Another Moon and Star Trails

[Diane Miller]

The star trails and the trees on the left were the same exposure. Canon EF 16-35 f/2.8 II at 23mm, shot with Polaris in center for less distortion then cropped. Stack of 3 minute exposures.

There was a more OOF tree on the right that got covered up by a more interesting one. The gradient was added after the fact -- the trails seemed too abrupt running smack into the trees. Sky watchers may figure out that I flipped the trails horizontally. The brighter stars are the Big Dipper and I needed them on the right. Will have to shoot trails again in the spring when the Dipper is over there. (Oh, yeah, the moon was added too. Almost forgot to mention that.) It was shot with the 600 + 2X. All with Canon 5D3.

[Cheryl Slechta]

Diane, it's an impressive image I think you could crop from the bottom and eliminate some of the solid black and still have an effective image.

[Paul Lagasi]

Very neat image, good advice given above. I may have to try a few long exposures and stacking (maybe you could explain how the stacking works)...TFS

[Nancy Bell]

Wow! You put together a very cool image. Love the colors of the star trails against the deep colored sky. I know nothing about getting star trails and you have made me very interested. A good idea to think about keeping the star trails from running right into the trees. The moon is lovely, and I can also see a version without the moon.

[Diane Miller]

Thanks, everyone! Back in the last century we could shoot star trails on film with many-hour exposures and not worry about noise. (But you did worry about reciprocity failure and, worse, somebody wandering up with a flashlight to check out what you were doing, or the sky getting too light before you woke up and closed the shutter. Today, the digital darkroom comes to the rescue. (Except for the folks with flashlights.)

I shot these at ISO 200, f/6.3 (for better corner quality on my 16-35 II), for a series of exposures, using a remote with a timer function (Canon TC-80N3), of the sort used for time lapse. I set it to shoot three minute exposures with 1 sec in between (the minimum I can do). I can do about 85 before my 5D Mk III battery runs out, and I could probably pull a quick battery change without too much of a gap. (I do mirror lockup, which doesn't seem to shorten the battery life, and turn off the LCD display.

At this ISO and time there is virtually no noise if you set the exposure correctly to give a dark sky but bright stars. Since the earth's movement burns in the trails, you can get by with less exposure than you would probably want for stars as points. And you don't need the super-clear air and dark skies of high altitudes.

I do an adjustment in LR on one frame, to make the sky really dark and brighten the stars. I want to swamp out the many very weak stars that you never knew were there and leave the brightest ones. Then I select the whole series and sync that setting.

Do Photo > Edit In > Open as layers in PS. (You can do these same steps from Bridge if you don't use LR, and can probably do it in Elements as well.) Then simply select all the layers and set the blend mode to Lighten.

It's always a delight to see the colors come out. I didn't enhance them here. Stars have a range of temperatures!

Best done in winter because the Milky Way will appear as a foggy smear in summer, when it is visible. For circular trails, use a wide angle lens and put Polaris right in the middle. Otherwise you'll get some very odd-shaped curvature to the trails.

[Nancy Bell]

Diane, Thank you lots for the detailed explanation. Amazing that you took 85 images!

[Diane Miller]

One of the beauties of digital processing, and Lightroom in particular, is that 85 images are not really harder than one!

A while back someone posted a reference to a web site by Floris van Breugel where he gives a method to get rid of the small gaps in the trails. It sounds complicated but is really very straightforward and I need to try it.

[Judy Howle]

I really like this one! The moon is a good addition but I'd like to see it toned yellow-gold like some of the trails. Nice work!!

[Diane Miller]

Thanks, Judy! I did try various subtle coloration on the moon (easy to do) and decided I liked the cooler look on this one -- not sure why, though. Maybe because there is so much blue in the sky. An orange tinit would certainly work with the orange trails, though. I'll look at it again and re-post when I get time. Might be a few days.

If there's one hting I still struggle with in all this digital darkroom stuff, it's the decisions! But I'm not complaining...