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H Beta filter - is it any good?

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#1 Abhat

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Posted 29 September 2014 - 05:27 PM

I have opportunity to buy 2" Orion H Beta filter for $49.

I am not sure if 8" is too low of an aperture for H Beta and if there are enough targets for this filter that will wow.



#2 kfiscus

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Posted 29 September 2014 - 09:10 PM

I bought my H-beta (used Lumicon) as the last filter in my set, to deal with objects that didn't respond that well to my O-III or NPB.  It has already helped with the Horsehead and California.  I will eventually work on the other 20-some objects that David Knisely has identified as helped by the H-beta.

 

At that price, I'd probably buy it, try it, and then hang on to it for a few more objects.  You can always resell it at that price and be out nothing.



#3 star drop

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Posted 29 September 2014 - 09:19 PM

A good price indeed.



#4 David Knisely

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Posted 30 September 2014 - 12:22 AM

An 8 inch rich-field telescope can use the H-Beta to show larger objects like the Gamma Cygni nebular complex (IC 1318) or segments of Barnard's Loop and the California Nebula.  There are other fainter targets which the H-Beta can be used on, although some require moderate to large aperture:

 

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 (and some may be slightly better in other filters), 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. 

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: SEAGULL NEBULA (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)   
22. Sh2-273 "Cone" Nebula portion south of nebulous cluster NGC 2264

 

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.


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#5 Abhat

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Posted 30 September 2014 - 04:59 AM

Thanks David.



#6 havasman

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Posted 30 September 2014 - 05:31 AM

Tonight I used a Thousand Oaks H-Beta and ES82 30mm to pull the California nebula in very easily. After viewing for a bit, I removed the filter and looked again to see stars and a general void in the area that had just been filled with readily apparent nebulosity. It works very well on the right target and your'e getting the right price. :waytogo:


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#7 Fuzzyguy

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Posted 30 September 2014 - 11:39 AM

Thanks for the list David. I've been thinking about adding this filter, but wanted to know if you think 8" is the minimum aperture for this filter. I ask because my OIII came with a caveat that it wasn't useful in apertures under 8", but I've had good luck looking at some of the larger objects like NGC 7000 and the Veil Nebula in my 80ED with a wide, 4mm exit pupil EP. Thanks!



#8 David Knisely

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Posted 30 September 2014 - 03:42 PM

Thanks for the list David. I've been thinking about adding this filter, but wanted to know if you think 8" is the minimum aperture for this filter. I ask because my OIII came with a caveat that it wasn't useful in apertures under 8", but I've had good luck looking at some of the larger objects like NGC 7000 and the Veil Nebula in my 80ED with a wide, 4mm exit pupil EP. Thanks!

 

Yea, that old "OIII needs an 8 inch" myth just refuses to die.  It is just a case of the larger the scope the more you will see, regardless of whether a filter is used or not.  It does take some darkness and a larger exit pupil to do it, but these filters can still be useful on some nebulae even in some rather small apertures.  Clear skies to you.


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#9 Abhat

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Posted 30 September 2014 - 03:58 PM

Finally made the purchase of 2" Orion H Beta. It will arrive in 2 days. David's list will come in really handy. Orion is nicely visible around 5 AM in the morning. I will try my luck on M43 and Horsehead as soon as I get clear skies.



#10 GlennLeDrew

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Posted 30 September 2014 - 07:05 PM

The old 'bigger aperture for narrower filters' rubric does indeed refuse to roll over and expire.

 

For extended objects, a larger aperture merely affords to detect smaller objects/details. At given exit pupil, all telescopes deliver the same image surface brightness (discounting the generally small differences in transmission efficiency.) And no telescooe can deliver higger surface brightness than the bare eye. This is why such large objects as the California and Barnard's Loop are within naked-eye detection with an H-beta filter.

 

Many large, dim nebulae are within reach of small apertures. Once an object subtends sufficient angle on the retina, further increases in magnification--even if by application of a larger aperture!--do not necessarily permit more ready visibility. A good example is afforded by the California. This ~2.5X1º nebula subtends ~25X10º in a 10X50 bino; as large as the naked-eye Big Dipper! A large scope can see only a portion at one time. This very low contrast, visually detail-less cloud will be more readily detected in tge smaller instrument because its full perimeter is framed by (slightly!) darker sky, which better facilitates edge detection.

 

There are times when smaller can be better.


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#11 Fuzzyguy

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Posted 30 September 2014 - 07:29 PM

Thanks David and Glenn, That's what I thought you'd say, but with the very narrow band width of the H-beta and the eye's trouble at seeing that particular wavelength, I wasn't sure. Now that you've said it, I think I've read both of you saying the same thing before, but it's good to have confirmation!


Edited by Fuzzyguy, 30 September 2014 - 07:31 PM.


#12 GlennLeDrew

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Posted 01 October 2014 - 05:20 AM

The eye has no trouble seeing H-beta. Indeed, it's almost precisely at the peak of the dark adapted response, right there beside O-III on the spectrum. For instance, red H-alpha is over 2X more intense than bluish-green H-beta, which is why red dominates in color images. But to our dark adapted eye, for which the response at the H-alpha wavelength is perhaps 5% that at H-beta, the red contributes essentially nothing to our perception of virtually all nebula (outside of a mere handful of objects.)

 

The difficulty of the 'H-beta nebulae' stems only from their being insufficiently ionized for--or lacking the presence of--oxygen emission. This makes for reduced surface brightness. A highly ionized nebula has the addition of a pair of O-III emssion lines, often each of which is brighter than the H-beta, making for a visual surface brightness usually at least 4X brighter.


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#13 Fuzzyguy

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Posted 01 October 2014 - 06:20 PM

Thanks for the explanation Glenn. I guess I need to take a look at the lines again. I was under the impression that H-beta was closer to red than blue or green. Serves me right for not looking in the first place!  :bigblush:  Now that I've hijacked the thread, back to your normally scheduled programing.


Edited by Fuzzyguy, 01 October 2014 - 06:22 PM.


#14 David Knisely

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Posted 01 October 2014 - 11:35 PM

Thanks for the explanation Glenn. I guess I need to take a look at the lines again. I was under the impression that H-beta was closer to red than blue or green. Serves me right for not looking in the first place!  :bigblush:  Now that I've hijacked the thread, back to your normally scheduled programing.

 

 

The Lumicon H-Beta often has a big "red leak" secondary passband, so if you look through it, you may see red as well as the regular bluish-green hue.  You probably won't see much of the red passband's effect in the telescope other than on brighter stars (and maybe in portions of M42 if you have enough red sensitivity in your eyes).  Clear skies to you.


Edited by David Knisely, 01 October 2014 - 11:36 PM.


#15 Dave Mitsky

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Posted 02 October 2014 - 02:10 AM

I had one of my best-ever views of NGC 1499 last week while observing from the lofty wilds of West Virginia.  The telescope was a 22" f/3.6 SDM Dob equipped with a 30mm Leitz Planokular 88° AFOV eyepiece and a Lumicon H-beta filter.  Scanning back and forth along the length of the nebula with the telescope's drive disengaged proved to be an exceptional experience.  The nebulosity was readily visible and its namesake shape was unmistakable.  The California Nebula just seemed to go on forever!  ;)

 

http://chesmontastro.org/node/11650

 

I also had a good view of NGC 1499 on quite a different scale through my filtered 101mm f/5.4 Tele Vue refractor.

 

http://chesmontastro.org/node/11649

 

B33 (the Horsehead Nebula) was an easy target through the 22" Dob and the H-beta filter. In fact, it was even visible without a filter.

 

Dave Mitsky



#16 Abhat

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Posted 03 October 2014 - 05:10 AM

I received Orion's 2" H Beta Filter yesterday in mail. The darn thing would not screw on to my eyepiece or the 1.25"-2" focuser adapter. With some force it catches on to couple of threads and then thats it. I am wondering if that is OK or I should return the filter. I am afraid that it may fall on the secondary and then the primary during the observation.



#17 Tom Polakis

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Posted 03 October 2014 - 09:55 AM

I received Orion's 2" H Beta Filter yesterday in mail. The darn thing would not screw on to my eyepiece or the 1.25"-2" focuser adapter. With some force it catches on to couple of threads and then thats it. I am wondering if that is OK or I should return the filter. I am afraid that it may fall on the secondary and then the primary during the observation.

 

That's definitely not OK.  If the filter doesn't readily screw into your 2" eyepieces, you should return it.  Orion is good with returns in my experience.

 

Tom



#18 Abhat

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Posted 03 October 2014 - 10:08 AM

I had sent Don Pensak a PM. He replied pretty quickly. He said that is a problem with all Orion filters made in Korea. He gave me couple of options such as manual re-threading or transferring the filter cell into a different housing of a cheap color filter. I will try that out. The clearance deal I got was too good. I will have to spend another $100 to get a new one.



#19 Achernar

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Posted 05 October 2014 - 11:06 AM

 

Thanks for the explanation Glenn. I guess I need to take a look at the lines again. I was under the impression that H-beta was closer to red than blue or green. Serves me right for not looking in the first place!  :bigblush:  Now that I've hijacked the thread, back to your normally scheduled programing.

 

 

The Lumicon H-Beta often has a big "red leak" secondary passband, so if you look through it, you may see red as well as the regular bluish-green hue.  You probably won't see much of the red passband's effect in the telescope other than on brighter stars (and maybe in portions of M42 if you have enough red sensitivity in your eyes).  Clear skies to you.

 

I've noticed that, on some objects I did see a reddish hue through one of those, but never through the Orion H-beta filters I use. The Lumicon H-beta filters do work exceedingly well though on the appropriate objects, not doubt about it.

 

Taras


Edited by Achernar, 05 October 2014 - 11:06 AM.


#20 Abhat

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Posted 05 October 2014 - 03:30 PM

I tried H Beta on Horsehead Nebula today AM and I could not see a thing. Not sure what am I missing. M43 looked little prominent than usual but no signs on Horseheads anywhere.



#21 David Knisely

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Posted 06 October 2014 - 01:04 AM



I tried H Beta on Horsehead Nebula today AM and I could not see a thing. Not sure what am I missing. M43 looked little prominent than usual but no signs on Horseheads anywhere.

 

1. You have to have a fairly dark sky to begin with (no moon and little in the way of light pollution, with Orion near the meridian).

2. You have to be *very* dark adapted and use averted vision. 

3. You need to use the optimal magnification range for the Horsehead (2.5 mm diameter exit pupil to 5.5 mm exit pupil, or roughly from around 4.6x per inch of aperture to around 10x per inch of aperture).

4. You need to be prepared for something that is FAINT, even when using the filter, as much of the time, the Horsehead appears as a mere darkening in a very dim glow that is scarcely brighter than the regular background skyglow.

 

There is a thread at the beginning of the Deep-sky forums which covers a lot of what you need to see the Horsehead.  While it has been glimpsed in some failry modest apertures by experienced observers, the Horsehead remains one of the more difficult deep-sky challenges in the sky.  Clear skies to you. 


Edited by David Knisely, 07 October 2014 - 09:21 PM.

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#22 kfiscus

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Posted 09 October 2014 - 05:39 PM

+1 on what David posted about the "About to go after the Horsehead" thread.  The thread's sketches and advice "it's bigger than you expect" were the keys to success on my first serious HH attempt.




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