David's Images of the Day Photoblog
Late August Star Trails. Since it looked like the sky was going to be clear last night, I left a camera out on the deck to get some star trail images. The first one was before midnight, and the second one after midnight. I did this set with a fisheye lens to get as much of the sky as possible. There is a tree in the front of the house that is blocking the northern star. I also used the images to create a time-lapsed video of the night sky.
Star Trails and Lens Distortion. One problem I had with the star trail image I just published was that the circles looking toward the north star were not exactly round. This is probably due to the non-linear distortions characteristics of wide-angle lenses, especially toward the edges. There is a program, DxO Optics Pro that corrects for distortion of various cameras and lenses. (Note that the current version of Adobe Camera Raw also does lens corrections for some camera/lens pairs, but not for the Nikon D3s camera and 24 mm f/1.4G lens used for this image). I used the DxO Optics program to process and correct the 328 images. It took over 12 hours for DxO to process all of these images.I then ran the reprocessed images with startrails.exe program. Let me know (comment, or send me an e-mail) if you think the resultant image looks better, no different, or worse.
The following image is a composite of five 30 minute night sky exposures taken during a Elderhostel/Road Scholar photography workshop at Kelly Place outside of Cortez, Colorado in 2008. It was really dark other than the Christmas lights at the main building, and you could see a lot of stars in the sky. I moved the tripod as far away from the lights as possible and decided to do this series with a fisheye lens that would give a 180° field of view. The five images were combined using Startrails. This program is old (only works with jpg or 8-bit tif files) but works better than when I try to merge the images as layers in Photoshop.
Individual images in this slide show can be viewed here.
Images of star and jet trails plus a time-lapsed video looking south from my house in New Jersey. This was a couple of days before the Geminid meteor shower was supposed to peak, but I did catch a few meteors during the night. A series of images were taken with a Nikon D3x and 24 mm f/3.5 PC-E lens (ISO 400, f/4, 30 sec). The star trail images are composites of 120 images combined with the Startrails program. A time-lapsed video of the entire set was also created using Adobe Photoshop CS5 export to video. When you see Orion, tell me what I did wrong…
