M42 and the Running Man

[grc02]

This was taken under a moonlit Bortle Class 5 sky with an astro modified Fuji XT-1 14 bit camera.

EDIT: The beginning of a project which has been delayed for several years

180 30s lights iso1600 with long exposure noise reduction on- plus flats and bias frames.

It was necessary to apply the bias during calibration- the advice given about LENR was to apply the flats only but that ended up in a mess.

EDIT: it seems the bias is not subtracted from the light frame with LENR. Not in my camera anyway. Likely LENR may not be the best approach.

EDIT: The result after background extraction in Siril was acceptable but colour manipulation except for saturation and removing green signal was unworkable in both StarTools and Siril. Issues not seen when applying darks traditionally.

Obviously, it could do with more data and better control over the stars. It has that gritty look nested among interstellar dust.

[happy-kat]

one of my favourite targets to see images of

[Stefan B]

Very nice image!

I had to google what LENR is My understanding is that indeed no bias frames should be applied since LENR does the subtraction itself without taking dedicated bias frames manually. Without applying the bias frames did the image look overcorrected? AFAIK this is what happens when no bias frames are used. And that's what I saw once when I forget to take bias frames...

Image looks good and lots of dust visible which is nicely colored! Maybe the core is a bit blown out. Did you try using the HDR module? It usually really helps with the core of M 42. Also if you used FilmDev maybe OptiDev would also help controlling the core.

Regards
Stefan

[grc02]

Thanks Stephan. Yes. Without bias subtraction the overcorrection was unmanagable. And as you have mentioned the dynamic range could be better. As this is a long term project I will use a mix of exposures. Which should improve the HDR result.

I think the data is clipped to an extent. Due entirely to my application. Definitely not the software. LENR seemed like a good idea but I'll stick to conventional out of camera processing in future.

[Stefan B]

Yes, M 42 can definitely benefit from a mix of exposures. With my last attempt somehow my short exposures failed and I was left with only 3 min exposures which were meant for bringing out all that dust. To my surprise application of OptiDev and HDR did a nice job on the core (https://app.astrobin.com/i/qe320u) and I never went back to recollecting the short exposures.

Anyway, good luck with your Orion project! But hurry up before it's gone

Regards
Stefan

[grc02]

One of my favourites too happy kat.

The moon and weather is going to limit opportunities in the coming weeks. Next year, perhaps.