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.
Backyard Summertime Sky Over New Jersey. Solar Disk and Sunspots.
One of the websites that I follow for sunspot and auroral (northern light) activity is SpaceWeather.com. I noticed yesterday and today that there are three new sets of active sunspots (1260, 1261, and 1263). My telescopes have solar filters to allow safe viewing of the solar disk. The following images were taken with a 3.5″ and 7″ Questar telescope and clearly show the sunspots. The third image has some clouds passing in front of the solar disk. The solar filter for the 3.5″ telescope is darker (lets through less light) than the filter for the 7″ telescope. This required increasing the ISO and decreasing the shutter speed for the smaller telescope. Another issue with the smaller telescope is that it is much more sensitive to mirror slap and shutter motion. In order to get a sharp image, I used the mirror-up feature and waited 30 seconds to let the entire system stabilize. With the larger telescope this is still a problem, but attenuated due to the overall extra weight of the telescope relative to the Nikon D3s camera. The higher magnification of the larger telescope however, increases the effect of vibration. Focusing was done viewing the image through the camera using LiveView — and using a HoodMan to be able to view the LCD screen. After shooting images (and videos) for about 30 minutes, I did get a sensor over heating warning (which then turned LiveView off).
Hot Summer Evening. While out sitting on my deck, I took some images of a Doe. I also caught an image of a distant commercial jet passing in front of a rapidly growing storm cloud.