Backyard 1-3-05 pagan chants working

by Mark Bracewell


Somebody up there heard me, and I was finally able to split Theta Aurigae earlier this evening - this was I think the fifth attempt, previously using an 80mm refractor. This one was difficult. The 33 doubles folks give it a 95 difficulty rating (where 100 is excruciating). I think it's the difference in magnitude that makes it tough. Anyone else had a go at this one? It's on the AL doubles list.

Theta Aurigae

Component 1 Magnitude2.60
Component 2 Magnitude7.10
Separation3.6
LocationSan Jose
Date2005-1-3 22h30m ( TU + -8h00m )
Scope100mm Bruno (75 yr. old brass f/15 refractor)
EPs100 plossl - 146x 4.8mm nagler - 304x
Limiting mag3.9-4.2
Seeing7-8/10

A break in the week old cloudy weather, just for an hour or so, and just after I had done a lot of work on the old scope adapting it to use a diagonal and modern EP's - doesn't have the finder back on it yet... Grabbed the opportunity - Auriga was approaching zenith where the hole in the clouds was. Took a while to get the star in the FOV, had to back off to a 25mm EP to find it, and then try to keep the the scope steady while changing to a 10mm plossl and the nagler. The SVP mount has a lot of backlash and the scope is right at the weight limit (20 lbs) so a bump can throw it out a degree or so, and it wiggles like jello when touched. Never mind all that - I got the star in there, at 146x it had a nice, just slightly turbulent single diffraction ring and blue-white disk. I *thought* I saw the companion at about PA 300 just in a moment where the diffraction rings went wobbly. Went to the nagler and a small cloud formed which I noticed after a few minutes of looking at a suspiciously dim orange star where it was bright just a moment before. After a minute of cursing I went and looked at Saturn (nice but scope too wiggly to focus properly), M42 (couldn't see it, my deck has a beam that is right between mount and the celestial equator) and Rigel (ack, blinding in the bigger scope but a mile of separation). So then the cloud passes and all is clear - my quarry is right at zenith and I'm propped on one elbow lying on the deck, get it centered, focused and there it is, clear as anything, a tiny white B star in the faint second diffraction ring. A mag 10 star just to the north about 2' and a couple of mag 11 stars to the south about 3' Estimated PA at the eyepiece as 330, looks more like 310 once sketched. The first diffraction ring is so much brighter than the B star, with anything less than very good seeing it's no wonder I couldn't make it out before. Very pleased with the scope. I figured a way to get flocking paper into the tube between the baffles, the inside of the tube is very shiny brass, and I think this bought me a lot more contrast. At 75x per inch of aperture I thought it might suck, but it's pretty groovy. Happy camper.


Posted on sf-bay-tac Jan 03, 2005 23:59:03 PT
Converted by report.pm 1.2 Jan 25, 2005 19:30:44 PT