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dstndstn / astrometry.net

Astrometry.net -- automatic recognition of astronomical images
http://astrometry.net
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How to resolve Polaris in 3 seconds #169

Closed supermyc closed 4 years ago

supermyc commented 4 years ago

Hi，How to resolve Polaris in 3 seconds？I know that the analytic image is near the North Star，This is my parsing process：

solve-field -p -O -U none -B none -R none -M none -N none -C cancel -d 1-10 --downsample 2 --scale-units arcsecperpix --scale-low 30 camera.jpg Reading input file 1 of 1: "camera.jpg"...===>4ms Extracting sources...===>1252ms Downsampling by 2...===>1267ms simplexy: found 212 sources.===>3070ms Solving...===>4365ms Reading file "./camera.axy"...===>4449ms mo field stars:===>4452ms star 2; field_xy 1248.0,121.1, field_orig 1248.0,121.1===>4453ms star 0; field_xy 348.2,574.6, field_orig 348.2,574.6===>4453ms star 1; field_xy 785.0,415.3, field_orig 785.0,415.3===>4453ms log-odds ratio 52.7089 (7.78353e+22), 7 match, 0 conflict, 31 distractors, 11 index.===>4454ms RA,Dec = (270.529,87.9002), pixel scale 30.7316 arcsec/pix.===>4454ms Hit/miss: Hit/miss: +-+--++++----------------------------+(best)--------------------------------------------------------------===>4455ms Field 1: solved with index index-4116.fits.===>5094ms Field 1 solved: writing to file ./camera.solved to indicate this.===>5095ms Field: camera.jpg===>5164ms Field center: (RA,Dec) = (270.608286, 87.890078) deg.===>5166ms Field center: (RA H:M:S, Dec D:M:S) = (18:02:25.989, +87:53:24.280).===>5169ms Field size: 10.9046 x 8.18569 degrees===>5170ms Field rotation angle: up is 71.7962 degrees E of N===>5170ms Field parity: neg===>5170ms

dstndstn commented 4 years ago

Are you saying that you want to get the whole thing running in 3 seconds?

.... buy a faster computer?

Just detecting stars is taking 3 seconds, so you could try --downsample 4 and see if that works. It should be a bit faster.

You can add --scale-high 40, but that's only going to help the solving part, which is only taking 2 seconds here.

dstndstn commented 4 years ago

Also, the speed will depend a great deal on caching. The first time, it has to read the index files into memory, and then when you run again, it will use the cache.

supermyc commented 4 years ago

Yes, I run solve-field on raspberry pie.I want to parse for a short time，I want to parse the short time, I guess it is not a problem with my running command. I use the solve-field command, is it necessary to cache every time you run the solve-field command? how to use the command to load only the cache once.

supermyc commented 4 years ago

I am running the command in Raspberry Pi 3b+, so I guess it is faster for me to use other parameters, for example the parameter: use-sextractor, but I will not use this parameter.