Object of the Week July 29, 2012 - NGC 6745 Bird's Head Galaxy
NGC 6745 “Bird’s Head Galaxy”
Triple Galaxy System
Lyra
RA 19 01 42 DEC +40 44 40
Megastar listed size and magnitude
Size: 1.4x0.6’ Mag: 13.3
NED listed size and magnitudes
Component A (Main body of the head) – Size: 0.9x0.6’ Mag: 13.5
Component B (Tip of the head)– Size: 0.2x0.2’ Mag: 16.2
Component C (Beak) – Size: 0.3x0.2’ Mag: 15.9
This is a very interesting galaxy system in Lyra. It truly looked like a bird’s Head through a large telescope.
I’ve observed it several times recently through my 22” and Jimi’s 48” scope. This object was one the targets during evaluation of differences between several 6mm eyepieces over several nights. One evening, at least five different observers with skill levels ranging from novice to very experienced saw the same differences and realize the advantage of low glass count eyepieces.
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Below is the comparison of the 6mm Ethos, 6mm BGO (UO HD) and 6mm Zeiss Abbe Ortho – Series II (Note: I’ve copied the text from my website)
NGC 6745 (triple galaxy system) in Lyra was nearly overhead under NELM 6.9 skies, average seeing and above average transparency. Telescope used - 22" f/4 reflector.
The first image is with the 6mm Ethos and the second image is with the 6mm Zeiss ZAO-II, both giving about 383x. The details seen in the triple galaxy system was evident as the three cores were a bit more distinct, especially in the Zeiss. The two cores in the body were lost in the Ethos. The upside down house asterism shows only six stars in the Ethos and NINE with the Zeiss. We had at least five other observers that confirmed this observation, including at least one beginner. If a beginner can see the difference, than anyone can.
-- A recent observing note:
22” at 306 and 383x – Bright glow with a separated beak.
The head is a bright 5:2 irregular elongated glow with well-defined with some diffuse edges that truly looks like the head of a bird. There were two slightly brighter cores in the head, component A and B. The two cores are about 0.5’ apart, one at the center of the head and the other at the north tip. The north tip is very sharply defined compared the base of the head at the south and west with fairly diffuse edges. Otherwise the rest of the “head” is fairly even surface brightness. About 1.0’ long and PA = 20.
The separated galaxy, component C the “beak”, has a slightly brighter surface brightness than the head. The beak is about 0.2’ north of the tip of the head and about 0.2’x0.1’ with somewhat defined edges.
This is one of my favorite objects after Jimi showed it to me in his 48” reflector. He called it the “Bird’s Head Galaxy”. It was amazing with his scope! Sorry I don’t have those notes handy as I’m traveling on business now.
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