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A fine field in bootes: this ragtag herd of galaxies is worth corralling.

OFTEN OVERLOOKED by galaxy hunters, the giant Herdsman is not without extragalactic attractions. As evidence I offer the edge-on spiral galaxy NGC 5529 in the western part of the constellation. My interest in this 11.9-magnitude wisp dates back to Sue French's Deep-Sky Wonders column of June 2004 (page 84). Sue's impression of NGC 5529 as a "remarkably flat galaxy" inspired me to scrutinize it with my 17.5-inch Dobsonian under a country black sky. I had no trouble finding the little guy less than 1[degrees] northwest of the 5th-magnitude star A Bootis. And, as often happens when one digs deep with large optics, I unearthed other subtle treasures nearby. Let's tour the area beginning with that flat fuzzy.

Sue reported that NGC 5529 "is one of the entries in the Revised Flat Galaxy Catalogue, a compilation of 4,236 galaxies that appear at least seven times longer than wide." At 6.4' x 0.7 '--a ratio of 9:1--NGC 5529 qualifies easily. My initial inspection of the galaxy at 83x resulted in the following statement in my logbook: "Very slender and gently brighter toward the middle. Slanted northwest-southeast with a dim star off southeast tip." At 285x I added: "Small, distinct core with some mottling." I interpret that blotchy texture as a hint of the galaxy's dust lane. The image on the facing page shows the dust lane cutting north of the nucleus, indicating that NGC 5529 isn't precisely edge-on. My log entry agrees: "North edge fairly straight; south side bulges slightly."

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Two very faint galaxies hover near NGC 5529. PGC 50952, also known as MCG 6-31-87, is visible in my scope at 222x about 4' southeast of the edge-on's hub, as shown on the facing page. PGC 50925 (sometimes identified incorrectly as NGC 5527) is an extremely difficult object located a similar distance southwest of the hub. Both companions are comparable in size, but while PGC 50952 has a bright core and glows at magnitude 15.3, PGC 50925 is diffuse, with much lower surface brightness. When I try for the fainter galaxy, I first note the 14th-magnitude star directly south of NGC 5529's core. On the best nights, my averted vision occasionally glimpses an exceedingly faint patch whose position relative to the star and the other two galaxies matches what I see in images. Consider PGC 50925 your challenge of the night!

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Eagle-eyed observers might pick up three other small fry in the same high-power field. Two of the galaxies, PGC 2076761 and PGC 2076843, lie close together 4' east of NGC 5529. I only recently noticed these tiny targets on photographs and haven't yet attempted them telescopically, but they seem brighter than the aforementioned PGC 50952. They'll likely appear stellar unless high magnification is applied. Another midget is 15th-magnitude PGC 50944 (MCG 6-31-86), almost 9' north of NGC 5529. This pale blob flickers on and off in my optics at 285x, east-northeast of a 10th-magnitude star.

Less than 1/2[degrees] northeast of NGC 5529 is a compact galaxy pair I call "the comet." NGC 5544 and NGC 5545 (together known as Arp 199) make a pretty picture: NGC 5544 is a yellowish, face-on barred spiral partly overlapped by NGC 5545, a bluish, nearly edge-on spiral. At 83x this tight twosome is just an irregularly-shaped nebulosity, but 285x reveals a binary galaxy oriented northeast-southwest. NGC 5544 glows at magnitude 13.4 and exhibits an obvious core inside a 1'-diameter halo. NGC 5545 is about 1 magnitude dimmer and elongated 1.0' x 0.3'--a faint "tail" flowing away from the bright "head" formed by NGC 5544. Delightful!

Your scope can sweep up three additional NGC galaxies within 3A[degrees] of the "comet." The most prominent of these is 11.0-magnitude NGC 5557, whose 2.3' x 1.9' halo surrounds a bright core and nucleus. At 285x I see a dim star in the halo southeast of the core. Also in the region are 14.2-magnitude NGC 5572 and 13.8-magnitude NGC 5527. The latter object is labeled NGC 5524 on most star charts, but in a note on the NGC/IC Project website (www.ngcicproject.org), Harold G. Corwin, Jr. argues that NGC 5527, the name sometimes given to faint PGC 50925, should apply to this much more prominent galaxy. According to Corwin, NGC 5524 is likely a faint double star mistaken for a galaxy by Lord Rosse while observing NGC 5529 through his 72-inch reflector in 1855.

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Ken Hewitt-White hunts galaxies from western Canada.
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Title Annotation:Going Deep
Author:Hewitt-White, Ken
Publication:Sky & Telescope
Geographic Code:1USA
Date:May 1, 2010
Words:758
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