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RW Tauri Eclipsing Variable Star Observing (oops); Moon

Posted: 15 December 2016

Clouds returned on Monday, 5 December 2016. On Tuesday and Wednesday, 6 and 7 December, I did more iOS app tests for the ScopeBoss developer during the daytime. Thursday, 8 December, was clear. Did some more tests of ScopeBoss. Was saddened to learn of the passing of John Glenn, American Jet Fighter Pilot, Astronaut, and Senator. I have some items that celebrated his Project Mercury orbital flight:

photo photo

I had to go to Phoenix on Thursday evening so didn't open the observatory that night. Friday, 9 December, was partly cloudy. Saturday, 10 December, dawned mostly clear, but with a forecast of a cloudy sky returning by sunset, which it did. Cloudy skies continued until Wednesday, 14 December, when there was some clearing in advance of another approaching storm system. During the morning I did some more ScopeBoss tests. Even though the sky was partly cloudy I decided to try to observe RW Tauri, an eclipsing variable star, that night.

Open: Wednesday, 14 December 2016, 1817 MST
Temperature: 72°F
Session: 1052
Conditions: Partly cloudy

Equipment Used:
12" f/8 LX600 w/StarLock
Wired AutoStar II handset
2" 24mm UWA eyepiece
2" 50mm eyepiece

D7200 DSLR
iPhone 6s Plus

1821 MST: LX600 ON, StarLock OFF, High Precision OFF.

Since this was the first observing session since last week's local power outage that occurred while I was doing some daytime ScopeBoss testing, I needed to do an AutoStar alignment for the LX600. 1829 MST: completed alignment and viewed Venus, 102X.

I then wanted to SYNC the observatory clock to radio station WWV but the shortwave radio could not receive WWV at either 5 MHz or 10 MHz. This was the first night I've ever had a problem receiving WWV inside the observatory.

Next, I began preparing to start observing RW Tauri, for what I hoped was a good view of it going from Magnitude +8.0 to +11.5. Mid-eclipse was to be at 2124 MST this night (I thought). Clouds could be a problem though, but they didn't deter me. Slewed the 12" telescope to the star Aldebaran and SYNCed the AutoStar on it. The eastern sky was beginning to brighten from the rising one day past Full Moon. Switched to a 2" 50mm eyepiece (49X). 1838 MST: Wi-Fi Adapter ON. Used SkySafari 5 Pro on my iPhone to GOTO RW Tauri. This chart (from Sky and Telescope, January 2017 issue) shows the approximate field-of-view (FOV) I was seeing in the eyepiece (although the actual view was mirrored left-right):


Many of these stars were visible through thin clouds. The numbers by some of the stars are Magnitudes (without the decimal point).

1854 MST: this handheld D7200 DSLR photo, f/3.5, 2 seconds, ISO 1600, FL 18mm, shows the eastern sky and some clouds:


RW Tauri is located near the Pleiades above center. The constellations of Auriga and Taurus are just below center on the left and right, respectively. The constellation of Perseus is at the top left.

1917 MST: the Moon had risen over the hill east of the observatory.

1930 MST: I began monitoring RW Tauri, 49X. The clouds were a definite factor in trying to watch for any star dimming and do Magnitude comparisons with other stars in the FOV.

1944 MST: this DSLR photo, f/5.6, 1/60sec, ISO 400, FL 140mm, shows the Moon and clouds:


2030 MST: still no dimming of RW Tauri. I added RW Tauri to the AutoStar "User Objects" for use on future sessions. I tried again to receive WWV, but got only static. So I SYNCed the observatory clock to the correct time using the iOS app "Emerald Time".

2050 MST: I finally located the Magnitude +11.5 star closest to RW Tauri. The clouds and bright Moon had made it difficult to see.

2102 MST: still no dimming of the RW Tauri (except by the clouds). I began to wonder if I had made a mistake on the date and/or time of mid-eclipse.

2124 MST: mid-eclipse (or so I thought), but there was still no dimming to +11.5. In fact, it was still Magnitude +8. 2130 MST: I decided I had made a date error.

2130 MST: slewed to the Moon. Took this handheld iPhone 6s Plus photo, afocal 49X:


2139 MST: returned back to RW Tauri, but it was still Magnitude +8.

Took a final look at the Moon, 102X.

2142 MST: LX600 OFF.

Close: Wednesday, 14 December 2016, 2151 MST
Temperature: 57°F
Session Length: 3h 34m
Conditions: Partly cloudy

After I left the observatory I was able to determine that I had made a date error. This eclipse was on the previous (overcast) night! Oops. I will try again on 24 December.

I have posted my review of the Vortex Diamondback 12x50 Binoculars. I have also updated the Astronomy Mementos Photo Album page.

Here's a great blog posting from Rod Mollise: "So, What’s Gonna Happen to Us?".

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