Groombridge 34

Groombridge 34

Also known as GX/GQ Andromedae, HD 1326, GCTP 49, BD +43º44, LHS3/4, GJ15A/B, GI 171-047/171-048, SAO 36248, LTT 10108/10109, LFT 31/32, 

Vyssotsky 085 A/B, HIP 1475

 

     The 19th Century was in many ways a unique period in the history of science, perhaps never to be repeated. Other than in the field of biology (which was then reeling from the Darwinian revolution), it was generally felt that “there was nothing left to discover” of any significance. The almost universal feeling was that all that remained for future generations of researchers was to extend by one or two more decimal places the already comfortably established basic facts of nature (the mind-shattering revelations of relativity and quantum physics being at the time totally unsuspected). As a consequence, the 19th and early 20th Centuries were a Golden Age for catalogicians. It was then that much painstaking work was done on creating massive lists of stars, galaxies, nebulae, craters of the Moon, etc., that are responsible for so much of today’s heavenly nomenclature. Typical for the age, when Beer and Madler published their definitive maps of the Moon’s visible hemisphere in the 1830s, they were so detailed and comprehensive that they paradoxically practically killed off subsequent serious study of our satellite for more than a generation.

     So when in 1806 Stephen Groombridge began work on his Catalog of Circumpolar Stars (published posthumously in 1838), he was representative of the spirit of his times. He spent more than 10 years observing stars down to the 9th magnitude, using the Groombridge Transit Circle which he himself had designed and built, followed by another 10 checking and re-checking his work. Groombridge 34 is of course the 34th entry in his catalog. A glance at the catalog entry shows that he measured its magnitude at 8.9 (its true magnitude is 8.08), that he had observed it four times, and made no reference to any companion stars.

     His most famous entry is perhaps Groombridge 1830 in Ursa Major, which for the remainder of the century was the star with the highest known proper motion (and to this day holds 3rd place).

     Groombridge 34 itself is a multiple star system, similar to Struve 2398. Its two components, A and B, are magnitude 8.08 and 11.06 respectively. Widely separated by at least 147 AU, they take more than 2,600 years to complete a single orbit of each other.

Observing Groombridge 34

     Now how often will you ever see star hopping directions that begin with “Start from M31”? But that is exactly what we are going to do. The Great Nebula in Andromeda, M31, the Andromeda Galaxy, the Granddaddy of all Faint Fuzzies, is indeed the most convenient starting point for searching out Groombridge 34. So enjoy the sight for a minute or two, then slide a bit to the northeast until you come across two nicely-matched 5th magnitude stars, HD3346 and HD2421 (HD3346 is a bit redder than its neighbor to the east, but the color difference is not that dramatic.) Using binoculars, you will see that these two are situated on the left side of a rather pathetically squashed “W” (see star chart right above this paragraph). All of the stars making up this asterism are brighter than magnitude 7, so you should be able to take in the whole thing without any problem.

     From this point a telescope is required. The magnitude 6.11 star just south of Groombridge 34 is 26 Andromedae. (The magnitude 6.15 star to its right missed out on a Flamsteed Number, and has to settle for being HD1185.) Let’s zoom into this area, using your widest field eyepiece. At magnitude 8.08, you should already be seeing Groombridge 34, but let’s make sure you’re identifying it correctly.

     This star chart shows a wide field view of the final search area. Note how Groombridge 34 is near the center of a box formed by four relatively bright nearby stars, with 26 Andromedae along the south side. Once again, by this time our target ought to be in plain sight, but there is one last rather important error to be avoided. Groombridge 34 is a double star, and when you observe it you might be tempted to mistake the extremely close 9.73 magnitude star TYC 2794-1397-1 for the B component of our objective (as I myself did, the first time I observed this star). The true B star is a much fainter magnitude 11.06, and is a difficult split to make without switching over to a much higher magnification (and narrower field) eyepiece. It can be done, but don’t make the rookie mistake I did!