NGC/IC Project Restoration Effort

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NGC7730

 

Basic Information


Location and Magnitude


Right Ascension: 23:40:45.8
Declination: -20:30:32
Constellation: AQR
Visual Magnitude: 14.0

Historic Information


Discoverer: Tempel
Year of discovery: 1876
Discovery aperture: 11.0

Observational


Summary description: pB, pL, E
Sub-type: Sc

Corwin's Notes

===== NGC 7730. Tempel found a pretty isolated "Nebula, good class II, extended, 2 arcmin diameter, no known star in the area", and published it with an approximate position in his first paper devoted to nebulae quoted by Dreyer in the NGC. Dreyer also has an IC Note that the NGC position is actually from a letter that Tempel sent to him in 1876. This would explain the difference between the NGC position and Tempel's position in his first paper. Unfortunately, there are no galaxies near Tempel's position that match his description. ESO 606- G002 is usually taken as NGC 7730 (except in SGC where I noted the NGC object as "not found" in the Note for NGC 7736), but as Steve Gottlieb points out, this is quite a faint galaxy. Would Tempel have called an object with B_t = 14.8 a "good [William Herschel] class II"? I doubt it, too. Given the uncertain nominal position and the sketchy description, I searched the area for several degrees around and found nothing that matches. The only "class II" nebulae nearby are NGC 7736 -- but that is exactly round and has three pretty bright stars just 6-7 arcmin to the northwest -- and ESO 605- G016, both at B_t = 13.65. The ESO object, too, is round (though is also a beautiful, large, ringed spiral in which Tempel just might have glimpsed some structure that would have allowed him to call it "langlich" -- "extended" or "elongated" in English), and has a 10th magnitude star about three arcminutes to the southeast. I've listed Andris's object as the most likely candidate in spite of its faintness, and have added the spiral to the list as well (but not NGC 7736; it is just too featurelessly round to begin to match Tempel's "extended"). But I'm going to suggest that Tempel's position is bad in Declination as well as in RA, and that his object is some other galaxy altogether. A search over a larger area is in order. ----- After that search over a larger area, the result is still the same -- there is nothing at any reasonable digit error that matches Tempel's observation. I've left the table as it has been, with two poor candidates. This object is probably lost.

Steve's Notes

===== NGC 7730 18" (11/22/08): very faint, very small, round, 15" diameter (viewed core only?), weak concentration. Located 8' WSW of a mag 9.6 HD 222507. The NGC identification with this galaxy is uncertain due to Tempel's poor position and description ("pretty bright").