Virgo Galaxy Cluster with D70 DSLR
30 May, clear and no breezes in the evening. Opened the SkyShed POD at 1927 MST, 82°F. At 1941 MST, took quick looks at Venus and Saturn. In the 26mm eyepiece, even though the sky was still bright, I could see Titan. I then began doing some research on my planned astrophotography target for the night: the Virgo Galaxy Cluster. I used The Trained Sky Star Atlas and Burnham’s Celestial Handbook to determine positioning and expanse so that I would hopefully capture the best view. I finished my review at 2012 MST. I viewed Saturn again and now I could see four moons: Titan, Tethys, Dione, and Rhea. At 2021 MST, the twilight sky was still somewhat bright but I could just see the first of tonight’s DSO targets: M86 galaxy in a 2” 50mm eyepiece. Then began waiting for darker skies.
2030 MST, the galaxies M86, M84, and M87 in the Virgo Cluster were now visible in the 26mm eyepiece. M84 and M86 were in the same FOV. Since I was going to use the focal reducer for the imaging, I added it now. In the 26mm + focal reducer, M84 and M86 were easy to see and I could just make out some fainter galaxies in the FOV. At 2051 MST, mounted the Nikon D70 DSLR at prime focus (PF) + focal reducer (FR) + Off-Axis Guider (OAG) and did a couple of focus tests on Spica with the Bahtinov Mask. At 2105 MST, I did a 1 minute, ISO 1600, framing test exposure on M84 and M86. Satisfied, I then did 5, 10, and 15 minute guided exposures. The 15 minute had too much noise in the image but the 10 minute exposure (slipped cropped) shows seven galaxies:
I then did 5, 10, and 15 minute, ISO 1600, PF + FR + OAG, guided exposures of M87. Again, the 15 minute exposure had too much noise. The 10 minute exposure of M87 is at the top of this page. The Virgo Galaxy Cluster has over a hundred galaxies spread across a large portion of the sky. But I was happy to be able to image some using a an older consumer-level DLSR.
At 2234 MST, the sky was getting very bright from the rising moon, so I ended the DSO astrophotography. I then began waiting for the moon to clear the hill to the southeast. At 2346 MST, I captured this image of the moon at PF + FR + OAG, 1/500sec, ISO 500:
2355 MST, did some terminator observing with the 15mm eyepiece + 3X TeleXtender. The moon was still too low for good seeing. Waited until it was higher in the sky before beginning lunar photography. At 0015 MST, seeing was better. I did some images of the terminator at prime focus + 3X TeleXtender (hat trick, ISO 200) and prime focus + 2X Barlow Lens (BL) + 3X TeleXtender (TX, hat trick, ISO 200/400/640). The best image was PF + 3X TeleXtender, ISO 200. I then cropped the image to have the same image scale as I had with the PF + 2X BL + 3X TX. Here’s the result:
Checkout the shadows of the mountain peaks.
Closed the observatory at 0040 MST, 65°F.
Monday, May 31, 2010