DSS image of 100Psc
Overlaid DSS image of 100Psc, 60' x 60' with north at top and west to the right

Aladin viewer for the region around 100Psc
BD+11 201, HD 9656, SAO 92521, GSC 00627-01377, HIP 7364

Type  Star
Magnitude  7.3
Right Ascension  1h 34' 51.6"  (2000)
Declination  12° 33' 31" N
Constellation  Pisces
Classification  A3V
Observing Notes

Captain William Henry Smyth
Nov 10, 1833    No. 6 The Crescent, Bedford, England (map)
150mm f/17.6 refractor by Tully 1827

A neat double star. A 7, white; B 8, pale grey. This fine object is on the ribbon under the tail of the Northern Fish, and forms Piazzi's Nos. 1ll and 112 of Hora 1; a line from α Arietis through γ, the first and third of the Ram's head, hits upon 100 Piscium, at about 8° south-west of γ. It is, as H. and S. have remarked, a miniature of 77 Piscium, but not so faint in my telescope as to render the measures at all difficult. It was classed by William Herschel V 131, and thus measured:
    Pos. 85°00'  Dist. 15".88  Ep. 1783.59
It was then rigidly examined by H. and S., who made it:
    Pos. 80°25'  Dist. 16".01  Ep. 1821.91
[ 77° 15".70 2016 WDS]
showing a slow np sf, or retrograde orbital change, which appears to be confirmed by my measurements. This movement is also countenanced by Piazzi's mean apparent places, from which we find that, in 1800, B was at an angle from A = 83°; so that, under all the conditions, there is presumptive evidence of an angular retrocession= -0°.120 per annum. Ulterior measures will be very desirable, since the slow progress indicates so long a period for an active revolution of the satellite, that if the orbit be circular, 3000 years may be estimated.

[The Gaia DR2 dataset shows the two to have matching parallax and proper motion, most likely a binary pair.]
― A Cycle of Celestial Objects Vol II, The Bedford Catalogue, William Henry Smyth, 1844
Other Data Sources for 100Psc
Nearby objects for 100Psc
7 objects found within 120'
104Psc IC 148 IC 1715
NGC 569 NGC 658
UGC 1195

Drawings, descriptions, and CCD photos are copyright Andrew Cooper unless otherwise noted, no usage without permission.

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