H-Beta for narrowband imaging?

[GTom]

Does it make any sense to shoot H-beta along H-alpha for narrowband imaging? They are both arising from the same element, although I don't know whether their ratio remains the same for all emission nebulae...

[Knight of Clear Skies]

Interesting question. The info here suggests that only a few objects emit strongly in H-Beta, I don't know which ones though and whether the same ones are also bright in Ha. I don't know if a nebula would appear much different in H-Beta, it's a larger energy transition so perhaps you'd see more of it close to very hot stars pumping out more higher energy UV?

The fact that people rarely shoot in H-Beta makes me suspect it's not worth doing, but I haven't tried searching properly for H-Beta images so I could be wrong.

[michael.h.f.wilkinson]

Typically H-alpha is much stronger than H-beta, and both have essentially the same spatial distribution so little would be gained. H-beta is mainly used for visual on objects that are strong H-alpha and H-beta emitters, but do not emit much O-III or the like. H-alpha is barely visible to the dark adapted eye, whereas H-beta is

[Physopto]

Have  a look at this Astronomik website page it will explain a bit that may help you. I have an Hb filter from them but rarely use.

http://www.astronomik.com/en/fotografische-emissionslinienfilter/h-beta-ccd-filter.html

Derek

[GTom]

Thanks for all the responses! True, the H-beta needs a strong UV excitation = nearby O or B type star, which are quite rare. I may skip investing in a photographic H-b for the moment.

[michael.h.f.wilkinson]

My H-beta filter usually resides in the EP case, not in the filter-slide diagonal, which almost permanently holds a UHC and a O-III filter. The H-beta has served its main purpose of getting a visual on the Horse-Head Nebula, and has been of use on the California as well, although UHC works well on the latter too.

[ollypenrice]

I don't use mine at all. It traces the same gasses as Ha but is blue and very weak. To be honest you can, if you like, put a whiff of Ha into the blue channel as a surrogate H beta. I've tried that but, again, don't generally do so any more.

Olly

[Knight of Clear Skies]

2 hours ago, michael.h.f.wilkinson said:

H-beta is mainly used for visual on objects that are strong H-alpha and H-beta emitters, but do not emit much O-III or the like. H-alpha is barely visible to the dark adapted eye, whereas H-beta is

Thought this may be the case but wasn't sure, when it comes to the visual side I have very little experience.

[DaveS]

I've put a H-beta into my wheel with the idea of adding it to any blue channel if I should do RGB. theoretically it should be in the correct ratio to the red H-alpha.

[GTom]

4 hours ago, DaveS said:

I've put a H-beta into my wheel with the idea of adding it to any blue channel if I should do RGB. theoretically it should be in the correct ratio to the red H-alpha.

If RGB can be shot (LP allows) I see little sense to do H-beta, but correct me if I am wrong...

[ollypenrice]

14 hours ago, DaveS said:

I've put a H-beta into my wheel with the idea of adding it to any blue channel if I should do RGB. theoretically it should be in the correct ratio to the red H-alpha.

This will only be true if you give it the same stretch as the Ha. The way most people use Ha is to stretch it far harder than they do the red channel. If you don't do this the Ha will not show above the red signal so there would be no point in using it. (The Ha signal is entirely contained within the red. The filter itself cannot pass more Ha than the red filter, it can only suppress the reds not coming from the Ha emission line. What the filter allows us to do is change our red layer so that the Ha componenet of red is exaggerated by comparison with the rest of the reds. There is no reason in principle to believe that you won't be able to do this with the blues but the signal will need the same enormous stretch as the Ha. How practicable it will be to collect sufficient H beta to affect blue in the way that Ha affects red will be something decided by experiment.

Olly