Jump to content

Stargazers Lounge Uses Cookies

Like most websites, SGL uses cookies in order to deliver a secure, personalised service, to provide social media functions and to analyse our traffic. Continued use of SGL indicates your acceptance of our cookie policy.

stargazine_ep3_banner.thumb.jpg.5533fb830ae914798f4dbbdd2c8a5853.jpg

GTom

H-Beta for narrowband imaging?

Recommended Posts

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...

Edited by GTom

Share this post


Link to post
Share on other sites

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.

Share this post


Link to post
Share on other sites

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

  • Like 2

Share this post


Link to post
Share on other sites

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.

Share this post


Link to post
Share on other sites

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.

Share this post


Link to post
Share on other sites

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

  • Like 1

Share this post


Link to post
Share on other sites
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.

Share this post


Link to post
Share on other sites

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.

Share this post


Link to post
Share on other sites
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...

Share this post


Link to post
Share on other sites
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

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Recently Browsing   0 members

    No registered users viewing this page.

  • Similar Content

    • By AstroRuz
      SkyTech L-Pro Max Light Pollution Suppression Filter
      Used for about a year now and still in very good condition. really helped me out in my garden but now I've moved to tougher skies and need a slightly stronger filter. So it's time to pass this on to someone else.
      Filter is in very good condition with no scratches on it. Used extensively to great effect. Cardboard box slightly tatty but to be expected.
      Creates very nice pictures with good star colour retention and no halos. Horsehead is a HaRGB composite photo where the RGB was shot with this filter.
      2" fitting (M48). Will come with outside box, interior box and of course the filter.
      £100 + £8 P&P (Royal Mail Special Delivery)








    • By crossingsymmetry
      Greetings everyone.
      I recently scored a great deal on facebook marketplace and bought Skywatcher Skymax 180 mm Maksutov-Cassegrain Telescope (f/15) with EQ6R-pro mount. I understand that long focal length telescopes are more suitable for planetary imaging. However, as I am tight on budget, I would like to use the same scope for deep-sky astrophotography. I have Canon Rebel T5 DSLR camera that I am using for taking images. Without autoguiding and a decent polar alignment, I can get ~30 seconds long shots without any star trailing, but that's not sufficient for imaging objects like M51. I would like to be able to integrate longer, say few minutes, thus would like to purchase an autoguider.  Here are some specific questions I have.
      1). The telescope comes with an 8 x 50 straight-through finder.  If I were to use it as a guidescope, what type of image integration time can I expect? Has anyone done autoguiding for f/15 scope with an 8x50 or other finderscopes?
      2). If the integration time will be an issue with the 8x50 finder scope, I am open to purchasing an off-axis-guider. However, considering the narrow field-of-view of Mak-180 telescope, I am concerned about not having enough photons from guidestar for autoguiding. For instance, with my DSLR camera, I need to integrate 20-30 seconds to see the nearby stars in M51. What type of OAG and camera would I need to autoguide with my scope? Are there affordable cameras (~$200) that would do the job for me? Would ASI120MM Mini Monochrome (~$150) do the job? What about OAG?
      I plan to use phd2 software for autoguiding rather than relying on the build-in guide port on the mount.  Instead of integrating for hours, I am planning to do DSS stacking of few mintues long multiple shots, hopefully this will put less strict requirements on the autoguider.
      In case this information is relevant: with my current setup, I have no issue pointing my scope to a desired deep-sky object, track the object within the field-of-view of my DSLR camera for hours using the mechnical tracking of the EQ6 mount. For instance following is a single raw image of Ring nebula taken with 30 seconds shot.  But it is not enough for generating high-quality images. 

       
      Thank you in advance for your help.
       
      Regards,
      Jay
       
    • By joelshort
      I'm selling a 1 year old Moravian G3-16200M Mark II camera. Please note this is the newer Mark II camera with faster downloads (on my NUC computer it was 9s.). Everything is in like new condition.
      The Moravian G3-16200M MKII has a class 2 chip and the standard cooling. The camera cames with an M48 nose piece (unused), power supply with both USA and European plug, 10ft USB cable and hard case. There is also a 17mm extension that can be used if you purchase separately the larger M68 adapter. There are currently 2 read out lines that completely disappear with active cooling and proper image calibration, as is typical with a class 2 sensor.
      £2240 PLUS SHIPPING, no fee for paypal.  NOTE: ships from USA.
    • By rgrickert
      Hello
      I am wondering if anyone has a suggestion that might help me
      My imaging set up is an RC reflector with an FLI proline 16803 camera and 50mm Astrodon filters (LRGB + 5nm narrow band)
      I have had a string of issues...everything from my mount had mechanical problems to my telescope had issues with the mirror cell to some family distractions...but at long last I seem to have everything working with the exception of the Astrodon Ha filter.
      Attached are representative 30minute subframes of the horse head and Pacman nebulae in Ha, SII, and OIII.  I get similar results with different objects although for bright, broad spectrum targets like M42, I will get data from the Ha filter (much as the stars shine thru on the HH and Pacman) although even that data does not comport with other imager’s Ha images of those objects. The LRGB performance appears to be normal.  My hypothesis is that this Ha filter is defective, perhaps not centered on 656.3nm
      I have contacted Astrodon and exchanged a couple of emails with Cary Chleborad seeking some help.  At first he claimed there was no issue because with enough manipulation some data could be extracted from the Ha. Later, when confronted with the other narrowband frames and the obvious difference to the Ha, at first he ghosted me, but when I said I would ask other imagers for help, he responded with a new position stating that because of the way the filters are made and their robust quality processes, it is impossible for the filter to be defective and therefore something else must be at issue.  He does not offer a suggestion of what might be the problem, nor is he interested in having me send the filter back for evaluation. Frankly, I’m more than disappointed given the premium I paid for Astrodon filters
      All that aside, and taking Cary’s position at face value, does anyone have an idea of what might cause this behavior other than the filter?  In a perfect world, does anyone live in the Austin, Texas area who would be willing to try my filter one night and see what they get with their equipment?
      The attached link is to the raw, uncalibrated files right off the camera.  I think a simple blink process in PixInsight will show what I’m talking about.
      I’m a little at my wits end, please help!
      https://www.dropbox.com/sh/60mvhzb717hdhnl/AACcAMkQdDsJuk1RU10PXvgja?dl=0
    • By Astrofriend
      A friend ask me about filter size, I already had a Excel sheet with that calculation. But I did a new web calculator.
      It's the first version but it looks to calculate it correct, have a look:
      http://www.astrofriend.eu/astronomy/astronomy-calculations/minimize-vignetting/minimize-vignetting.html
      It's not any high precision calculation, but gives knowledge enough I think.
      Too small filter gives vignetting, too big filter empty the wallet.
      /Lars
×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.