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NGC3190 Galaxy, Coma Galaxy Cluster Attempt, and Saturn

Posted: 22 April 2012

Opened the observatory Saturday, 21 April, at 2245 MST, 72°F. As I walked to the observatory, I saw a nice meteor from the Lyrid Meteor Shower. I powered up the 8" LX200-ACF and once again used the wired AutoStar II. (I will return to using the Wireless AutoStar II on the next session.) The first object viewed was Saturn at 77X. Four moons were visible. At 206X, I could see the C Ring against the planet's disk. At 364X, I could see the C Ring to both sides of the planet's disk. I then viewed Mars at 364X; the small North Polar Cap, one dark area, and the sunrise cloud were visible.

At 2306 MST, I began setting up to re-image the NGC3190 galaxy at prime focus of the 8" using the D7000 DSLR. As on the previous session, I used the Vello ShutterBoss remote to control the camera. Used Regulus for a focus test with the Bahtinov Mask and did a framing test exposure of NGC3190. I then did this (cropped) guided, 10 minute, ISO 6400, exposure:


NGC3187 is the spiral galaxy slightly up and to the left from NGC3190. NGC3193 is the featureless galaxy near the bottom of the image.

Before starting the next DSO imaging, I began watching for more Lyrid meteors beginning at 2348 MST. By 0031 MST, I had seen only two more, and then resumed imaging.

My next target was the Coma Galaxy Cluster (see Sky & Telescope magazine, May 2012, page 60-63). I slewed the telescope to the location of NGC4889 but could not locate any guide star. I then slewed to NGC4874 and found a faint guide star. I did a framing test exposure (1 minute, ISO 6400). It was difficult to tell what was captured during the short exposure when viewing the image on the camera screen. I decided to do a guided 10 minute, ISO 6400, and see what resulted. This is that image:


Unfortunately, the guide star was too faint for reliable guiding, so there is some image trailing. But a few galaxies are visible in the image. NGC4874 is the galaxy in the lower righthand corner, to the right of the bright star. (This image is rotated 90° from the image on page 62 in the S&T article.) I will make another attempt to capture the Coma Galaxy Cluster on another session.

I ended DSO imaging and viewed the NGC4889 and NGC4874 galaxies in the same FOV at 77X. No other galaxies in the Coma Galaxy Cluster were visible with the 8" telescope.

At 0118 MST, I returned to Saturn for some imaging. I attempted a video recording of Saturn using the D7000 DSLR but Saturn was too underexposed to be usable. I then did an afocal video recording (45 seconds) at 231X using the iPhone 4. 1103 frames were stacked using Keith's Imager Stacker, resulting in this image (upscaled 200%):


I ended imaging and began checking the 8" collimation using Thierry Legault's collimation technique. Since receiving the telescope in October 2008, I had not felt a need to re-collimate the telescope. I frequently did "star tests" to check the collimation, but never saw enough mis-collimation to worry about. However, using Thierry's technique, I could detect a very slight mis-collimation using the star diagonal and the same amount of mis-collimation using the visual back. Since the amounts were identical, the star diagonal was not introducing any additional mis-collimation. I will correct the collimation on a future session.

At 0247 MST, I took a quick look at M57, the Ring Nebula, at 77X and 133X. My Lyrid count for the night was 5.

Closed the observatory at 0300 MST, 68°F.

I have posted my Vello Wireless ShutterBoss Timer Remote review. Check it out.

Comments are welcome; use the Comments section below, or you can Email Me. Thanks.

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