Andrew Cooper
Jan 2, 2016    Waikoloa, HI (map)
28cm f/10 SCT, NexStar 11" Gypsy @ 80x
Seeing: 6 Transparency: 6 Moon: 0%

A beautiful blue-gold pair, the gold star is notably brighter than the blue, magnitudes 2.3 and 4.8, separation 10"

Captain William Henry Smyth
May 1, 1843    No. 6 The Crescent, Bedford, England (map)
150mm f/17.6 refractor by Tully 1827

A splendid double star, on the right ankle of Andromeda. A 3½, orange colour; B 5½, emerald green; and of these colours I feel pretty positive, although the high authority of William Herschel and Σ. has pronounced them to be yellow and blue. This beautiful object was seen to he double by C. Mayer in 1778: it is No. H 5 III., and was thus measured when first classed:

    Pos. 70°23'  Dist. 9".25  Ep. 1779.65

Between this period, and my attack, the following results were recorded:

    H.and S. Pos. 64°46'  Dist. 10".91  Ep. 1821.91
    Σ.            62°26'        10".33      1830.02
   [WDS           63°            9".60      2019]

whence there would appear to have been a slight motion npsf, or retro- grade. But even without the excellent comparison of recent observers, my own results are sufficient to establish the relative fixity of these stars; although this is against the opinion, that high coloured stars possess the greatest velocity. A is remarkable as forming, with a star in the head, and another in the belt, an almost direct line, across the parallel, from east to west; it is called Al'mak, from the Arabic Al-'Anák-at-ard, the "badger," or caracal of Buffon. Scaliger's clever notion, that Al'mak, as the star at the foot, was derived from Al-mauk —cothurnus— is now given up.

This star is readily found, by drawing an imaginary line through the three stars of Orion's belt, and thence over the Pleiades; or, a ray from Thuban to the Pole-star, at about two-thirds the distance beyond, leads to it. Should Orion's neighbourhood be obscured, an occult line carried through β and α, the two brightest stars of Cassiopea, and extended to rather more than five times their distance from each other, will strike upon Al'mak, after passing the star upon Andromeda's left ankle.

It has a slight proper motion assigned, which my meridian observations, albeit the determination of so delicate an element is beyond their object, do not confirm; this is the registered amount:

    P....  RA +0".26  Dec. -0".ll
    B....     +0".06       -0".04
    A....     +0".03       -0".05
   [Gaia DR2  +0".030021   -0".051640]

Since the above was written, Mr. Baily put into my hand a letter which he had received from M. Struve, in October, 1842, announcing the unlooked for tidings that he had detected γ Andromedæ to be triple, and that the companion is composed of two stars of equal size, separated by an interval of less than 0".5.

I lost no time in notifying this to my friend Mr. Dawes, who, as well as myself, had so repeatedly gazed at this, merely as a double star. On the 1st of November, he informed me that he charged Mr. Bishop's refractor with an excellent single lens magnifying 520 times, and when the star was best defined, became satisfied of an elongation sf and np in the companion, making it look like a dumpyish egg. By the measures he obtained, the angle of position was 125°48', and the distance of the centres was estimated at 0".4.

I also received a letter from the Rev. J. Challis, under date of December 9, 1842, after his attacking it with the Northumberland equatoreal, at my request, of which the following extract is most interesting. "I looked at γ Andromedæ the first opportunity after receiving your note, and was surprised to find that I could easily recognise the small star as being double. I cannot say that I saw the components separated, but there was a decided elongation, and several measures which I took of position agreed well with each other. The distance is certainly not more than 0"'5. My impression was, that the components are not equal."

When I repaired to Hartwell, in February, 1843, I was baffled in my attempts to examine this object in the evening twilight. But on returning thither in the spring I was enabled to catch some fine early views of it. On the 1st of May, the morning atmosphere was perfectly diaphonous, and I teased γ under various powers from 118 to 600, until I fairly saw that the comes was not round, but elongated, in a direction np and sf to the amount above estimated. It was, however, so slightly oval, that, but for M. Struve's unexpected announcement, I must assuredly have overlooked it.

[Since discovery this companion star WDS J02039+4220C has become much closer to the primary and is currently 0.2" @ 96°. As Rev. Challis surmises above it is not equal with the B/C pair reported as 5.3/6.5 magnitude in the WDS.]

― A Cycle of Celestial Objects Vol II, The Bedford Catalogue, William Henry Smyth, 1844

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