Ansvr: install 4100 indexes by default

Up to now, ansvr download and install 4200 indexes series from AN (astrometry.net). Indeed, AN suggests to use a 4100 series for wide field. Some other users of SGPro came to the same conclusion.

I discussed with the guy from AN. 4200 indexes are made using 2MASS J-band, at 1.25 µm, completely out of the sensitivity range of our sensors. In opposite, 4100 indexes are using Tycho-2 catalog with magnitude in the visible light range. As AN algorithm is sensitive magnitude ordering of stars, it is doing a better job with 4100 indexes when using camera operating in the visible light range.

Therefore, I would suggest that ansvr download 4100 indexes when available, i.e. from 4119 down to 4107.

My 2 cents

Eric

Thank you, great to know.

For those who are interested, I made a new version of 4100 indexes that are using Tycho-2 Vt magnitude. This magnitude from hipparcos Vt band as its maximum around 525 nm, like green pixels from DSLR. It seems more suitable than default Bt band (maxium around 425 nm).

It can be downloaded at:
http://dl.free.fr/st6FqJZaT
This is a single zip file with indexes from 4119 down to 4107 (named index-41xx-Vt.fits). You have to put it in the same folder as your 4200 or 4100 indexes (and remove the corresponding indexes to avoid search in all indexes).