Andrew Cooper
Aug 20, 2017    Oregon Star Party, OR (map)
14.5" f/4.5 Starmaster @ 103x
Seeing: 7 Transparency: 7 Moon: 0%

A small group of five stars in a rough line, 11 to 13th magnitude, quite conspicuous, easy to see why this could be mistaken for a deep sky object in a smaller 'scope

Captain William Henry Smyth
Dec 13, 1834    No. 6 The Crescent, Bedford, England (map)
150mm f/17.6 refractor by Tully 1827

A double star between the feet of Cassiopea and Cepheus, where a line from δ Cas carried a little east of ψ Cas, and about 5° further, will strike it. A 6, yellow; and B 12, pale blue. This is a delicate though rather wide object; and is one of the principal members of Custos Messium, an asterism placed by Lalande between Rangifer and Cassiopea, in poorish punning compliment to his friend Messier, the "comet-ferret."

The first register I find of it, is No. 2054 of John Hershels's Fifth Series. It is in a poor field, but about 10' or 11' to the sp is Σ.'s curious nebula No. 2 [NGC 629, actually sf, about 12' south and 2 east]; and nearly following it, about 4s, is a pair of minute stars lying across the parallel, about 10" apart.

The star A has had a small motion in space assigned to it, of which the following are the most authentic values:

    P.... RA -0".16  Dec. -0".15
    B....    -0".12       +0".02
    T....    -0".21       +0".13
   [Gaia DR2 -0".011566   -0".013364]

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

Harold Corwin

NGC 629 is a short line of five stars six or seven arcminutes west-southwest of Struve's position. I've pulled the data for this from Auwers's list of novae attached to his catalogue of William Herschel's nebulae and clusters. There he notes "Not seen in the Heliometer." However, Struve's description ("Irregular nebula with 3 stars") with his 9-inch Fraunhofer refractor certainly fits the asterism well enough. It reminds me of NGC 7150 (which see), another -- though somewhat smaller and fainter -- asterism also found with a refractor (the 15-inch at Harvard) by an experienced observer (G.P. Bond).

I note that Brent Archinal sticks rigorously to Struve's "3 stars", choosing only the three north-eastern stars. My feeling is that the other two stars are also part of Struve's object.

― NGC Notes by Harold Corwin

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