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NGC3704

 

Basic Information


Location and Magnitude


Right Ascension: 11:30:4.6
Declination: -11:32:45
Constellation: CRT
Visual Magnitude: 12.9

Historic Information


Discoverer: Tempel
Year of discovery: 1878
Discovery aperture: 11.0

Observational


Summary description: vF, pS, * 9ยท10 2' ssf
Sub-type: E1

Corwin's Notes

===== NGC 3704 and 3707. This pair was found by Ainslie Common around 1880. His position for the pair is only approximate, but his description clearly identifies the nebulae, "2, F, R, on the parallel, star symmetrically placed between." The star is indeed there. The brighter object (N3704) was also seen (in 1878) by Wilhelm Tempel who published a micrometrically measured position for it in his fifth paper on nebulae. His descriptive note on the nebula reads, "Class III; a star 15m (nebulous?) follows 2 sec; near the comparison star is another fainter nebula." The star 2 sec following the measured nebula is the same one mentioned by Common. The positions that Dreyer adopted for NGC come from a letter to him from Tempel. In this letter, summarized by Dreyer in a note in IC2, Tempel says that he saw the brighter (which Dreyer mistakenly calls N3707) four times, but the fainter only once. Further, the position of the fainter comes from a sketch made on 25 May 1881, the same night on which Tempel measured the brighter. After quoting Common's description, Dreyer continues, "I assumed, perhaps erroneously, that 3704,07 are the same as Common's, the place of which is 11h 22m 57s, 100d 33.3m [1860], though Tempel's nebulae are not on the parallel." Dreyer's first assumption was correct, at least concerning the brighter nebula. What is wrong, however, is Tempel's place for the fainter. There is nothing in that position in spite of its being just about 2 arcmin north of his comparison star, and -- presumeably -- shown in that place on the sketch he sent to Dreyer. My guess is that Tempel somehow confused his observations, and that his note about the star and the fainter nebula refers to another field altogether. In any event, Common's observation is clear enough, even if his position isn't, to reliably assign the two numbers to the two galaxies in the field. There is also the faint possibility that Ormond Stone saw NGC 3704; see NGC 3696 for that. Finally, the pair may also be IC 703 and IC 704 (which see). But the case for that is very weak.

Steve's Notes

===== NGC 3704 17.5" (3/29/85): fairly faint, very small, round, bright core. A mag 15 star is 42" E of center. Forms a close pair with NGC 3707 1.7' E. Located 2.6' ESE of a mag 10 star.