Easiest Double Stars for Astronomy Viewing

[admin]

Hello guys,
Im trying to compile a list of easy (and great) double stars.

Actually right now i dont know of many but will get back to you here.

Please let me know which ones to add.

Cheers

[Michael Steen]

I've observed only two: Mizar is the middle of the handle in the Big Dipper, and Alberio is the head of the swan in Cygnus. Both are honeys!
I am eagerly looking forward to observing the famous double double near Vega in Lyra. From the charts it appears just to the left as you're looking up.

[Carlos_dfc]

Hi - I have a personal list of about 50 that I'm currently working my way through.

It's in excel file format - if you want it, PM me your e-mail addy and I'll send it.
Actually - anybody else wants it, you're welcome, just PM me your email.
(I'm off out in a few minutes, so please allow a couple of hours for a reply)

For now though, a couple off the top of my head...
Michael, if you like Albireo, try Almach in Andromeda.
It's tighter then Albireo at 10 arcsec separartion (Albireo is 34 arcsec) - but is also a yellow-blue pairing - In Almach, the yellow/orange star is a deeper orange then Albireo, and the blue is a paler colour.

Epsilon Lyra - the double-double - is a beauty
It's VERY easy to see as a double, even with binocs - but those two are themselves VERY tight doubles, only about 2.5 arcsec separation each.
120x or better required for a clean split

Castor - in Gemini is a tight-ish double (4 arcsec) - two white stars magnitude 2 and 3 - with a dim (9th magnitude) orange star, just over an arcninute away.

Algieba, in Leo - Yellow and Orange double, mag 2.5 and about 4 - about 4"

Eta Cassiopeia - yellow and red, mag 4 and 7, separation 13"

And many people don't realise, but Polaris is also a double.
Yellow mag 2 primary, with a faint blue companion (mag 9) about 18" away - difficult to see the secondary so close in to the glare of the primary

[Carlos_dfc]

Just a quick update...
I've had a look at my doubles list - I didn't realise, but it's now up to about 70 entries - including maybe 7 or 8 systems of more than 2 stars.

This isn't a definitive list by any means, and I add to it as and when I find new doubles/multiples - and I also have a couple of links that I've yet to sort through for new ones (other people's lists)

Splitting doubles is something I only just got into recently - my main interest for a long time has been star clusters, so I have quite a few other lists which may be of interest to some people...
The Caldwell list - Messier (obviously) - Herschel's 400 - The Collinder list of 471 open clusters - and a few others.

And last year I put together a list for myself of all the ngc-designated deep sky objects that it's feasible to see from between 45°N and 60°N - with a 10" scope.
I call it my "1200 Northern NGCs" - and I'm expecting it to keep me busy for many years to come.

As I said, my double/multiple star list is far from finished at the moment - but anyone who wants a copy as it is at the moment, is more than welcome

edit
Double-star list now up to 113, plus 8 multiple systems

[admin]

thanks for the update, i will try and update the SOD database here
Sky Object Database SOD
with some doubles.

[Carlos_dfc]

This thread has prompted me to dig deeper for double stars.

This morning I went through SkyAtlas 2000 and noted down all the stars marked as doubles, that have either a bayer letter, or flamsteed number designation - and that aren't already in my list.
A further 270 of them
No doubt though, quite a large percentage will probably be too close to see the split with an amateur scope - so the next step is to check them all out using 'Starry Night pro', and I'll add all those that have 1 arcsec separation or more, to my list.
It'll probably take a while to do (gonna start tonight), but I'll update here when I'm finished, and have my definitive list.

*note*
Sadly my list won't all be usable to those in the Southern hemisphere - From Europe, and most of USA, anything below -30° declination is down in the murk that hangs above the horizon - so -30° dec is the lower limit for stuff on any observing lists that I put together myself.

[philip d]

thats a big list Carlos!

are they the best ones? would love to see that list

[admin]

Hey guys,
Carlos do you have viewing notes with that list?

just updated the SOD with doubles:
Sky Object Database SOD

I will try and add more features to it so thats its more useful..

[Carlos_dfc]

Hi Guys
Not been too well for a couple of days, but I have continued and finished my personal 'doubles' list.
As I said further up, It's not a definitive list by any means - but is simply a list of the doubles and multiples that have a 'flamsteed' and/or 'bayer' designation, that are possible for me to view from my home location (lower declination limit of -30°) - I've also left out doubles with a seperation of less than 1 arcsec
Less than 3 arcsec requires big aperture or great optics - less than 1 arcsec requires big aperture, great optics, high magnification and very good 'seeing (atmospheric steadiness)
I'm talking about getting a clean split here, with a definite gap between the stars - It's possible sometimes to see an 'elongation', or maybe even a 'peanut' shape, to many tight doubles, but it isn't a clean split unless you can see some 'black' between the stars.
I have a 10" dob, and a 4" apo-chromatic refractor - both of which can do a 'clean' 1 arcsec seperation on a good night, but less than 1 arcsec and they begin to struggle - so anything under 1 arcsec has been left out of my list.

The finished list has at 265 doubles, and 23 multiple systems.
Ranging from 'very easy', through to 'challenging' - so that even experienced observers might find it useful - and it could feasibly keep a beginner busy for years.

Originally Posted by admin

Carlos do you have viewing notes with that list?

Sorry, no 'viewing notes' as such...
The list, as it stands has the constellation and the bayer/flamsteed designation - the 'proper' name If the star has one) - magnitudes of the elements - seperation (in arcseconds) - the colours of the stars - and the minimum magnification required to get a clean split (this assumes good optics and good sky conditions - in reality it often takes more than the theoretical minimum to successfully get a clean split)
And if you print out the excel sheet - there's also a box where you can tick them off as you 'bag' them.
There are a LOT on the list that I haven't viewed myself yet - I'm only recently getting interested in doubles, after being a big cluster fan for a good few years - I might add notes as and when I view them - but that will be a long, slow process.

Originally Posted by phillip d

thats a big list Carlos!

are they the best ones? would love to see that list

It does include the best ones - but has many, many more, as well as the best ones.
As a general rule of thumb for picking out the best ones - look for those which have a seperation between about 3" and 45", and have stars of contrasting colours.
Examples:
Albireo in Cygnus - 34" sep, yellow primary, blue secondary
Almach in Andromeda - 10" sep, orange primary, pale blue secondary
eta Cassiopeia - 13" sep, yellow primary, red secondary

The vast majority of viewable stars fall in the colour range from white, through 'cream', and 'yellow-ish' - so the most interesting doubles to view, tend to be those with red, orange, or blue elements.
In fact, in England 150 years ago, 'colourful double observing' was a big fashion trend among rich Victorian 'gentleman' astronomers.

If anyone wants the list, send me a PM with your e-mail address.
I'd also recommend my '1200 Northern NGCs' list for anyone interested in deep-sky observing.
A list of every NGC-categorized object, that you can feasibly see from 45°-60° North, with an amateur 8"-10" scope.

[Carlos_dfc]

Another update

I have just acquired a huge list of double stars. The guy who compiled it used Burnham's celestial handbook, as well as Otto and FGW Struve's lists.
Unfortunately, it's in a paper 'hardcopy' format, so would be awkward to upload here.
In quiet times over the last few days, I've compared it with my own list of doubles - and have removed duplicates, as well as weeding out those which are too close to split or have very dim components.
I'm left with a total of just over 1200 double/multiple star systems within the following limits:-
At least 1 arcsec separation
Primary component at least mag 8
Cutoff of mag 12 for dim components
Lowest declination limit of -35°
(The compiler of the large list is in Netherlands, an I personally don't know the Southern sky well enough to make much of a Southern list)

I'm gonna be typing this lot up, into Excel, in the near future - list will include magnitudes, separations, angular positions, Co-ordinates (RA/dec), and colours of many entries.

Anyone interested in the finished list, watch this space - I'll update here when I'm finished.
Don't hold your breath though - I'm expecting this to take quite a while to type in - LOL