Brightness of Horsehead nebulosity?

[Bugdozer]

I understand that seeing the Horsehead nebula, i.e. the dark patch itself, needs a decent aperture scope and good dark skies, or a long exposure, but what about the long streak of nebulosity it's embedded in? I can't find any real information about how bright that is in itself. Last time I was out looking at Orion I had a reasonably dark sky and thought I might be possibly seeing it in my 5" scope with my UHC filter on, but I wasn't sure if I was just imagining it because I knew where it was. If I was really seeing the bright nebula, there's definitely no way I could make out details like the Horsehead itself.

[bosun21]

I have only glimpsed the HH once and that was in a B2 sky with a friends 12" dobsonian. He used a low power eyepiece with a H beta filter. It was faint but easily distinguished. I wouldn't even try with a 5" scope.

[John]

Here is my report of sighting the Horsehead Nebula from my back yard a few years back. I've done it once since then, again with the 12 inch.

Here is the Sky at Night magazine guidance on seeing this target:

How to see the Horsehead Nebula - BBC Sky at Night Magazine

IC 434, the nebulosity that the Horsehead lies in front of is itself a very challenging visual target. It is described as "a bright strip" quite often but my experience is that it is anything but bright, at least under the conditions that I normally observe under (nornally around bortle 5-ish).

It is possible to see the Horsehead with a small aperture scope - there is at least one member of SGL who has seen it, or perhaps detected it is a better term, with a 100mm refractor.

For me, it is probably the hardest visual target that I have managed to see in my years of observing. 

I love Jeremy Perez's description of this one:

"Really, it's like trying to see a little bit of nothing with a little bit of less than nothing resting over it" 🙂

 

Edited November 15, 2023 by John

[Kon]

I have seen it with my 8" and an H beta filter. You need to be able to see the flame to see the nebulosity running along.

See my report here:

 

[scarp15]

A 5" scope is inadequate, at least for all but the most experienced observers and in optimum circumstances. A reasonably dark sky is also inadequate. 

My first encounter was whilst out with an astronomy society that I was a member of a few years back. At their dark sky site and using I think at the time my 12" dob (though could had been the subsequent 14" cant remember), using a 25mm TV plossl eyepiece and excellent Lumicon H-beta filter. Anyhow an experienced observer positioned accurately the field of view through the plossl (keeping Alnitak out of view) and declared that it was the best view that he had seen of B33. He implied where to look and a grasp of what to expect / see, yet could I or another member see it - no, not a chance -  we were clueless as to what we were actually looking at, or to be more precise how to look at it. 

As experience and attempts developed, I eventually did see it and grew accustomed as to how to see it. Therefore comprehending exactly what you are trying to look for, employing averted vision, becoming fully dark adapted and spending a prior period looking at faint DSO's are at the very least what is required. Having the optimum equipment, under very dark skies (at least 21.1 mag) in excellent transparency and when Orion is nearing its southerly position are necessary requirements. If or when you do encounter it, you will know, as credible drawings that you would have studied before hand from experienced observers will acknowledge this. It is a eureka moment and accomplishment but from a visual perspective there almost nout there. 

Just to conclude, this topic comes up almost year on year most often tin the Observing Deep Sky section (not in beginners observing), packed with info and general personal experiences. 

A more delightful subject with a H-beta filter and low power wide field eyepiece at around this time of year, is the California nebula.

 

Edited November 15, 2023 by scarp15

[bomberbaz]

Just to add to what the others said. There was a really well written article on viewing this and some of the prerequisites. I cannot find it but they were as below:

An eyepiece that gives you a exit pupil of around 5mm and circa 1 degree fov.

An h beta filter, preferably a good quality one.

At least 10" of aperture.

As dark a sky as you can get to and no moon at all.

Well dark adjusted eyes.

There are as mentioned above documented successes by some not meeting the above, however to give yourself the best chance you should try to do so.

And John's description of what you see is spot on. 

[Bugdozer]

33 minutes ago, scarp15 said:

 

Just to conclude, this topic comes up almost year on year most often tin the Observing Deep Sky section (not in beginners observing), packed with info and general personal experiences. 

 

 

Does, it, though? I can't find any real comment on the forum about how bright IC 434 (as you have informed me it's called, thank you) actually is. Wikipedia says it's mag 7.3. Another site says it's mag 11. That's quite a difference. 

All the threads you are talking about are focused on people trying to see the Horsehead itself, B33, which I have no particular interest in because I know it will be almost impossible with my equipment. 

[bomberbaz]

Found the sgl article, seems the links in it no longer work, but if you read it you will see we do not speak with forked tongues

https://stargazerslounge.com/topic/220171-eyepiece-for-that-notorious-nag/page/1/

[bomberbaz]

1 minute ago, Bugdozer said:

Does, it, though? I can't find any real comment on the forum about how bright IC 434 (as you have informed me it's called, thank you) actually is. Wikipedia says it's mag 7.3. Another site says it's mag 11. That's quite a difference. 

All the threads you are talking about are focused on people trying to see the Horsehead itself, B33, which I have no particular interest in because I know it will be almost impossible with my equipment. 

I think you are missing the point, you cannot see one without the other. The hh is overlayed on ic434, if you see the nebulosity, you will see the hh too. 

[Kon]

21 minutes ago, Bugdozer said:

Does, it, though? I can't find any real comment on the forum about how bright IC 434 (as you have informed me it's called, thank you) actually is. Wikipedia says it's mag 7.3. Another site says it's mag 11. That's quite a difference. 

All the threads you are talking about are focused on people trying to see the Horsehead itself, B33, which I have no particular interest in because I know it will be almost impossible with my equipment. 

It is a lot lot fainter than looking at the flame without a filter and a lot lot fainter than NAN with a good OIII. With the H beta IC 434 is 'there'. You can trace it and see where the sky gets darker. What skies where you observing from?

Edited November 15, 2023 by Kon

[Bugdozer]

1 minute ago, bomberbaz said:

I think you are missing the point, you cannot see one without the other. The hh is overlayed on ic434, if you see the nebulosity, you will see the hh too. 

That’s not necessarily true, though, is it? If an object is very low contrast and dim, we can often see it's there, but not necessarily make out many small details - they may look smudgy and ill defined. Many galaxies are a good example of this. Given that IC434 is relatively large and linear, more cells in your eye picking it up will theoretically make it more detectable than a smaller object of the same surface brightness. 

 

[John]

1 hour ago, Bugdozer said:

That’s not necessarily true, though, is it? If an object is very low contrast and dim, we can often see it's there, but not necessarily make out many small details - they may look smudgy and ill defined. Many galaxies are a good example of this. Given that IC434 is relatively large and linear, more cells in your eye picking it up will theoretically make it more detectable than a smaller object of the same surface brightness. 

 

I found seeing IC 434 very, very difficult. I've looked for it lots of times when the sky has been good and I've been using my 12 inch dob, a suitable eyepiece and a good H-beta filter. On the 2 occasions that I have seen it, seeing the darker "bite" out of it that demarks Barnard 33 (the Horsehead) was quite possible. The Horsehead itself is not small.

Even seeing the Flame Nebula can be quite challenging under a less than very dark and transparent sky and you really need to be able to see that quite obviously to have a chance of the more subtle IC 434.

[Bugdozer]

12 minutes ago, John said:

I found seeing IC 434 very, very difficult. I've looked for it lots of times when the sky has been good and I've been using my 12 inch dob, a suitable eyepiece and a good H-beta filter. On the 2 occasions that I have seen it, seeing the darker "bite" out of it that demarks Barnard 33 (the Horsehead) was quite possible. The Horsehead itself is not small.

Even seeing the Flame Nebula can be quite challenging under a less than very dark and transparent sky and you really need to be able to see that quite obviously to have a chance of the more subtle IC 434.

So can we conclude that Wikipedia's assessment of it as a bit dimmer than mag 7 is probably very, very wrong? 

[bomberbaz]

28 minutes ago, John said:

Even seeing the Flame Nebula can be quite challenging under a less than very dark and transparent sky and you really need to be able to see that quite obviously to have a chance of the more subtle IC 434.

I agree entirely with this. The only time I saw the HH/ic434 the flame was clearly visible with no filter.

I was in Galloway, B2 skies with my 14" dob and even then it took quite a while with my head under a light hood before they became visible.

EDIT. Both aspects suddenly just became visible, it wasn't an obvious pop into view, just I became aware of them almost simultaneously. As in,"ahhh there it is!"

I had tried very many times before I got this success.

Edited November 15, 2023 by bomberbaz

[Nik271]

I have found many magnitudes of extended objects (on Wikipedia and elsewhere) are completely misleading. In this particular case I think 7 is the integrated magnitude of all of IC434 which includes the Flame nebula  in its northern part.

I have tried but cannot even see the Flame nebula from my suburban garden (SQM 20)

Edited November 15, 2023 by Nik271

[John]

17 minutes ago, Bugdozer said:

So can we conclude that Wikipedia's assessment of it as a bit dimmer than mag 7 is probably very, very wrong? 

Magnitude figures for deep sky objects can, oddly, be little or no help in guaging how easy or difficult it will be to see an object through the eyepiece.

Surface brightness is often a lot dimmer than the integrated magnitude figures quoted in sources such as Wikipedia but it is this, plus a host of other factors, that determine the actual visibility at a given time.

The galaxies M33 and M101 are good examples of this.

 

Edited November 15, 2023 by John

[mikeDnight]

I managed to see IC 434 some years ago. I'd had some success with the Flame Nebula and fancied the challenge of seeing how far I could push my scope, and my observing skills. The night was transparent and so I thought that to maximize my chances I'd need to block out all stray light. I used a blackout blanket around my head and focuser, and observed the region for quite some time so as to achieve good dark adaption. It took a while but eventually a thin shard of bright nebulosity appeared to me eminating it seemed from a tiny star. Once I'd seen this shard, everything else gradually started to become apparent. All this was visible only by using averted vision, but what I found to be most obvious was the black nebula which gave the impression of a solid wall of jet black dust, blacker than the space around it. The bright and dark nebula was quite extensive and after an hour under the blanket I dared to try making an eyepiece drawing of what I was seeing. While sketching under a dim red light I noticed a tiny black notch protruding into IC434. It was difficult to place on the drawing precisely as I was using averted vision, and it was on the border of discernability, but I'd seen it for long enough to be certain of its reality. I was really thrilled to have seen IC434 let alone what I believed to be the Horse Head, and to this day it remains the most challenging DSO I've ever detected. I was using a 100mm F7.4 refractor and prism diagonal!

The use of a prism and its orientation while observing means the angle of the mirrored sketch may appear strange, but this sketch illustrates the overall view. I kept Alnitak out of the field of view throughout the observation, until the very end when I wanted to catch the Flame. What may have been the HH certainly didnt have any discernible form to it, so may be itvwasnt the horse head, or may be it was?

A blackout blanket to block out any peripheral stray light really does help. It would have been an impossible challenge for me without it.

Edited November 15, 2023 by mikeDnight

[scarp15]

2 hours ago, Bugdozer said:

Does, it, though? I can't find any real comment on the forum about how bright IC 434 (as you have informed me it's called, thank you) actually is. Wikipedia says it's mag 7.3. Another site says it's mag 11. That's quite a difference. 

All the threads you are talking about are focused on people trying to see the Horsehead itself, B33, which I have no particular interest in because I know it will be almost impossible with my equipment. 

IC 434 is too impacted by the glare from Alnitak to distinguish it from the background. B33 when glimpsed, is a velvety black thumb print around the same size as M1 (which is a good subject to observe prior to this). 

If you wish to attempt to observe a diffuse nebula within this vicinity, then try for NGC 2023, nothing amazing, a small reflection nebula around a dim star and close to the position of B33. 

[scarp15]

I think that Gerry @jetstream would be a good contributor into this, though had not heard from him for a while. 

[mikeDnight]

10 minutes ago, scarp15 said:

I think that Gerry @jetstream would be a good contributor into this, though had not heard from him for a while. 

He'll be out fishing or chopping wood ready for winter. ☺️

[scarp15]

39 minutes ago, mikeDnight said:

He'll be out fishing or chopping wood ready for winter. ☺️

I hope so, its just concerning with the extent of forestry fires in Canada this year. 

[tomato]

This is not my area of expertise, but one other comment I would make is that from my mid UK location this object doesn’t get above 30 deg altitude, this is not helpful for any type of faint diffuse object. 
 

I am only an occasional visual observer but I have glimpsed the Flame nebula with a 16” Dobsonian from my Bortle 5 location, but B33, no chance.

[bomberbaz]

4 hours ago, tomato said:

This is not my area of expertise, but one other comment I would make is that from my mid UK location this object doesn’t get above 30 deg altitude, this is not helpful for any type of faint diffuse object. 
 

I am only an occasional visual observer but I have glimpsed the Flame nebula with a 16” Dobsonian from my Bortle 5 location, but B33, no chance.

Yeah 33.5 degrees from my home town, less if I drive north for the darkness. 

I did a little fov check and I stick by the circa 1 degree being optimum.

Enough to get the nebula yet small enough to avoid alnitak. 

[John]

A whole bunch of boxes need to get "ticked" for this one to be achieved visually.

Over the past 10 years I've had the right eyepieces, the right filters, enough aperture, enough experience (well, almost !), good star charts, good advice etc, etc and yet things only came together a couple of times over that period from my backyard. If I'd travelled more to really dark sites I could have improved on that though. But at least I've had a couple of glimpses of it 🙂

I'm no imager but I'm told that the Horsehead is relatively easy to image and is quite straightforward with an EAA setup.  

Edited November 16, 2023 by John

[Captain Scarlet]

I finally achieved B33/HH a couple of years ago, and I attribute it to the following combination of factors: dark site (21.8); perfect transparency (any thin cloud is enough to extinguish it); no Moon; no alcohol (important - optic nerve is affected. Learned that from @jetstream); 12” of aperture; full dark adaption; four years experience/learning of how to try to see really faint things. It was possibly my ~5th attempt to see it and I literally danced with joy when I’d convinced myself I’d detected it.

Magnus

Edited November 16, 2023 by Captain Scarlet