backyard splitting dewdrops

by Mark Bracewell


Got in a little bit of double splitting last night before the dew got me. Seeing from here was dramatically variable, with moments of high tubulence (swimming), moments of slow but strong rippling (stars doing the hula) and fleeting moments of dead calm. Unfortunately the transparency was kinda awful - limiting mag never better than 4 at best.

San Jose2005-1-11 21h26m ( TU + -8h00m )
Scope100mm Bruno (75 yr. old brass f/15 refractor)
EPs10mm plossl - 146x 4.8mm nagler - 304x

Polaris

A real bear getting polaris in the FOV on EQ mount - had to kick the legs around - crude! No idea where north is from here - in FOV with zenith up, secondary at about 88 degrees clockwise. Whopping difference in magnitude makes B star look really tiny, but easy to see as the sep is pretty big.

Eta Cassiopeiae

Great color - primary yellow, secondary very red. Not as crisp tonight as the 100x view I had at MB back in summer. All my previous D* observations have been near the ecliptic looking east - so figuring PA on this really threw me a curve, got it totally wrong (me 17, actual 307). Easy enough to figure north, but my previous mental calculations somehow involved the scope position, my sense of north, tilt of diagonal, and how I hold my eyebrows or something... I need to just look at the view, note north and stick to that, figure PA from the sketch. Another tetrahedron asterism around this double. Moments of seeing as good as 8/10, but transparency failing a bit and dew getting on finder. First use of the Stellarvue RDF - man what a breeze, smack on target.

Sigma Cassiopeiae

Separation: 2.4" Used the 10mm to locate this, and it was just barely suspect as a double - getting dew all over and things getting fuzzy, RDF useless from dew. Stuffed a wad of kleenex in the dew shield (just made, at least I have one now) to buy me a minute to change EPs once I had what I thought was sigma centered. Looked in the EP to focus - no sign of a star - oops, pull out the kleenex! Focusing annoying, lots of scope wiggle. @ 304x secondary star just outside primary diffraction ring, about 1/4 the brightness. Glare, maybe from dew. Getting little spikes off the primary. Couldn't make a good color guess, too fuzzy, though seeing seemed great at times I couldn't make out a real disk on the B star. It might have just been because everything was fuzzy and that damped out the turbulence. Real cold and wet.

Ambience - I took a photo of the scope - keeping a shoddy record of it as I make changes and get it functional - somewhere I learned to exhale before taking a picture - you can kinda tell it's cold and humid: http://wgg.com/scope/cold_night.jpg You can also see that my family is now fully adept at keeping the lights off in the back of the house - yay!


Posted on sf-bay-tac Jan 12, 2005 12:46:51 PT
Converted by report.pm 1.2 Jan 25, 2005 20:45:54 PT