HOO or SHO? Using the Antlia Hb-SII Dual Band Filter for OSC Cameras 

There’s always something to learn in PixInsight. Very daunting at first, but just take it one step at a time. You don’t have to use every process in the box. Have fun!

Thanks for watching! Yes, I'm very happy with the near-mono image quality I'm getting out of the OSC camera and these dual-band filters. Once upon a time, I did setup the GPU for crunching through the time-intensive calculations. I guess I'm going to cave in and set that up again.

Great! H-beta is new for me. I was surprised and happy to see its contribution. Hope you enjoy your new filter when it arrives! Thanks for watching!

Hey Pat. That is surprising/disappointing about the Optolong H-beta. I hope you get better performance from the Antlia filter. I've used it for all of two nights. So far, so good. Monochrome still has its place. More "trouble" than a OSC camera, but better overall image quality/detail. I must say, the convenience of the OSC is attractive. By the way - You've mentioned difficulty focusing your SCT with the Celestron Focus Motor. I ran across this video that refers to the same thing and provides a fix. See 12:56 in ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-zdADiHmGLpw.htmlsi=oKyx9M9vO6ckBADT

Haha. I had a lot of the processing in the video but took it out because it was too long. I'll try to make some of those kinds of videos in the future. Thanks for watching, Adriana!

Thanks for watching! Yes, I'm very impressed with what these OSC filters let you get away with.

Let me know how it turns out. Thanks for watching.

Glad you were able to get something out of it! Thanks for watching, Bryan.

Thanks, Tom!

Gotta agree with your there - I prefer the SHO palette myself when there's enough SII to grab onto. I also like that Antlia created a filter with SII and H-beta (rather than SII and OIII). I like have the H-beta contribution. I bought my OSC camera mostly for galaxies (with the SCT), but I felt I was missing something when shooting legit SHO targets with just the one dual-band filter. Enjoy!

Hi, Rich. Thank you for the kind words. When I started in astrophotography, I had no experience with PI or PhotoShop so I decided to hitch my wagon to the more astrophotography-centric app. It is complicated and daunting at first. There are processes in PI that I've never used. Still others that I'm not using "properly". The only way to climb the learning curve is to jump in and start learning. It's a good (heck, probably great) program. I paid for it once and haven't had to send any more money. Not sure that's the case for PhotoShop. But there are cheap/free photo processing tools out there so that's still an option. You'll find a lot more on-line discussion/instruction with PixInsight. Good luck and thanks for watching!

That's a good question. I would assume that the H-beta and H-alpha are present but at very different concentrations. Or does the H-beta exist more closer to the ionization source and where the Hydrogen is more dense? I'll have to look into that. As for where to add the H-beta, I believe it should be added to the color channel best associated with the emission wavelength rather than the source atom. H-beta falls in the blue/green spectrum and OIII in the green/blue area, so I think it makes more sense to add those channels together rather than put H-beta and H-alpha together just because Hydrogen is the source atom. Thanks for watching!

I did a video on the Antlia TriBand Ultra RGB filter. I was using it to image several galaxies. It's a nice filter. But it won't let you get the SHO palette out of your emission nebulae images because the SII and Ha are combined in the red channel. To do SHO, you need separate images for the SII (goes in the R channel) and the Ha (goes in the G channel). But the TriBand is a great RGB filter that provides a ton of light pollution protection and gives you the Ha in galaxy spiral arms.

Yes. I'm combining images taken with one dual band filter (the OIII-Ha) with other images taken with another dual band filter (the Hb-SII) to get the SHO color palette. Thanks for watching!

Hi Rob. Thanks for watching. Yes, there are some excellent filters out there for OSC cameras. Well, you definitely lose something on resolution with a OSC vs mono depending on aperture. With my C9.25, I’m probably not losing anything because the RGGB binned “pixel” is still less than the seeing-controlled resolution (Nyquist limit vs Dawes Limit vs Seeing limit). Seeing controls for my skies and a C9.25 SCT. The story changes when you get below about 700 mm focal length and you have a 100 mm aperture. Now, the binned RGGB pixel may hurt somewhat as the color of that pixel comes from debayering whereas a mono system gives the proper color balance for each pixel (half the size of the RGGB “super pixel). For lower apertures and focal lengths (say 350 mm focal length at 80 mm), the aperture (Dawes Limit) takes over. The good thing about the ZWO ASI294MM is that you can use the bin1 mode and recover more resolution for mono systems. Sorry for the complicated answer!

@@Aero19612 James, thanks for this detailed answer. Your insight is greatly appreciated. I'm teatering on moving to mono, but my hobby list is longer than my budget, so I need to make logical choices. I currently have the Askar 107PHQ paired with the 2600MC. I'm looking at the 2600MM with the Antlia 4.5nm SHO filters. Thus, kind of at the edge @ 740mm. From what I've seen thus far, mono generally tends to benefit from overall better sharpness and detail. That being said, the price point it rather significant. Would love to hear your thoughts?

It’s a convenience VS resolution (+ a little SNR) issue. Your 107PHQ pics would likely benefit from the mono setup. It is costly to go mono and you’ll spend more time with flats and processing, but I like the mono images better than my OSC images (but not by a lot). The 2600 is a 16bit camera and you’re getting great tonal resolution as a result. You’d be buying a filter wheel to accommodate 2” filters so you don’t get vignetting. For me, I have the 1.25” filter wheel and feel “trapped” with cameras that have small enough sensors that don’t get blocked by the filters (no 2600 for me!). In conclusion: if you stay with the MC, then dither and drizzle to get the best resolution that seeing permits. If you go mono, you may not need to dither/drizzle and the nice thing is you’d be buying a filter wheel and filters that will likely work with any camera going forward (unlike me). No obvious answer (sorry).

I do have the Antlia TriBand Ultra. I used it for several galaxies (there's a video on it). My objective with this OSC camera and SCT is to "keep" it simple" and just use one filter: ether the Triband for RGB targets or the OIII-Ha for emission nebulae. As it turns out, I felt I was missing the SHO palette, so I decided to trade some simplicity for using the Hb-SII filter. Thanks for watching!

@@Aero19612 I mean one of those *narroband* tri-band filters, such as the OPT Triad Ultra Quad-Band filter. I'm just curious, I went mono since my 1st day of astro shooting :)

Hi Brad. I think I had about the same imaging time on Ha/OIII as Hb/SII. But, as is often the case, Ha dominates and you’re lucky to get OIII and maybe SII. I view Hbeta as a “gift” - I get some, great. I never try to match imaging time for OIII and/or Hbeta to get the same detail as I get with Ha. I’m just hoping for some color and I’ll take the detail I get from Ha. The Hbeta is nice because it provides a different version of blue/green than OIII. There are some exceptions, such as when Imaging the Squid and Flying Bat nebula. I really try to get a lot of OIII to pull out the Squid. Always a tough case for Bortle 8 though.

Absolutely. No need to worry about matching bandwidths.

Hmm. Not sure how you’re applying it. Load the reference file name into LinearFit, the drag and drop the triangle icon onto each of the other 3 images. Should work ok. Let me know if it isn’t and give me more detail about how you’re using it and I’ll try to help. Good luck!

Hi Dan. Thanks for watching! As for combining blue and green data, there are several potential ways to do it. My approach is arguably the simplest. I doubt there would be much benefit using ImageIntegration with just the 4 images I used. I wonder if the different noise levels would cause ImageIntegration to de-rate the noisier Hb-SII images. That's why I used LinearFit to balance the median noise levels. Now, if you want to go to a lot of trouble, you could extract the RGB channels from all of the images, select a reference, and then use batch LinearFit to equalize all of the blue and green images, and then combine them using ImageIntegration. That way, you might get some benefit from noise reduction and outlier rejection. I'm way too lazy for that!

I'm not the best person to ask since I don't do visual astronomy. I would guess that a larger aperture scope would be best.

@@Aero19612 thank you for your answer.

Absolutely!