How easy do you find the North America nebula to spot?

[pipnina]

I've always found it to show up in images very quickly, by most measures I think it's a bright and very large nebula.

However at home and at my bortle 4 site I have never managed to spot it, though at my bortle 4 I did spot the flame, markarians chain etc which aren't necessarily easy visual targets.

Perhaps its very high concentration of hydrogen plays a factor, though I know it has a fairly strong oxygen presence as well. Either way neither my 10x50s or my 10" dob have caught it as yet.

[Ags]

William and John Herschel both described this nebula as very faint and its resemblance to a large landmass was only a photographic discovery. 

[Stu]

@pipnina do you use an OIII or UHC filter as this makes it much more visible. I am also under Bortle four skies and saw it easily recently with 7x50 widefield Bino’s fitted with filters (one OIII and one UHC), and to me the shape is quite obvious. My favourite tool for the job is my Genesis f5 with a 31mm Nagler and OIII filter which gives a 5 degree field and frames it very nicely. Getting clear space around it definitely helps with seeing it properly, otherwise you risk looking through it and not seeing the contrast at the edges.

Transparency is definitely key to this one too. It can prove totally invisible if there is any hint of high haze, so a lovely clear night after a heavy shower which cleans the atmosphere, for instance should give you the best chance.

Obviously choose your largest field of view in the 10”. Not sure which eyepieces you have, but this image shows the fields with a 24mm 68 degree eyepiece (1.36 deg) and a 2” 30mm 82 degree (2.05 deg)

I’ve also heard of people spotting it with the naked eye by holding a filter up to it, but I’ve never managed that.

I’m sure if you have managed the Flame then your skies are good enough for the NAN. I suspect the issue in the 10” may be that you are not seeing the contrast at the edges. The second image shows a 1 degree field and with the entire field filled with nebulosity you would not really detect anything.

Keep trying, sure you will get it, and get yourself a decent OIII or UHC if you haven’t already.

[josefk]

@pipnina this has been on my list of "things i didn't see last night" last weekend and this 😞

@Stu i understand the FOV challenge (i can't get wider than 1 degree myself). In your view do you think a UHC or O-III would make the difference to see the brighter edges rotate into the eyepiece (even a FOV restricted eyepiece) if your lying in wait for it in the west as it where. This technique is NOT working for me without a filter I should say; waiting at the eyepiece to see if i discern brightening while that patch of sky rotates over - i couldn't honestly say there is any brightening as the nebula rolls through (or should be rolling through)...

[Stu]

1 hour ago, josefk said:

@pipnina this has been on my list of "things i didn't see last night" last weekend and this 😞

@Stu i understand the FOV challenge (i can't get wider than 1 degree myself). In your view do you think a UHC or O-III would make the difference to see the brighter edges rotate into the eyepiece (even a FOV restricted eyepiece) if your lying in wait for it in the west as it where. This technique is NOT working for me without a filter I should say; waiting at the eyepiece to see if i discern brightening while that patch of sky rotates over - i couldn't honestly say there is any brightening as the nebula rolls through (or should be rolling through)...

I definitely think it is worth it to try with an OIII or UHC. I think it will also matter which way you are approaching it. Best to try from the Gulf of Mexico side as there is more contrast to the edges; from the other end it just kind of tails off gradually so there is less to latch onto.

Which scope and eyepiece are you using? Best to keep the exit pupil as large as possible too, especially with a narrowband filter.

[josefk]

Thanks @Stu  it would be “just” 2.4mm exit pupil with the current set-up. 186mm/79x. I will give the UHC a try first I think. It won’t be wasted to get one for the toolkit anyway. Cheers

Edited August 28, 2022 by josefk

[Stu]

1 minute ago, josefk said:

Thanks @Stu  it would be “just” 2.4mm exit pupil with the current set-up. 186mm/79x. I will give the UHC a try first I think. It won’t be wasted to get one for the toolkit anyway. Cheers

What is your scope? I’m assuming a Mak or SCT of some sort? Bear in mind that these filters work best at 4mm or more, you do risk a dim image at 2.4mm. Any way you can work with a longer focal length to increase this? Even moving from a 32mm to a 40mm plossl on a Mak helps as it increases the exit pupil even though you don’t get a wider field of view due to the field stop being the same.

[josefk]

@Stu well there is that as well. I have the GSO 8” cassegrain. Nearly 2.5 meters focal length. I had thought about a 55mm plossl just for the larger (maybe 4mm or so) exit pupil (I wouldn’t really gain FOV with it). That EP would then be a bit specialised though. Not totally redundant but a bit niche. Mmhh. 

[Stu]

27 minutes ago, josefk said:

@Stu well there is that as well. I have the GSO 8” cassegrain. Nearly 2.5 meters focal length. I had thought about a 55mm plossl just for the larger (maybe 4mm or so) exit pupil (I wouldn’t really gain FOV with it). That EP would then be a bit specialised though. Not totally redundant but a bit niche. Mmhh. 

I think it would be worth a go for these targets. In this case it’s not about field of view but a 4.5mm exit pupil would make a difference to visibility. The CC is not the ideal tool for the job so I suspect the small exit pupil is what is killing the views for you.

I had a Meade 55mm 2” plossl for just that reason, wasn’t too expensive so perhaps you could pick one up used?

[Nyctimene]

Under Bortle 4 skies, the NAN can be made out in good, transparent nights without a filter, even with binoculars. For fun, I'm using sometimes my tiny Docter 8x21 monocular with success. Of course, the view with filters is way superior, and your 10" the adequate scope. But you have to know, where to look. For a first approach, imagine an ancient crossbow; the "handle" represented by 56 and 57 Cyg, pointing NE (away from Cygnus). The "bow" is located already just inside the NAN along it's W border (the brightest stars HR 8023 and 8035). There is also a small "Orion" asterism just opposite of the "Gulf" region for further confirmation. You can make it out close to the upper part of the inner FOV circle in Stu's first screenshot above. Usually, the "Gulf" region is the most prominent part of the NAN. Get the eyepiece with the longest focal length, screw in an UHC or OIII filter, and give it another try! You will succeed!

Stephan

Edited August 28, 2022 by Nyctimene

[Zermelo]

I'm also Bortle 4.  On a good evening I can comfortably make out the structure in a 150mm reflector, using an Astronomic UHC on a 30mm Plossl, giving an exit pupil of 6mm and true field of 2°.

[Stu]

4 minutes ago, Zermelo said:

I'm also Bortle 4.  On a good evening I can comfortably make out the structure in a 150mm reflector, using an Astronomic UHC on a 30mm Plossl, giving an exit pupil of 6mm and true field of 2°.

Actually one of my issues with the Bortle scale is the range of sky brightnesses covered by each number. Bortle 4 covers mag 20.49 to mag 21.69 which is a huge difference. Mag 20.5 is a reasonable sky where the Milky Way starts to be nicely visible, whereas 21.69.... well I’ve never knowingly observed under those sorts of skies, mag 21.3 or 4 is probably the best and the Milky Way looks far better under that sort of darkness.

[Zermelo]

2 minutes ago, Stu said:

Actually one of my issues with the Bortle scale is the range of sky brightnesses covered by each number. Bortle 4 covers mag 20.49 to mag 21.69 which is a huge difference. Mag 20.5 is a reasonable sky where the Milky Way starts to be nicely visible, whereas 21.69.... well I’ve never knowingly observed under those sorts of skies, mag 21.3 or 4 is probably the best and the Milky Way looks far better under that sort of darkness.

Good point, it's a wide range, and for diffuse nebulae could make a big difference.

My location is apparently SQM 21.27 according to the web sites, but those are based on upward illumination measured by satellite rather than sky brightness measured downwards. I recently bought a simple meter and have been taking measurements each session. The best I've done so far (in astro darkness, no moon) is 21.00 dead, but that was pointed straight up at the Milky Way.

[pipnina]

11 minutes ago, Stu said:

Actually one of my issues with the Bortle scale is the range of sky brightnesses covered by each number. Bortle 4 covers mag 20.49 to mag 21.69 which is a huge difference. Mag 20.5 is a reasonable sky where the Milky Way starts to be nicely visible, whereas 21.69.... well I’ve never knowingly observed under those sorts of skies, mag 21.3 or 4 is probably the best and the Milky Way looks far better under that sort of darkness.

It is a bit too wide for sure. My "bortle 4" site has a huge sky gradient, city light on one side and clean sea-overlooking darkness on the other. Thankfully in my case the sea is to the south and the city to the northwest. So most southern and high altitude objects are easier.

At my home in bortle 5, I can see the milky way, but only because I know what to look for and I have to stare for a minute or so to let my eyes adapt. When going to my B4 dark site I can see it very clearly and a lot of detail by eye going through not just Sagittarius and Cygnus, but Cassiopeia and Orion as well.

 

This is the FOV I get approximately with my widest EP and my 10" dob:

So it's somewhat wide given the scope, but still very narrow compared to the size of the subject

 

I used to own a visual OIII filter, but it was a 1.25" and I sold it when I got rid of my first visual scope (sold it and used the now not-as-useful OIII to help move it on).  Not being so into visual as I used to be, I don't know if I'll be buying filters at this time, but maybe if I catch the bug in the future (and when I have more money to spare!).

For the most part I've been considering a downsize in my visual gear, keeping my eyepieces and getting a more grab-and-go scope as the 10" requires multiple careful and long (and heavy) trips down stairs or out of a very loud wooden front door to set up and pack away. But I'd also be giving up a LOT by going down in aperture.

All looks good for tonight on the forecast, hopefully I can take a trip out to my B4 and see if I can spot it from there as transparency has been OK even yesterday when high clouds were getting in the way.

I'm also curious about the binocular filters, do they cover the eyepieces or the front lenses? I've not seen them around before.

 

Cheers for all you guys' insights!

 

[Moonshane]

I found this quite easy with a Oiii and a 150mm f5 newt and a 32mm plossl (2.2 degree field approx) from Glan Conwy. The site was not ideal (street lamps etc) but as the underlying darkness was good I had good views tucked away in a dark corner of the garden.  That said it's the only time I have seen it!

[Stu]

1 hour ago, pipnina said:

I'm also curious about the binocular filters, do they cover the eyepieces or the front lenses? I've not seen them around before.

 

I have 2” Lumicon UHC and OIII filters, and they fit perfectly on my binocular front objectives, held in place by some 3D printed adaptors provided by a kind chap from here, Peter (and my ex local observing group). Thinking about it, they are actually 7x35s I think. I’ve previously done this with 15x50IS Canon binos which have threads on the front objectives so you just need a couple of step down rings to hold the filters. You can do it the other way too, I’ve used 1.25” filters on the eyepieces of a pair of 22x85 bumps which worked but I didn’t find as easy or comfortable to use.

[bomberbaz]

Coincidentally I saw this on Thursday, well the part below in the inner circle.

I was using my 14" DOB, an Astronomik OIII filter and switching between a APM 24mm and 26 Plossl for different exit pupils in B4 skies.

It's quite distinctive but my problem is it is so big you can lose perspective as I simply can't fit enough of it into a full FOV.  Both EP above give less than a degree.

Anyway, it is to my eyes not distinct in edge definition but there is good structure within it if that makes sense. I moved the FOV in and out of the nebulosity and it is relatively easy to pick it out doing so. 

[Mircea]

I saw first ''North America Nebula'' from the city, with my 200mm Dobsonian, using a UHC filter.

I followed the instructions of Steve O'Meara in his ''Herschel 400 Observing Guide'', page 262.

What I saw is actually the part of NGC 7000 discovered and observed by William Herschel and logged as H V 37.

 

From suburban sky HV 37 was visible in my 90mm F/ 6.7 RFT refractor, fitted with UHC.

H V 37 is a small object, about 10' so accessible to any kind of telescope.

 

From the same suburban location in nearby woods, most of NGC 7000 was visible,  especially the Gulf of Mexico and the Cygnus Wall.

To the West of Gulf of Mexico there are two pair of stars and between them there is a row of three dim stars.

I search that asterism before dropping the anchor and start looking for NGC 7000 or parts of it.

One can see the described asterism in my sketches below of July 25, 2019.

I shared those views with Armand, my observation buddy.

Mircea

 

 

[Moonshane]

ps the above excellent post just reminded me that I also saw the Pelican the same night. I think I need to move to Glan Conwy.

Edited August 28, 2022 by Moonshane

[pipnina]

@Stu

@Nyctimene

@Mircea

Many thanks for your helpful tips, I went out with my dad to the B4 site to have a gander. In periods without divers and their head torches (grr!) we got a look at a fair few items. I didn't consider the neck strain aspect of looking for NAN at this time, as it is practically transiting the zenith. Although that means in theory I should see it more easily, it did make searching the region rather hard in my dob.

With my 10x50s and the dob I wasn't convinced I could see anything unfortunately. If the nebula was there, it was lost in the sea of the milky way more broadly as there were a lot of bright and dark patches in that region north east of Deneb.

I think I have seen the milky way more clearly from that site, maybe light pollution has gotten worse, or maybe the atmosphere is a bit too opaque for some reason. Either way, there were still lots of other nice things to see.

I visited Andromeda first. I was actually able to discern it by naked eye alone, which might be a first. It required averted vision, but stunning in its own right to see another galaxy without any assistance whatsoever! In the 10", I could clearly see both companions, and with some patience the first dust lane became visible which looked very nice indeed.

Then we visited triangulum, which was a bit sad as all we saw was a little faint fuzzy. I suppose it's hard to compete with andromeda.

Swinging over the other way, we had a good look at the ring nebula in my 10mm SLV. Easy to spot and bright for a DSO. Always a good sight.

Then I hunted down the veil nebula. Starting at the broomstick because it has the easiest star to locate by eye and in the telrad finder. To my surprise it proved an easy spot, with the bright rip running to the bright star in the middle being quite easy to see and containing a fair bit of detail.

Scanning around, I found the "face" part of the veil nebula as well, which I would argue was even more impressive. My dad seemed to think so too. I couldn't exactly see the face aspect of it visually, but it filled a large part of my 24mm 68 deg eyepiece. and again had some nice detail to see. Spent some time here on those two.

Looking at Sadr, it was hard to tell if I could see the nebulosity there or not. Maybe my eyes were playing tricks on me, since that region is very bright, but as far as I know only bright with hydrogen. It appeared to have the right shape and size though.

We took some time to see Jupiter and Saturn while we were there. Mars not yet having risen enough. The atmosphere seemed rather calm, unfortunately I don't have a higher mag eyepiece to see them with as I think I could have easily gone above the 120x that scope and EP provide me with. Saturn's rings looked sharp and contrasted, while Jupiter showed a healthy colour and contrast in the bands.

That concluded the night.

I think I may consider a UHC or somesuch for wintertime when I may try for objects like the flame again, maybe enhance M42, attempt the horsehead, and have a go at the rosette... No doubt other objects should be in my reach as well. At least if I can bear the cold!

[Stu]

Great report @pipnina 👍