Great Springtime Observing Up At Fremont Peak Last Night, March 8, 2008

Peter Natscher

After some anxiety over seeing approaching cirrus from the west at the KSBW-Fremont Peak weather cam, I packed up the A-P 10 in. Mak-Cass and headed up to Fremont Peak. Monterey was totally fogged in and windy as I left at 3 pm and I was only able to see the sky condition above when I reached Prunedale, 30 minutes drive east. Away from the coastal fog, the sky looked reasonably good with some high cirrus, so I continued on to Fremont Peak State Park and our FPOA site. Upon reaching the FPOA site at 4 pm, Ron Damman had already open the observatory for himself and an imager was setting up on the pads. David Cooper soon arrived 15 minutes after me.

The sky cleared up from the scattered cirrus nicely by sunset and by 7 pm, I was testing the seeing conditions at 320x with my 10 in. Mak-Cass. There was still a good jet stream overhead controlled the overall weather and this showed up well at my eyepiece on defocused stars as a fast running river. The jet stream was strong but laminar. The seeing was very good at around 1 arc-sec and less. Around us, the steady 5-10 mph wind was heard through the nearby row of tall Coulter pines, but we were protected from most of it by the surrounding buildings and trees. March is still winter and the wind with cold air is still to be expected. Some of the best observing I¹ve ever had up at Fremont Peak has been during the wintertime when a fresh blast of cold dry air from the NW provides great transparency and dark skies. Last night was another one of these as fresh cold-dry air came through to push away the cirrus and give us great transparency and very good seeing for four hours. The seeing was good enough for me to spot Sirius B (The Pup) at 7 pm. Rising Saturn looked very sharp at 320x and 450x even though it was only 45 degrees up in the east. In my crisp view of Saturn, Rhea, Dione, Tethys, Enceladus, and tiny Mimas all were close by. As Saturn¹s rings tilt to a smaller angle to us, we¹ll see less of Saturn¹s southern side. Last night, the thinly angled rings allowed me to see both the North and South Equatorial Belts for the first time this year. By 2010, we will be seeing the north side of the rings and the North Polar Region. Also, the A-F stars in Orion¹s Trapezium showed up very sharply at 320x. Seeing was below 1 arc-sec. The air was fairly dry with no dew at all and the transparency was good. In the hours Œtil 11 pm, David and I had very good conditions for observing. I spend the night without an observing list ­ I just winged it, enjoying being out under the springtime night skies and sharing great views with visiting campers. We packed up by midnight after the night sky returned to lower transparency and encroaching cirrus from the NW.

Peter Natscher
Monterey