• Choose a post by category or constellation

  • Learn the Night Sky

  • Search strategies

    Use the Search box below to find doubles by popular name, RA, or telescope size. For example, a search on "15h" will find all doubles we've reported on that have an RA of 15 hours. A search for "60mm" will find all doubles where we used that size telescope.


Here  are some key resources – both on the Web and in print – that we find especially useful to our star splitting efforts. You may find them useful too.

This is not a comprehensive list, nor is it intended to be. This is simply what we use  and frequently reference in our posts.  We’ve included a brief explanation of why we find each item useful. They fall into these three general categories:

A few good – and useful – books!

Web Resources

The Washington Double Star Catalog (WDS)  (Also, try THIS interface)

This is huge. It is THE resource for double stars. It also can be confusing and overwhelming to the newcomer (in which case, look at the interface above) in its presentation of tables of double stars with numbers which, in some cases, are more meaningful to the professional.  That doesn’t mean you shouldn’t use it. It is the single, best authoritative resource on double star data in the world.  It’s just that there are other, simpler, less comprehensive lists that the amateur observer may find both more useful and easier to understand. See, for example, the Sissy Haas book listed under “Print Resources” below.

Double Star Club Observing List

This is a  list  of 100 doubles – many of the best ones you’ll ever see.  While they can’t all be  split with a 60mm telescope, they suggest you don’t use anything smaller.  I know lots of them can and I’m starting a project of looking at the list with just that – a 60mm telescope. The stars are in right ascension order. The list is provided by the Astronomical League and those completing it and submitting information as instructed can earn a certificate from the League..

Search: The Bright Star Catalog

This is a search engine that allows you to search for bright stars (essentially naked eye visibility), in several catalogs, including the Washington Double Star Catalog.   This is a great cross reference tool, at least for naked eye stars, allowing you to find a  variety of designation for the same star, plus much of the data known about that star.The Bright Star Catalog contains 9,110 entries of all stars brighter than magnitude 6.5 . It’s one of the most widely used star catalogs and provides detailed basic astronomical and astrophysical data.


This is a web site founded by Jim Kaler that gives detailed descriptions of selected stars, putting some flesh on the bare statistics you find on other sites.  However, it is limited  to fewer than 1,000 stars and the organizational structure leaves something to be desired. I find the easiest way to use it when I’m looking for a star is to go to the home page, then scroll well down until I come to a list of star names in alphabetical order. If that doesn’t work, I keep scrolling to where the stars listed by constellations.

Print Resources

Double Stars for Small Telescopes: More Than 2,100 Stellar Gems for Backyard Observers”  by Sissy Haas

This is the book I reach for first when planning an observing session. Stars are arranged by constellations and for each one you get the vital statistics – position, name, position angle, separation, magnitude, plus a sentence or two of observation notes from either Haas, or other observers, contemporary and historical. In addition, there is a seven-page introduction to double star observing that is packed with useful information. By “small telescopes” the author obviously means those that the typical amateur owns, for in more than one instance the telescope used to split a given star may be an 8-inch – which is not “small” in my book, so don’t lett he title mislead you.  Many of the stars – in fact many of the best – can be split by a 60mm scope. gs

“The Cambridge Double star Atlas” by  James Mullaney and Wil Tirion

This for me is the must companion to the Haas book. Armed with these two, I feel ready to go double star exploring any clear night.  The charts are up to the standard Tirion is well-known for and while they contain many other objects, the emphasis is on double stars  and their double star catalog designations – designations that can be confusing, but are explained in the text with a detailed listing of  the designations used along with the Washington Double Star code , and the discoverer/catalog/observatory. Spiral bound so it will lay flat. Again,the introduction is must reading for those going down the double star path, and while I use this primarily as an observing planning tool, it often finds its way into the observatory with me as well. gs

Sky & Telescope’s Pocket Sky Atlas by Roger W. Sinnott

The introduction begins: “Think of this as your working sky atlas, the one you carry out to your backyard telescope. . .”  Yep! In fact, I like this so much – and use it so much – I have two copies – one that stays in the domed observatory all the time and one that stays in my library and/or roams with me. It’s small, but remarkably comprehensive with 80 charts containing 30,796 stars to visual magnitude 7.6. Doubles are shown with a line through the star and frequently include a catalog designation. I also use this in planning some times simply because I’d rather get where I’m going clearly in my head while in the comfort of my library – then I use it for reference and as a memory jogger at the telescope. gs

The Night Sky Observer/s Guide – Volume 1 Autumn and Winter, Volume 2 Spring and Summer – George Robert Kepple and Glen W. Sanner

This is an excellent, comprehensive Observer’s guide that updates – and largely replaces, for me – the three-volume Burnham’s Celestial Handbook.  It is organized by constellation and provides charts and photos with an emphasis on a variety of deep sky objects.  From a double star standpoint it provides two major resources. First, it gives a list of selected double stars for each constellation with vital statistics for each, and second, it usually pulls out one or more double stars in each constellation to write more about. This last serves as an informal guide to some of the best doubles in the sky. I use this, however, primarily for reference and cross-checking after an observing session.  gs

“The Hundred Greatest star” by James B. Kaler

This is simply my favorite book on stars. The extensive “Introduction and Allegro” give the best introductory look at stars in general – what they are, how they work, and how we classify them – that I’ve found anywhere including in Kaler’s other works. He then  devotes a couple of pages to each of the 100 stars, many of which are doubles.  It is this book that leads me to Professor Kaler’s web site frequently for a comprehensive and authoritative statement on a particular star.  gs

“Burnham’s Celestial Handbook: An Observer’s Guide to the Universe Beyond the Solar System” by Robert Burnham, Jr.  Revised edition (1978) in three volumes.

While I agree completely with Greg’s comment above that the Night Sky Observer’s Guide has pretty well replaced Burnham’s classic work, I still find myself going to it frequently to find information I can’t find elsewhere — and it’s surprising how often Burnham will have it.  So even though a fair amount of the observational and technical information in these three volumes is outdated, it remains an excellent reference source.  Every constellation, from Andromeda to Vulpecula, northern and southern hemispheres, is covered.  Each one starts with a table of data for double and multiple stars, followed by variable stars, and then a final table listing clusters, nebulae, and galaxies.  Following the tables are discussions of the highlights of each constellation and usually numerous black and white photos of objects in that particular constellation.  The major stars in each constellation usually get a paragraph or two, which often includes historical information regarding names and ancient lore.
And don’t overlook the introduction to astronomy at the beginning of Volume One, which can be found in chapter three, “Fundamental Knowledge for the Observer.”  There’s a particularly good section there on astronomical directions.

The amazing thing about these three volumes is that they were compiled by a single person — and both Greg and I have often wondered about that person.  There has been a singular lack of published information about Burnham.  I just recently came across this article on him that was published in 1997 — it is really one of the most fascinating things I have read in a long, long time.  If you’ve found yourself wondering about the author of these three massive volumes of information, it’s well worth taking the time to read it. jn

Software Resources

Starry Nights

This is the “planetarium” software I use, not because it is the best – I honestly don’t know what’s the best planetarium software – but because I’ve been using it for years and so am used to it.  I have the “pro” version and again, I don’t know enough about the other versions to know whether the “pro” is really needed for what most of us want.  The features I most use on this are two they don’t mention much in their promotions. First, the ability to flip a chart so it is oriented correctly for whatever telescope you are using. Second, the ability to tell the software what equipment  I use so it can calculate a true field of view depending on my choice of telescope and eyepiece.  Those two features help me tremendously in my search for double stars and star hopping. But while I have a laptop with this software on it, I still take traditional paper charts to the observatory and in the field. For me, computers just get in the way when I’m observing. But that’s a very personal choice based on what and how I observe.  gs


Stellarium is free, runs on Windows, Macs, and Linux operating systems, and gives what I feel is a more aesthetically pleasing view of the night sky than Starry Nights. However, as near as I have been able to determine, it does not offer the  features I find most useful with Starry Nights – the ability to flip charts to match the view at the eyepiece, and the ability to supply it with an equipment list so it can calculate true field of view at my eyepiece. So I use Stellarium when making display charts on my web sites. But I seldom use it to plan observing sessions. Bottom line – it does the basic job of helping you find your way around the sky, it f does it attractively, and it does it for free! gs


I use this program primarily because it has a huge database of double stars, all of which comes from the Washington Double Star Catalog.  The user has the option of turning on an indicator which identifies all double stars on the screen by displaying the usual horizontal line through the center of each one.  It also allows each of the identfiying names to be displayed.  I frequently leave that option turned off because it tends to clutter the screen, and the names often overlap, causing them to be illegible.
There are two ways to get to the data.  The simplest is to click on the star, which will give you a pop-up box showing all the pertinent data: coordinates, magnitudes, separation, position angle, stellar classification, and the dates the information was derived.   One piece of information not included is stellar distances.
The second way to get the data is to display it in a table for every double star on the screen.  That information can then be copied into a word processor or spreadsheet.
And it does a good job of generating maps — and allows the user to select a limiting magnitude as low as  fifteen.  jn

10 Responses

  1. Anybody use Carina’s Voyager for double-star research?

    • I’m not and I don’t believe John is. i think both of us tend to start with the Haas book. I frequently will check Starry Night Pro just before going out to get a field in mind for idenitification, since it allow sme to set my telescope field and to limit the stars visible to only those bright enough to see int he scope I plan to use. For thelast word in informationabout doubles we go to the Washington Double Star Catalog,

  2. Hi Greg
    Thanks for the reply.
    Personally I observe 4-6 hours each night, 29 out of 30 days per month. Yes, I am a double-star fanatic. For many years I used books & charts etc until I came across Voyager. I now usually observe anywhere from 30-80 double-stars each session. I can’t help myself. No-I have no connection to Carina. Cheers, Ernstenator

  3. That’s terrific. You have a whole lot more energy and clear nights than either John or I can find, and you look at more doubles in a night than I do in a season. I’m curious where you find so many clear nights?

  4. Greg
    I’m blessed to be living in Valencia, CA “The land of milk & honey”- just joking. It’s 35 miles north of L.A. but has its own weather system, mild LP, low desert (1400 feet altitude) & lots of clear nights !
    I’m trying out a 127 refractor f/7.5 right now. Any suggestions concerning other refractors to experiment with.

  5. I just came across a very interesting article about Robert Burnham, author of the three volume Burnham’s Celestial Handbook, which is referenced under our “Resources” tab at the top of this page. I’ll leave this comment up for a few weeks as a reference to it. The article can be found here: link.

  6. Greg: I have enjoyed your pages since i listened to you and John on At the Eyepiece. I am slowly reading all your posts. I have seen you mention “Admiral Smyth – Bedford Catalog” many times, but maybe some of your readers don’t know that both the earlier version (1844) and the 1881 second edition are available for free on Google Books.


    Anticipating each new post – Rich McCormick

    • Thanks, that is helpful – but for the record, it is John who is good friends with the admiral – mosto f my friends are younger ;-)

    • Just saw your comment, Rich, which is very much appreciated.

      Seems like most of my friends are older than Greg, and most of his are younger than me — haven’t quite figured that one out, yet, but there must be a message in there somewhere.

      Just took a look at your blog, also — very impressive. Should keep me busy for a while looking at what you’ve done.

      Clear Skies!


  7. Thank you John. You rekindled my interest in double stars. I sure do enjoy your wonderful collection of classic refractors. Rich

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s


Get every new post delivered to your Inbox.

Join 80 other followers

%d bloggers like this: