Known to Aratos 260 B.C.
[Mem. Acad. for 1771, p. 451-452 (first Messier catalog)]
At simple view [with the naked eye], one sees in Cancer a considerable nebulosity: this is nothing but a cluster of many stars which one distinguishes very well with the help of telescopes, & these stars are mixed up at simple view [to the unaided eye] because of their great proximity. The position in right ascension of one of the stars, which Flamsteed has designated with the letterc, reduced to March 4, 1769, should be 126d 50' 30", for its right ascension, & 20d 31' 38" for its northern declination. This position is deduced from that which Flamsteed has given in his catalog.
[p. 458] 1769.Mar. 4. RA: 126.50.30, Dec: 20.31.38.B. Cluster of stars known by the name of the nebula of Cancer: the position reported is that of the starc.
[Messier reports to have measured the stars of the Praesepe cluster in 1785, 1790, and 1796.]
No. m RA Dec 38 o 8 127:38 08:30.6 +20:32 39 6 127:39 08:30.6 +20:46 40 6 127:46 08:31.1 +20:47 41 i 7 127:57 08:31.8 +20:18 42 c 7 128:02 08:32.1 +20:30The small cluster of starsPraesepe in Cancer is represented in the 16th plate in the upper part, to the right, by 12 of the principle stars afterFlamsteed & T. Mayer. But on the 30th plate, Fig. 3, it is represented consisting of 40 stars accordint to the observations ofde la Hire & Maraldi.
[Plate XXX, p. 38]
Fig. 3. The wellknown star cluster in Cancer, thePraesepe orManger with 40 stars visible throgh telescopes projected afterMaraldi andde la Hire.
Last Modification: January 18, 2007