? cassiopeiae

[starf]

eta cassiopeiae is a spectroscopic binary easily viewed in a small telescope with the A component being somewhat similar to our sun with a magnitude of 3.00 and G0 V spectral class. The B component being a red dwarf dM0 and magnitude of around seven.

For anyone with an interest in binary or multiple stars this is probably the first one they look at, but ive never done so yet. so i thought id have a go, but according to starry night pro it would need something like a 6mm or 4mm eyepiece at 4000mm to split them.

is this really the case? at any rate the contrast in colour may be enough to distinguish each of them. looking forward to giving these an eyeball next time out but if anyone has any viewing tips could you please pass them on.

regards

[Sam]

Sounds like a tricky one.

[Andrew*]

I'll have a go next time I see cassiopeia and get back to you, but I've just checked my SN pro 4 and eta cas looks elongated at under 100x and cleanly split at 200x.

Andrew

[lunator]

Eta Cassiopiea (STF 60) is the 1st double I split.

The separation is around 13" (arc seconds) and the pair are splitable in just about any scope at moderate magnifications.

My 1st split of this pair was in my 4.5" reflector at x100 using the 9mm eyepiece that came with the scope.

In my larger scopes the magnification required to split is much lower.

Cheers

Ian

[starf]

Thanks for the information chaps.

had a peek at it tonight and found that 4000mm with a 32mm eyepiece seemed to work nice ie 4 x powermate with a 32mm plossl. 125x mag. also looked at RR lyrae and after putting a 6mm split one of the pair. Then went back to delta cep with 125x mag and also took a picture with a 2x powermate and dsi pro iii as a quick test 60 secs each in RGB. couldnt resist having a look at DO cep and again the 125x easily split them but no flare was noticed definately need to go back and image some of these more cleanly.

how did you get on andrew?

kind regards

[Astroman]

Eta Cas is a nice double, but is no longer known as a spectroscopic binary. A little caution should be exercised when throwing the term around.

A "spectroscopic binary" is by definition, only detectable by the spectral detection of a companion star. While Eta Cas A&B were first split by Herschel, the B component was thought to be a binary, but has since been disproved.

[Andrew*]

how did you get on andrew?

Not had a chance yet, Starf

Andrew