Plate solve images for both "very wide field" and "long focal length"?

[JL9]

Han, thanks very much for ASTAP, it is an invaluable tool!

I've been using it very successfully for several years (mostly with NINA), at long focal lengths. I've been using database H18, and it has been working great.

Recently, I started doing some widefield shooting at 50mm. I ran NINA, and use ASTAP for platesolving. I get a warning (which I believe is generated by ASTAP), "ASTAP - Large FOV, use V17 database!" .

I thought V17 was for Photometry? But will it work OK for doing regular platesolving?

Can I just download V17 along with H18, and ASTAP will know which database to consult?

Can I also load in W08, if I want to try even wider field; say 18mm focal length?

Thank you!
JL

[han.k]

Thanks for the feedback.

Yes the V17 is both for photometry and wide field. You can set the star database selection in ASTAP on auto. See tab alignment (CTRL+A), setting "Star database used". Save this setting by menu File , Settings, Save settings. Or exit nicely by File, Exit (and save settings). Then the database will be selected automatically based on the FOV.

This is typical usability range:
http://www.hnsky.org/astap.htm#database_usability

Han

[JL9]

I was able to load in both V17 and W08. In the "star database used," I now see three options plus "auto". So, I set it to auto. I'll try it out tonight to see how it works.
Thanks!

[han.k]

The selection mechanism is very simple.

If the image height in angular degrees is larger then 20 degrees then it will select the w08.
If the image height in angular degrees is larger then 10 degrees then it will select the V17.
else H18 or H17.

Han

[JL9]

Thanks. Last night while shooting at 24mm focal length, initially it wouldn't solve because not enough stars were detected. When I did longer exposures, and set the database setting to W08, it solved reliably.
Now that I know how to set my camera for sufficiently bright stars, I will set "star database used" to auto.