It has been a very productive and fun Spring for this observer. I accomplished two years worth of NGC work in Leo, and am still going strong in Bootes. Of course it has also been a planetary feast, beginning earlier in May with the transit of Mercury, and continuing on to the opposition of Mars, the rising of Saturn, and fully utilizing the high position of Jupiter. These have been heady times for ardent observers!
Because this blog is mostly dedicated to deep sky NGC objects, much of my other observing interests do not get reported here. However, I really love to observe double stars. Readers of my small telescope posts know that Space Eye does fine double work. However, so does my 12" Dob! In this entry I would like to tell you about a fantastic tool to help you generate your very own personalized double star viewing list. So far I have done this for work in Lacerta and Vulpecula, and am now working on Sagitta. My Vulpecula list, tailored to suit my needs, runs to 160 different objects, including doubles, triples and multiples.
Have you ever gazed at the the WDS double star catalogue and gone bleary eyed? Believe it or not, this is the most incredible resource for double star observers in the entire galaxy! What if I showed you how to extract information from this list, easily obtaining only the stars you wanted? Here's how.
Open this website in a different window. Prepare to be amazed. On the Stellie Doppie (Double Star) website, click on "Database" at the top, or from within the paragraph. You will get a 238 page list of "popular" double stars. Ignore it for now. You can come back later and drool over it. On the left side of the page, click on "Advanced Search." Since this is a website for advanced amateurs, I will show you how I tailor a search that I would use with the 12". It contains some pretty faint stars, but nothing that isn't shown on Uranometria 2000, All-Sky Edition.
You will now see an overwhelmingly complicated list of parameters to fill in. DON'T PANIC!! You only need to fill in a few things. Start by finding the "Constellation" space, about halfway down. Let's use Lyra as an example. Find Lyra from the drop down list and click on it. Now scroll down the page until you see the "Search the Database" button. Click on it. You will get a 34 page list of ALL the doubles in Lyra. This would be great if you had a 40" refractor, so let's narrow that down a bit.
Find "Mag. Pri" from the list nearer the top. Leave Lyra right there. Type in 9.6 in the empty space beside it. Leave the "less than" default setting alone. Scroll down and search the database again. You now have an 11 page list, which includes all primary stars brighter than 9.6. However, there are still companion stars on that list too faint to see (with my 12"), so go back and set Mag Sec. to 13.6. Generate your list again, which is now down to 10 pages. We're getting there. No companion fainter than mag. 13.6 will show up on the list.
The final step (for me) is to put in a minimum separation. I don't need stars separated by 0.1" and so on. Find the "separation" button and set it to 1" (these are my settings for the 12"; you may set your own parameters later). Change its default setting to MORE THAN. My final list now has 8 pages. It can be printed right from there (button at top right of webpage), or exported to various viewing software programs.
Just for fun, leave the same parameters but change the constellation. Cygnus, using the same settings, generates 28 pages of double stars!! Cassiopeia gives 15 pages, Hercules 13, and Bootes 5. I also generate lists for Deb and her 6" Dob. I set her separation to 1.5", and her mag. to 8 and 12.
As a final check I go through my list and eliminate stars that I know won't work. For instance, a 4 mag. primary with a 13 mag. secondary at 1" will appear on the list, but is impossible for me to split. I number the usable stars 1-160 (or whatever) and plot those numbers in pencil on Uranometria beside the correct star. I am then ready for dark sky double star work! On nights when transparency doesn't allow for faint work with galaxies, my double star list keeps me going late into the night.
You can do other amazing things here, too. For example, if you only wish to observe the Struve doubles, look down the left side and Voila! Have fun! Message me if you have any questions.
Enjoy, and clear skies!
Mapman Mike
