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Grumpy Martian

Double star observing - what does it take?

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Well after years of seeing the easy double stars, I have decided to get serious. Epsilon Lyrae immediately comes to mind. I have a Celestron C5 and a 120 ED refractor. Surely these telescopes would be capable of resolving these doubles. 

What experiences have others had in seeking out doubles? 

What advice is there. I have various astronomy books. But none seem to have lists or good advice on them. I understand that Capella is a double star. If so can it be resolved? 

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Both those scopes will do doubles but I think the ed120 would do better due to no central obstruction.

Capella has a very faint secondary beyond the reach of those (and most) scopes and isn't one I would go for.

Epsilon Lyra is doable with those scopes.

The Cambridge Double Star atlas is my favourite doubles book, and the doubles lists in sky safari are also useful.

In my small scopes I find splits over 2" on similar magnitude pairs fairly reliably doable and below that depends on things like the conditions, patience at the eyepiece, a cooled scope, etc.

For close ones a big difference in magnitude adds to the toughness of splitting them.

There are a lot of them up there, enough to keep you busy all year around! Unfortunately a lot of books neglect doubles and focus on the more famous dso's.

 

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Virtualcolony.com has a double star database. http://www.virtualcolony.com/sac/star_search.html

You can search by constellation, and print up a list of stars that your scope has a sporting chance of resolving.  Typically a page per constellation.

There is also the Washington Double Star catalogue which includes everything. http://ad.usno.navy.mil/wds/

Epsilon Lyrae's close pairs should be easy  with  a C5.  It isn't the only double-double in Lyra. There's an exercise for you. ? 

Needless to say, a GoTo mount speeds up the hunt.

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I find SkySafari 6 very useful for creating lists of doubles of particular splits or different areas of the sky.

As has been said, very different magnitudes make for harder splits, aswell as the separation.

Give Polaris a go, brighter primary and lovely small secondary but quite easy. Izar in Bootës is a lovely close one of different colours, and Pi Aquilae is one of my favourites too, 1.4” separation but similar brightness so is relatively easier (though still tough).

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61 Cygni is easy and very pleasing but it has a lot of fascinating history to it.

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I find my ED120 an excellent double star splitter :icon_biggrin:

I've "done" Zeta Hercules with it which is a tough challenge I think.

I've not quite managed Sirius as yet with it - I needed my 130mm refractor to do that.

I do find that refractors give slightly tighter star images than other scope designs, which makes getting the split a little easier. The C5 is going to be OK but the ED120 will be quite a bit better.

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29 minutes ago, John said:

I've not quite managed Sirius as yet with it - I needed my 130mm refractor to do that.

Now that will be an interesting target for the SW ED150.....

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Sometimes its just nice to aimlessly sweep a constellation slowly just to see what pop's into the field. You'll be amazed at the intensity and contrast of colours displayed by many of these gems. Often we sweep across the stars in search of nebulous prey, paying little or no attention to the far more jaw dropping beauty of the star fields surrounding them. Attached are a few doodles from my double star mystery tours. The drawings are in colour but artificial light has washed them out somewhat!

Your 120ED is a perfect instrument for this task!

 

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Edited by mikeDnight
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Definitely go for the challenges!  Those scopes are more than capable. And for comfortable viewing go for some dimmer doubles, like pairs at magnitude 5 or 6. These provide exquisite splits well under 2” separation. Much easier than those with a glaring primary. 

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