Improved Feature : Target Selection from Full Catalog

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Improved Feature : Target Selection from Full Catalog


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Hi folks,

this is an area that I have been wanting to tweak for a while - the 'Full Catalog' target list that can be accessed from the GOTO tool and the Deep Sky Sequence Planner and a couple of other places.

Previously this tool showed the time to meridian and allowed you to filter so that targets close to the meridian were not shown (why start looking at something that will require a meridian flip soon after). Of course the meridian isn't the only limit on how long you can observe for - when the target sets is also quite important!
Screenshot 2024-02-05 212910.png
Screenshot 2024-02-05 212910.png (77.08 KiB) Viewed 423 times
The new, updated version as shown above adds a column showing how long until the target sets - note that this is *NOT* necessarily the time until the target goes below the altitude=zero horizon. Not many people have an observing position where they can image right down to zero altitude, and anyway the results are rarely worth it...

If you are familiar with picking a target using this window then you will notice that the filters shown in the top left are now 'Horizon Altitude', 'Faintest Magnitude' and 'Minimum Time to Image'. Previously 'Horizon Altitude' was 'Minimum Altitude' and 'Minimum time to Image' was 'Minimum time to Meridian'.

What does all this mean?

* If you have ticked the 'Horizon Altitude' box then the 'Time to Set' column tells you how long it is before the target sets below the selected horizon altitude. If this is unticked then the 'Time to Set' is calculated to the standard altitude=zero horizon.

* The 'Minimum Time to Image' is calculated as the time until the target sets for AltAz mounts and the smaller of the time until set and the time to meridian for EQ mounts. This filter should now give you a decent indication of how long a target is available for, providing the horizon altitude is set reasonably.

I did wonder about custom horizons - ie being able to enter different altitudes in different directions to deal with local obstructions, light pollution in particular directions, etc. It's possible (the calculations are harder, but do-able), and I've seen it in other applications, but I'm not sure how much it actually gets used - I never bothered... Feedback on that welcome.


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