SharpCap Forums

Will Sharpcap plate solve quicker if I delete index's that aren't being used?

Hi,

I think it's possible that it would – if you have less indices installed then the plates solving algorithm has less data to work through against the stars found in your image. On the other hand though, it could reduce the reliability of plates solving if you remove too much data.

Cheers, Robin

In the past I've removed index files to speed up the plate solving and this worked fine. Suggest you make a folder inside the index folder name it "notused" and move files there. This will keep you from having to download again if u need them in the future. Look at the SharpCap log and it will tell you which index files are mostly used to solve for your field of view. Keep those files and move the rest to the "notused" folder. Would suggest to keep one index range before and one after the index used most often to solve.

As an aside I've stopped doing this since I've built a much more powerful PC and plate solving usually happens withing 8-15 seconds covering a wide field 70 mm APO and narrow field 150 mm RC.

-Chris

Cheers guys.

cuivenion wrote: ↑Wed Mar 25, 2020 5:43 pm Will Sharpcap plate solve quicker if I delete index's that aren't being used?

Yes it will. I downloaded and installed ansvr - local Astrometry.net plate solver for Windows. I noticed that the same program can be invoked from three applications that SharpCap uses. So any of them would perform equally as well. ansvr seems as good as the rest?

I calculated the FOV for my guide camera and main imaging camera using 20% of the guide camera and 100% of the main imaging camera.

Afterwards I downloaded the recommended indexes 4202 - 4211. These were more than I needed for the main imaging camera.

This "belt and braces" approach has two negative aspects: the space for the lower indexes can almost double one level further down. Secondly when searching for a match, the program searches 1-10, then 11-20, then 21-30 etc.

My solution was to move (to one side) the indexes that were less than my main camera @20% (and to err on not having too many indexes) e.g. remove 4202 indexes. At the other end the indexes are small. Again, I didn't see a benefit in having extra indexes (just in case).

One way to look at how it works is to consider what gets done in a unit of time e.g. 30 seconds. For the available indexes it compares them all to objects 1-10, then again for 11-20 and then 21-30 and so on. So with fewer indexes you get faster processing and a more likely match across a wider number of points e.g. it has tried fewer indexes and found a match on 21-30 on the third iteration.

Simon

Thanks Simon. I had a look through the logs and and indices that I that I didn't think where necessary do get used ocassionally. Are you saying that I would get a plate solve with a different index If I removed them?

I recommend using ASTAP : http://www.hnsky.org/astap.htm
Very fast plate solver.

Cheers I'll give that a go ASPS hasn't been updated in a few years.

Just tested with the simulator, works great thanks!