FUZZY SPOT, June 2002, Ursa Major
Ah, Ursa Major, known to most as the Big Dipper. It was most likely the first constellation you learned as a child, and probably the most prominent star pattern in the northern skies (the Big Dipper is actually an asterism within Ursa Major).
For some reason, Ursa Major is my favorite constellation of the springtime galaxy rich sky. This constellation is the 3rd largest in the sky, and has 7 Messier objects. As in the previous columns, I am going to focus on the Messier objects. With the exception of NGC 3587 (M-97), all of the objects described here are galaxies.
NGC 3031 (09 55.6 +69 04) M-81 along with M-82 are real showpieces. In the 10" scope it is very large, very bright, has a much brighter middle which suddenly brightens to a non-stellar nucleus. Using averted vision makes the halo extend quite a bit, especially in the minor axis. 2 stars are involved to SE. Some possible mottling is suspected, but mostly seen as very even. In the 20" scope, it is very bright, very large, and has an elongated halo 5:1 NE/SW. The halo gradually and smoothly brightens to a brighter middle elongated about 2:1 the same orientation as the halo, and then suddenly there is a much brighter non-stellar nucleus. Averted vision may show a clockwise spiral structure, especially on the SE side. 2 stars are involved on the SW end.
NGC 3034 (09 55.8 +69 41) M-82 In the 10" scope, this is seen as pretty bright, fairly large, extremely elongated ENE/WSW, with no central brightening, and very mottled. There are possible dark notches at the middle. A fainter halo surrounds the main central streak. There is a nice string of 3 stars leading away from the galaxy to the SW, and several other stars close by. In the 20" scope, M-82 is bright, pretty large, elongated about 6:1 WNW/ESE, extremely mottled, and contains no real center or nucleus. There are two brighter patches near the middle separated by a dark lane. Averted vision extends the halo and shows tapered ends. There are several stars nearby, but none are involved. This is a very nice streak of light in the sky. (Note the different orientation designations. With objects near the pole, it is hard to tell the orientation since the drift is so small. The correct orientation based on the Digital Sky Survey is ENE/WSW.)
NGC 3556 (11 11.5 +55 40) M-108 In the 10" scope, it is very bright, very elongated WNW/ESE, pretty large, has a very bright middle, and a stellar nucleus. The halo is pretty bright, but shows no mottling. Using averted vision makes it stand out somewhat. Upping the power to 140X, there is a very definite stellar nucleus and perhaps some mottling. In the 20" scope, it is very large, pretty bright, very slightly brighter in the middle with a very bright stellar nucleus, or perhaps a foreground star. It is elongated about 5:1 E/W with the halo being extremely mottled, especially with averted vision. Suspected are 2 or 3 involved stars. Wow!
NGC 3587 (11 14.8 +55 01) M-97 is better knows as the Owl Nebula. In the 10" scope, it is very round (I don't know how you get rounder than round, but this object apparently is!), has a bright star to N side, and the dark spots suspected. Using the UHC filter brings the object out and does bring out the eyes. This object is very large for a planetary. In the 20" scope, it is pretty large, pretty bright, round, and gray in color. Dark are spots suspected with and the central star is occasionally seen with averted vision. The dark spots are oriented WNW/ESE with ESE spot being most prominent. The edge fades out evenly.
NGC 3992 (11 57.6 +53 22) In the 10" scope, M-109 is somewhat bright, elongated, with a bright middle, a non-stellar nucleus, and a star involved near the center. Averted vision makes the halo grow a little. Increasing the power to 100X, there is a definite bright middle, and the halo extends between ends (this ranks right up there with very round as my most unusual note). The elongation is E/W. Using averted vision makes the star near the center really pop out. In the 20" scope, it is somewhat bright, pretty large, containing a halo that is somewhat faint and mottled. The middle is slightly brighter with a faint sub-stellar nucleus. The object is elongated about 3:1 E/W, using averted vision makes it less elongated.
NGC 5457 (14 03.3 +54 22) In the 10" scope, M-101 is very very large, pretty bright, has a fairly bright halo and a nice sharp center. There is a definite clockwise spiral structure including some knots seen with averted vision. At 100X, a bright non-stellar nucleus is seen along with 2 knots to SW and one to SE. Seen in the 20" scope, stupendous!!! It fills the full field of view. Very very large, a little bright, contains a round middle that is only slightly brighter than the halo, which gradually brightens up to a non-stellar nucleus. A bright star is involved to the NW of the middle situated nicely between spiral arms. Several other stars are involved further out. The spiral arms are almost indescribable! At least 7 or 8 nebulous patches are visible. The clockwise spiral arms are obvious with 2 main arms and many segments.
Winnecke-4 (12 21.9 +58 06) M-40 is perhaps the most peculiar of
the Messier objects. In the 10" scope, it is a wide
pair of stars, white and slightly red, kind of hard to tell with
the seeing. The white star is the brighter of the
two. Not surprisingly, it isn't much different in the
20" scope. It is seen as 2 fairly bright equal stars
oriented ENE/WSW. The E star is bluish and the W star is
Herschel 400 Objects
2681, 2742, 2768, 2787, 2841, 2950, 2976, 2985, 3034, 3077, 3079, 3184, 3198, 3310, 3556, 3610, 3613, 3619, 3631, 3665, 3675, 3726, 3729, 3813, 3877, 3893, 3898, 3941, 3945, 3949, 3953, 3982, 3992, 3998, 4026, 4036, 4041, 4051, 4085, 4088, 4102, 5322, 5437, 5474, 5631
SACs 110 Best of the NGC Objects
3841, 3077, 3079, 3184, 3675, 3877, 3941, 4026, 4088, 4605
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