Click here if you are having trouble logging into the forums
Privacy Policy |
Please read our Terms
of Service | Signup and
Troubleshooting FAQ | Problems? PM a Red or a Green Gu.... uh, User
azure1961p
professor emeritus
Reged: 01/17/09
Posts: 731
|
|
I've seen the Horsehead - 18" reflector, H-Beta filter, nice dark Connecticut site. Ive read however apertures as small as 8" have been used to see the notch when knowing the exact proximity.
I figure the Sonwball turned into such a dandy thread with some neat sub threading I'd toss this one out there. What do you guys say - is 8" with an H-Beta too optimistic? Were these guys using "averted imagination"?
Ill never blow anything on that filter - too limited in available targets for my wallet to say yes.
Pete
--------------------
|
Hrundi
Pooh-Bah
Reged: 02/06/08
Posts: 1235
Loc: Estonia
|
|
I'm also curious as to the visibility of the old horsehead. Unfiltered 12" possible?
--------------------
|
square_peg
Postmaster
Reged: 03/26/04
Posts: 29428
Loc: Maple Valley, WA
|
|
I'd love to have an H-Beta but as you say, the cost per object is prohibitive.
A 2" Lumicon H-Beta is $200. An Orion is $156.
--------------------
Tom (Pegster)
DSH-8 (GSO Dob)
15x70 Oberwerks
SVP/ED80
WO 66 Petzval
Sears Discoverer EQ 60/900
8x42 Regals
History is Philosophy teaching by examples.
Thucydides
|
Phillip Creed
Idiot Seeking Village
Reged: 07/25/06
Posts: 1302
Loc: Canton, OH
|
|
With filtration, the Horsehead is quite doable in an 8" from a dark sky under good conditions. If it's a *REALLY* dark sky (Cherry Springs, Spruce Knob, or the middle of the desert), 8" is enough to see it without filters.
Without filtration, it's tougher. The smallest apertures I've heard of that yielded a sighting of the Horsehead without filtration is 4". There's an account of that in Walter Scott Houston's "Deep Sky Wonders" book.
I haven't seen the Horsehead in a 4" refractor, but I've seen the Horsehead without filters with a set of 25x100s twice. I was under Bortle Class 1 sky one time (Big Bend National Park) and a Bortle Class 2 sky the other time (Calhoun County Park, WV), and in both cases transparency was exceptional. A set of 100mm binoculars is roughly the equivalent of a 119mm (4.7") refractor, so it wasn't pioneer territory. And, again, that requires *exceptional* conditions.
Transparency is everything with the Horsehead. The H-Beta emission line is 486nm, significantly shorter than the 507-nm peak of human night vision. As a result, H-Beta emissions are more susceptible to atmospheric extinction.
Clear Skies,
Phil
--------------------
"The hopeful depend on a world without end, whatever the hopeless may say"--Rush, "Manhattan Project"
Wilderness Center Astronomy Club member since 1995
ICQ Comet Observer Code: CRE01
*****
(1) 12" f/4.9 Skywatcher Collapsible Dobsonian
(2) Orion 120mm ST Refractor
(3) Oberwerk 15x70 Binoculars
(4) Minimalist Eyepiece Set:
"23"-mm Axiom LX (~24mm; long story...)
13mm Nagler Type 6
9mm Nagler Type 6
7mm Nagler Type 6
1.75X Siebert Barlow
*****
|
blb
sage
Reged: 11/25/05
Posts: 214
Loc: Piedmont NC
|
|
Quote:
As a result, H-Beta emissions are more susceptible to atmospheric extinction.
I bought a used H-Beta filter at the Mid-Atlantic Star Party last year and can see very little thru it. I wonder if atmosphric extinction is the reason due to our very humid skies.
Thanks Buddy 
--------------------
C-11, C-6, XT10i Dob, ETX125PE, TV102, & AT66
|
HellsKitchen
sage
Reged: 09/05/08
Posts: 356
Loc: Melbourne Australia
|
|
I've seen it as a very faint notch with my 12" and H-beta filter from my outer-suburban backyard.
--------------------
S 38º 00' E 145º20'
Custom 12" F/4.6 dob
10" GSO dob
Intes M500 Mak
4.5" Meade Newtonian
Set of Vixen LVWs + TV barlows + powermates
Astronomik 0III, UHC, H-beta filters
|
Matt Lindsey
member
Reged: 06/06/08
Posts: 94
Loc: Baltimore, MD, U.S.A.
|
|
For me, the H-Beta was a great addition. Under my 5.5 NELM sky the Horsehead was invisible. With the filter, it was actually fairly easy to spot. Same goes for the California neb. The view from Grayson Highlands, VA this summer on the cocoon neb. was just amazing--I found it instantly. So, for me it's certainly been worth it. And, it does work well on at least 20 other objects.
--------------------
Matt
12" f/4.9 custom strut Dob.
8x56 binos
Member: Howard Astronomical League
Working on: Herschel I and II lists, RASC challenge objects.
|
7331Peg
professor emeritus
Reged: 09/01/08
Posts: 718
Loc: North coast of Oregon
|
|
I've seen the "notch" numerous times in my TV102, both with and without the Horsehead filter. On the other hand, I have yet to actually see the horsehead silhouette, even in a C11. I did get a look at it earlier in the week, after the moon had set and just as dawn started to brighten the sky. This time I was using a six inch Antares refractor with just a UV filter, and once again, I could see the notch and even a faint hint of the dark nebulosity in that area, but not the silhouette. Considering how low Orion was, and that the sky wasn't totally black, that seems like a promising start to the Horsehead season. I'll nail it this fall or winter, even if my fingers freeze to the focuser! 
John
|
David Knisely
Postmaster
Reged: 04/19/04
Posts: 8275
Loc: Beatrice, Nebraska
|
|
Quote:
I've seen the Horsehead - 18" reflector, H-Beta filter, nice dark Connecticut site. Ive read however apertures as small as 8" have been used to see the notch when knowing the exact proximity.
I figure the Sonwball turned into such a dandy thread with some neat sub threading I'd toss this one out there. What do you guys say - is 8" with an H-Beta too optimistic? Were these guys using "averted imagination"?
Ill never blow anything on that filter - too limited in available targets for my wallet to say yes.
Pete
No, they weren't using "averted imagination". Under very good dark-sky conditions, it is possible to see the Horsehead nebula in some surprisingly modest apertures. However, most of the time, what is seen is a small notch in the eastern side of the very faint nebular band of IC 434 rather than the full horsehead shape. I have caught the "notch" of the Horsehead in my 100mm f/6 refractor using the Lumicon H-Beta filter, but it was fairly marginal. A friend of mine used the H-Beta in my 80mm f/5 refractor to see the notch, but I didn't get much of it in that little scope. Without an H-Beta filter, it can be considerably tougher, requiring outstanding dark and clear conditions to be seen. Larger scopes help make it easier to see, but the object is still fairly faint and often somewhat elusive. I have seen it from my driveway here in town (ZLM 5.6) using my 9.25 inch SCT and the H-Beta filter, but it was only a vague notch. It starts to show a little of the "snout" when viewed under dark sky conditions if you choose the power wisely. The best magnification range for seeing the Horsehead tends to be one which yields exit pupils from 3.5mm to 5mm in size (6.7x per inch to 4.7x per inch of aperture), as going too low or too high can often result in failure. On nights when I have seen the Horsehead well in my 9.25 inch SCT, it has also been visible with the DGM/Omega NPB filter, although the contrast in the H-Beta filter was still somewhat higher. Here, all you can do is try repeatedly to see it, as some nights it is fairly easy and other nights it can really be challenging. As for the H-Beta filter being "too limited", that too is a myth:
..........USEFUL TARGETS FOR THE H-BETA FILTER..........
While the H-Beta is probably one of the less-used nebula filters, the commonly expressed idea that it works only on a handful of objects is not necessarily true. Here is a list of some of the more prominent objects that the H-Beta may be at least somewhat useful on. Some may require larger apertures, but a few have been seen from a dark sky site by just holding the filter up to the unaided eye and looking at the sky. Some of these will also be helped by a narrow-band filter like the Lumicon UHC or DGM NPB filters:
1. IC 434 (HORSEHEAD NEBULA)
2. NGC 1499 (CALIFORNIA NEBULA, naked eye and RFT)
3. M43 (part of the Great Orion Nebula)
4. IC 5146 (COCOON NEBULA in Cygnus)
5. M20 (TRIFID NEBULA, main section)
6. NGC 2327 (diffuse nebula in Monoceros)
7. IC 405 (the FLAMING STAR NEBULA in Auriga)
8. IC 417 (diffuse Nebula in Auriga)
9. IC 1283 (diffuse Nebula in Sagittarius)
10. IC 1318 GAMMA CYGNI NEBULA (diffuse nebula in Cygnus)
11. IC 2177: (Diffuse Nebula, Monoceros)
12. IC 5076 (diffuse nebula, Cygnus)
13. PK64+5.1 "CAMPBELL'S HYDROGEN STAR" Cygnus (PNG 64.7+5.0)
14. Sh2-157a (small round nebula inside larger Sh2-157, Cassiopeia)
15. Sh2-235 (diffuse nebula in Auriga).
16. Sh2-276 "BARNARD'S LOOP" (diffuse nebula in Orion, naked eye)
17. IC 2162 (diffuse nebula in northern Orion)
18 Sh2-254 (diffuse nebula in northern Orion near IC 2162)
19. Sh2-256-7 (diffuse nebula in northern Orion near IC 2162)
20. vdB93 (Gum-1) (diffuse nebula in Monoceros near IC 2177)
21. Lambda Orionis nebular complex (very large, naked-eye)
In addition, a number of the brighter nebulae like NGC 7000 or M42 will respond to H-Beta use for revealing certain specific detail, although other filters may provide a somewhat better view overall.
Clear skies to you.
--------------------
David W. Knisely
Hyde Memorial Observatory
http://www.hydeobservatory.info
Prairie Astronomy Club
http://www.prairieastronomyclub.org
|
JakeSaloranta
sage
Reged: 09/18/08
Posts: 234
Loc: Sisu, Sauna, Sibelius...
|
|
B33 is quite a challenge from my northern location as it never rises higher than ~28°. I've seen it two times from our family cabin in rural Finland (sea level, SQM-L reading ~21.40+) using a 8" dobson and UHC filter.
I've also spotted it with my 3" and 4.7" refractors. Here is a quick sketch made on location with the 4.7" Sky-Watcher:
Object: Barnard 33
Obs. place: NOT, La Palma, Spain (2390m / 7840ft)
Date: 28./29.3.2008
Bortle class: Class 1
NE Lim.mag: 7.5m
Background sky: 1-2
Seeing: 2 (>5")
Transparency: 2
Weather: NW wind 10 m/s, +3°C, humidity ~47%
As it is with most of deep sky objects knowing what to look and what to expect is half the battle. Never let aperture bring you down and limit your views 
/Jake
PS. Using "search" on the deep sky-forums brings up several similar posts regarding the B33 and the visibility with an 8" telescope. For example:
http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/2934263/page/0/view/collapsed/sb/5/o/all/fpart/1/vc/1
|
blb
sage
Reged: 11/25/05
Posts: 214
Loc: Piedmont NC
|
|
Quote:
I have seen it from my driveway here in town (ZLM 5.6) using my 9.25 inch SCT and the H-Beta filter, but it was only a vague notch. It starts to show a little of the "snout" when viewed under dark sky conditions if you choose the power wisely. The best magnification range for seeing the Horsehead tends to be one which yields exit pupils from 3.5mm to 5mm in size (6.7x per inch to 4.7x per inch of aperture), as going too low or too high can often result in failure. On nights when I have seen the Horsehead well in my 9.25 inch SCT, it has also been visible with the DGM/Omega NPB filter, although the contrast in the H-Beta filter was still somewhat higher. Here, all you can do is try repeatedly to see it, as some nights it is fairly easy and other nights it can really be challenging. As for the H-Beta filter being "too limited", that too is a myth:
David,
Do you see any star's in the field-of-view when using the H-Beta filter? Or do you just see the nebula? Or do you see both?
Buddy
--------------------
C-11, C-6, XT10i Dob, ETX125PE, TV102, & AT66
Edited by blb (09/05/09 10:45 AM)
|
Jeremy Perez
Carpal Tunnel
Reged: 08/12/04
Posts: 1930
Loc: Flagstaff, Arizona, USA
|
|
Here is a report using a 6 inch Newtonian from a dark sky site: B33, IC434, NGC 2023
The notch did show up unfiltered, but a UHC filter did help. It is a very difficult object to observe, like a little bit of nothing with a little bit of less than nothing resting over it. Bill Ferris was at the site that evening, and also confirmed the view through the 6 inch scope. However, another observer was quite dubious that we were seeing anything other than stars "...I'll have to take your word for it..."
Find the darkest site possible on the driest night possible, know the star field you need, and give that 8 inch scope a try. See if you can spot fluffy NGC 2023 first, then just to the west see if a dim field of slightly brighter sky indicates IC434. If you've found those two, start the averted vision scan for the darker ghost intruding into it. Wishing you success!
--------------------
Orion SVP 6LT (6" f/8 Newt) || Orion XT8 (8" f/5.9 Dob) || 15x70 Oberwerk Binoculars || Coronado PST
The Belt Of Venus || Sketch Gallery || Sketching Resources || Astro-Photo Gallery
|
David Knisely
Postmaster
Reged: 04/19/04
Posts: 8275
Loc: Beatrice, Nebraska
|
|
Quote:
Quote:
I have seen it from my driveway here in town (ZLM 5.6) using my 9.25 inch SCT and the H-Beta filter, but it was only a vague notch. It starts to show a little of the "snout" when viewed under dark sky conditions if you choose the power wisely. The best magnification range for seeing the Horsehead tends to be one which yields exit pupils from 3.5mm to 5mm in size (6.7x per inch to 4.7x per inch of aperture), as going too low or too high can often result in failure. On nights when I have seen the Horsehead well in my 9.25 inch SCT, it has also been visible with the DGM/Omega NPB filter, although the contrast in the H-Beta filter was still somewhat higher. Here, all you can do is try repeatedly to see it, as some nights it is fairly easy and other nights it can really be challenging. As for the H-Beta filter being "too limited", that too is a myth:
David,
Do you see any star's in the field-of-view when using the H-Beta filter? Or do you just see the nebula? Or do you see both?
Buddy
I can see quite a few stars in the H-Beta filter, although they are noticeably fainter than they are without the filter. One big factor is that Zeta Orionis tends to really cause problems with seeing the nebula, so the filter helps here as well by dimming it down to some degree. Some people who observe the Horsehead without filters use narrow field of view eyepieces like Kellners so that they can keep Zeta well out of the field and still see the dark nebula. Clear skies to you.
--------------------
David W. Knisely
Hyde Memorial Observatory
http://www.hydeobservatory.info
Prairie Astronomy Club
http://www.prairieastronomyclub.org
|
skyward_eyes
Carpal Tunnel
Reged: 12/12/06
Posts: 2101
Loc: Arizona
|
|
Under some dark skies my 16" with a 22 Panoptic and a 1.25" H-Beta can make quick work of the Horsehead, its one of my favorite objects to observe becasue of how challenging it is.
--------------------
www.skywardeyes.webs.com
|
7331Peg
professor emeritus
Reged: 09/01/08
Posts: 718
Loc: North coast of Oregon
|
|
As has been mentioned, you need dark and transparent skies to see the Horsehead. Just as critical is "patience." I've found that after looking at the area for anywhere from fifteen minutes to an hour, the detail will slowly emerge. When I say I've seen the notch, it wasn't immediate by any means. Unless you get lucky with the viewing conditions, it takes a lot of persistence. But if you stay with it, you'll first pick up the nebulosity behind the Horsehead and then the notch will gradually become more distinct - probably not sharply defined, but it will be there, as in Jeremy's sketch, which is a very good approximation of what you can see. Start with a very good map of the area so you know exactly where to focus your attention.
A good method that has worked for me is to start with NGC2023 and then slowly work my way over to the IC434 area. A lot of times, the contrast between the darker sky around NGC2023 helps to make the faint nebulosity of IC434 stand out a bit more. I normally have to move my scope back and forth between the two areas half a dozen times before the nebulosity starts to become visible. You really have to work at getting your vision to adapt to the nebulosity of IC434 because it is barely brighter than the dark background.
And keeping Zeta Orionis out of the field of view is also critical!
John
|
FirstSight
Post Laureate
Reged: 12/26/05
Posts: 3883
Loc: Raleigh, NC
|
|
I saw it through someone else's 18" scope w/H-Beta filter at Winter Star Party last February, and the view was closely similar to Jeremy Perez's sketch above, except the contrast was much dimmer (sort of like the view you'd get on a laptop screen of Perez's sketch if you tilted the screen away from you to beyond a really good viewing angle, but not so much that it disappears). The "snout" feature seemed to each observer to be elusively visible intemittently, but it was so tenuously on the border of averted imagination that we felt we needed a group discussion to confirm which way we each thought the "snout" was pointing (and I can't remember which direction, leftward or rightward we wound up agreeing on). I'm not sure averted-vision by committee observing is the most reliable sort of confirmation of a sighting.
I did take away one clear impression from the experience: the Horsehead is the best illustration out of all the objects I've ever seen of the admonition "don't expect it to look anything like it does in astrophotographs".
--------------------
Chris M., aka "First Sight"
Orion XT12i Dob with Moonlite CR-2 focuser
WO Megrez 90 refractor on UniStar Light mount
Nikon 10x50 Binoculars
Edited by FirstSight (09/06/09 05:41 AM)
|
Cames
member
Reged: 08/04/08
Posts: 49
|
|
My suggestions for observers not utilizing the H-Beta filter:
When observing it for the first time, it helps to wait until the nebula is nearing the meridian. (At that point you will likely experience the least atmospheric attenuation of the faint glow of its companion IC 434). In subsequent encounters you can go for the greater challenge.
As David recommended above, stay away from Alnitak as it seems to me to be bright enough to impact dark adaptation.
Test the sky transparency. If you cannot see the Flame Nebula clearly, you will be severely handicapped in your quest for the Horsehead.
----------------
C
Edited by Cames (09/08/09 09:01 AM)
|
7331Peg
professor emeritus
Reged: 09/01/08
Posts: 718
Loc: North coast of Oregon
|
|
It's been my experience that if the transparency is too poor see the Flame Nebula, the Horsehead is out of the question.
John
|
Stef
super member
Reged: 04/07/07
Posts: 146
Loc: Aylesbury, UK
|
|
David K,
What is the best magnification to see the notch in your 9.25"?
Thanks
Stef (UK)
--------------------
Celestron NexStar 9.25" GPS XLT Sky Align
TeleVue NP101 on Gibraltar Alt/Az Mount + Sky Tour
Fujinon 10x70 FMT-SX Virgo Astronomics Bino Mount
-----------------------
Celestron 40mm E-Lux Plossl
Tele Vue 31mm Nagler
Tele Vue 22mm, 17mm & 12mm Nagler T4
TMB 9mm Super Monocentric
Tele Vue 8mm Radian
Pentax 5.2mm XW
Tele Vue 3mm Radian
-----------------------
Lumicon 2" UHC, Baader 2" OIII
Telrad, TeleVue Starbeam
WO SCT Dual Speed Focuser (Orange)
Celestron SkyScout
|
blb
sage
Reged: 11/25/05
Posts: 214
Loc: Piedmont NC
|
|
It seems like I read something within the last year about the magic eyepiece for looking at the HH. I think this was using a low power eyepiece for the brightest image of HH, if I remember corectly. Anyone remember the formula for the correct eyepiece to see the Horsehead?
Clear Skies, Buddy 
--------------------
C-11, C-6, XT10i Dob, ETX125PE, TV102, & AT66
|
|
5 registered and 7 anonymous users are browsing this forum.
Moderator: Olivier Biot
Print Thread
|
Forum Permissions
You cannot start new topics
You cannot reply to topics
HTML is disabled
UBBCode is enabled
|
Thread views: 604
|
|
|
|
|
|
|
Previous
Index
Next
Threaded
Edit
Reply
Quote
[Re: 
