JimFox

Moderator
Staff member
This was from a month ago out in Joshua Tree National Park. I have a favorite little spot to set up there that has almost the whole sky open to shoot.

I gave up on processing this one at least twice over the last month. It's a super faint Nebula, it's one you can't see by eye or see in the camera. You just have to hope you are pointing in the right direction. :)

My problem in processing this one was that as I stretched the image to pull the faint Nebula out of the background the image kept getting tons of color noise. The last time I tried editing this about 2 weeks ago, I tried for a while and ended up thinking it's just too faint, and to shoot this one I would need a dedicated Astro camera instead of just my Nikon D850. It is super faint after all, and despite getting some good results on some of the DSO's, I do realize there is a limit as to what I can capture with an unmodified DSLR camera.

Well, like a dog returns to a buried bone, I returned to this image last night, and started processing it again. I decided that as I stretched the image by careful use of the Curves adjust in Photoshop, that as the color noise started to creep up, I would apply Color Noise reduction from Noiseware to knock it back down. I had zero sharpening and zero Luminance Noise Reduction on, so I wasn't affecting the actual noise or losing detail, I was simply removing that red/green background color noise that can creep up.

The background image is darker then Mike has suggested that I have my background at, but looking at other peoples images of the Witch Head, going dark seems to be very common. Perhaps because it's so faint. I know letting the background go darker also helped cover up the color noise. So that may be why others do it to?

This is my first shot at Witch Head. I plan on shooting it some more with the same settings I used for this, so I can get a couple of hours of detail to stack and process next time. So perhaps next time I can pull the detail out better without so much trouble.

The bright star in this is Rigel.

Nikon D850
Tamron 150-600mm at 300mm
SkyGuider Pro
20 x 60 secs at ISO 3200 f5.6
10 x Dark Frames
12 x Bias Frames
12 x Flat Frames

All comments are welcome,

Jim

Witch_Head_Nebula_20200218_dw.jpg
 

Jameel Hyder

Moderator
Staff member
That’s a very nice end result. It’s a beautiful nebula. I am amazed that anyone can blindly point at it without a visual confirmation. Impressive.
 

JimFox

Moderator
Staff member
That’s a very nice end result. It’s a beautiful nebula. I am amazed that anyone can blindly point at it without a visual confirmation. Impressive.
Thanks Jameel. It is tricky for sure at times. I try to use reference stars or clusters of stars, but honestly when looking through the viewfinder at 300 to 500mm the little window that is it definitely is challenging. I have shot a couple of sessions where I had to put a question mark down in my notebook as I was shooting because I wasn't 100% sure where I was at. Witch Head isn't as bad since it does have the Rigel star close to it, but it's still hard to know am I zoomed in too tight or too wide? I don't want to cut part of it off, but when it can't be seen by the naked eye that's a bit of a guess too. I am taking notes so as I go, it will be easier to know what Focal Length is good to shoot a specific DSO at.
 

Colorado CJ

Well-Known Member
Looks great Jim.

The Witches Head is definitely faint, and makes processing hard since the star that lights up the nebula is so bright.

For the fainter stuff up there, you camera will definitely still work, but you will find you need a lot more "time" on the target to bring out such faint details as this one has.

Many shoot for HOURS on a single target to bring out the faint fuzzies and dust/gas. My longest single image was around 6 hours, I have a hard time being patient to shoot for much longer.

I think all of us newer astrophotographers have that same problem. Everything is new and wide open to us, so we want to get one or more images per night, just because there is SO MUCH STUFF out there.

It's pretty exciting and really feeds the addiction.

You will see that astrophotographers that have been doing this for years and years finally settle down and image 20-30-40 hours on one target. Their images are incredible, but I just don't have the patience for that kind of imaging yet. I am too excited to get onto the next target.
 

Mike Lewis

Staff Member
Very good job on this very faint target! Gotta look up JTNP on a light pollution map - it must be very dark there. The blue maybe looks a teensy bit hot to me, but that is really personal preference. Fun to see you adding to your astro library and also adding to your astro post processing bag of tricks!

ML
 

Mike Lewis

Staff Member
As a follow-up to my post, I went off and checked Joshua Tree National Park on a light pollution map. It is actually as dark or darker than a number of sites I have imaged from in southern New Mexico and Arizona, check it out here:

https://www.lightpollutionmap.info/#zoom=6&lat=4028913&lon=-12770389&layers=B0TFFFFFFFFFFFFF

With the most current 2019 VIRS overlay selected, it is in an area that shows as the darkest available in the USA. Jim, those are some pristine imaging skies you are using, and no doubt helping those results you are getting. Conversely, if you were to take those same exposures of the Witch Head in an area without those dark skies, you would not see equivalent results without a LOT more imaging time.

I have imaged from Abiquiu Rservoir in northern New Mexico and Rodeo in southern New Mexico, neither of which profile on this map as dark as JTNP, and Portal in southern Arizona, which looks to be about equivalent. So you are truly at an impressively dark site there, depending on what part of the park you are in I assume.

For anyone who has not seen the night sky from a truly dark sky site, I urge you to make it a priority at some point in your life. You will not believe the difference from even normal suburban skies, much less any city skies.

Keep up the good work Jim!
 

JimFox

Moderator
Staff member
Thanks so much Mike! I knew there was a reason why Joshua Tree has been my 2nd favorite NP (begins Yosemite) and have been camping and hiking out there since I was a teenager.

I would guess that Trona Pinnacles is also pretty dark, that’s the next place that I hope to image from.
 
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