Click Here for Full Resolution
Another image of the Bubble Nebula may be found here
Designations: M52,
NGC 7654 Designations:
Bubble Nebula, Caldwell C11, NGC7635
Object Type: Open
Cluster Object Type:
Emission Nebula
Constellation: Cassiopeia Constellation: Cassiopeia
RA: 23
hrs 24.8
min RA: 23hrs 20.7 min
Dec: + 61deg 36 min Dec: +61 deg 12 min
Visual Magnitude: 6.9 Visual Magnitude:10
Size:
16' Size:
15' x 8' - 3' X 3' (bubble)
Distance: 5,100 light
years Distance: 7,100 light years
Discoverer: Messier, 1774 Discoverer: William Herschel, 1787
Visual Description: M52 lies about 1/2 degree south of 4 Cassiopeiae, a reddish 5th-magnitude star about 6 degrees northwest of Beta Cassiopeiae. M52 is a very rich telescopic cluster. About 20 million year soung, it measures 24 light years in diameter and contains nearly 200 members brighter than 15th magnitude. The cluster's computed central star density is 56 stars per cubic parsec; in Messier's catalogue, only M11 and M67 are denser open clusters. You will be immediately struck by the forceful presence of an 8th magnitude topaz field star on the cluster's southwestern edge. This star but leaps out at you, as if trying to steal the show. It is an imposter however, not an actual member of the cluster. Interestingly, when I first looked at the star, and then at the cluster, which has an overall bluish hue the topaz color of the star seemed even more pronounced. Webb and Smyth saw this star as orange, and Mallas recorded it as a conspicuous reddish star. Webb almost sounds sarcastic in his description of M52 "Irregular, with orange star, as is frequently the case," but he is merely noting that usually the most outstanding member of an open cluster shines with a ruddy hue.
With a quick glance at low power, M52 looks like a tight ball of tiny crystal chips reflecting blue light. A longer view will reveal a little isolated patch of starlight just to the northwest of a heart-shaped central body; a much larger patch lies to the southeast. With 72 X, the shape of the cluster's stars looks rather arachnoid, like a scorpion. Thin wisps of faint stars jut from the body like tiny legs, and patches of starlight form the claws. The scorpion's swooping tail curves to the north, where it joins the topaz star. Two stinger stars follow to the east.
The main, heart-shaped body of starlight contains many uniformly-bright stars caging a haze of fainter members, which requires peripheral vision to resolve. When you don't stare directly at this cage, do you see the thin, dark rift running along the southeastern side of the scorpion's body
While in the vicinity, try to glimpse the elusive Bubble Nebula (NGC7635). Only 36' southwest of M52, this very dim ring of gas, whose brightest section surrounds an 8.5-magnitude star, is only weakly visible from dark skies. Although it resembles a planetary nebula, the Bubble is a fairly ordinary HII region, a vast cloud of ionized hydrogen.
Another image of the Bubble Nebula may be found here
Telescope:
Takahashi
TSA102 APO Refractor
Focal Length: 610 mm
with a dedicated reducer/flatterner
Mount:
Takahashi NJP 160
Camera:
SBIG ST-10XME
& ST402ME
autoguider
Exposure: 9
5-Minute exposures for M52. The Bubble
nebula was also imaged separately with nearly 3-hours of hydrogen alpha
exposures which were used to enhance the image. The Bubble Nebula along
with it's surrounding nebulosity requires a much longer exposure to be visible
in the same image as the star cluster.
Image Processing: CCD Stack and Photoshop CS2
The Visual description of the M52 Globular Cluster was writen by Steven James O'Meara in the book "The Messier Objects" by Stephen James O'Meara. Page. 163. ISBN number 0-521-55332-6.
Copyright(c) 2007 Doug Sanqunetti. All rights reserved
