Second Prize...

[Diane Miller]

Well, I missed photographing Venus and Mars very close to the crescent moon, although I did enjoy the sight greatly. The crescent moon was one of those where you can see a faint hint of the dark side.

I didn't shoot it because my big tripod was already set up with my Astrotrac to try for the Orion Nebula, which I did get as second prize (although it will be there for a while). This one is actually one I shot a couple of nights later that I processed a little better. (Still lots to learn in both shooting and processing this stuff.)

Canon 7D2, 300mm f/2.8 IS + 1.4X III TC. ISO 1600, 30 sec, f/4. Stack of 17 processed to remove very fine noise. Tonal optimization in LR5 and PS with Nik Detail Extractor and some Curves teaks. A lower exposure (ISO 400) layered over the brightest central area.

Wish I had aimed a little higher but it's very difficult to "steer" the lens at that magnification. If I lose an object it can take a long time to find it again. About 40% of the original frame, mostly from the sides and a little from the bottom.

I wonder if there is some "astigmatism" in the lens/TC combo -- the stars are slightly elongated but it isn't from poor tracking. Possibly mirror slap, although there is a delay programmed in. Need to try the bare 600 and the 100-400 II at 400 if weather cooperates the next dark of the moon.

[Warren Spreng]

Nice job Diane, a difficult object to keep the core intact and still bring out the fainter nebulosity! The stars appear elongated because if you blow up the image you will see two distinct "stars" instead of one nice compact one for each. A number of things can cause this, mirror slap causing the camera to move just enough that ends up in a double star appearance, a skip in the tracking that is periodical, any other sort of vibration that occurs during the exposure. I assume each of your sub exposures exhibits these elongated stars, but if not, possibly eliminating those particular subs would improve your star shapes.

Be careful, photographing these objects can be pretty addictive!

[Diane Miller]

Hi Warren, thanks! I'm already addicted, and it may be more expensive than drugs.

Will be checking out factors causing elongated stars as soon as it's dark enough again. The Astrotrac isn't supposed to have periodic error because of the drive design. Each sub is the same, and stacking didn't make it worse. I suspect mirror slap. I've just started using Helicon Remote for focus and capture and it doesn't keep the camera in Live View during the session. There is a MLU delay but it's probably not enough. It's fantastic for remote control of fine focus, and great for framing and preview, but I may need to go back to the intervalometer and Live View for the actual capture. I wish Lightroom's Tethered Capture would get updated for the 7D2.

Hard to find capture software that works on a Mac. From what I hear, things like darks, flats and biases aren't necessary with that camera, so I'd rather just stack and average in PS and go from there.

Just what I need -- a new hobby!

[Don Railton]

Hi Diane, this is very nice, and congratulations on 2nd prize.... I can see why you 'kept your eye on the prize' and did not shoot Mars & the Moon etc.. The engineer in me doubts the elongation of the stars is mirror slap because the brightness of each star is pretty consistent across itself and I would expect mirror slap is only significant for a second or so of the 30 second exposure, so i would expect slap to cause only a faint blurry edge around a much brighter center. I doubt the whole camera/tripod system would be resonating for 30 sec, but maybe I am wrong, you know I am a beginner in this astro stuff and I can't offer much else.

DON

[Robert Kimbrell]

Congrats Diane, A very impressive image. Keep posting I find this very intriguing. Are you happy with the Astrotrac?

[Diane Miller]

Thanks, Robert! The AT was meant to work with existing photography equipment but it has some major issues and I get the impression the company is no longer supporting it. I had to return a major piece (the wedge) to the UK for repair, defective (frozen movement!) when it arrived new, and the polar scope illuminator is apparently a piece of junk, with the scope (crucial for polar alignment to allow accurate tracking) not far behind. I'm on my third in a year. But I'm able to make the rig work, with some trouble and adaptation -- and a personal machinist. I haven't kept track, but there is a rapidly-fading Yahoo e-group devoted to it, and people are now talking about a replacement rig that sounds much better.

[Robert Kimbrell]

Thanks for the feedback Diane, It must be a thrill processing shots like this. I am really interested to shot this type of photography, but have a lot of learning ahead. Your shot is a inspiration. Thanks,and keep posting.

[Diane Miller]

Thank YOU, Robert -- I will! I'm probably a whole baby step ahead of you. There are a lot of online forums and groups. Roger Clark's website has a lot of information, mostly very technical, but you don't have to understand all the details to believe the conclusions. http://www.clarkvision.com/ I like the Astronomy Forum -- http://www.astronomyforum.net/forum.php. And it's interesting to subscribe to www.spaceweather.com.

But beware that almost all of the processing information you see is really outdated for DSLR users. Lightroom/ACR and the newest cameras have changed the game. (See the information with Clark's comet shot: http://www.clarkvision.com/galleries/gallery.astrophoto-1/web/comet-lovejoy-rnclark-mauna-kea-c01.15.2015.0J6A3169-89_h-c1-1400us.html)

I'd love to see others here with similar interests add to the list of sites and information.

[Andrew McLachlan]

Hi Diane, either way this is quite lovely, elongated stars and all. I know nothing about photographing the night sky but would the AT require some sort of calibration?

[Diane Miller]

Thanks, Andrew. The AT relies on polar alignment, where you view through a carefully collimated polar scope that looks down the axis of rotation of the mount(carefully leveled and set to the appropriate latitude), and align Polaris at a marked offset point, as the Earth's axis of rotation doesn't point exactly at it. The AT rotates around this true north point and you can aim the camera, on an offset balanced arm (or on a ballhead) anywhere in the sky and it will follow the apparent motion of the stars. Polar alignment is subject to visual error, and if it's off you'll get star steaks instead of points.

But I'm not getting that kind of streaking at 30 sec. because exposures many minutes apart (I shoot a stack of 20 or more for noise reduction) only drift a little, and not in this direction. (They can be aligned in PS, so not a huge issue.) I think this is mirror slap. I think now I may have had mirror lockup delay set wrong on the laptop, which controls the camera. Next dark of the moon with clear skies will tell....

[Morkel Erasmus]

I really can just sit back and enjoy this one. Great work!!
:5

[Dvir Barkay]

Nice shot, did you use DSS for the stacking of the images? That is what I use when I play around with astrophotography. I haven't tried it in a while (probably because the sky in Philadelphia makes seeing even regular bright stars difficult), but honestly I should after seeing such a nice shot with good colors of the M42. Yes the stars are not tack sharp, but it can be hard to get them pinpoint sharp without making sure nothing moved in the exposure. Did you check that maybe one of the photos had some movement and didn't ruin the whole stack?

[Diane Miller]

Thanks, guys! DSS won't run on my Mac -- a lot of the astro software won't. It is supposed to run in some kind of "package" but gives errors. To the extent that I did get it to run (ignoring the errors and just trying for the stacking part) it didn't give as sharp a final result as PS. A lot of the fancy programs are outdated now with LR's removal of hot pixels and lens corrections, and with the low fixed pattern noise and dark current suppression of the 7D2. No need today for flats, biases and darks, which most of the astro programs deal with.

I'm not convinced that PS isn't just as good as the fancy stacking programs, with good subs. All of the raw files were identical and there was no significant degradation from the stacking and median averaging, even in the corners, except what could be attributed to the averaging of noise.

I think the issue here is not mirror slap (I've confirmed it is up the whole time I shoot a series), but shutter shake. If I lay the camera on a table and run a series (using Helicon Remote's Time Lapse function), there is a lot of clunking going on, but looking in the lens, the mirror is up the whole time.

Still figuring this stuff out, though.

[Dave Mills]

Hi Diane,You know you have a strong image when one keeps looking at it. The colors and flowing gases(?) really draw me in. Fascinating area of space. Nicely done!

[Anita Bower]

Beautiful image! Thanks for mentioning in OOTB.

[Warren Spreng]

Thank YOU, Robert -- I will! I'm probably a whole baby step ahead of you. There are a lot of online forums and groups. Roger Clark's website has a lot of information, mostly very technical, but you don't have to understand all the details to believe the conclusions. http://www.clarkvision.com/ I like the Astronomy Forum -- http://www.astronomyforum.net/forum.php. And it's interesting to subscribe to www.spaceweather.com (http://www.spaceweather.com).

But beware that almost all of the processing information you see is really outdated for DSLR users. Lightroom/ACR and the newest cameras have changed the game. (See the information with Clark's comet shot: http://www.clarkvision.com/galleries/gallery.astrophoto-1/web/comet-lovejoy-rnclark-mauna-kea-c01.15.2015.0J6A3169-89_h-c1-1400us.html)

I'd love to see others here with similar interests add to the list of sites and information.

The best Forum I have found is www.cloudynights.com It is free and there is a specific DSLR Imaging Forum where folks can post their images and look for feedback and suggestions. For a site that you can use to search for images taken with similar equipment, www.astrobin.com is simply a site for posting and saving images. You can do a search by equipment to find what others are doing with similar setups.