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.
Perseid Meteor Shower. Conditions for viewing the Perseid Meteors this year were not good. The moon was full with relatively high humidity and some clouds. I set two cameras up to take images overnight, and got maybe three images of meteors. I’ve made a time-lapse movie from the two image sets.
As a side note, I am running out of hard disk space. I could get another WD My Book external drive, but have run out of USB and Firewire ports on my computer. I’m thinking about a Dobro disk array. What ever I do, I also need to maintain an off-site backup copy. I worry about some of the cloud options, both due to cost and the fact that ATT limits me to 5 GB/month of broadband internet access.
Multi-Exposure View of the Waxing Gibbous Moon. I went out last night to see about setting up a camera to do some star trails and possibly catch some Perseid meteor trails. I gave up because of the bright waxing gibbous moon (90% illuminated) and some fast-moving clouds. After midnight, it did clear up long enough to get this multi-exposure view of the moon. I set it up for 2 minutes between exposure. I think I need to go to 2.5 minutes for no overlap for a full moon.
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.
Going from sunspots to startrails. The view is from my back deck over the roof. A tree in my front yard just blocks the north star. The image is a composite of 326 30-second exposures combined using the Startrails program. There are at least four jet trails, and a couple of meteor trails. The meteor trails are too faint in the composite, so I included a crop from a single image showing a meteor trail. I’ve also added a version of the startrails in B&W, converted using Nik Silver Efex Pro 2.
