New D60 Star Trails picture

Started Sep 6, 2002 | Discussions thread
W3IWI Regular Member • Posts: 181
Re: New D60 Star Trails picture

I thought I'd offer my contibution with my project of last nite. Here in the Balto/Wash area the last few evenings have been exceptionally clear.

In this case I have stacked 70 (yes, I said seventy) frames using Max Lyons' Stacker software (see ).

Each of the 70 frames is a 50 second exposure, with a 10 second gap. This was enabled by using a TC80-N3 timer. The D60 used a 20-40mm Sigma EX lens at 20 mm, f/2.8. It was set for ISO 200 and white balance was set for daylight to give the best contrast between the hot blue and colder red stars. [To answer the question about the Sigma lenses -- yes they do focus past infinity. I blew the first nite of pictures because of this!]

Max's software is "fed" from JPEG photos, and each of the 70 frames was recorded in HiRez JPEG. The frames were stacked using the "brightest pixel" mode, so each pixel you see came from just one of the 70 frames. One "dark frame" was used to eliminate any CCD hot spots.

The view is of the northwestern sky and was taken 10 PM last nite. Polaris is next to the trees on the right. The Big Dipper is the bright stars skirting the trees to the left. Each star trail is made up of dashed lines due to the 50/10 second sequencing.

Lots of airplane trails are seen. When you see an airplane trail disappear, this is due to the 50 of 60 second sequencing I used. The planes DID NOT blow up and disappear! If you look near the top, above Polaris, you will see a short "vertical" streak -- this is from a random meteor. The circular arcs are 17.5 degrees in size (70 minutes at one earth spin per day). The glow in the sky is from the nearby town of Clarksville, MD which is pretty bright because of a multi-dealer auto sales park.

So here is the picture -- all 2.5 Mbytes of it!

Thanks to Max for some great software.

Tom Clark

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