Andrew Cooper
Feb 24, 2020    Waikoloa, HI (map)
20cm f/6 Newtonian, Cave Astrola @ 61x
Seeing: 7 Transparency: 7 Moon: 0%

A pretty double, a yellow 5.8 magnitude primary with a white 7.4 magnitude companion 17" away

Captain William Henry Smyth
Oct 30, 1830    No. 6 The Crescent, Bedford, England (map)
150mm f/17.6 refractor by Tully 1827

A neat double star, in the Greater Dog's left fore knee, and about 3° to the south-west of Sirius. A 6½, pale garnet; B 8, grey. The last is Piazzi's No. 178 of Hora VI., and the pair is followed in the sf quadrant by ν2 . This is 81 ♅ IV., recorded as having a distance of 18".32, but with a position "nearly preceding" in 1782. From ♅.'s remark this object was sedulously attacked at Palermo, and the place of both components in RA and Dec. were established; though the angle of position and distance derived from such data, is rather too vague for relying upon. But H. and S. then micrometrically measured it, and the results stand thus:

    P.        Pos. 255° 30' Dist. 19".01 Ep. 1800.00
    H. and S.      259° 52'       17".24     1821.22

Sir William's expression of "nearly preceding," being irreconcileable with a deviation of 10° from the parallel, it was concluded, that an obvious and considerable change had occurred in the angle of position: but this was not confirmed by my observations. Yet, as a friend considered the angle to be =256° in 1839, I requested the Astronomer Royal to re-examine it, and he kindly handed me the following measures by the Rev. Robert Main :

             Pos.  261° 36' Dist. 17".34 Ep. 1842.82
            [WDS   264°           17".40     2019   ]

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

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