IMprovements to Fits Header

[GaryS]

Hi Folks

It would be really helpful in my quest (others as well I'm sure) to use SC for most of my astronomy work, if the Fits Header SC delivers could be more complete ala Maximdl. I realize SC doesn't do many things that Maximdl does but it would be helpful for the scientific observing that I do, if the following could be added:

AIRMASS
JD_UTC TIME
HISTORY - appropriate entries

Many thanks for considering this...
Gary

[admin]

Hi Gary,

Adding a JD_UTC hearer for the time of mid-exposure is possible - even not too hard

The other two are trickier.

Right now SharpCap doesn't have any source for airmass data - I presume that getting this data wound involve talking to an ASCOM observing conditions driver and working from the pressure reading. At some point in the future I might add observing conditions support, do that would be the time that Airmass would be available.

I can also see that you can in theory record the processing history of the frame in the HISTORY header(s). I can't find any specific documentation of what text is expected in that header to represent common processing actions (ie dark subtraction, flat correction, etc), so I presume that ever application just 'does its own thing' on this. Are you using processing in SharpCap (darks/flats/etc)? If not then this would just be empty...

cheers,

Robin

[GaryS]

Hi
AIRMASS is the most important of the ones I listed. Since I always plate solve after a slew, I thought that SC knew the Target and/or the RA and Dec where it had slewed. Knowing this it would know it’s Target’s AZ and ALT for calculating AIRMASS. If that’s not the case, I’ll just need to use another application since getting AIRMASS in the original capture Header is necessary for my main area of activity.
Thank you
Gary

[admin]

Hi Gary,

ah, so you are just looking for the light path as calculated by 1/sin(altitude) without any correction for atmospheric pressure. That's do-able as long as you have a GOTO mount connected I think.

cheers,

Robin

[GaryS]

Hi

I don’t know how apps like maximdl do the calculations relative to pressure but all calcs should be done the same. Are you thinking this may make it into a future update ?
Thank you
Gary

[admin]

Hi Gary,

OK, I have a formula now for calculating the airmass from the target elevation - I will add that and the JD_UTC to SC 4.1

cheers,

Robin

[GaryS]

Outstanding Robin - thank you very much...
Gary

[GaryS]

Robin
Thanks very much for adding AIRMASS to the fits headers as a part of 4.1. It makes life easier for many of us.

One comment I wanted to offer relates to the following text which was included when 4.1's new features were being explained:

".. increased importance of using the catalog to pick a target rather than just entering co-ordinates."

It's good to keep in mind that those of us working on exoplanets, variables, eclipsing binarys, asteroids, etc, either with pros or as pros, usually find ourselves working far ahead of any catalogs which you might make available within SC. We hope SC will always provide 'quick and easy' means for us to directly enter RA and Dec addresses.

Thanks again for all the great features in 4.1.
Cheers,
Gary

[admin]

Hi Gary,

glad that the header update is helpful

I think I have the option to enter co-ordinates pretty much everywhere that you can use the catalog to pick a target - if you find a place that is missing that then do shout about it. I'm rather fond of the co-ordinate entry boxes because of the way that they accept co-ordinates in pretty much any format (decimal, H:M:S, H:M, etc). SharpCap 4.1 tends to put the co-ordinate entry second below the catalog selection rather than the other way around though.

cheers,

Robin