I am in the process of installing ANSVR for platesolving. Not too sure which files for the FOV in need to download. At the moment i have selected them all and downloading… lots of files!
Is there a sweet spot of files to download which will give good results rather than having GB of data on my system which will never be used?
You only need the indexes that will cover your field of view. As the Index Downloader says, choose the index that corresponds to about 20% the size of your narrowest FOV. On the other end, choose the index that covers your widest FOV.
If you need help determining your FOV, tell me your camera(s) and scope(s), and any focal reducers that you use.
Hi Joel,
Thanks for the reply. I “thnk” i might have worked out what indexes i actually need but not too sure. I am using two scopes
Esprit 120 - FL 840 Sometimes with a .8 Focal reducer
Altair EQDR - 72mm - FL350 no Focal reducer
I am also using two cameras depeding on what i am imaging.
ZWO ASI 1600 pro mono - 4656 x 3520 Pixel size 3.8um
Atik 460ex - 2749 x 2199 Pixel Size 4.54
SGP shows pixel scale as follows for the scopes/cameras
E120 - 1600 without FR = 0.93 and with the 460 - 1.11
E120 - 1600 with FR = 1.38 and with the 460 - 1.38
EQDR - 1600 = 2.24
EQDR - 460 = 2.65
Would i be right in saying that the indexes i need should cover 0.93 to 2.65 ? So 4209 to 4213?
Many thanks
No, the indexes are based on FOV, not image scale. You need indexes 4203 - 4213. That gives you a little cushion on either side.
Many thanks. With my conclusion not being right, what calculation did you use to deterine the correct indexes?
Go to www.astronomy.tools and you can input your equipment to see pixel scale, FOV, dawe’s limit etc. The ANSVR index downloader suggesting taking 20% of your narrowest FOV for the bottom end, and your widest FOV for the top end. So if your narrowest FOV is 1 degree, you would need the index that corresponds to 20% of 1 degree = 12arcmin.
Many thanks. Makes more sense now… and now got ANSVR setup and able to PS a loaded image into SGP. Now just a case of putting it into practice for real!