M42 Again

[TrevorW]

My attempt so far using LRGB still can't resolve the Trap - this was using 10s subs- a total of 300L 120R 150G 87B


Scope Orion 110ED Camera ZWo1600GT used HDR in PS

[Startrek]

Trev,
Nice M42 and 10/10 for effort
The Trap stars at your image scale / focal length are pretty small , tracking / guiding has to be tight , seeing has to be good and focus has to be tight as well.
Only my observation but your stars don’t look like tight focus ?
Even with super short subs , focus has to be tight ( all night long )

You could try some Layering tools with super short subs say 5sec and longer subs at 30 sec, not sure if PS has such a feature ? ( Startools has a Layering module where you use foreground and background images to expose the core of M42 )

Cheers
Martin

[CaptainCook]

Hi Trevor,

You should be OK at that resolution, (I did this (https://images.cdn-files-a.com/uploads/5360032/2000_665bc7a7cdae2.jpg?width=1600) at 360 mm FL) but the short 5s exposure was the key (I used 5 & 180s *I acquired 20s which looked like a clump and did not end up using this data but only because I had added spikes to it*) and then HDR composition...which was such a pain to do and was massive trial and error, that I swore never to revisit it, and looking at the weather I probably never will...but if you cant ''window'' it to see it at 10s then go to 5s.
Cheers
Gary

[TrevorW]

Thanks Martin and Gary- Martin the run was set for autofocus - so the only thing I an think of was tracking maybe -although roundness when stacking was fairly good- albeit the filters may be causing some flaring- attached is a non HDR version

[Startrek]

For tight focus , I never just rely on numbers on the dashboard , I visually check my stars on the fly ( zoomed in ) every 15 to 20mins in ASTAP’s Fits viewer.
Yes it’s time consuming but your eyes are the best litmus test for focus.

[AlexN]

Agreed... I watch the HFR value during my imaging run, and once it gets to the upper end of what I call acceptable, I pause the running sequence, run AF, then make a few micro-step adjustments to be completely sure that I'm happy with where it landed..

It means that fully automated imaging is simply not how my imaging nights go, but at the same time, I'm always awake anyway because I don't really trust my neighbors, or the weather!

[CaptainCook]

After the moon came up last night and I'd stopped O3 on another target, I thought I'd have a quick go on the trapezium to see what I could get at 1.1 arc s resolution (only previously ever used 2.1").

Results attached: few min of 5 s (left) versus 60 s data (right) for both pre (top) and post BXT (bottom).

Summary: 5 s data makes for a cleaner '4 star' (A,B,C&D) appearance even without BXT (note these are heavily cropped), as 1 min causes more bloating BUT if you do have BXT you can *just* start to see the much fainter 5th star (E) more clearly using the 60s data. I also tried to do a HDR combination of both for the wider image but tbh the 60s data was still better on its own overall.