Dark nebula observing

[jetstream]

@scarp15 I'll try to find a good image of the 2 features I mention- "too much nebulosity" in many images drowns them out.

[globular]

I was a bit surprized at how all the dark nebulae are in and around the milky way.
Here is a plot of the LDN:

But then I thought about it some more and realised there is dark nebulae all round... but it's only the milky way ones that are "set off" enough to pick out.
May be????

[jetstream]

32 minutes ago, globular said:

But then I thought about it some more and realised there is dark nebulae all round... but it's only the milky way ones that are "set off" enough to pick out.
May be????

What we see of these and other nebula are in our home, the Milky Way. Not much of the way in other galaxies visible- that glob in M31 comes to mind that I observe regularly.

Dark nebs are everywhere and are included in a lot of sessions depending on the time of year. When some experienced is gained ie object recognition a fun way to observe is "sky cruising", just slowly panning high percentage areas to see what pops out.

One night I followed nebula from the NAN over to Cepheus, stumbling across the Wizard and so many more. Another area of huge nebulosity of all types is around Sadr- a perfect dark site hunting ground IMHO.

 

ps the southern hemisphere observers are blessed with the likes of the galaxy- "Large Magellanic Cloud", something thats on my list, Tarantula neb and all.

Edited August 29, 2021 by jetstream

[jetstream]

Forgot to mention HII regions in galaxies- pretty pumped to get vg views of some in M51 a while back- these are also an excellent target in some galaxies.

[jetstream]

Off topic but interesting

 

[globular]

Most of these are at or beyond the limiting magnitude of my scope.  I can't always play with the big boys. 🙃 

[jetstream]

Just now, globular said:

Most of these are at or beyond the limiting magnitude of my scope.  I can't always play with the big boys. 🙃 

Are you sure?

The C8 is a very capable instrument...what eyepieces do you have?

Never say never... espc with respect to M101 and M33...

[globular]

I can do M101... I meant the individual NGC you highlighted.... 

e.g. NGC 5449 is mag 14.0.  8" limiting mag is 14.  Bit off because of central obstruction.... maybe 13.9.  My skies are 20.4....  a bit unlikely to get it.

Fun trying.... but I doubt I'll get 'em.

Edited August 29, 2021 by globular

[jetstream]

5 hours ago, globular said:

I can do M101... I meant the individual NGC you highlighted.... 

e.g. NGC 5449 is mag 14.0.  8" limiting mag is 14.  Bit off because of central obstruction.... maybe 13.9.  My skies are 20.4....  a bit unlikely to get it.

Fun trying.... but I doubt I'll get 'em.

I dont put much into limiting mags, espc with objects like HII "knots". I have zero doubt that you will see some of these from truly dark skies- my 8" dob does...Yes 20.4 wont do it most likely, every little bit over 21 helps...

You ever go on dark site trips?

[globular]

2 minutes ago, jetstream said:

I dont put much into limiting mags, espc with objects like HII "knots". I have zero doubt that you will see some of these from truly dark skies- my 8" dob does...Yes 20.4 wont do it most likely, every little bit over 21 helps...

You ever go on dark site trips?

You may have spotted from some of my posts that I like to think things through and do the maths.  It doesn't stop me just trying anyway though - nothing better than giving things a go for myself.  And I agree, magnitude calcs are only ever approximate and vary wildly by conditions and person to person.

I have been to 21.5 in the Shropshire Hills and 21.6 on North Yorkshire Moors.... but only with my eyes and binoculars, not with my telescope.  I'm not sure I want to take my scope anywhere darker as I fear it might spoil my enjoyment in my back garden - I still get lot of wows here and don't want to risk spoiling that... yet anyway.

[scarp15]

34 minutes ago, globular said:

 

I have been to 21.5 in the Shropshire Hills and 21.6 on North Yorkshire Moors.... but only with my eyes and binoculars, not with my telescope.  I'm not sure I want to take my scope anywhere darker as I fear it might spoil my enjoyment in my back garden - I still get lot of wows here and don't want to risk spoiling that... yet anyway.

It perhaps depends upon what you anticipate observing. My backyard can reveal adequately, brighter objects including M1, it becomes necessary to embark on dark sky trips to see the Milky Way, become fully dark adapted and encounter subjects that will be impossible from home. Equally objects observed from home are starkly much more defined when observed in darker skies. It becomes a balance between different perspectives and yet binoculars or a small telescope at a dark site can become very exciting to.

There are a few Barnard's class patches to include on a trip out in the coming two weeks mainly within Cygnus but will have another go for B174 in Cepheus. Doesn't matter either way, I will just be pleased to get out under the Milky Way.

[jetstream]

1 hour ago, globular said:

You may have spotted from some of my posts that I like to think things through and do the maths.  It doesn't stop me just trying anyway though - nothing better than giving things a go for myself

This is a good thing, but these days I just try stuff- like Einsteins Cross in the 24"-bit off more than I could chew (so far) but I'll keep trying, got the lensing galaxy anyway.

 

1 hour ago, globular said:

I have been to 21.5 in the Shropshire Hills and 21.6 on North Yorkshire Moors...

These skies are similar to mine- I vary between 21.4 and 21.9, with avg around 21.7 and at 1100' above the sea. For sure take your scope IMHO, there are lots of targets that will wow from home regardless.

[jetstream]

15 minutes ago, scarp15 said:

My backyard can reveal adequately, brighter objects including M1

I have to say that this objects has surprises- the 24" shows bright spikish "crab" features in the 24"- the 15" under the best conditions here will start to reveal them faintly. Bottom line is to enjoy the hobby and continue with pursuits regardless of conditions IMHO.

I hope you have a great trip Iain!

[jetstream]

Here is a borrowed image that marks the 2  challenge features I'm talking about. Years ago at least one other SGLer observed these- anyone else since? I hope its ok to use the image for this illustration.

[globular]

Looks like their centres are about:
20h55m37s  +45°02'
and
20h55m09s  +44°50'

Endless cloud here, but I'll try as soon as I can.

[scarp15]

The top one looks like it will be B353, which in the Sue French article is referenced as 20h 57.4m +45' 29'. However it could also be likely the Birds Nest, described as a dark oval in the Hudson Bay region - B353 embedded in its eastern border considered the 'inkiest' section. These coordinates relate this image reference Gerry to my Interstellarum Deep Sky Atlas, so certainly the Birds Nest and possibly also B353. 

Not certain about the other sighting,  LDN 935, referenced as 20h 56.8m +43' 52', this is located at a lower point below the Gulf of Mexico.

Details are in the Sue French article, here though is the map.

 

 

[globular]

If you scale, rotate and superimpose the two images (lining up the key stars) then you get this:

Which, to my eyes, suggests that Gerry's target is not B353 nor the Birds Nest.
It's around there somewhere though.

[scarp15]

Its a conundrum.

[globular]

4 minutes ago, scarp15 said:

Its a conundrum.

Call them GDC1 and GDC2 - Gerry's Dark Conundrum 1 & 2.

Edited August 31, 2021 by globular

[scarp15]

It might therefore become necessary to get access to the Lynds catalogue - LDN - of dark nebulae. This was published in 1962 and there are some cross overs with Barnard's much earlier catalogue. 

Neil @Littleguy80 I understand that you have the Barnard's catalogue, could you delve into whats specifically there featured in NGC 7000?

Edited August 31, 2021 by scarp15

[globular]

Skysafari has LDN and none are in the right place.

I got skysafari to highlight all entries in it's library (EVERYTHING not just LDN or dark nebulae) for that region; and got this:

And zooming into the target areas gives this:

You can see Gerry's two dark areas (yellow).... but there are no catalogued items in SkySafari in them (other than the odd star and a bit of overlap with NGC 6996 and NGC 6997).

<shrug>

[jetstream]

2 hours ago, globular said:

Which, to my eyes, suggests that Gerry's target is not B353 nor the Birds Nest.
It's around there somewhere though.

I dont believe its either, Ive never seen the features named. These 2 are challenges for sure but under the right conditions with the right eyepiece for the scope they are not bad.

Eagerly waiting reports!

[Littleguy80]

2 hours ago, scarp15 said:

It might therefore become necessary to get access to the Lynds catalogue - LDN - of dark nebulae. This was published in 1962 and there are some cross overs with Barnard's much earlier catalogue. 

Neil @Littleguy80 I understand that you have the Barnard's catalogue, could you delve into whats specifically there featured in NGC 7000?

Here’s the image and chart for NGC 7000 from Barnard. Credit to https://exhibit-archive.library.gatech.edu/barnard/bpdi/bpdi.php

[jetstream]

Well the 2 features mentioned are still there... 👍

Conditions were ok but trans was down. The MW had light structure, not horizon to horizon but was not bad at zenith. No stars visible till about 10 deg above the horizon and M31 was easily visible but subdued and not the bright streak it is under better conditions. No M33 naked eye. Trans worsened during the session so I came back in.

The 15" was used and the NAN was visible no filter but not the best, I used the UHC to bring out the features and the one is next to that cluster, the other coming in near the first.

I figured Id try under these conditions to illustrate that super good conditions are not needed. What is needed IMHO is the MW to be easily visible at zenith and with a bit of washed out structure.

Eagerly waiting reports!

Edited September 1, 2021 by jetstream

[globular]

Finally had a clear night tonight and had a very enjoyable 3.5 hours. (Jupiter was stunning!).
I dedicated about 50 minutes of that to NAN.  I had a lovely time surfing around the (bright) nebulosity and going over the target area and trying to spot any dark nebula.  The two areas in question were darker but, no my eyes, they were darker due to less bright nebula and fewer stars rather than anything I could call dark nebula.
Conditions were pretty good for my back garden - it's the best views of NAN I've had in my limited time observing - so I suspect I need a darker site and some wider views to find the illusive stuff.