Planetary nebula?

[Manok101]

a couple of days ago, through my xt4.5 i saw what looked like a cloud in near perfect circle around a star that was very hard to see, the star was kind of orangeish, and was just wondering, can the atmosphere make you think you're seeing a nebula sometimes when you aren't even with such a small scope as a 4.5 inch?

[Talitha]

Absolutely... i've seen that effect with the 80ST. The glow can also be caused by a slightly fogged up eyepiece, especially in cold weather.

[Manok101]

I know what you're talking about, but this was much dimmer and harder to see, I only caught it because I was looking for differences in the stuff I was looking at. The top half was visible, and was very dim. It still could be that, is this what planetary nebulae look like without filters?

[Chris H]

Message deleted

[John]

I know what you're talking about, but this was much dimmer and harder to see, I only caught it because I was looking for differences in the stuff I was looking at. The top half was visible, and was very dim. It still could be that, is this what planetary nebulae look like without filters?

Planetary nebulae are quite variable in appearance and size - there are a few which appear as you describe although I can't think of any where colour or the central star is visible with a 4.5" scope

Where abouts in the sky were you looking ?.

I've certainly seen the sort of effect you are describing caused by atmospherics or fogged mirrors / eyepieces though so thats probably the most likely explanation.

There are some planetary nebulae that would be visible with your scope without filters - M57 (the Ring) and M27 (the Dumbell) for example are pretty clear on a good night.

[Manok101]

I was looking north east, fairly high in the sky, not overhead sometime between 10 and 2, I wasn't being too careful, this was one of my frequent random star hopping nights (random star hopping to me is just looking at stars at random, stopping to observe whatever looks interesting) l don't really know the northern area of the sky that well so I couldn't tell you what constellation I was looking at. This was the only time I noticed this effect (or is it affect?) that particular night.

[acey]

No planetary nebula (or deep sky object of any kind) looks "orangeish" - except perhaps if you've got upwards of 20" aperture and a very, very dark sky. Sounds like you were seeing a star through some misting on the eyepiece - happens all the time.

[LukeSkywatcher]

I totally agree with Carol and Acey. Unless you are 100% sure of your target.....the most minor thing (a star) can look nebulae like through a misted up EP.

As acey says..........it happens all the time. Specially in cold weather.

In the past i have even mistaken a star observed through a fogged up lens as a diffuse comet.

[Manok101]

When it does happen what do I do for cleaning? I've had a few nights where it was so misty on the optics that I've given up and gone to eyeball observing.

[acey]

Keep eyepieces covered when not in use, either capped or in a container. If an eyepiece mists, put it in your eyepiece box uncapped for a few minutes where it will soon demist, and use another EP in the meantime. Another option is to warm the eyepiece, either with a bare hand (but that freezes your hand) or a portable hair-dryer (but you need a power source for that). Personally I prefer to put the EP away and let it demist. For the finder objective and newtonian secondary you want a dewshield: camping mat for the scope and a bit of cardboard for the finder, projecting a decent distance (typically 2 times aperture) beyond the end of the tube. There are also dew-strip solutions, again involving power supply.

[Manok101]

Another question is, how do I know I am looking at a nebula vs a cloud or some atmospheric phenomena? Are nebula typically as big as the one in orions sword just dimmer? or are some really tiny because of distance? I'm beginning to understand when I see magnitude of a listed object and be able to sort of guess if i will be able to see it at all or not. Size is my next big hurdle.

[brantuk]

You can definitely see shape when viewing nebulae. The Swan neb looks roughly like a swan, the Ring neb looks like a ring, etc. Best to put together a list of maybe 20 targets for the evening noting positions, look them up in Stellarium, then see if you can find and recognise them with the scope - you get better recognising stuff over time

[sixela]

No planetary nebula (or deep sky object of any kind) looks "orangeish".

Except perhaps one: IC 418, the Raspberry Nebula (and perhaps NGC40). But you're right in saying that most are, if they reveal colour at all, typically blue-green.

[acey]

Except perhaps one: IC 418, the Raspberry Nebula (and perhaps NGC40).

That's right, which is why I added the remark about 20" or more of aperture and a very dark sky.

[sixela]

Actually, given the Raspberry nebula is quite small and that you're using quite some magnification, you don't need extremely dark skies, and I see that colour in 12" scopes as well. But we're straying off topic...

[acey]

I'm interested that you've seen the pink colour in the Raspberry with a 12": it's generally considered to need a lot more. And there are of course plenty of reports of seeing red in the Orion nebula with that sort of aperture.

But how about orange?

[sixela]

Well, despite its name, I think the Raspberry nebula is a bit orange, actually, at least at moderate magnification (it's much more raspberry coloured at lower magnification and that should be more reliable, so it's probably partly an illusion and maybe only with my eyes).

NGC40 certainly is orange but you do need low magnification to see it, and if the sky background is grey that won't work so you need a dark site. And I do agree you actually need a 16" scope for that.