The Crescent Nebula - NGC 6888

[John]

I've seen this object mentioned a few times in various threads recently so, as I've not seen it before, I thought I'd have a look for it tonight.

Cygnus is just about at the Zenith as I'm posting this so in the darkest part of the sky for me albeit one that can be challenging for a dob to view.

I used my 12" dob with the trusty Nagler 31mm and Astronomik O-III filter attached. Stellarium gave me the approx position and it took me about 15 minutes of slow scanning before I picked up the faint loop of nebulosity with embedded stars that is NGC 6888.

Encroaching cloud cover limited my time so I could only spend 10 mins or so studying this object. It's a subtle and delicate affair which reminded me a little of the Eastern segment of the Veil although the Crescent is quite a lot fainter, somewhat smaller, is more curved and seems to face the opposite way the the Eastern Veil.

The arc of nebulosity seemed to have strands and tendrils reaching in towards the centre of the curve. A little averted vision helped increase it's extent and it "popped" quite nicely when viewed out of the corner of my eye. I read one description of this object that likened the visual view to the Euro symbol and I think thats an apt description.

The rapidly moving cloud cover limited my time so I was not able to try other eyepieces or without the O-III filter although I have the feeling it would be extremely hard to find filterless, at least under these conditions.

Nice to bag a new nebula and I'll be back for another visit real soon 

Thanks to those who have mentioned the Crescent in other threads for putting it on my radar, so to speak 

[PhotoGav]

Nice report John and congrats on bagging The Crescent. It's funny, having met you at sgl9 and enjoyed views through your Dob, as I read your report, I can hear it spoken in your voice! I am gathering OIII subs of The Crescent as I type... A slow, faint and occasionally cloudy affair, but hopefully will be worth it in the end!

Clear Skies.

[jetstream]

Great report John and congrats,eagerly waiting more of your observations.I'm not too sure I'll see it without a filter from here,but its worth trying,if you do see it no filter I am very interested and may try a different site for a hair more contrast.The Euro description is very good and I also like swampthings "brain" description!I noticed the filaments kind of went across the neb sideways,not up and away from it and starting brighter from the shell edge,extending in.Similar to your view I think.

Thanks for taking an interest in this object John and reporting

[Mike73]

Nice description John.

Its a great object that demonstrates how well averted vision works aswell IMO. Looking straight at it like you I can see filaments on the inside, the central spike and nebulosity but when I look slightly off I lose the detail in the filaments but around 3/4 of the internal area is filled with a puff of nebula. Its easy to lose track of time switching from direct to averted vision seeing the benefits each shows.

The recent thread on OIII filters has been interesting aswell, I'm using a DGM Optics NPB filter at the moment and it works very well but I pretty much know for a fact that a aggressive OIII would work better on the Veil and the Cresent. Knowing that I could be getting better views of these great objects is frustrating but I struggle to justify the cost, knowing me I'II probably just buy one on pay day anyway!

[swamp thing]

The summer skies nebulae are fantastic objects aren't they

The nebulae in and around Cygnus are just fantastic. The level of detail one can get from the crescent by using an O-III filter from a good dark site is breathtaking.

The fine tendrils are superb aren't they. I spent some considerable time studying this object from a good dark site and thoroughly enjoyed it.

Well worth a prolonged study John

Enjoy

[Bart]

Nice one John. Skysafari pointed me to this last year. I found it reasonably ok. I was using 16" though.  I went back another day to find it and failed. Only then did I discover that it is a tricky beast visually. Must go back again as I like a challenge!

Edit - Apologies, I was thinking of the Medusa Nebula in Gemini. Hard one. Must hunt down the Cresent soon. Thanks John. Sorry again

Barry

[Mike73]

Nice one John. Skysafari pointed me to this last year. I found it reasonably ok. I was using 16" though.  I went back another day to find it and failed. Only then did I discover that it is a tricky beast visually. Must go back again as I like a challenge!

Completely agree with this Barry.

Sometimes I can pick it out no problem without a filter, other times I can look straight at the keystone stars and look right through it as if its not there and this is at a reasonable LM 6.3 dark site. Its not all about dark skies but transparency plays a huge part in DSO's aswell. 

A lot to be learnt from this little nebula methinks.

[RikM]

From home on a good night I can just make out the € shape. The center spine and lower half of the curve are brighter, so most times it looks like a short arc ending at a 90° corner. I've never made out any internal wispy bits though but I have never looked at it from a dark site.

[spaceboy]

It's a subtle and delicate affair which reminded me a little of the Eastern segment of the Veil although the Crescent is quite a lot fainter, somewhat smaller, is more curved and seems to face the opposite way the the Eastern Veil.

Congratulations on bagging this one John. I am aware this is no easy target. I was lucky enough to have an experienced observer (moonshane) and his 16" dob at PSP 2011 to show me this testing nebula although for weeks I'd thought he'd shown me the present nebula  . Needless to say under ideal conditions and in large aperture it was far from faint but your description summed it up well.

[Daniel-K]

Hi john interesting that you have compared it to the veil. i used the 31mm axiom last night with the astronomik UHC and it was no small curve it was infact the full shape of the "brain" shape as i call it. i hope you can get out again and spend some more time on it. when you where observing the curve did the OIII bring out a red curve?

[John]

Hi john interesting that you have compared it to the veil. i used the 31mm axiom last night with the astronomik UHC and it was no small curve it was infact the full shape of the "brain" shape as i call it. i hope you can get out again and spend some more time on it. when you where observing the curve did the OIII bring out a red curve?

I didn't get much time on it Dan because of the cloud that I mentioned which swept across literally 15 mins or so after I'd located the darn thing !

I'll certainly look it up again and spend much more time on it on the next clear night.

The averted vision glimpses I mentioned did seem to show a fuller form to the nebula, with the area within the curved arc appearing to contain nebulosity.

I did not see any colour in the object at all but then I rarely have on any DSO apart from a green tint in M42, even when I had a few peeks with a 20" dob a few years back. 

I was just pleased to find it and "mark it's card" so I can come back and study it in more detail 

DSO observing is not great from my back garden generally because of the usual issues of neighbours lights, tall trees and fences and the glow of Bristol to the NE and Newport / Cardiff to the E. Overhead things are much better but it does limit you to stuff which gets to that part of the sky 

[Rustysplit]

Nice report John. Can be a tricky one to find the first few times. You know you are in the right place when you see a group of 4 stars that look just like a mini "keystone" in Hercules. I am looking forward to getting a proper look at it in Wales late september.

[michael.h.f.wilkinson]

Great report John. I have been able to spot it with a UHC filter, but it is by no means easy!

[Scosmico]

Glad that you made it. I, some how, didn't manage to see it in my previous two attempts. I will see it this summer! I wonder if people can see it without UHC or OIII filter.

[pyrasanth]

You should all cheat- get a Hyperstar & image this baby. You can then look at the picture with the sun on your face. I just love imaging- the memories are kept fresh for ever!

[John]

You should all cheat- get a Hyperstar & image this baby. You can then look at the picture with the sun on your face. I just love imaging- the memories are kept fresh for ever!

Imaging is a great arm of the hobby but this is the observation section, hence all the reports of visual observations

[Daniel-K]

You should all cheat- get a Hyperstar & image this baby. You can then look at the picture with the sun on your face. I just love imaging- the memories are kept fresh for ever!

ah but the photons are dead after they hit your chip, where as ours stay alive in our memories for ever!