves just fine. 

The second file is your masterLight. 

It solves just fine.

Please see the screenshots. You did not show me a screenshot of your ImageSolver... but I believe you are confusing "pixel size" and "plate scale" which is arcseconds per pixel. THAT number is indeed 1.325. 

Would you agree with me?

So for this system, your pixel size is 3um (if I looked up the correct sensor)... and the focal length is 466m giving you 1.3" per pixel.

Concerning your masterlight. It is poor quality compared to your best frames (which the LN reference used). I suspect some of your data is slightly out of focus... or as you say poor conditions. So striving for more high quality data is a good idea. Be certain your weighting your data properly.

-the Blockhead

BlockHead

Hi Karen,

If you get a chance... would you mind watching this video?

https://www.adamblockstudios.com/articles/plate-scale

-the Blockhead

Karen F

I will watch that video.     I been trying things from the fastback videos on my old data to see what I can do.  

Yep, out of focus and poor quality.     The telescope is the Unistellar evscope2.  I'll have to go back and check where I got 450 mm for the focal length.    I will let you know if I get it to work.    Thanks for the fast response.   

BlockHead

Karen,

Just to push a concept... it doesn't matter where you got the number from at the end of the day. Published values will not always match the instrument in hand. The measurement we make by finding the answer... is the real answer no matter what is published. It is best not to assume anything, but use published values as a guide.

Did you switch the values as I guessed in my response? The focal length of 466 compared to 450 is the SAME answer... this is not a larger enough difference to worry about. This is not the issue. 

-the Blockhead

Karen F

Yes, I just now fixed it and it ran.   Everything is good.

I have two different devices and the 1.3 number was for the other device.  It's a wonder I was able to platesolve for this telescope in the past.   But I have, I have used the Render-annotate image for other images with very nice results.    The Free trial for PixInsight gave me just was just enough time with the software to get me started but, there are things I clearly do not understand yet.  

I'll keep working on it.