Nebula in Orion

[andyschlei]

I was looking through old astro files and I found my source data for an image of the Nebula in Orion that I never processed. Certainly not the time of year for this object, but here is a shot I took over 2 years ago.

Taken with an NP-101 and ST-10. 3 minutes each on RGB with 10 second subs and 16 minutes of Ha in 60 second subs. Processed in PixInsight and finished in Photoshop. The Ha was added to the red and then combined with green and blue for the final image (per Robert Gendler's recommendations). When I was using Ha as luminance, I kept getting salmon colored nebula. This way the red comes out nicely, without turning pink or salmon.

A full-sized version is available on my web site.

Thanks for looking.

--Andy

[paul f. campbell]

Hi Andy.
Great job.

[JAICOA]

Hi Andy, The red is beautifully rendered very nice indeed. Excellent job you did well and Clear Skies.

[galacticphoto]

Nice image, any time of the year.

Robert

[andyschlei]

Paul, Efrain, Robert -- Thanks!

[RickJ]

It's amazing what you find when you comb through the hard drive. I've made three passes through mine and still am finding things I had forgotten about. Some deserve to stay lost!

But yours certainly doesn't fall into that category. Nice find! Keep looking. There are likely more winners hiding someplace.

Rick

Rick

[andyschlei]

Rick, Casus_belli, Matsukov, and Chrissy -- Thanks! I appreciate the comments and encouragement.

Rick, per your comment:

It's amazing what you find when you comb through the hard drive. I've made three passes through mine and still am finding things I had forgotten about. Some deserve to stay lost!

I came across one of those too. I found some data of M101 that I tried valiantly to resurrect. Maybe something in black and white, but the color was a mess. On that one, now I know why I didn't process it at the time!

Clear skies,

--Andy

[Casus_belli]

Very nicely done. I wonder what other gems are hidden on various hard drives?

[Maksutov]

Great pic, Andy! Absolutely beautiful! Really like the detailing in the gas/dust clouds.

That was the first Messier object I ever saw thru a scope (8" reflector) and I never tire of looking at it.

[chrissy]

it is a beautiful picture Andy. thank you. clear skies.


chrissy

[Moya]

Absolute beauty! Great job.

[winensky]

An absolute beauty. Hear Hear on the detail in the gas clouds and the colour is rich but natural. Great great work.

Kind regards
Matt

[bunker9603]

What a stunning image. Great job!

[andyschlei]

Moya, Matt, Bunker -- Thanks so much! I appreciate the wonderful comments.

[clop]

Very nice indeed!

What causes the slight striations running WNW to ESE? I get them on some of my images too. I've always assumed it was my overzealous removal of dark pixels from the lights. I'd be happy to hear other suggestions?

clop

[andyschlei]

Clop,

Very nice indeed!

What causes the slight striations running WNW to ESE? I get them on some of my images too. I've always assumed it was my overzealous removal of dark pixels from the lights. I'd be happy to hear other suggestions?

clop

Thanks!

In the case of this object, I think it is because there is a larger nebular phenomenon that is very faint, but captured in the image. There is also an element of high clouds in the image, which makes the question harder. And I haven't re-imaged this in years, but next year I think I will to answer this question.

I have attached a severely stretched (and HDR wavelet stretched to give the nebula detail) image from the Ha data I took. You can clearly see the striations in the background. My first thought was that this was noise from high clouds passing while I took the images because they look so noisy. This was part of the reason the data sat on the hard drive for over two years. But I am not sure if there is a faint, larger scale nebula structure to which the striations are only a hint. As this wide field shows, there is a lot going on here.

What do you think? It would be interesting to see one of your images severely stretched to reveal the striations. Perhaps they are the same?

Anyone in the group have anything to add?

--Andy

[clop]

Hmm,

Here's M83 overstretched. I think the horizontal bands are a sensor artefact, probably thermal. It's the diagonal lines that puzzle me.

Suggestions would be appreciated.

clop

[winensky]

In Andy's streched M42, The striations have imbedded bright and dark 'dotted line' traces which are reminiscent of the hot pixel tracks you find in non-black stacks where the object slowly moves across the field over many exposures. I wonder if adjacent pixels of slightly differing sensitivity could produce parallel traces of differing intensity yeilding a similar effect which becomes more noticeable with streching. Just speculation here as I don't know how sensitive blacks are to these more subtle variations in pixel sensitivity.

[tvdavis]

Yup, very nice,

Tom

[andyschlei]

I've gone back to the other data I have from that night and there is no trace of the diagonal lines in any other color, no matter how hard I stretch it. So whatever it is, it is only visible in the Ha.

The Ha was combined with a sigma reject algorithm, so it's not likely noise. It could be cloud movement that didn't show up in the much shorter RGB exposures, but I would think that would vary enough between exposures that the sigma reject would make it go away. If not, then it's clouds.

There is a hint of the phenomenon when I look at a single shot. So it could be really faint nebulosity.

Given that it doesn't exist in the RGB or in other Ha images with the same camera, I am certain that it is not a camera / pixel anomaly. It is something that is captured in the data. So the question remains, is it in the nebula or is it in the atmosphere?

[winensky]

Yes you have ruled out the camera.Given the continuity across the almost the entire field I would be tempted to suggest atmospheric. High altitude ice crystals?