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LRGB Ha Filter Suggestions

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#1 sysvector

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Posted 08 April 2021 - 01:27 PM

Hello all,

 

I just hit buy on a 294mm and the ZWO 5 pos filter wheel.  The vendor did not have any filters in stock.  I wanted to reach out and see if anyone opinions or suggestions for entry to mid range 1.25" or 31mm LRGB filters other than the ZWO ones.  I'll likely add an Ha soon, so if you want to weigh in on that as well please do.  

 

Can't wait!

 

Thanks



#2 klaussius

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Posted 08 April 2021 - 01:32 PM

I have the ZWO LRGB and they're fine.

 

With that chip size, I would go for 31mm. With my OTA the 1.25" ones cause noticeable vignetting, which makes processing harder.


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#3 DRK73

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Posted 08 April 2021 - 01:43 PM

The market for astro-stuff is kind of a strange place right now. On one hand, new stuff is being snapped up so fast that it seems like everyone is constantly sold out of stuff, and basic items (like a stupid extra counterweight!!!) are months backordered. 

 

On the other hand, people are constantly upgrading to larger chip sizes and selling off pretty decent stuff (though be warned - UPS destroyed a mount that I shipped, and USPS has, for the time being, sent a camera I sold on a wild-excursion to Hawaii which is not even close to on the way from my place to San Diego - but I digress - like a camera travelling from Maryland to California...)....

 

Anyway, I also grabbed a 294mm a couple months ago. I already had an Astronomik 6nm H-a, and managed to find a set of Astronomik Deep Sky RGBs and an Astronomik L2 UV filter here on the CN classifieds. Digging around, it seemed to me that Astronomik is probably the best value *for my purposes*, but I don't have any data to say whether they are better or worse than Baader or Optolong. I've used both at various points, and I know my experience with the Optolong L-extreme was bad when there were bright stars in frame, and I've also heard people lament halos with Baader, but I also know that I don't want to spend more for Antlia, Chroma, Astrodon, etc. I've had Astrodon in the past, but think it may be one of those things were they are "better", but whether an individual user gets "better" results may depend more on that user's skill than on anything intrinsic to the filter itself? 

 

I'm trying to stay Astronomik also to minimize the filter offsets even if they are designed to be parfocal; I want to eliminate need for larger focus offsets if use different manufacturer's filters.

 

Finally, I only really shoot at f/5.6, so felt comfortable buying 1.25" filters. 



#4 sysvector

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Posted 08 April 2021 - 01:53 PM

I have the ZWO LRGB and they're fine.

 

With that chip size, I would go for 31mm. With my OTA the 1.25" ones cause noticeable vignetting, which makes processing harder.

Interesting.  Even with your QHY?  or just with your Canon?



#5 sysvector

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Posted 08 April 2021 - 01:55 PM

The market for astro-stuff is kind of a strange place right now. On one hand, new stuff is being snapped up so fast that it seems like everyone is constantly sold out of stuff, and basic items (like a stupid extra counterweight!!!) are months backordered. 

 

On the other hand, people are constantly upgrading to larger chip sizes and selling off pretty decent stuff (though be warned - UPS destroyed a mount that I shipped, and USPS has, for the time being, sent a camera I sold on a wild-excursion to Hawaii which is not even close to on the way from my place to San Diego - but I digress - like a camera travelling from Maryland to California...)....

 

Anyway, I also grabbed a 294mm a couple months ago. I already had an Astronomik 6nm H-a, and managed to find a set of Astronomik Deep Sky RGBs and an Astronomik L2 UV filter here on the CN classifieds. Digging around, it seemed to me that Astronomik is probably the best value *for my purposes*, but I don't have any data to say whether they are better or worse than Baader or Optolong. I've used both at various points, and I know my experience with the Optolong L-extreme was bad when there were bright stars in frame, and I've also heard people lament halos with Baader, but I also know that I don't want to spend more for Antlia, Chroma, Astrodon, etc. I've had Astrodon in the past, but think it may be one of those things were they are "better", but whether an individual user gets "better" results may depend more on that user's skill than on anything intrinsic to the filter itself? 

 

I'm trying to stay Astronomik also to minimize the filter offsets even if they are designed to be parfocal; I want to eliminate need for larger focus offsets if use different manufacturer's filters.

 

Finally, I only really shoot at f/5.6, so felt comfortable buying 1.25" filters. 

Yes, slim pickings... which is why when I saw they had the camera, FW and EAF in stock I just ordered right away.  I'm at 480mm F6, but figured I would go with 31mm.  Depends on what I can find though.

 

I had not seen Astronimik filters anywhere, but I'll see if I can find any in Canada.

 

Thanks!



#6 klaussius

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Posted 08 April 2021 - 01:59 PM

Interesting.  Even with your QHY?  or just with your Canon?

With the QHY, yes.

 

I was not expecting that, but I believe it's because my sky is heavily light polluted. Even if flats correct the vignetting per se, the loss of SNR is still onticeable on the final stack after aggressive stretching (and I'm constantly doing said aggressive stretching).



#7 Der_Pit

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Posted 08 April 2021 - 03:48 PM

Yes, slim pickings... which is why when I saw they had the camera, FW and EAF in stock I just ordered right away.  I'm at 480mm F6, but figured I would go with 31mm.  Depends on what I can find though.

 

I had not seen Astronimik filters anywhere, but I'll see if I can find any in Canada.

I started with 470mm F/5 and the ZWO filters, with an ASI1600 (MFT sensor).  Also went for 31mm, and that is vignette free.  1.25" would likely work, too.  Flatfielding would take care of the (slight) vignetting, maybe at F/6 even very slight only.

I switched to Astronomik later, as the blue filter did produce blue bloat with my refractor.  If you can get them anywhere, I can highly recommend them (DeepSky RGB set).  With an refractor, get the L3 as L, and the 6nm Hα.  A bit more expensive than ZWO, but (IMO) absolutely worth it.

(bought the Astronomiks again in 36mm for my 2600MM...)



#8 sysvector

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Posted 08 April 2021 - 04:01 PM

With the QHY, yes.

 

I was not expecting that, but I believe it's because my sky is heavily light polluted. Even if flats correct the vignetting per se, the loss of SNR is still onticeable on the final stack after aggressive stretching (and I'm constantly doing said aggressive stretching).

Hmm.. I will definitely go 31mm then.  I am in bortle 7-8 for most of my imaging.  Will try to get out of town as much as I can though.  Thanks!



#9 sysvector

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Posted 08 April 2021 - 04:12 PM

I started with 470mm F/5 and the ZWO filters, with an ASI1600 (MFT sensor).  Also went for 31mm, and that is vignette free.  1.25" would likely work, too.  Flatfielding would take care of the (slight) vignetting, maybe at F/6 even very slight only.

I switched to Astronomik later, as the blue filter did produce blue bloat with my refractor.  If you can get them anywhere, I can highly recommend them (DeepSky RGB set).  With an refractor, get the L3 as L, and the 6nm Hα.  A bit more expensive than ZWO, but (IMO) absolutely worth it.

(bought the Astronomiks again in 36mm for my 2600MM...)

The seem to be rare in canada for sure.  Also, the ones I did find in stock were 31mm mounted?  I have never seen 31mm mounted listed elsewhere.  The FW takes 1.25" mounted or 31mm.  I would have to check the filter holder size to be sure it would work or not.

 

Thanks!



#10 Der_Pit

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Posted 08 April 2021 - 04:23 PM

The seem to be rare in canada for sure.  Also, the ones I did find in stock were 31mm mounted?  I have never seen 31mm mounted listed elsewhere.  The FW takes 1.25" mounted or 31mm.  I would have to check the filter holder size to be sure it would work or not.

 

Thanks!

In doubt you should be able to get them from Teleskop-Express, they deliver world-wide.  Not sure about customs though - Canada might be expensive....

 

The 'mounted' 31mm is a speciality of the Astronomiks.  They are only 1mm thin, which is fragile and difficult to handle.  Therefore they are inserted in a thin aluminum ring (3.5mm high).  But they are not threaded, and have the full clear aperture in the typical 31mm wheels, in which they perfectly fit.



#11 imtl

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Posted 08 April 2021 - 04:45 PM

I image at F/4.3 with the ASI294mm and 1.25" filters and there is no vignetting from the filters. The spacing between the filters surface and the sensor is 10mm.


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#12 terry59

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Posted 08 April 2021 - 04:47 PM

Hello all,

 

I just hit buy on a 294mm and the ZWO 5 pos filter wheel.  The vendor did not have any filters in stock.  I wanted to reach out and see if anyone opinions or suggestions for entry to mid range 1.25" or 31mm LRGB filters other than the ZWO ones.  I'll likely add an Ha soon, so if you want to weigh in on that as well please do.  

 

Can't wait!

 

Thanks

How about the Chroma HaLRGB package. The 8nm filters aren't that expensive and they have no haloing


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#13 Stelios

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Posted 08 April 2021 - 06:02 PM

The seem to be rare in canada for sure.  Also, the ones I did find in stock were 31mm mounted?  I have never seen 31mm mounted listed elsewhere.  The FW takes 1.25" mounted or 31mm.  I would have to check the filter holder size to be sure it would work or not.

 

Thanks!

What is your scope F/L and aperture? That's what matters. See this calculator. In 99% of cases you will be perfectly fine with 1.25" filters (which have about 27mm clear aperture), and THERE'S NO BENEFIT TO BUYING LARGER THAN YOU NEED

 

What I would recommend is that you send back the 5-pos FW and get a 7-pos FW. You will eventually want narrowband, and switching filters is a pain.

 

As for filters, I recommend the Astronomik. Get the L-2 or L-3 for Lum, and the Deep Sky RGB (which I wouldn't trade for anything). Their Ha filter is also superb, with no halos at all. 


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#14 klaussius

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Posted 08 April 2021 - 06:34 PM

I image at F/4.3 with the ASI294mm and 1.25" filters and there is no vignetting from the filters. The spacing between the filters surface and the sensor is 10mm.

 

The bolded part is the difference, I now realize.

 

I went to the QHYCCD site, and the 163M camera itself consumes 17.5mm spacing, and the QHYCFW3-S-SR is 20mm thick. Assuming the filters are in the middle, that's 27.5mm away from the sensor, and for that kind of distance the calculator does recommend 31mm filters.

 

I went and looked for the documentation that recommended the QHYCFW3-S, and lo and behold, it has been changed. They now recommend the medium CFW.

 

foreheadslap.gif

 

So... the lesson... think about spacing.

 

The ZWO 294MM says backfocus distance is 6.5mm, so filters will be considerably closer.


Edited by klaussius, 08 April 2021 - 06:36 PM.


#15 sysvector

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Posted 08 April 2021 - 06:37 PM

How about the Chroma HaLRGB package. The 8nm filters aren't that expensive and they have no haloing

Huh, I was going to say "because I just spent 2.5K and I think I will be ok with less expensive options", then I checked and the Chroma's are $989 whereas the Astronomik deep sky set + CLS-CCD + Ha is $947 :p

 

Worth considering.

 

I'm also looking at the optolong LRGBHa for $610.

 

Thanks!



#16 sysvector

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Posted 08 April 2021 - 07:06 PM

What is your scope F/L and aperture? That's what matters. See this calculator. In 99% of cases you will be perfectly fine with 1.25" filters (which have about 27mm clear aperture), and THERE'S NO BENEFIT TO BUYING LARGER THAN YOU NEED

 

What I would recommend is that you send back the 5-pos FW and get a 7-pos FW. You will eventually want narrowband, and switching filters is a pain.

 

As for filters, I recommend the Astronomik. Get the L-2 or L-3 for Lum, and the Deep Sky RGB (which I wouldn't trade for anything). Their Ha filter is also superb, with no halos at all. 

Thanks,

 

TS 80mm/480mm.  Already went over the filter size calculator.  The 294mm should be fine in my setup with 31mm.  ZWO even states that 1.25" has no vignetting.  Distance from sensor to the filter is 10mm.  

 

I'm kicking myself as well about the FW, so I just went to go change the order and they already shipped!!!.  I've never had something ship so fast.  Oh well.  I'll make it work for a bit and it's not too much extra money to buy bigger and sell the 5 position.  



#17 stresspro

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Posted 11 April 2021 - 11:37 AM

What is your scope F/L and aperture? That's what matters. See this calculator. In 99% of cases you will be perfectly fine with 1.25" filters (which have about 27mm clear aperture), and THERE'S NO BENEFIT TO BUYING LARGER THAN YOU NEED

 

What I would recommend is that you send back the 5-pos FW and get a 7-pos FW. You will eventually want narrowband, and switching filters is a pain.

 

As for filters, I recommend the Astronomik. Get the L-2 or L-3 for Lum, and the Deep Sky RGB (which I wouldn't trade for anything). Their Ha filter is also superb, with no halos at all. 

I went directly through Astronomik. Had these filters within one week from Germany! In fact, I emailed directly with Gerd Neumann, who suggested the L-2 and L-3 and Deep Sky RGB set over the standard LRGB kit.  Impressive company.




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