Rosette Nebula

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Rosette Nebula

Postby Aratus » Mon Jan 14, 2019 4:21 pm

Typically it has been cloudy over the last couple of weeks while the moon has been out of the way. On the 13/14th January it clears but there is a half moon around!!! :( I waited until midnight, and moonset.

I wanted to take some long exposures of the Rosette Nebula (Cluster - NGC2244. Nebula - NGC2237). The Rosette is a large, but very faint nebula in Monoceros, but I always think of it as being left of Orion! 'Rosette' is very large, about the size of 9 full moons, but with a very low surface brightness. The first problem is that it requires a wide field lens, so I used the 80mm guidescope, and the ZWO1600. The second problem is that it needs a very long exposure for such a small telescope. The third problem is that a very long exposure will wash out the nebula with light pollution. The answer is to use a Ultra High Contrast filter. That means having to increase the exposure time even more! I tried 1, 2 & 3 minute exposures, but it hardly registered the nebula at all. However 5 minute exposures just about showed it. With the wide field and a well behaved mount I had no problems with trailing. I took 6 x 300sec exposures. I stacked them, and manipulated the image to bring out the faint nebula. Image
The Rosette is a 'stellar-wind bubble', and not a planetary nebula, even though it looks a bit like one. The central star cluster is easily seen through binoculars or telescope. From a dark sky site the cluster can even be located with the naked eye. I have taken photos of the nebula before by simply using a camera mounted on to the telescope, but this is the first decent one I've taken through a telescope.
I use an 11" reflector (Celestron CPC 1100) and a 3" refractor, (Sky-Watcher ST80) mounted on an equatorial wedge, housed in a 2.2m Pulsar observatory. I use a ZWO ASI 120MM, ZWO ASI1600MC and Canon 1300D for imaging.
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Re: Rosette Nebula

Postby Graeme1858 » Mon Jan 14, 2019 6:38 pm

That is really nice! 5 minute exposures just using the mount!
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Celestron CGX 9.25" SCT
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Re: Rosette Nebula

Postby Aratus » Mon Jan 14, 2019 10:45 pm

Sometimes it works! Remember the field of view is over 3 degrees, so any drifting error would be a lot less obvious that it would be through the larger telescope. Also the Rosette was on the southern meridian, which takes the strain off the motors. I also made an effort to get the alignment as best as I could by using a reticule, rather than guessing. Still, I think I was fortunate that the mount gearing settled down! No one was more surprised than me to find that there was no trailing after 5 minutes! 8-)
I use an 11" reflector (Celestron CPC 1100) and a 3" refractor, (Sky-Watcher ST80) mounted on an equatorial wedge, housed in a 2.2m Pulsar observatory. I use a ZWO ASI 120MM, ZWO ASI1600MC and Canon 1300D for imaging.
Aratus
 
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Joined: Tue Jan 12, 2016 2:17 pm
Location: East Lincolnshire

Re: Rosette Nebula

Postby Aratus » Tue Jan 15, 2019 11:09 pm

On the same evening as I imaged the Rosette I took some images of the moon using the same set up. This photo of the moon is on the same scale as the one above, and therefore gives some idea of how large the Rosette really is.

Image
I use an 11" reflector (Celestron CPC 1100) and a 3" refractor, (Sky-Watcher ST80) mounted on an equatorial wedge, housed in a 2.2m Pulsar observatory. I use a ZWO ASI 120MM, ZWO ASI1600MC and Canon 1300D for imaging.
Aratus
 
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Joined: Tue Jan 12, 2016 2:17 pm
Location: East Lincolnshire


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