Tag: Questar

Thursday (06-December-2012) — New Jersey

Backyard Late Autumn Early Morning Sky: Last Quarter Moon.

It has been a long, but mainly productive day. I got up very early to get a picture of the last quarter moon. I wanted to try out photography of the moon through a 500 mm telephoto lens using the Nikon 1 V1 camera. Because of the smaller size of the image sensor vs. a 35 mm (FX in the Nikon digital world) the effective field of view with this setup is equivalent to using a 35 mm camera with a 1350 mm lens (~2.7x). Since the N1V1 camera does not have a mirror (the mirror in a DSLR needs to move out-of-the-way when taking pictures) and has an electronic shutter mode — there is no mirror slap or shutter motion when taking pictures. This is important when taking pictures through large telephoto lenses where any motion or vibration will blur the image. I had hopes that this would help to get a sharp image of the moon. One limitation with the N1V1 with the FT1 adapter is that it can only autofocus through the center autofocus sensor. For this image I manually focused the lens (and set the camera to manual focus so it would not try to autofocus before releasing the electronic shutter). I used the remote (IR) shutter release so I would not be adding additional vibration to the system. I was impressed with the result. I did take several images trying different settings, and this was one of the better ones.

Last Quarter Moon, Late Fall in New Jersey. Image taken with a Nikon 1 V1 camera, FT1 adapter, and 500 mm f/4 VR lens (ISO 100, 500 mm, f/4, 1/500 sec). (David J Mathre)
Last Quarter Moon, Late Fall in New Jersey. Image taken with a Nikon 1 V1 camera, FT1 adapter, and 500 mm f/4 VR lens (ISO 100, 500 mm, f/4, 1/500 sec). (David J Mathre)

Friday (04-November-2011) — New Jersey

Backyard Astronomy in New Jersey: Sun and Moon.

The sky was clear so I took my telescope out. First to see the big sunspot (AR 1339), and then later the waxing gibbous moon. The Questar telescope comes with a solar filter to safely view the sun and sunspots.

Sun with Sunspot AR 1339. Image taken with a Nikon D3x and Questar 7" telescope (ISO 400, ~2500 mm, f/16, 1/2000 sec). (David J Mathre)
Sun with Sunspot AR 1339. Image taken with a Nikon D3x and Questar 7″ telescope (ISO 400, ~2500 mm, f/16, 1/2000 sec). (David J Mathre)
Waxing Gibbous Moon (69%). Autumn Night in New Jersey. Image taken with a Nikon D3x and Questar 7" telescope (ISO 400, ~2500 mm, f/16, 1/200 sec). (David J Mathre)
Waxing Gibbous Moon (69%). Autumn Night in New Jersey. Image taken with a Nikon D3x and Questar 7″ telescope (ISO 400, ~2500 mm, f/16, 1/200 sec). (David J Mathre)

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.