Paul Alsing
January 17th, 2017, 11:39 PM
Object of the Week - January 15th, 2017 - NGC 2346, The Hourglass Nebula = M 1-10, PN G215.6+03.6, PK 215+3.1
Monoceros
R.A. 07h09m22.5s - 00°48'23" (2000)
Size 60"x50"
Mag; V = 12.5; central star = V651 Mon (mag 11.3-13.5)
NGC 2346 is well placed this time of year, culminating just before midnight. Since it is almost exactly on the celestial equator is can be seen from almost anywhere in the world. Carrying the nickname "The Hourglass Nebula" (it is also known as the "Butterfly Nebula", photos of this planetary nebula leave little doubt as to how it got this name...
2447
NGC 2346 is a bipolar PN and was discovered by William Herschel in 1785. It is approximately 2,000 light-years away from us and is about one-third of a light-year in diameter. In my 25" f/5 dob it is tiny although fairly bright, even without filtration, but it responds wonderfully to just about any filter, OIII, UHC or my trusty NPB. I saw it as being a bright star with a hazy ring around it, and almost round. Upon pumping up the power I could get a hint of a pinch in the middle, and a hint of the 'wings' to either side. I think I would have seen more detail if the darn central star wasn't so bright!
That central star's history is quite interesting. It is actually a binary star, an A5 main sequence star and a hot subdwarf, in a close orbit of about 16 days. See this page http://www.wolaver.org/space/ngc2346.htm where it is written...
"It is believed that the binary star was originally more widely separated. However, when one component of the binary evolved, expanded in size, and became a red-giant star, it literally swallowed its companion star. The companion star then spiralled downwards inside the red giant, and in the process spewed out gas into a ring around the binary system. Later on, when the hot core of the red giant was exposed, it developed a faster stellar wind, which emerged perpendicularly to the ring and inflated two huge "bubbles." This two-stage process is believed to have resulted in the butterfly-like shape of the nebula." Isn't that fascinating?
As always, give it a go and let us know
Monoceros
R.A. 07h09m22.5s - 00°48'23" (2000)
Size 60"x50"
Mag; V = 12.5; central star = V651 Mon (mag 11.3-13.5)
NGC 2346 is well placed this time of year, culminating just before midnight. Since it is almost exactly on the celestial equator is can be seen from almost anywhere in the world. Carrying the nickname "The Hourglass Nebula" (it is also known as the "Butterfly Nebula", photos of this planetary nebula leave little doubt as to how it got this name...
2447
NGC 2346 is a bipolar PN and was discovered by William Herschel in 1785. It is approximately 2,000 light-years away from us and is about one-third of a light-year in diameter. In my 25" f/5 dob it is tiny although fairly bright, even without filtration, but it responds wonderfully to just about any filter, OIII, UHC or my trusty NPB. I saw it as being a bright star with a hazy ring around it, and almost round. Upon pumping up the power I could get a hint of a pinch in the middle, and a hint of the 'wings' to either side. I think I would have seen more detail if the darn central star wasn't so bright!
That central star's history is quite interesting. It is actually a binary star, an A5 main sequence star and a hot subdwarf, in a close orbit of about 16 days. See this page http://www.wolaver.org/space/ngc2346.htm where it is written...
"It is believed that the binary star was originally more widely separated. However, when one component of the binary evolved, expanded in size, and became a red-giant star, it literally swallowed its companion star. The companion star then spiralled downwards inside the red giant, and in the process spewed out gas into a ring around the binary system. Later on, when the hot core of the red giant was exposed, it developed a faster stellar wind, which emerged perpendicularly to the ring and inflated two huge "bubbles." This two-stage process is believed to have resulted in the butterfly-like shape of the nebula." Isn't that fascinating?
As always, give it a go and let us know