Currently Ekos allows incorporating the filter, exposure time, and time stamp into the output file during a sequence.

I would find having the option to have the camera temperature included would be useful, and perhaps there is other data people would like to include.

Adding these options to the current UI would make it more cluttered and also too tall for many laptop screens.

I've used several capture programs that allow the specification for the output filename during capture using a format language usually using '%' syntax.

Something like:

M13_%et_%fi_%ts_%ct-%zi

where

%et exposure time (secs)
%fi filter
%ts time stamp
%ct camera temperature
%zi file index with leading zeros

It could be extended obviously - this is just a simple example.

We could continue to use the "Prefix" area to store the filename template.

I'm interested in working on this feature but would like to see what people think.

Being able to format the timestamp would be neat too.

I was thinking about doing something similar but haven't had the time yet. I like the way SGP handles this.

It seems with the current functionality in ekos that it is somewhat hard to reuse sequences in the scheduler without the subs from different targets going into the same folder (unless I am missing something).

Great idea. TheSkyX uses a similar %x approach and I find it a godsend. In particular I’ve now developed an appreciation for having each night’s content in one sub directory into which I copy my flats and darks for that sensor and setup.

It also might help to have a unique incrementing file name counters vs. starting from zero for each sequence depending on your preferred fiolder structure top recent clobbering images over multiple runs.

There is an issue about this in KStars Gitlab here: invent.kde.org/education/kstars/-/issues/54

Jassem is of course 100% correct in reminding us that the UX side of the INDI project sits with the KStats project and should be logged/supported there vs. INDI.

My bad, with the two projects being so closely intertwined, it’s easy to forget.

When that MR is merged into master and released, will it include the ability to put captures into subfolders based on the object being observed? That would be super useful to reuse sequence templates for more than one object. 
BTW, thanks for all the effort on this software to date; just stumbled onto it a few months ago and love what's been accomplished so far! 

Correct, though sequence file always had Target prefix which can be set, so it's always been the case.