Cassiopeia Observatory

Rainbows, Milky Way, Asteroid Juno,
M74 Supernova SN2013ej
Posted: 8 August 2013

Monsoon season cloudy skies returned on Tuesday, 30 July 2013. Had a brief rainshower on Wednesday (0.06"). Thursday morning, 1 August, a partial rainbow appeared to the west:

Watch the rainbow set in 48 minutes in this short time-lapse video from my Live Webcam.

Cloudy skies continued on Friday. Saturday, 3 August, dawned mostly clear, but monsoon cumulus clouds began popping up mid-morning. A good ISS pass occurred Saturday night, but overcast skies prevented imaging it. Sunday dawned overcast, and I lost another good ISS pass that night due to cloudy skies. Monday, 5 August, was also cloudy with another brief rainshower (0.02"), and another good ISS pass was missed. Overnight had another brief rainshower (0.04").

That got my hopes up for being able to get back in the observatory. But on Tuesday, with cloudy skies continuing, the forecasts deteriorated to cloudy skies that night, which matched reality. After waking up Wednesday morning, 7 August, I looked out the window to the west and saw a lovely full rainbow over the observatory. This photo (slightly cropped) was taken with a D7000 DSLR and 8mm fisheye lens:

The forecasts for Wednesday night were for clear skies, so I took the rainbow as a good sign of things to come. By mid-morning, the sky was clear, but by mid-day there were cumulus clouds in most of the sky. Fortunately, the sky cleared again as sunset approached. Satellite images showed a band of clouds nearing the western border of Arizona but I decided to open up the observatory to take advantage of the clear sky here.

Cassiopeia Observatory was opened on Wednesday, 7 August 2013, at 1822 MST, 101°F. The sky was mostly clear with a band of clouds low along the western horizon. Viewed Venus at 1830 MST, 83X and 222X. A nice gibbous phase was visible. At 1834 MST, I began trying to view the just past one day old crescent moon, 83X. Also tried using 7x50 binoculars. Finally at 1907 MST, I gave up due to clouds in the west and tree branches. The moon was never seen. At 1910 MST, viewed Saturn, 83X and 222X. Sunset occurred at 1920 MST. The clouds were staying low in the western sky. The view of Saturn at 222X was very good, with nice shadows, some cloud bands, and the Cassini Division visible. At 1932 MST, after several minutes of excellent seeing at Saturn, the views began to deteriorate. At 1940 MST, the moon Titan became visible, followed in a few minutes by three other moons. Ended Saturn viewing at 1950 MST.

I began making preparations to photograph the Milky Way using the D7000 DSLR and 8mm fisheye lens. This would be a repeat of the photograph I took on the last session, but without clouds this time. This photo was taken at 2046 MST, f/5.6, 30 seconds, ISO 5000:

I then returned to the observatory and slewed the telescope to NGC4236 (galaxy). It was too low in the northwestern sky for imaging; I will reschedule imaging for several months from now when it is higher in the northeastern sky.

At 2120 MST, I powered on the GC Wi-Fi Adapter and used SkySafari Pro on the iPhone 4 to GOTO Asteroid 3 Juno. Juno was in opposition on 3-4 August, but I was clouded out on those nights. I mounted the D7000 at prime focus of the 8" LX200-ACF using a visual back. I did a focus test on the star Altair using the Bahtinov Mask. At 2139 MST, I captured this unguided, 30 second, ISO 6400, exposure of Asteroid Juno:

I then repeated the exposures after 30 and 60 minutes. This animated GIF shows the movement of Asteroid Juno over one hour:

In between imaging of the asteroid, I viewed M13 and M92 globular clusters using 7x50 binoculars. At 2200 MST, saw the first Perseid meteor of the night. It was faint and fast moving, in Scorpius. At 2224 MST, a gorgeous and very bright Perseid meteor went overhead, paralleling the Milky Way.

At 2241 MST, I began setting up to do piggyback photography of M13 and M92. I took several guided images but none captured the globular clusters. I suspect that the poor optical alignment of the piggyback adapter was the culprit. Ended imaging at 2319 MST.

At 2328 MST, viewed M74 galaxy, 83X, low in the eastern sky. At 2340 MST, I visually sighted the recently discovered supernova SN2013ej in M74. The supernova was still very bright (about Mag 12). Clouds had appeared in the southern sky and I began monitoring them closely to see if they would impact the planned imaging of M74 once it was higher in the sky. But by 0000 MST, the clouds had dissipated.

At 0011 MST, saw my 3rd Perseid meteor. At 0015 MST, saw the 4th and 5th Perseid meteors, and at 0020 MST, saw a 6th Perseid meteor. By 0026 MST, clouds had appeared in the southwestern sky. At 0038 MST, the clouds were now in the southern sky and getting higher. I began preps for imaging M74.

I mounted the D7000 at prime focus of the 8" telescope using the off-axis guider. Did a focus test on the star Alpha Andromeda with the Bahtinov Mask. After two framing test exposures of M74, at 0055 MST, I captured this 5 minute, ISO 6400, guided image of M74 (slightly cropped) showing the supernova:

By 0100 MST, the clouds were now in most of the southern half of the sky. At 0104 MST, saw the 7th Perseid meteor; it was another nice one. With the (unforecasted) cloud cover increasing, I began closing the observatory.

The observatory was closed at 0125 MST, 73°F. After the recent cloudy nights, it was great to be able to spend 7 hours in the observatory this night.

Wayne Parker, amateur astronomer and owner and designer of SkyShed POD, is also a member of the Canadian rock band "Glass Tiger". Here's a nice review.

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