M42 with a surprising amount of background nebulosity

[Earl]

I was very pleased to see the background nebulosity coming through with this image as I only have 20 180s Subs (before the cloud rolled in)

The overall pallet is not quiet right and there are some interesting bands from the bias or darks not working quiet right.

Taken with a QHY8L OSC with a Televue Reducer on my Meade 80mm Triplet, (which as to have the most awful focuser I have used to date!) guided in PHD

[Earl]

There is alot more than the fist image shows, this image is a full on stretch to pull it out

[Earl]

oops this should be in imaging not observing, could a Mod please move this.

Cheers

[Psychobilly]

Your Wish....

Nicely done Earl... I am hoping to pay M42 a visit over the crimbo break..

Peter...

[Earl]

Im going to have a play with this latertoday, iI want to work out whats going on with the bias frames, I stacked them in Astroart, where my darks were stacked in Pixinsight.

Ill post my results.

[Revs]

Great result there bud. As you said, plenty of the faint stuff coming through

[Earl]

This is my Reprocess.

I really need to get some more Data on this as im curious as to how much ill be able to pull out of the background.

[ollypenrice]

Wow, yes, lots going on in that one and the fast f ratio is paying dividends.

There are two issues with artefacts, I think. One is the dark cross shape going across the image orientated x and y and crossing over just below the Great Nebula.

I suspect some Bayer Matrix thing for that one. My OSC chip is divided down the middle by a line which debayering removes.

The other is a pattern of streaking at about 45% to that, running upper left to lower right. It creates an effect a bit like looking through slanting rain. Now I have seen this effect before once or twice on my own cameras and I'm trying to remember what caused it. I think it may have been down to the cooler not working properly. (Sometimes there is a difference between the displayed temperature and reality if a run is interrupted by a computer gremlin.)

First I'd try a full recallibration in AA to see what that does. Does your camera have set point cooling? If not, do the darks match the lights? The other thing might be the need to debayer the flats. I think this may have changed in AA5 but I haven't tried my OSC in it yet. In AA4 you just stacked the flats using a master bias for a dark and then when into Image, Offset, and plugged in 0.5 on both axes.

Almost all non-premium Crayfords are useless after more or less time in use. Join my campaign to consign them to history!

For the Trapezium region, do you know this tutorial? It's bang on.

Compositing 2 Different Exposures via Layer Masks

Olly