17 February 2006

I don't think we got either the amount of wind or precipitation today that they had forecast. The last time I checked both the sustained wind and the gusts were only about 50% of the forecast values. But it is windy. The trees outside my windows are in pretty much constant motion. The sky is very clear. I can't detect any haze looking out to the east. It looked like the pressure had bottomed out around noon and was trying to rebound. I am going to continue my chart of the observed conditions to see when the wind shift occurs.

NOAA graphic

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Tonight the Moon will occult spice. Around here the occultation will already be in progress when the moon rises at 2203 EST. spice may appear from behind the dark limb at around 2258 EST. I say it may appear because CSC and NOAA are at odds over what the conditions will be like at that time.

CSC says that the sky will be 30% obscured by clouds and that is too cloudy for them to forecast transparency. And they say there will be a moderate wind that will make seeing poor.

Clear Sky Clock graphic

NOAA, on the other hand, says cloud cover will be about average for good observing nights in the park and the RA will be below normal all night. They do agree that the temperature will be around freezing and are predicting winds of 17 MPH, gusting to 26 MPH.

NOAA graphic

It has been beautifully clear but windy here all day today. When I left the library at around 1700 EST there were some light cirrus clouds out to the SE. When I got home at around 1845 EST I forgot to look up to see what the sky looked like even though I had try to check it out through the windows of the subway.

I am planning to head downtown a little later to see if I can observe the event. I am torn between going to total and to CUSP. The Moon will be at around 9° in the EASE when the occultation ends so it will probably be visible from total, but CUSP is a surer bet. The major downside to CUSP is that Peter and Kin are more likely to be at total and I will miss spending time with them.

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Observing Location	CSP
Observational Period	2210-2310 EDT
Atmospheric Conditions	Clear and cold. There was some wind from the west but I put my hood up and it didn't bother me. I wasn't wearing long underwear or any of the really cold weather gear, just flannel lined pants, so was starting to chill by the time it was all over. There were some clouds low, <8°, but they were never thick enough to completely block the moon and spice might have even shown through them in the binoculars.
Instruments	Canon 15x50 Image Stabilized binoculars - Charlie
Observing Party	Charlie Ridgway

Target	Occultation of Spica
Constellation	Vir
Category	Occultation
Time	2302:42 EST
Comments	I knew the batteries in my short wave radio were getting weak but it played when I first got to the park and I was able to receive WWV on 5000 KHz. Then after about 10 minutes the radio died. I switched to my pocketwatch which I have calibrated against the Official U.S. time web site to calculate the time when spice reappeared. When I saw spice reappear I started counting seconds and walked over to a street lamp to set the bezel on my watch opposite the minute hand then after I had counted 60 seconds noted the seconds showing on the watch. I would estimate my time to be accurate to ±2 seconds. When I got on the subway I pulled out my Palm PDA to make the last update to my notes and found that the cold had sapped its battery which was at 50% charge when I left home, and it kept shutting itself off before I could write anything. Now that it has warmed up a few minutes at home it is fine. There is a definite advantage to making observations like this from a fixed observatory. 0310 UTC The Moon was just rising from behind the buildings across the river and slightly to the left of the Roosevelt Island lighthouse. 0315 UTC The Moon is rising into clouds and is very orange. 0319 UTC The Moon has risen out of the clouds and is a beautiful golden color. 0402:42 UTC BANG! It is like someone just flipped a switch. All of a sudden Spica just appeared. There was no gradual brightening although there may have been a one flash. 0403 UTC I can see Spica naked eye next to the Moon. I am not sure I would notice it if I didn't know it was supposed to be there, but it is plainly visible. Moon waning gibbous 19d13h55m 79% illuminated Mag -11.2 Spica Mag 0.98