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Old 19-03-2007, 07:08 AM
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glenc (Glen)
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IC2220 Toby Jug Nebula NB

We looked at this nebula from Leyburn (altitude 400m) last Saturday night using William's 25" f5 telescope and a 17mm (186x) eyepiece. The nebula is 1.7 degrees north of the brilliant OC NGC 2516 and surrounds the magnitude 7 orange star V341 in Carinae. The 6' x 4' nebula was Y shaped through the 25" scope and an orange colour was visible in the nebula. This image is similar to what we saw:
http://www.myastroshop.com.au/guides...c2220-lrgb.jpg
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Old 23-03-2007, 11:00 PM
ariane
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Glenc and all

The size of the nebulosity here seems a little larger than it appears in the telescope - or for images for that matter, and is more like 4.5x3.5 arcmin. I would have loved to have seen it in the larger Dob. The colour is interesting, as the orange colour has never seemingly been reported before. I'd assume this is from the light of the bright star - but you would expect the nebulosity to be blue - as most of the light is reflection, though the inner nebulosity has been shown to be fluoresing.

There is an useful and interesting article on the internet by Andrew James on this strange nebula, which might be of interest to IIS members here. it is highly
detailed and a good read.

The web address is;
http://homepage.mac.com/andjames/IC2220.htm
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Old 24-03-2007, 07:05 AM
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glenc (Glen)
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Thanks for the correction and the web page. The size is about 2' x 2' not 6' x4'. I doubt if an OIII filter would help as it is a reflection nebula. I looked at it with my 12 inch last night, the nebula seemed to be orange but I could not see the Y shape. Have you seen it?

Last edited by glenc; 25-03-2007 at 10:52 AM.
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Old 27-03-2007, 12:00 AM
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astroron (Ron)
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I have observed this object on a few occassions with a 40cm truss newtonian at the suggestion of William, I concluded that an O111 filter did no good whatsoever, it also takes as much magnifaction that you can give it. A very interesting object, the more you observe it the more you can see the shape of a butterfly.
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Old 29-03-2007, 02:40 AM
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Sorry for the delayed reply.

To answer Glenc question, the Y-shape is probably only able to be seen in smaller scope in the order of 20cm, which my observing notes describe. This is orientated by 135 degrees from north, with the bottom point of the Y facing upwards at the top of the field.

This is probably because the butterfly shape (as described by astroron) is visible in large apertures.

As for the OIII, your are probably right. I though this brightened the nebulosity in 20cm very close to the central star / progenitor - agreeing with the article's statement. This actuality is given in the literature during the 1970's as well, which some have assumed was direct evidence of a close blue star causing the inner nebulosity to shine not by reflecting light but by acttual llumination by flouresence. As the star is variable, you could assume the nebulosity closeby is also changing in brightness - though several papers comment that this has not ever been observed.

Perhaps we are missing something not noted here???
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