Hi,
I am preparing my setup for a real test to night. I have a FOV for my telescope + CCD of 27.5' x 20.6'.
From the tutorials I read that I need to install index file ranging from 100% to 10% of FOV.
When downloading I see that the 4202_0.45_all?deb file is 3.5GB big what is huge.
I wonder what the impact will be on the memory use when guiding and aligning my telescope on a Rasperry Pi2.
Is it really necessary to install index files from 100% to 10%?
Thanks in advance,
Stefan

3.5gb is probably about correct. I installed the full set (on a PC) and I think it was about 32gb.

This index file sits on your HDD/SD-CARD and is not all loaded into RAM. I would not expect any impact on guiding.

In any case, you must install the astrometry-data-4208-4219_0.45_all.deb for FOV 30'... 2000' (it needs 160MB on disk).

P.S. Also, you can install the astrometry-data-4207_0.45_all.deb for FOV 22'...30' (it needs 165MB on disk).

Ìndeed, it is what surprises me. If I need to install index files covering the 100% to 10% range then I need all indexes from 4207 down to 4201 and that takes more then 10GB. Are you saying that you have no problem with only installing the index files in the range 30` to 20` so only the 100%?

In any case, what are these index files? From plate solver approach I would think they are datasets of the stars seen at the observer's location and the observer's equipment (FOV). If the FOV is known from basic equiment parameters, why then should one convett and use star positions in pictures for other setups (FOV)?
Is image distortion so important that data with such a FOV range need to be used?
Stefan

astrometry-data-4201-*** indexes are needed for FOV 2.8'...4'!
Your CCD has FOV 27.5' x 20.6'

In any case, you can test your CCD images with astrometry.net on home computer.
You can use the CCDCiel for it.

This is what I cannot understand, why in the tutorial it is recommended to load index files from 100% to 10%of the FOV.
Thanks for your hint about ccdciel. I will have a look one of these days.
Regards,
Stefan

Stefan, wait...

1. In any case, you must install the astrometry-data-4208-4219_0.45_all.deb for FOV 30'... 2000' (it needs 160MB on disk).
2. If these indexes doesn't work for you FOV, then you must install next package astrometry-data-4207_0.45_all.deb for FOV 22'...30' (it needs 165MB on disk).
3. If these indexes doesn't work for you FOV, then you must install next package astrometry-data-4206_0.45_all.deb for FOV 16'...22" (it needs 328MB on disk).