Log in

View Full Version here: : Joining the 'in' crowd - M42


AstroViking
18-12-2022, 02:46 PM
Hi all,

Out last night capturing what I think is a passable attempt at M42, the Orion Nebula. Well, everyone else has posted one, so I might as well be fashionably late to the party, too... ;)

Of course, I broke the golden rule. I made two changes to my setup, introduced a problem, and now don't know which change is the culprit.

So I'll now be digging into my horizontal noise bands and working out whether it was the WB_B change or the installation of the filter drawer (and the corresponding 90 degree change in camera rotation) was to blame. Something to play with over the Christmas break...

BTW - Alex, I used your idea of stacking a small number of subs to have a "dim" core section and then overlaid that layer with the main image layer. Took a bit of fiddling about to get both layers to roughly the same colour / brightness, but it worked really well. The core is not blown out - it's bright, yeah, but you can see the 3 bright stars if you look carefully at the second (zoomed) image. :thumbsup:

Cheers,
V

Gear: SWED72 @420mm / ASI183MC-Pro / HEQ5 / SV305 + SV165
Software: KStars / Ekos

Image details:

* Gain: 50
* Offset: 10
* Temperature: 0 degrees C
* Exposure: 10 seconds
* Lights: 360
* Darks: 25
* Flats: 25
* Dark Flats (Bias): 25
* Stacked and proc'd in Affinity Photo

oska
18-12-2022, 05:17 PM
Nice one Steve, really nice. And don't fuss being late, your hair is perfect. Sorry cant help specifically with the banding other than the more generalised when in doubt redo your calibration data. More gain (unity?) will get you more of the outer detail. Yeah that Alex is smarter than he looks :p

xelasnave
19-12-2022, 04:16 AM
Nice ... no blow out...very good effort.
Alex

Stephane
19-12-2022, 11:57 AM
A very fine effort Steve, you should be proud! The trap really pops out nicely too! In regards to not blowing it out, stacking a small number of subs or a large number of subs will not affect core brightness. It will only affect how far you can stretch before hitting the noise threshold. What will affect the core brightness though is the sub exposure length. Typically, much shorter subs for the bright core and longer subs for the rest of the image for all the faint gas and then blend the core in. A little tricky, but rewarding.

Regardless of all that though, your image is very fine indeed. And the core is perfect. Well done!

AstroViking
20-12-2022, 08:02 PM
Thank you for the kind words. Made me feel very pleased to receive such feedback.

Kevchu
23-12-2022, 05:32 PM
Nice Steve, I will behaving a go at this one myself soon, as soon a work out how to attach & get back focus on my SW Esprit 100 with D850 or QHY286C.
Kevin