[Chaos-l] Observing report, 12/1/2012

[Jon Stewart-Taylor]

Hi all.  Had the 10" out last night chasing the last few doubles for  
the AL double-star certificate.

Alpha Piscum was first, and most frustrating.  I was unable to split  
it at all.  I dunno if it's the fact that it's a _very_ close double,  
the mediocre seeing, indifferent collimation, the presence of the  
waning gibbous moon, or what (maybe all the whats), but it it never  
even looked fat.  At the highest power i had available (170x), it got  
blobby.  It never showed even the hint of a companion.  The only other  
time i've been skunked this badly was with Gamma Virginis.

94 Aquarii was a pleasant double, with a bright yellow primary clearly  
separated from a blue/green secondary at 45x.  A nice double with good  
color contrast, but might be a bit hard to track down in light  
pollution, so probably not a tourist trap for public sessions.

Delta Orionis showed a bright pale blue star next to a much fainter  
celadon companion.  It had a nice wide separation, and is easy to  
find.  Probably won't draw much attention away from M42 right next  
door, but worth a quick stop before or after.

Theta 2 Orionis might be a good binocular target.  At 45x in the 10",  
all three components were visible, widely separated, in an almost  
straight line.  It looked more like an asterism than a double star.   
It was far overshadowed by Theta 1 (the Trapezium) in the same FOV,  
which showed 5 stars nestled in the nebula just next to the "fish's  
mouth" dark patch.  Now that i know T-2 is there, i'll probably glance  
at it when i'm looking at M42, but it really was underwhelming.

Last for the night was Epsilon Canis Majoris.  This was a much more  
difficult object than the wide separation (7.5") would lead one to  
expect.  Part of the problem is due to the wide magnitude difference:  
primary is mag 1.5 vs. the secondary 7.4.  At 45x and 67x, there was  
no hint of a companion.  At 110x, a very faint companion showed at a  
wide separation.  I thought that now i'd seen it, i should be able to  
detect it at 67x, but nothing doing.  At 170x, the stars got blobby  
again, and the companion vanished.  The on-line references to this  
star claim it's only splittable in "large telescopes".  Dunno if they  
mean "bigger than 3 inches", or "12 inches or larger".  In any case,  
it wasn't an exciting view last night in a 10".

Probably need to try Alpha Psc and Epsilon CMa on a steadier moonless  
night after double-checking the collimation. I've been spoiled by the  
Coulter over the last 20 years.  Despite the cardboard-and-chipboard  
construction, it's held collimation so well i only needed to fiddle  
with it every other month or so.  Something's apparently changed, so i  
now need to collimate every time (i can hear the tears of pity shed  
for me by folks who've _always_ had to collimate every session).

Has anybody observed either Gamma Vir or Alpha Psc recently?  What  
condition/magnifications did you need to split them?  On-line  
references seem to think 150x should be enough for both, but i know  
that both stars have orbits which made the separation Very Narrow over  
the last decade.

J.
-- 
Jon Stewart-Taylor:  joncst at earthlink.net
Chapel Hill Astronomy: http://www.rtpnet.org/chaos
Cape Fear Astronomy: http://www.capefearastro.org/