Tips for improving Astrometry.net solves

Sequence Generator Plate Solving
1

Hi all – I’m running Astrometry.net locally and have all the indexes from the widest to the smallest for my SCT. All works great – but last night, I decided to image with just my Canon with a ~200mm lens.

I’m having a bear of time getting these to plate solve locally (timeout after about 5 minutes, which is my specified timeout), however they solve crazy fast using Astrometry.net online. Any tips on how to figure out what to tweak to get success / better performance locally?

Thanks!
Brian

2

I’m not sure but suspect you will need indexes wide enough for the 200mm lens as well. if you only have ones for your SCT they may not be wide enough…I base this solely on what I’ve read so happy to be corrected if this is wrong.

3

Hi Dave–

Definitely a good idea to check, but I do have the indexes. Fortunately the wide field indexes take up very little space. I’ve been playing with tweaking various settings – I can solve the long exposure images, but now the trick is to bring the exposure time down to something more reasonable. Depending on the area of sky, I need close to 2 minute exposures to ensure it will solve (200mm lens at about f/5). At shorter exposures, I can pretty clearly see the stars if I stretch the image, so wondering if it’s picking up noise or requires other tweaks to get it to solve…

Thanks again for the suggestion,
Brian

4

Is f5 the widest aperture ? If not it may be worth using the widest possible during solving. I assume you crank up the iso?

5

Yeah, that’s about as big as this one lens gets. Honestly I’m not that happy with the pictures from any of my lenses, and thinking about picking up a 200mm f/2.8 EF-L lens. My understanding is that you still want that stopped down a little for sharper images.

6

Hi Bhwolf,
in order to plate solve at all, on the local astronomy.net with a Canon 350D and 5sec exposure i use the field : Noise level → 90 in the ansvr configuration page.
With a value of 90 - 95 , and by having only the indexes that i know i need for solving with this setup in the indexes folder, it usually takes 3-9 seconds to successfully platesolve a RAW file from the mentioned Canon.
Give it a try!

7

Thanks! I’ll give it a shot!