The observatory was opened at 1802 MST, 86°F. The sky was mostly clear, with some clouds along the northern horizon. I immediately began preparing for a pass of the International Space Station (ISS) that was to begin in about 20 minutes. I updated the ISS TLE data in the AutoStar, attached the D7000 DSLR to the 8" LX200-ACF at prime focus + 3X TeleXtender, and did a focus test on the star Arcturus using the Bahtinov Mask. For some reason I had some difficulties getting the star into the camera FOV, and had to spend some extra time on this step. But I finally got the star focused. I SYNCed the AutoStar on the star as the ISS would pass near the star. I finally completed everything and was ready for the pass with two minutes to spare! The pass was a low one but rather bright, moving from the west to the northeast. Tracking was very good for the first two-thirds of the pass and I was able to keep the ISS close to the crosshair in the finderscope. Due to the short exposure I was using on the camera (1/1600sec, ISO 5000), I could not actually see the ISS on the camera viewscreen during the video recording. The recording lasted 4m50s.

During post-processing of the video, I could see the ISS and hints of its structure. Unfortunately, due to the short exposure and high ISO settings, the image was too low contrast with too much noise. I had moved to faster shutter speeds for my recent ISS video tests to try to remove image blurring due to the rapid motion of the ISS. Of course, the faster shutter speed meant higher ISO settings were needed. No amount of image processing yielded an acceptable view of the ISS from this pass. I have decided to go back to imaging at just prime focus (no TeleXtender) and use 1/1000sec at ISO 2000. Unfortunately, the next favorable pass is over a week away.

1844 MST: SYNCed on the star Altair, near the meridian. Slewed to M33 (Pinwheel Galaxy), low in the northeast sky; it was just barely visible in the 26mm eyepiece against a still bright sky. 1902 MST: the sky was darker now but M33 was still too low in the sky for good viewing. 1920 MST: M33 was better now. I began comparing views of M33, and then M31 (Andromeda Galaxy), through the following eyepieces: 1.25" 26mm, 2" 30mm, and 2" 50mm.

M33:

• 1.25" 26mm (FOV=45'): Faint, but could see (with averted vision) some spiral structure
• 2" 30mm (FOV=57'): Brightest view with a larger FOV, spiral structure just visible
• 2" 50mm (FOV=1°02'): Bright but more diffuse due to the lower magnification

M31:

• 1.25" 26mm (FOV=45'): Dark lanes just visible, structure difficult to see well way from galaxy center
• 2" 30mm (FOV=57'): Dark lanes clearly seen, structure visible well away from galaxy center
• 2" 50mm (FOV=1°02'): Bright, with dark lanes visible, structure visible well away from center

M31 (with focal reducer):

• 1.25" 26mm (FOV=1°24'): Excellent view, dark lanes and structure visible the full length and width of the galaxy
• 2" 30mm (FOV=1°49'): Good view, dark lanes visible, but structure more difficult to see well away from galaxy center
• 2" 50mm (FOV=1°56'): Nucleus overwhelmingly bright, difficult to see full length and width of the galaxy, no dark lanes visible

1956 MST: ended eyepiece tests and removed focal reducer. Viewed Jupiter with 26mm; 4 moons visible. Tried 15mm eyepiece but Jupiter was too low for good viewing.

2000 MST: began closing up. Planning a much longer session for the next night.

Closed the observatory at 2015 MST, 72°F.

Comments

Go to the previous report.

Return to the Cassiopeia Observatory Welcome Page.