Horsehead nebula

[BLiTZWiNG]

Should I be able to see it through an 8" dob?

I don't do this often enough, so with a clear patch of sky I decided to look at it (after realizing where it was while using starry night). I'm pretty sure I found the star, but I couldn't see anything next to it.

I was using a 12.5mm plossl that came with my scope. I tried the 6mm but it was really hard to see anything.

[mswhin63]

I tried to see it in my 12" DOB and failed, I believe it is a really faint object and mostly for Astro Photography. Correct me if i am wrong.

It is also close to a bright star so making it harder to see.

[mental4astro]

Hi there,

The Horsehead nebula is one of the targets in the December & January Obs. Challenge. You might want to have a read of the Challenge description, and have a look into the link it has to the IIS thread on the topic of the "Horsey":

http://www.iceinspace.com.au/forum/showthread.php?t=68833

In a nut shell, if you want to see the Horsehead, YOU NEED a really, really dark sky, and know where to look. It is one, if not THE hardest object to view through amateur scopes. Certain filters may help, and the link contains details on these.

I haven't seen it to date. One of my many tasks this Summer season.

It has reputedly been seen in a 6" scope. Most people I've read quote a 10" is the smallest apeture. Have a go and let us know.

Another helpful tip, if you can't see the Flame Nebula, which is the flame like looking nebula right next to the emission nebula the Horsehead juts into, you have no chance at seeing the Horsey. A very helpful indicator.

[jenchris]

Horsehead is visible with an 8" but you have to have really complete darkness and eyes that have been dark for an hour - I managed it fleetingly with my 8"SCT but when I looked a few minutes later, it was gone.
I was out at our dark sky site which is 100k from civilisation

[Osirisra]

I had a look with my 14" Dob tonight but was only able to see the faint outline of the surrounding neb in suburbia and intend to have a good crack at it on the weekend at my regular dark viewing spot.

[BLiTZWiNG]

ahh thanks guys. I had no idea how difficult it was to see. Given I have street lights and am not that far from the lights of Brisbane, I really have no hope of seeing it!

I really need a laser pointer on my scope.

[jenchris]

Beachmere is pretty open territory - but street lights will kill it stone dead and LP from Bris means that the humidity has to be zero to get decent seeing.
Looking South from there must be a nightmare!
I at least get to look South - I have Bris to my north but 50k away

[mental4astro]

Why a laser pointer?

Having trouble with your finder? I'd suggest a red dot finder to add to the scope, along with the current optical finder. Very, very effective, no laser issues with the coppers, and cheap- Andrews Communications sells the one I use (I've got two actually) for $29.

Back to the horsehead.

The attached AAO pic shows all the various components that form the "horsehead complex".

The Flame nebula is the round bright firery splash of colour to the left of the Horsehead. This nebula is much brighter than the emission nebula the horsehead is superimposed onto. Don't confuse the Flame nebula with the Horsehead. Also, though the Flame Neb. is brighter, it is still very faint itself.

This one I have seen in my 17.5" scope. Yet I still couldn't manage the Horsehead itself that night. The Flame is such a beautiful nebula itself, just saddly overshadowed by the chance resemblence of some dust and gas to an earthly creature.

The emission nebula the Horsehead sits on, like I said is very faint. The dark pillar that the horsehead is, is really only a dark, finger-like shadow jutting into this very dim "mist". It will NOT appear anywhere as clear and distinct as in the picture below!

Jennifer said she saw it only "fleetingly" (marvelous stuff Jen, to see it at all!! Lucky bugger, :thumbsup:). This also leads to the need to keep in mind that atmospheric conditions need to be particularly good. One moment Jen could see it, the next not at all.

Oh, one last tip, it is essential that you keep the bright star Theta Orionius OUT of the field of view, or its glare will completely wash it out.

----

If you would like to have a go at the "dark pillars" that the Horsey is, have a go at the half dozen that line up in the bright nebula Eta Carina.

Dark pillars are of the same family as "Bok globuals". These are thought to be the gas and dust cocoons of protostars. These protostars, once their nuclear fire kicks in, will jetison this cocoon to reveal a new diamond in the sky.

[ausastronomer]

Hi Jen,

Are you sure you weren't looking at the Flame Nebula (NGC 2024)? This is a very very common mistake people make.

If you have a look at the two images I have attached, in colour and in grayscale, you will see that when you are observing visually where you only see black and white, how easy it is to confuse the "notch" in the Flame Nebula for the Horsehead Nebula. The Flame is to the left of Zeta Orionis (Alnitak) and the Horsehead is a bit further from Alnitak and below it.

It takes an exceptionally experienced observer, an exceptionally good telescope and outstanding observing conditions, to see it in any telescope under 12" aperture. On top of that a UHC filter helps somewhat and a H-Beta filter helps a lot. I have spent dozens of hours searching for it in 8" and 10" telescopes (good ones) with and without filters, without success. I remember I spent over an hour searching for it in my 10" scope at Wiruna ( at 2002 SPSP?) with Glen Dawes (co author of the Astronomy yearbook) under superb conditions without success. On the other hand, the Flame Nebula (NGC 2024) is very achievale in an 8" scope from dark skies.

The Horsehead is doable in my 14" under superb conditions and reasonably easy in my 18", with a filter. Under excellent conditions it is doable without a filter using averted vision. In the 25" scope it is visible with direct vision unfiltered.

Cheers,
John B

[mental4astro]

Hi John,

Ta for the diagram. I've hit the print button for it, :thumbsup: . No excuses now. Other than the sky, my mood, the beer,...

[BLiTZWiNG]

Yeah Beachmere is great for feeling like you're not in a city but being close enough to Caboolture to have everything one needs shopping wise! But yes, I my yard is on the east side of my house and I live on a corner, so I have a streetlight on the east and south side. I got the massive gum chopped down (it was throwing branches at me), but I still suffer light pollution. I can look at Jupiter and Saturn though :)

Alex, I don't even know what happened to my finder scope, it got lost in one of 3 moves :( I never cared that much because I found it useless anyway. I wasn't sure exactly how a red dot finder worked, but I'll take your word for it and try and find my finder scope (I took it off for transport, then tried to reattach it but failed, then lost it, which is unusual for me, I don't lose stuff).

I was also unable to see the flame nebula either, which does look quite kewl in the photo, but I also had that star in my scope the whole time so duh to me, thanks for that advice I will try again without it in my view! Granted weather here might mean waiting a long time, I'm just hoping for clear skies on monday night!

[BLiTZWiNG]

some quick searches indicate that people seem to prefer a magnifying finder over red dot in LP areas, which I consider myself to be in.

Ahh how I wish I was back in country VIC again... only from a dark skies perspective, the weather is far warmer up here!

[mental4astro]

Hi Trent,

Mate, a red dot finder & a Telrad work on the same principle of a red dot or target image projected onto a specially coated glass that makes the image some-what holographic - you move, but the dot or target seems to stay in the same place.

They are great as they can be easier to use with both eyes open.

The two pics below show my two red dot finders. One is "surgically enhanced" with a longer stalk on my 8" dobbie. Its original stalk was too short to make it comfortable to use. The other is mounted on a 3" reflector that inturn is a giant finder on my 17.5" dob (the picture shows the white tube of the giant before I rebuilt it. I still use this RDF & reflector finder on the rebuilt behemouth). Depending on the object I'm after, most times I don't need to use the 3" big finder, just the red dot.

These red dot finders a really easy to install, they even come with their own mounting block.

My 8" only has the RDF. I love to use this scope from my home in Sydney. I really don't have a problem with not having a 'traditional' finder on it.

BTW, my 17.5" has three finders on it, :rolleyes: , the RDF & 3" on its back, and a 2" up on the secondary cage next to the focuser. I really need to take a picture of the thing fully decked out...

[BLiTZWiNG]

Ok, so if I have a red dot finder, I dont need my old finder scope? I was looking at one on Andrews site (under Guan Sheng, because, you know, my scope is a GSO), and it says it doesn't come with the block, which atm means nothing to me... my simple hope is that I would by one and put it where the finder scope normally goes, as per your first two photos there, is that correct?

[mental4astro]

yep, and yep.

If you find it awkard to get you head to it, as the stalk is made from plastic, it is a simple task to cut and add an extension to it.

The 'block' is a dove tail block that stays on the scope. The RDF stalk has a dovetail that slides into it.

The magnified optical finder is good too. As it collects more light than our own eyes, they are useful in finding faint targets where there may not be enough naked eye stars to make using the RDF alone an easy task. That is why I use both on my big dob.

[BLiTZWiNG]

Ahh I had kinda thought that was the case but I'm still learning not to assume too much :)

$59 doesn't sound too bad, think I'll go order one and hope it comes before xmas!

[BLiTZWiNG]

Oh man... Lee!! Keep up with the times... Internet ordering mate, internet ordering..

[mental4astro]

I just had a quick look at the Andrews site. The $59 one DOESN'T come with the mounting block.

Give them a call. I've got the $29 one. That one did have the block.

[BLiTZWiNG]

I shouldn't need the mounting block though, unless it doesn't fit in the one my finder scope used?

[mental4astro]

Should be the same one. The 2" finder I have uses the same block. Same manufacturer. GSO.

[BLiTZWiNG]

Yeah I would hope that GSO make things to fit their own equipment, though stranger things have been known to happen. I did get my scope 6 years ago.

[BLiTZWiNG]

I don't see the $29 one listed...

nvm.. I'm blind, and the universe always waits for you to make a fool of yourself :)

I guess the question is, what is the difference between a $59 one and a $29 one...

Maybe it's the fact one is plastic and the other is aluminium :/ I'm on a roll today!

[jenchris]

Hi John,
Well telling you the story, I was out at Leyburn, our dark sky place South and inland from Toowoomba.
The night was exceptionally clear and I'd been looking in a friend's 18" dob.
I went back to my scope and dialled up alnitak and had a look at the photo I had (with a red light I hasten to add) orienting it so that I DIDN'T get Flame Nebula - I skipped the OTA over until Alnitak was not visible and went and got a beer - I sat down with my eyes closed for a while even though I could only see the milky way (which oddly enough was bright enough to cast a slight shadow) I got up and peered through my scope using averted vision and all the tricks, nothing did a bit of a spiral search - nope- sat down - had some more beer (same can, I'm not a soak!) about ten minutes later I got up thinking I'd head over to Saturn as it was clear of the trees.
After a minute or so I thought is that it? I could make out the softest variation with the darker horse's head - now whether this is my imagination playing tricks or not I don't know. Looked again, nope there's definitely something there. Looked again - nothing. Kept looking for a while - no it's gone. So it was very fleeting and also very there.
The scope was brand new as were my eyes! I'd spent 20 minutes with no visual input. Several hours with minimal input.
If you put me on a lie detector, I'll come out clean, whether it WAS Horsey, I will not be able to tell you until I repeat the situation.

I'm as certain as I can be, but I cold also be wrong.

[mental4astro]

It's listed a little further down in with all the finder scopes.

[BLiTZWiNG]

Yeah I'm a post editor. Thanks though :)

[BLiTZWiNG]

Out of curiosity, how do you find your $29 RDF?

[BLiTZWiNG]

I went for the $59. Lee said a competitor dared match his price so it's currently a lot cheaper :)

[Jeeps]

I have the $59 one that didn't come with a block. It fits fine with my Skywatcher Dob's standard finderscope block.

cheers

[BLiTZWiNG]

Awesome thanks Sam :)

[astro744]

This thread has gone off topic!

A H-Beta filter is highly recommended for viewing the Horsehead nebula. Lumicon make a good one. See http://www.lumicon.com/astronomy-accessories.php?cid=1&cn=Filters and scroll down.

Works best with reasonable aperture and good exit pupil.

[BLiTZWiNG]

I'm an expert at taking things off topic :)

when you say reasonable aperture size... what size is that?

[astro744]

Sorry, should have elaborated. 8" and over with H-Beta filter. Anything 12" and over also with filter makes it much easier. 6" is possible under very dark skies with a filter. Try different magnifications (giving different exit pupils) and you'll find something that best matches your local conditions.

[BLiTZWiNG]

Yeah, I looked at the price, I'll have to pass on them for now... I need to start spotting more visible things first, but thats kewl to know that it could be possible with filter at least!

[ngcles]

Hi Trent & All,



Trent, it is very hard to add to, or meaningfully expand the advice given by Bammo that I've reproduced (quoted above). It is 100% spot on gospel. It could be sugar-coated but that won't help. John is one of the most experienced visual observers in Australia.

Note carefully those words "exceptionally experienced observer, an exceptionally good telescope and outstanding observing conditions". Yes, several reputable and experienced observers have managed it in 8" and even slightly smaller 'scopes, but for a beginner, it is an extremely tough ask. It's not that experienced observers have "super" or even better eyes than beginners. But, experienced observers do have accurately tuned expectations of exactly what to look for and this is be big difference. Many experienced observers equally have failed with 8" 'scopes. The smallest aperture I've seen it in is 10".

There was a Deep Sky Delights article in the January 2009 edition of Australian Sky & Telescope that dealt with the subject of the Horsehead that some might find helpful.

You can get back issues at the magazine web-site:

http://www.austskyandtel.com.au/TheMagazine/BackIssues/tabid/619/language/en-AU/Default.aspx


The flame nebula is very frequently mistaken for the horsehead -- don't fall into that trap!

Have a go by all means but ...


Best,

Les D

[BLiTZWiNG]

Yeah I'm not expecting to see it. If I ever have enough money to buy a larger scope I'll start hunting it then.

So then, what are the requirements to view the flame nebula?

[Osirisra]

Just finished a great viewing session at my regular spot and picked up the flame neb nice and easy then proceeded to catch very faint glimpses of the Horsehead over about a hour while using different lenses and comparing charts. Really need a UHC filter and will be on my list for sure!