Touring the Orion Binaries

[John]

Good seeing conditions tonight so I've spent a pleasant couple of hours with my ED120 refractor checking out the binary stars in that fabulous constellation Orion. There are loads of options here but these are the ones I've picked up tonight:

Beta / Rigel - the mag 7 companion nicely defined even at 70x. The split is around 9 arc seconds so not too challenging but the major brightness inequality adds some spice !.

Theta / The Trapezium - A-D stars very nicely defined even at low power. At 112x The E & F components can be picked out quite easily tonight, even more so at 150x. E & F become harder to pick up at 225x as it happens - maybe a less effective exit pupil at that power ?

Sigma - all 5 components clear - the faintest being mag 10. A lovely multiple star

Eta - a close one this. Mag 3.8 and 4.8 components with a separation of 1.6 arc seconds. Needed 150x to get a split but 225x delivers a nice dark gap between the two stars. Tried "silly power" of 360x on this one and the pair actually started to look quite wide !. Showed the seeing was good too.

32 Orionis - New one to me and slightly tighter than Eta I reckon. I think it's listed as 1.5 arc seconds with mag 4 and mag 5 components but seems more challenging than this. Needed 225x to move from a touching, notched, pair of airey disks to spy that elusive ribbon of blackness between them. Stretching observer and equipment this one

52 Orionis - Another new one on me and a real toughie. Using all the useful power I could muster (240x) I could get a definite elongation of the pair - that sort of "peanut" shape that promised a split but it never quite came. One to try again at a later date I reckon. I think the component stars are equal mag 6 and the separation is documented from between 1.1 and 1.4 arc seconds - I can't find a definition of the current separation as yet.

Very rich constellation Orion, no wonder that its such a favourite with visual astronomers

[kniclander]

nice report. I have just acquired a new second hand celestron ed100 and must put it through its double star paces . Are there 5 visible components in sigma? I had thought there were only 4...

[John]

There is a 5th component of Sigma around 40 arc seconds or so away from the others. I usually overlook it but I thought I'd include it this time for completeness. The 3 plus the mag 10 one are the "famous" Sigma Orionis members though.

The ED100 should be an excellent binary star scope.

[kniclander]

There is a 5th component of Sigma around 40 arc seconds or so away from the others. I usually overlook it but I thought I'd include it this time for completeness. The 3 plus the mag 10 one are the "famous" Sigma Orionis members though.

The ED100 should be an excellent binary star scope.

aah - thanks.