| Observing Location | Riverdale Metro North Station adjacent to the southbound platform Westchester Co, NY Lat: 40° 54.?43' by GPS, 40.905733 by Google Maps Long: -73° 54.888' by GPS, -73.913453 by Google Maps  | ||||||||||||||||||||||
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| Observational Period | 2000-2115 EST | ||||||||||||||||||||||
| Atmospheric Conditions |
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| Instruments | Celestron C70 Mini Mak Spotting Scope with stock 27x-75x zoom lens - Charlie | ||||||||||||||||||||||
| Observing Party | Charlie Ridgway |
Tonight was the grazing occultation of ZC465 (Botein, δ Ari). NOAA had been predicting 50% cloud cover followed by rain and/or snow during the overnight hours but late this afternoon when I made a last minute check the cloud cover forecast had dropped to 15%. Low values usually mean clouds low on the horizon and clear overhead and since the Moon was going to be up around 50° altitude I thought it was worth taking a chance on it even though it meant a train ride out of The City.
I caught the last Peak train to arrive early so I would have time to find a suitable observing location. I had planned to observe from the NE corner of the Metro North parking lot at Riverdale since it would be out of the flow of departing cars even though Derek had advised that the southern end of the parking lot would likely yield more events. They yesterday it dawned on me that I could set up on the southbound platform since there were no scheduled departures until after the event would be over. In the satellite imagery there appeared to be a ramp from that platform down to grade and an adjacent roadbed and possibly to the river but I had no knowledge of whether it was accessible to the public. On reaching the ramp I found that it was unsecured and there were signs there indicating that river life in the area was toxic so I figured it was a public access. The roadbed there was fenced and gated and although maintained it did not appear to have been used recently. On the other side of the crossing was a cement footpath heading south along the river. I went to the northern end of the walk and set up there but quickly moved farther north along a dirt track to what I estimated to be the 0.55km S graze line which Derek had recommended.
It was perfectly clear when I got there but in 20 minutes a deck of clouds from the NW was encroaching on the Moon and shortly thereafter the whole western sky was filled with broken clouds. They weren't thick enough to obscure the Moon but they did block out δ Ari entirely. I was able to see the star through the edges of the clouds and in the gaps between clouds but the gaps were muck smaller than the clouds and were moving fast.
A few times the wind gusted up to 8 mph and caused the scope to jump around. I also learned the difference between light rail and non light rail. I had no trouble observing when the electric commuter trains were passing but when the diesel powered commuter, Amtrak and freight trains were passing the scope danced. There were a lot of through trains going past the station on the center tracks and observing from the platform probably would not have been possible do to scope shake when they were passing.
This is my first time attempting a graze with my backpack observatory so I learned all the shortcomings. The Mini Mak was up to the task but with the Moon this high I had to bend over and look up to see through the eyepiece. I probably would have been better off if I had brought one of my observing stools even though I have trouble finding a place for my knees when I am sitting at the tripod. I had been listening for WWV or CHU time signals during the week with my handheld ham radio but never heard anything. That was also my experience with my former handheld although I could pick up the signals on a portable Grundig Yachtboy short wave receiver. I was able to receive intermittent CHU signals on 3.330 MHz but it required a lot of moving the radio around when the signal dropped. The signal to noise ratio was very low so I was often listening to as much or more static as I was time signals. I was recording the event on my cheap Olympus digital voice recorder. I have found that this device is sensitive enough to pick up my mumbled voice when it was in a breast pocket inside my down parka. But today it particularly liked the static roar on the ham radio and set it's audio level for that sound source even though my mouth was closer to the microphone. I have listened to the recording to try to time events with the chronometer in my Gill RegattaMaster wristwatch but I don't know how to properly use the lap feature and I can't figure out how to pause the voice recorder playback. I will need to get the audio into my MacBook where I can work with it in Audacity or Garage Band. [3Feb12 Done. I plugged the earphone out of the voice recorder into the mic in of the computer and recorded the signals in Audacity. Then I sequentially clipped the recording until all I had left was a file starting at 0210 UT and ending after I identified separation from the limb. It was very easy to use the Audacity time scale to get the offset from the beginning of the recording and add that to the 0210 UT start of the recording to get event times. It looks like there is an error of about 0.5 seconds, minus I think, using this procedure. So now all the timing has been reduced.]
It was a little frustrating observing this event because I knew there was more going on than what the clouds were permitting me to see. If I hadn't had prior graze experience I probably would have missed much of what little I did see.
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It appears that this is the only observing I have done during the month of January.
