Double star challenges

[mdstuart]

So I have a new TAL 1. Better than anything I had as a boy when I first was excited about astronomy.

I am trying double stars. The pole star, Rigel, Castor al doubles...really...just waiting for a clear sky and I am going to give it a go.

M33,M57,M35 all seen for the first time..so exciting.

Comet Holmes was/ is great.....

Mars a bit washed out but coming closer at 22,000 miles per hour.....

Bring it on

Mark (north of Bristol)

[themos]

It would be interesting to note the magnification when you first become aware of the double nature.

[lunator]

The mag require is dependant on seeing conditions.

I have a rough rule of thumb that seems to work for relatively even pairs (delta M of <3)

Using the 8 inch scope on a good night.

Divide the focal length of the eyepeice by 6 and this will give you a good guide to the closest doubles you can split.

eg. 25mm orthoscopic will allow me to split pairs down to 4.2"

On a night slightly worse than average this figure drops to 5.5.

Hope this helps.

Cheers

ian

[mdstuart]

Well I split the pole star but the companion was very dim, Split y Aries 7.8" Gamma Andromeda 9.8" and Caster JUST at 2.2" using a 9mm lens with a barlow. I cannot split Rigel 9.5" Maybe too bright?

Also found M35, M36, M37 and M38. Very nice...

Tried hard to find Uranus but could not. I really need to use those setting circles.

Mark

TAL - 1 110mm f7.

[legion48]

Well I split the pole star but the companion was very dim, Split y Aries 7.8" Gamma Andromeda 9.8" and Caster JUST at 2.2" using a 9mm lens with a barlow. I cannot split Rigel 9.5" Maybe too bright?

Also found M35, M36, M37 and M38. Very nice...

Tried hard to find Uranus but could not. I really need to use those setting circles.

Mark

TAL - 1 110mm f7.

I'm pleased to hear of yet another member enjoying doubles.

As for Uranus, I'm still not sure that I've found it and that's using the goto!

What's the old joke?...I couldn't find it with a torch and both hands.

[The Warthog]

In Canada, it's 'you couldn't find your own in the dark with both hands.'

[lunator]

Well I split the pole star but the companion was very dim, Split y Aries 7.8" Gamma Andromeda 9.8" and Caster JUST at 2.2" using a 9mm lens with a barlow. I cannot split Rigel 9.5" Maybe too bright?

TAL - 1 110mm f7.

Hi Mark

Castor is about 4" apart. YOu should be able to see Rigel B but it very faint compared to the primary

In a reflector it will appear above the primary

Cheers

ian

[John]

A real challenge in a 4inch class scope I find is Iota Casseopea. It's a triple star - a mag 4.5 star with a mag 8 star nearby and a mag 7 star very close by. With my 102mm refractor the closer star is right on the 1st diffraction ring of the brightest one so it's quite a challenge I find. You will need 100x or more to split this triple I think.

John