Token M42 effort

Garbz (Chris) · #1 11-01-2013, 06:09 PM

Well after a summer of nothing but clouds we had a partially clear night at long last. I pointed towards M42 as a token effort.

Between wind and smoke despite being out for about 3 hours there is less than 1 hour of data in it. A token effort to say the least. As usually with the D800, bugger all Ha response and a very blue / purplish looking result. But a result none the less.

Glad I didn't pick a fainter target.

ISO400, 45 second subs, 8", f/6.3 and only pointed roughly south letting the poor autoguiding effort take care of the rest. Can you tell my heart wasn't really in it?

/EDIT: Any decent tips on how to process this one without cooking the centre? I tried in PI and every attempt to use HDR wavelet resulted in a flat looking rejected picture with a very grey centre.

alpal · #2 12-01-2013, 09:28 PM

Hi Chris,
Still a good job -
you have lots of detail there.
Thanks for your comments about my 12 minute effort!

For processing tips try & get hold of Louie's videos. (atalas)
I don't know what happened to them.

cheers
Allan

Garbz (Chris) · #3 14-01-2013, 09:12 PM

Thanks a lot. I'll see what I can dig up with a bit of Googling. This is certainly one of the more dynamic targets in the sky.

RickS (Rick) · #4 14-01-2013, 09:27 PM

Chris,

I'd expect you've probably saturated the sensor in the area around the Trapezium so there are limits to what you can recover. Ideally, you'd have taken one or more sets of subs with shorter exposures to capture detail in the brighter parts of the image.

In PixInsight you can use HDRComposition to combine image stacks taken with different exposure lengths.

HDRMultiScaleTransform can certainly flatten an image and needs careful use. Masks can help. LocalHistogramEqualization can also be used to bring back some contrast.

Cheers,
Rick.

Garbz (Chris) · #5 18-01-2013, 02:15 PM

Only a few stars in the centre ended up in saturation. I was more trying to figure out how to process the image in the way that it didn't look completely flat. I can't seem to get a decent picture out of HDRMultiscaletransform. Mainly because I'm certain I'm not using it correctly. It recovers detail wonderfully and in the process kills all dynamics in the picture.