Astronomy - David Mathre Photography

Thursday (11-August-2011) — New Jersey

Backyard Summertime Night Sky Over New Jersey.

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.

Multi-Exposure of Waxing Gibbous Moon over New Jersey. Image taken with a Nikon D3x and 500 mm f/4 VR telephoto lens (ISO 400, 500 mm, f/4 1/400 sec). Nine images taken at 2 minute intervals. Raw image processed with Capture One Pro 6, and Photoshop CS5.. (David J Mathre) — Multi-Exposure of Waxing Gibbous Moon over New Jersey. Image taken with a Nikon D3x camera and 500 mm f/4 VR telephoto lens (ISO 400, 500 mm, f/4 1/400 sec). Nine images taken at 2 minute intervals. Raw image processed with Capture One Pro 6, and Photoshop CS5.

Monday (01-August-2011) — New Jersey

Backyard Summer Nighttime Sky Over New Jersey.

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.

North View Star Trails. Summer Night in New Jersey. Images taken with a Nikon D3s and 24 mm f/1.4G lens (ISO 400, 24 mm, f/4, 1/30 sec). Raw image processed including Nikon 24 mm f/1.4G Lens Correction with DxO Pro. Composite of 328 images combined with StarTrails Program. (David J Mathre) — North View Star Trails. Summer Night in New Jersey. Images taken with a Nikon D3s and 24 mm f/1.4G lens (ISO 400, 24 mm, f/4, 1/30 sec). Raw image processed including Nikon 24 mm f/1.4G Lens Correction with DxO Pro. Composite of 328 images combined with StarTrails Program.

Sunday (31-July-2011) — New Jersey

Backyard Summertime Night Sky Over New Jersey.

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.

North View Star Trails. Summer Night in New Jersey. Image taken with a Nikon D3s and 24 mm f/1.4G lens (ISO 400, 24 mm, f/4, 30 sec). Composite of 326 images combined using the Startrails program. (David J Mathre) — North View Star Trails. Summer Night in New Jersey. Image taken with a Nikon D3s and 24 mm f/1.4G lens (ISO 400, 24 mm, f/4, 30 sec). Composite of 326 images combined using the Startrails program.

Meteor Trail. Summer Night in New Jersey. Image taken with a Nikon D3s and 24 mm f/1.4G lens (ISO 400, 24 mm, f/4, 30 sec). Raw image processed with Capture One Pro, Nik Define, and Photoshop CS5 (David J Mathre) — Meteor Trail. Summer Night in New Jersey. Image taken with a Nikon D3s and 24 mm f/1.4 lens (ISO 400, 24 mm, f/4, 30 sec). Raw image processed with Capture One Pro, Nik Define, and Photoshop CS5

Saturday (30-July-2011) — New Jersey

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).

Sun with Sunspots. Image taken with a Nikon D3s and Questar 3.5 inch telescope with solar filter (ISO 640, ~1500 mm, f/16, 1/250 sec). Raw image processed with Capture One Pro 6, Nik Define 2, and Photoshop CS5. (David J Mathre) — Sun with Sunspots. Image taken with a Nikon D3s and Questar 3.5 inch telescope with solar filter (ISO 640, ~1500 mm, f/16, 1/250 sec). Raw image processed with Capture One Pro 6, Nik Define 2, and Photoshop CS5.

Sun with Sunspots. Image taken with a Nikon D3s and Questar 7 inch telescope with solar filter (ISO 200, ~2500 mm, f/16, 1/2000 sec). Raw image processed with Capture One Pro 6, Nik Define 2, and Photoshop CS5. (David J Mathre) — Sun with Sunspots. Image taken with a Nikon D3s and Questar 7 inch telescope with solar filter (ISO 200, ~2500 mm, f/16, 1/2000 sec). Raw image processed with Capture One Pro 6, Nik Define 2, and Photoshop CS5.

Sun with Sunspots and Clouds Passing in Front. Image taken with a Nikon D3s and Questar 7 inch telescope with solar filter (ISO 200, ~2500 mm, f/16, 1/2000 sec). Raw image processed with Capture One Pro 6, Nik Define 2, and Photoshop CS5. (David J Mathre) — Sun with Sunspots and Clouds Passing in Front. Image taken with a Nikon D3s and Questar 7 inch telescope with solar filter (ISO 200, ~2500 mm, f/16, 1/2000 sec). Raw image processed with Capture One Pro 6, Nik Define 2, and Photoshop CS5.

Saturday (16-July-2011) — New Jersey

Backyard Summertime Night Sky Over New Jersey.

Multi-Exposure Waxing Gibbous Moon — Going Up, Going Down. A ten exposure image of the waxing gibbous moon going up or down using the in camera multi-exposure function. The exposure times were varied in 1/3 EV increments (1/1000, 1/800, 1/640, 1/500, 1/400, 1/320, 1/250, 1/200, 1/160, 1/125, second). The exposures were taken every 30 seconds and used mirror up to minimize camera/lens vibration.

In Camera Multi-Exposure of Waxing Gibbous Moon over New Jersey. Image taken with a Nikon D3x and 600 mm f/4 VR telephoto lens + TE-E III 20 teleconverter (ISO 400, 1200 mm, f/4 1/1000 to 1/125 in 1/3 EV). Raw image processed with Capture One Pro 6, and Photoshop CS5.. (David J Mathre) — In Camera Multi-Exposure of Waxing Gibbous Moon over New Jersey. Image taken with a Nikon D3x and 600 mm f/4 VR telephoto lens + TE-E III 20 teleconverter (ISO 400, 1200 mm, f/4 1/1000 to 1/125 in 1/3 EV). Raw image processed with Capture One Pro 6, and Photoshop CS5..