Imaging: Venus, ISS, Zodiacal Light, Milky Way,
NGC1600, 1637, 1501, 1569, & 2261
Posted: 12 February 2012
I opened the observatory on Saturday, 11 February, at 1735 MST, 77°F. The sky was clear. I had lots of imaging planned for the night: Venus, ISS, Zodiacal Light, and several small faint Deep Sky Objects (DSOs). At 1742 MST, viewed Venus at 77X. I then set up for iPhone imaging. Mounted the iPhone 4 on the 8" LX200-ACF with a 26mm eyepiece + Moon Filter + 3X TeleXtender using the MX-1 afocal adapter. I did a video recording of Venus using the Camera app. This is one frame, not cropped, from that video:
I then observed Venus at 77X for a few minutes. Next, I set up the photographic tripod on the observatory patio for later Zodiacal Light photography. I then updated the ISS TLE in the AutoStar. While waiting for the sky to darken, I did some planning for the night's DSO imaging. I wanted to image six DSOs that I had observed on the previous session. I determined the order of imaging based on the object Right Ascension.
When I completed the DSO image planning, I began preparations for the upcoming ISS pass. I centered Venus in the 26mm eyepiece and checked the finderscope alignment. It was good. At 1816 MST, slewed to Jupiter and viewed it at 77X and 206X. Seeing was good. The four Galilean Moons and the Great Red Spot were visible. I then prepared the D7000 DSLR for prime focus imaging and at 1839 MST, I mounted the camera on the 8" telescope. I focused on Jupiter and did a test video recording. At 1844 MST, I was ready for the ISS pass to begin. The ISS would rise at 1856 MST. Just before the pass started, a lens fell out of my eyeglasses. Once the pass started, tracking was very bad. And halfway through the pass, the telescope stopped moving for some reason. I had never had that problem before. I hoped these problems (lens falling out and tracking failure) were not bad omens for the rest of the night.
During post processing of the ISS video recording made with the D7000 DSLR at 1/1600sec ISO 2000, I found four frames that showed the ISS somewhat clearly. At least the images showed the changing size and perspective as the ISS went from near the horizon (far away) to nearly straight up (closest). Here are the images, cropped to the same size from the full-frame video and in order as the pass proceeded:
After the ISS pass was over, I went to the house to repair the eyeglasses. I returned to the observatory at 1916 MST, began re-dark adapting my eyes, and then looking for the Zodiacal Light. I saw it at 1925 MST and began photographing it with the D7000 DSLR. Here are two photographs, taken at 1927 MST and 1946 MST, f/5.6 and f/3.5, respectively, 30 seconds, 18mm, ISO 2000:
Jupiter is above center and Venus below center. The Zodiacal Light is a faint thin isosceles triangle visible from the horizon, through Venus, and fading out near Jupiter.
This is a photo of Jupiter (top) and Venus (bottom) taken with the iPhone 4 using the app "True NightVision":
Since the D7000 DSLR was on a tripod, I decided to photograph the Milky Way. This photo (f/3.5, 30 seconds, 18mm, ISO 2000) shows Cassiopeia near the center, Perseus near the top, the Double Cluster between the two constellations, and M31 (the Great Andromeda Galaxy) left of Cassiopeia:
This photo (f/3.5, 30 seconds, 18mm, ISO 2000) shows the Winter Milky Way (along the left edge), and the constellations of Taurus (top right), Orion (middle) and Canis Major (bottom left):
I ended sky imaging at 1956 MST and began setting up for DSO imaging. I mounted the D7000 DSLR at prime focus with the Off-Axis Guider (OAG). I did a focus test on the star Sirius using the Bahtinov Mask. I began DSO imaging at 2013 MST. For each DSO I would slew to the object, search for a suitable guide star, and take a 1 minute ISO 6400 (unguided) framing test exposure. Since these DSOs were faint, I elected to prefer a good guide star over good framing. As long as the DSO was in the image I typically went with the framing. Some objects required retakes if the guide star turned out to be too faint to maintain sight of it during guiding. After imaging the first four DSOs, I rechecked the focus using the star Betelgeuse and the Bahtinov Mask; it was still good. I was able to image the first five planned DSOs without too much difficulty. Here are the DSOs, cropped (approximately the same scale) from the full-frame images. All but NGC1501 (planetary nebula) were manually guided during the exposure.
NGC1600 - Galaxy - 5 minutes ISO 6400
NGC1637 - Galaxy - 5 minutes ISO 6400
NGC1501 - Planetary Nebula - 1 minute ISO 6400
NGC1569 - Galaxy - 5 minutes ISO 6400
NGC2261 - Hubble's Variable Nebula - 5 minutes ISO 6400
All of the DSO images were edited in Aperture. Then Neat Image was used to remove noise.
As I was imaging the last two DSOs, the wind began blowing stronger and stronger. At 2149 MST, I decided I had better remove the photographic tripod from the patio. I then went to NGC2217 (faint galaxy) for my last DSO imaging target. I did a framing test exposure but could not locate a good guide star with the current orientation of the OAG. Due to the strong wind, I decided to not continue imaging. I'll image NGC2217 on a future night. I ended imaging at 2157 MST.
At 2210 MST, I viewed Mars, low in the east, at 77X. But due to its low altitude and the wind, seeing was not good. I began closing up for the night.
Closed the observatory at 2222 MST, 56°F.
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