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NGC 6826 The Blinking Planetary Nebula


Moonshane
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Hi all

Also known as Caldwell 15, this was a new object for me and one that really made me smile when I saw it.

I was using a large aperture scope (16" dob) but it's a bright object am I am pretty sure this would be good in most scopes in the right conditions.

It is in the left wing of Cygnus and quite easy to find. It gets the vernacular name from the fact that when you look directly at the object, the nebulosity fades away, revealing only the central star which is very bright for a PN. Looking to one side of the central star with averted vision makes the nebula puff out again.

At about 140x this was a fairly large pale blue/green disk and I initially assumed that like many planetary nebulae this would benefit from an Oiii filter; how wrong I was.

At first I was slightly disappointed as the central star was not that bright at all and although attractive, there was nothing that special about the disk. I then referred to my guide book and this did not mention an Oiii filter so I took it off the eyepiece. What a difference! The disk, which is slightly oval, showed hints of structure radiating out from the central star and the whole thing became a more delicate bubble. The central star was also much brighter and the whole blinking worked much better.

If you have never seen this object it is currently well placed at the zenith as it gets dark and it's worth a look. I found the nebulosity faded out like a dimmer rather than turned off like a light switch but it pops out instantly. Very entertaining and as I said, an enjoyable and interesting object.

More info and a map linked below

NGC 6826 - Wikipedia, the free encyclopedia

File:Cygnus IAU.svg - Wikipedia, the free encyclopedia

cheers

Shane

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Back at you Michael! Never seen NGC 40 so we'll swap :)

It was a slightly peculiar (equatorial) star hop: moving due north from Caph, I first overshot the mark, ending up at an almost scythe-like shaped group of stars. Moving slightly west and dropping south again, I found a pair of stars that point to NGC 40. The nebula itself is quite bright and even my C8 seemed to show the central star in averted vision.

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I was looking for this last night with my scope and was struggling (unable) to see it. Saying that though it was quite hazy last night :)

Under my skies the Naked Eye limiting Magnitude was only around mag 3 (at zenith) last night which is a lot worse than it can be.

The blinking planetary Nebula I suspect is just a bit too small for my scope...

Went looking for the veil nebula and NGC7000 but I suspect I was being just a little too adventurous under the circumstances.

(All targeted using a UHC filter)

The moonlite focuser got its first run for its money as well. Mmmm very nice!

Edited by MjrTom
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Got it! The blinking planetary is a neat little object in my C8. It needed 119x magnification to clearly distinguish it from stars, but it is bright indeed. No UHC filter needed. The main difficulty in finding it by star hopping northward from delta Cygni oat in distinguishing it from a star. I slight blue tinge helped. A couple of students were on hand to confirm the sighting.

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  • 2 weeks later...

I bagged this for the first time last night. It was invisble at first, then I put an O-III Narrowband on and then it popped right into view ! I removed the filter and then used averted vision. It gave a view similar to Uranus , a bluey/green disc. I found that if I looked directly at it I could only see the central star but with averted vision i could make out the disc. Thats where it gets it's name from !

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I always found it confusing when looking for planetary nebulas because on Stellarium, there was always a star where the planetary nebula was supposed to be. Is the central star the 6.95 marked on Stellarium?

I have been looking for the blinking nebula tonight and I failed. It was really high up in the sky. I knew just where it was. I began star hopping to it and I got to within half a degree away from it but whichever way I turned my dob horizontally, the target area seemed to drift away. I could not physically get it in the FOV. Anyone got a solution to this.

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Do you know what , I had the exact same problem last night. I tried revisiting it after finding it the other night . I was so close but I couldn't physically get the object in view no matter which way I turned my dob . I had to wait a while until Cygnus had moved out of that area of the sky . I found using a O-III Narrowband helped me locate this object , it appears as a white ball in the eyepiece .

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Would tilting the dob not work? i.e. putting a thick book under one side of the dob base.

If not, I think option 3 would suit me the best as I don’t have any money.

It was a bit annoying having rain clouds passing by and only having about 15 mins of clear sky between them and trying to find this object and just not being able lol. :)

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Possibly , i may give it a go tonight and try and find a solution , but I think the problem exists for only a short amount of time. Last night I swung round and viewed the blue snowball nebula instead . Which is a better object in my opinion . In the half hour that passed I was able to get it back in view .

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I had the privilege of viewing this for the first time through a 15" dob and thought it was a really fun object. Its one of the few dso's to show much colour to me, it showed as clearly green to my eyes. The blinking effect is quite clear, the nebula disappears, leaving just the central star.

I viewed it on the same evening through my mak. It was clearly visible, just not as bright and the colour was less vivid.

Must re visit it sometime soon

Stu

Sent from my GT-I9000 using Tapatalk

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