Can I see the Crescent Neb in a 130P?

[RobertI]

Had another nice session with the Heritage 130P last night, enjoying the various parts of the Veil Neb at different mags with a UHC-E filter and catching the light blue Neptune in passing, but try as I might I could not find the Crescent Neb. I knew I was in exactly the right area and knew roughly what size it would be at mag x65, but I just could not see it. Removing the UHC-E didn't help. Should I be able to see it in a scope of this size? Would an OIII make this pop into view or should I be wheeling out the C8?

[John]

I find it a not particularly easy target with my 12" and UHC / O-III filter unless I get a pretty dark night here. My guess is that it would be visible in a 130mm scope with a UHC filter but you would need a really dark sky with little or no light pollution.

Both segments of the Veil nebula (E & W) are much easier to see IMHO.

 

[jetstream]

1 hour ago, RobertI said:

Had another nice session with the Heritage 130P last night, enjoying the various parts of the Veil Neb at different mags with a UHC-E filter and catching the light blue Neptune in passing, but try as I might I could not find the Crescent Neb. I knew I was in exactly the right area and knew roughly what size it would be at mag x65, but I just could not see it. Removing the UHC-E didn't help. Should I be able to see it in a scope of this size? Would an OIII make this pop into view or should I be wheeling out the C8?

It is easily seen in the Heritage 130 with an OIII under dark skies and it shows pretty small at the mag needed with the filter. A tight UHC also shows it but because of the small object size in the EP an OIII can work better.

 

1 hour ago, RobertI said:

knew roughly what size it would be at mag x65,

This mag will be tough to use with the OIII/tight UHC for nebluae- we use the supplied 25mm Super plossl with VG success.

[RobertI]

Thanks @John and @jetstream, very helpful. Unfortunately my skies are neither dark nor free from light pollution, but the Crescent sits directly overhead where conditions can be pretty good. It sounds like I need a OIII filter to stand a chance of seeing this (which I am planning on getting anyway) but interesting that a low magnification of x26 (25mm) is needed. My experience of the Veil was that higher magnification actually helped by (I believe darkening the sky background) but I guess this was partly because I was using a wide bandpass UHC-E and by using a 'tighter' filter like an OIII which darkens the sky still further, lower magnifications are possible? I may try the C8 but the lowest mag I can get is 50x with my existing eyepieces.

[John]

I found a big difference on the Veil between a UHC and an O-III filters. The UHC shows it but with the O-III you can study it's form and structure

I usually use either my 31mm Nagler or 21mm Ethos to view the Veil but sometimes the 13mm Ethos (depends which scope I'm using). The major segments really need a 1.5 degree true field to fit them in and the whole thing needs 3.5 degrees !

[Nyctimene]

11 hours ago, John said:

Both segments of the Veil nebula (E & W) are much easier to see IMHO.

I've made the same experience more than once. Even with the 8" f/4, widefield eyepiece and UHC/O III filter, it often remains elusive or invisible under 20.8 - 21.0 mag skies. Location is not quite easy; I've learnt to use the nearby "trapezium"  or "keystone" star pattern as a pointer (IIRC,  Nick (cotterless 45 on here) was describing this star hop here some years ago). You'll need to wait for a really dark sky night. I'd compare the Veil - Crescent difference with spotting the Helix (7293) and the 5 arc min planetary Jones 1 in Peg - the Helix is "glaring bright" in contrast to Jones 1.

Stephan

 

 

 

 

[jetstream]

We have a DGM NPB that shows the Crescent in the Heritage 130 but the OIII is really what you should have. As far as magnification goes try them all! I have- from a 32mm TV plossl,25mm plossls, 18mm orthos, 16T5 Nagler,12.5mm orthos, and the 10mm BCO.

A 20mm plossl might work well from less than dark skies but the 18mm is a bit too much for me. As John and Stephan mentioned this is a rather difficult object and it is well worth pursuing. I'd guess the bare minimum NELM for the Crescent is 5.5mag (using larger scopes) and 6 mag starts to really help things along.

Many say that the 24mm Pan and the 13mm Nagler are all we need with this scope... I'd agree if we could throw the 3-6 Nagler zoom in there to lol! (we use one a lot).

Keep trying this one Rob, you will see it.

[clarkpm4242]

Hi

I observed the main bright arc of  the Crescent with an OMC 140 and 32 TV Plossl.  This is about x60 mag.  Was filtered and a dark transparent night on Anglesey.

Keep trying!

Good lcuk.  Paul

[Tim]

For consolation, I can hardly see NGC6888 from home, even with an oiii filter and an 18" dob

At dark sites it is  much more observable, but even then I have found that mileage varies, and the same site on differing nights will yield quite different results with the same equipment.

If you check images of the crescent there is a particularly bright knot of emission nebulosity, and also next to the centralish star there is a dark patch, they might help you get fixed on the position. There is quite a distinct star pattern that makes it easier to find it if you are unsure.

Good look!

Tim

[Tim]

This pic shows the brighter areas  nicely, and the blotch;

[RobertI]

Thanks everyone for the encouragement and useful advice.  I think I need to do a bit more preparation next time, identifying the relevant star patterns for homing in on it and of course the OIII filter. I might even try and track down some sketches that people have made to get an idea what I am looking for. Will let you know how it goes. 

[jetstream]

1 hour ago, Tim said:

This pic shows the brighter areas  nicely, and the blotch;

Is that ever a great image! The lower left of the image, between the 2 guide stars is the area that shows nicely with no filter.

[pjsmith_6198]

I can see the Crescent from my backyard using a Z10 in a dark red zone but the conditions need to be near perfect using a Astronomik OIII on EP's ranging from 20mm to 10mm.    However what I see is only the faintest hint hint of an arc coming off a star.  I tried a UHC but that didn't work for me.   

I have the same experience with the veil, I need to have higher magnifications to see it better.  The 20mm is  better than the 24mm which is better than the 32mm which is usually not visible.  The smaller exit pupils darkens the background just enough to make a difference.

You might be able to see it in a 130P, but you will need, exceptional viewing conditions, view it near zenith,  an OIII and experiment with magnifications.  Give it a try, if you don't try, you don't see.