Eta Carina widefield

[rcheshire]

This was captured with 50% moon from a Geelong suburb. Approximately 3.5 hours. A dithered stack of 29 x 5min @ ISO200 plus 30 x 2min@ ISO400 - cooled modded DSLR @ a nominal -5C. Bias and flats @ ISO100 - no darks. No CLS type filters and processed on a laptop - colour might be a bit over saturated and stretched to see as much of the data as possible.

BTW. This is straight out my Linux based Asterism program, which has an auto post processing function. It takes less than a minute to 'develop' the linear stacked image. The process is still in development - but getting there - a bit Red, as in the histogram.

[Anth10]

Rowland, a grand effort, very rich starfield showing through and a stunning image overall. Hard to get the finer details with widefield- in this case the keyhole is probably a little overexposed but hey I’d be very very pleased with this, well done.
Ps I think the colour is spot on and not too oversaturated. Nice tone to it.

Anth

[xelasnave]

I love it and I bet you can bring out the robot with a little effort.
alex

[glend]

Rowland, as you know, that red is common to many nodded DSLRs, and is very similar to what I see with my cooled Canon 450D. Maybe just my preference, but it does seem to be pushed a bit too far, ie the blowout in the core. This robot, i take it your developing, will it have some control parametres? Can I ask, why did you shoot lights, bias, and flats at different ISO settings?

[cometcatcher]

Blown out core aside it's a very pleasant image. A uv / ir cut filter will get rid of that extra red with a modified camera.

[Nikolas]

Yep core is a little blown out tried toning it down in photoshop using curves?
One I tried using your date I hope you don't mind, 2 layers, bottom layer light reduced then top layer selectively erased gently to bring out the detail underneath, then a miniscule noised reduction

[rcheshire]

Thanks all. The feed back is really appreciated. Yes, agree, the core is a bit too bright. Nikolas has provided an idea that could be incorporated into the auto develop process without too much trouble. Colour calibration needs a bit more work.

Glen. I find it preferable to take flats at the lowest camera ISO and match up the bias ISO. The master bias and master flat are then combined using noise reduction strategies. It's an old technique and works well for older cameras - less noise in the calibration frames, less contamination of the light frames. Newer CMOS sensors tend to less noise.

Kevin. The camera has a uv/ir astronomical filter, but it tends to Red moreso than others I've used over the years.

[cometcatcher]

Yes sometimes there still is some red left even after ir cut. My 1100D does the same. I can't quite balance it in camera. Have to do it in photoshop.

[rcheshire]

With a little more work and the use of a mask, the core is much better, while retaining the gamma as much as possible. Could have touched it up by normalising and a contrast stretch but left it straight out of the program.

Managing core brightness is probably best achieved by adding a few shorter exposures to the mix.

Thanks again for your comments - motivation to improve the process.