33 Orionis

Addendum 2000-2001


 
Bob Hogeveen
Star: 33 Orionis
Date & Time: Januari 6, 2000 - 20:00 UTC 
Seeing: 5-6 <1-10 Seeing Scale (10 best)>.
Location of site: Annen, The Netherlands (53 N, 6 E)
Site classification: Village-backyard 
Sky darkness: 4 <Limiting magnitude>
Conditions: Hazy and almost full Moon in Tau, limiting mag.: 2.5
Temperature: 5° C
Telescope: Celestron 11" SCT 
Magnification: 100x
 
There is some different data on the magnitudes of this pair :
WDS gives : 5.8 and 6.9 (sep. 1.9")
Hipparcos, which I think is the most reliable : 5.46 and 6.51 (sep. 1.89")
The color of both stars is blue, Skymap Pro 7 shows that B is a bit more bleu than A 

Comments: 
First look was with 280x (my finder seems to centered well!) and the split was immediately obvious and clean. I had just collimated the scope a few minutes before and I think this helped a lot. The star images were quite sharp, both stars to bright for pinpoints, but nice little round dots.

Orion was still low in the sky and 33 was at the moment of observation less than 30° above the horizon. The whole sky in that area looked very hazy and had a yellow tinge. So did star A, it really looked a bit yellow.

Star B was able to maintain his bleu color, it was very obvious at 280x.
I "went down" to 140x and was a bit surprised that the pair was still split. I had expected it to merge to an elongated image, but no, although smaller star-images and closer together, the split was still there. I must say it was on the edge with 140x. Only moments of better seing revealed the tiny dark area between the stars.

Ambience: This evening I tested the ability of the cloudgods to react on putting a scope out. I measured their speed of reaction to be one hour. So there is some hope for those who can put up their gear and start observing well within one hour!
But I must say I'm afraid they were not paying much attention tonight, not expecting any fool to put a big scope out on a night like this, with mag. 2.5 sky and almost full moon. 

Nevertheless, I had a short opportunity to observe the Moon, Jupiter and Saturn with my CG-11. After that of course some doubles...
It turned out to be only one double. After that observation they started sending the clouds in.