Record Focal Length with images

Features suggestions that are not currently planned for inclusion will be moved here. In general features moved here are very unlikely to be added to SharpCap, perhaps because other programs already have this functionality or that the functionality could be achieved using SharpCap scripting.
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Record Focal Length with images

Post by howardgrams » Sun Jan 14, 2018 9:53 pm


I've been experimenting with various combinations of focal reducers and also with ASPS platesolving.

"One thing you may notice is that there is the option to include the current filter name in the filename using the {Filter} tag. If you are not using an ASCOM filter wheel then you can still use this feature by selecting 'Manual Filter Wheel' in the hardware settings - this will give you a filter wheel control in the camera controls panel which will not do anything except give a filter name to the file name template."

Inspired by that idea, I have started using the {Filter} tag to record the current effective focal length so as to get items like FL722 into the filenames.

It would be really nice if the current focal length could be recorded in the FOCALLEN FITS header and as a {FL} tag for use in filenames. Could you provide a Focal Length item on the Scope Controls panel similar to the current Manual Filter Wheel item and then use the value from there in the FITS header and template item for the filenames?

Presumably this would be useful for your internal calls to ASPS since platesolving is critically sensitive to focal length as well as pixel size.

(I just wasted a lot of time trying to figure out why I was no longer able to platesolve any new images nor to get Sharpcap 3.1 platesolving to work. It turned out that when I added an IR cut filter to my camera it made a 19% change in my effective focal length for images which was enough to keep any of them from solving since I was still using the focal length from before. So now I am very concerned about recording the effective focal length with any image!)


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Re: Record Focal Length with images

Post by mAnKiNd » Tue Jan 16, 2018 6:08 pm

Hi Howard, that's really interesting about the 19% change due to the filter glass thickness! Also, nice creative way to insert a note into your capture file, I use an ASCOM filter wheel so I don't have that option...hmmm! :) I posted another thread about inserting a notes section for the live stack, but perhaps this would be more apt for the program as a whole to be able to take any notes you might wanna add to your session.

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Re: Record Focal Length with images

Post by turfpit » Mon Feb 26, 2018 7:35 pm

I think the general facility to have an option to add a note which is saved with the capture settings file would be useful.


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