Orion's Belt - Snake Valley

[rcheshire (Rowland)]

This is the best I could do wide field with the weather at Snake Valley. Missed out on the last night of the camp, which was clear by all accounts.

Look closely and you will immediately notice a of lack data. 60 mins 180 second dithered, unguided subs @ iso800 and 0 Celsius with my cooled 450D. The usual compliment of bias dark and flats.

The spikes here and there are from a wire across the observing field. Thought I was low enough to miss it...

Might try this one without darks and see if that improves the noise - have a feeling darks may be contributing in this case...

Preprocessing in PixInsight. Post processing in StarTools.

[Atmos (Colin)]

Quite nice Rowland, especially for only 1 hours worth

[Mickoid (Michael)]

Looks great Rowland. What lens/focal length was it shot at? Nice colours and a soft glow to the bright stars, I'd be pleased with that result. A dark sky site makes a big difference.

[rcheshire (Rowland)]

Thanks Colin and Michael. I had big plans for a late season portrait of the Flame and M42, which just fits the sensor diagonal. But alas, cloud.

Michael. With reducer 255mm plus the 1.6 sensor crop factor, 408mm equivalent field of view.

For anyone interested, here's a bias only, no dark calibration version. I think it looks a whole lot better in the background.

In this case.

Signal = (light - bias)/(flat - bias) for a cooled DSLR.

The PI pixel rejection map tells the story.

[xstream (John)]

Nice result Rowland. Well done!

[Anth10 (Anthony M)]

Gorgeous widefield Rowland. I have yet to see an image of this subject with so much colour and detail in the one frame. This is a beauty!

[rcheshire (Rowland)]

Thanks John and Anthony. An hour or two more will reveal even more goodies.

[traveller (Bo)]

It's a beauty Rowland. Well done.

[LostInSp_ce]

Wow! That's one great shot you have there you still have some detail in the nebula from such a wide field of view and your stars are well saturated without blowing out. Nice work.

[rcheshire (Rowland)]

Thanks Bo and LostInSp_ce. Getting the balance right is a challenge with limited data.

[Camelopardalis (Dunk)]

Beautiful Rowland, well done

[multiweb (Marc)]

Mate, that's a great widefield. Very deep and the colours are just gorgeous. Straight to the poolroom.

[rcheshire (Rowland)]

Thanks Dunk and Marc. Love the widefields.

[samgibbs (Sam)]

Lovely detail...wide fields are really the way to bring out the majesty of the Cosmos.
What was your camera mounted on? Is it a fully modified DSLR...as in the IR filter tonsillectomy?

[rcheshire (Rowland)]

Originally Posted by samgibbs

Lovely detail...wide fields are really the way to bring out the majesty of the Cosmos.
What was your camera mounted on? Is it a fully modified DSLR...as in the IR filter tonsillectomy?

Thanks Sam. The mount is a Takahashi EM-200B. IR modified and cooled. Adenoids and all.

[sil (Steve)]

Originally Posted by rcheshire

Thanks Bo and LostInSp_ce. Getting the balance right is a challenge with limited data.

Great shot! Getting the balance right is an understatement. I've been working on optimizing my processing workflow to make better use of my data and revisiting some of my hardware settings too. Back and forth, its like trying to build a tower of single marbles on the back of a cat during a laser pointer exhibition.

I'm constantly amazed just how much can be done with limited data and the constant learning is great.

[rcheshire (Rowland)]

DSLR images benefit significantly by combination of the average luminance or L channel or the brightness channel L*.

Extract L or L* from the RGB image and recombine with RGB. Saturates without need of histogram or curves.

[ChrisV (Chris)]

Rowland, how do you do the extraction of luminance and then recombining ?

[rcheshire (Rowland)]

Chris.

EDIT: Do this with the L or L* as an inverted mask. Missed that all important detail.

Image > Extract L*

Processes > LRGBCombination

Select L channel image - the extracted L*

Deselect RGB channels below

Tick Chrominance noise

Top slider 0.5 nominally (default)
Slider below as required - 0.1 to 0.2 nominally. Light on data don't over do it.

Click the square button not the round.

Manipulating the contrast of L* in HistogramTransformation is a way of increasing /decreasing the saturation effect.

EDIT: This comes after Histo stretch, SCNR, L* Extract and use as mask, HDRWavelet...

[04Stefan07 (Stefan)]

Fantastic!!