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Chroma Ha filters - 8nm vs 3 or 5 nm

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11 replies to this topic

#1 John Miele

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Posted 08 November 2019 - 12:58 PM

I see Chroma sells an LRGB + Ha filter set at a pretty good price. But it looks like the Ha they sell as part of the set only has a 8nm bandpass. Anyone using the 8nm version? Are you happy with your results or do you wish you had bought a 3 or 5nm filter to start with?

 

Thanks...John



#2 NuclearRoy

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Posted 08 November 2019 - 01:36 PM

I'm hoping everyone says get the 3nm.

Used AstroDon 3nm NB set arrived yesterday :)



#3 skyward_eyes

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Posted 08 November 2019 - 01:37 PM

I have Ha filters in 7nm, 6nm, and 3nm. I think the contrast the 3nm provides and its ability to cut everything out. I think if I were to go back knowing what I know now that a 5nm is probably a good mix between the two. It will assist with the full moon and bright locations better than the 8nm would. The 3nm is the ultimate light pollution filter however and I have been able to image in the middle of down town under a street light without issue. 

 

If budget isn't a constraint a 3nm is without a doubt the way to go. But if its a little tighter a 5nm and 6nm would be the way to go. The 8nm would be fine but having that tighter bandpass would be better for contrast. 


Edited by skyward_eyes, 08 November 2019 - 01:39 PM.

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#4 Monkeybird747

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Posted 08 November 2019 - 01:48 PM

I have the 3nm chroma set and love it. Call them and they will probably set you up with 3nm LRGB Ha set. I worked with Dick and Ann and both are very easy to work with.

#5 santafe retiree

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Posted 08 November 2019 - 01:54 PM

Here is an interesting thread on the subject:

 

https://www.cloudyni...vs-3nm-h-alpha/

 

It confirms a recent discussion I had with the folks at Cloudbreak Optics in Seattle that 3nm Ha filters will exclude some of the Nii present in planetary nebulae -- It was recommended that I go with 5nm Ha and 3nm for Oiii and Sii

 

Regards,

 

Tom


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#6 richorn

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Posted 08 November 2019 - 01:58 PM

I have the 3nm chroma set and love it. Call them and they will probably set you up with 3nm LRGB Ha set. 

I am confused by this statement. 

 

I am under the impression that the RGB filters are near to 100nm wide, and a Luminance filter closer to 350nm.



#7 Monkeybird747

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Posted 08 November 2019 - 02:18 PM

I am confused by this statement. 

 

I am under the impression that the RGB filters are near to 100nm wide, and a Luminance filter closer to 350nm.

The OP posted about a LRGB + Ha set that includes an 8nm Ha filter. By "3nm LRGB Ha set" I'm referring to the Ha filter bandwith, not the LRGB. 

 

The price difference between 3nm and 8nm is $300. Very reasonable, imho. 


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#8 TelescopeGreg

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Posted 08 November 2019 - 07:59 PM

Will a 3nm filter work on an f/5 scope?  I understand they are more sensitive to fast optics (er, mirrors in this case).



#9 Monkeybird747

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Posted 08 November 2019 - 08:33 PM

Will a 3nm filter work on an f/5 scope? I understand they are more sensitive to fast optics (er, mirrors in this case).


I don’t think you get into special “high speed” filters until you’re f3 or less. I’m f5.
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#10 gunny01

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Posted 09 November 2019 - 07:38 AM

  I've got the 5nm with the Chroma lrgb set 50mm.  3nm is not worth the difference in price when it comes to Ha.  Individual choice though.



#11 ChrisWhite

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Posted 09 November 2019 - 08:59 AM

I've used 5nm Adon, 3nm adon and 3nm chroma....

 

Both the adon and the chroma are on par with each other, and 3nm all the way!



#12 rockstarbill

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Posted 09 November 2019 - 11:50 AM

Agree with Chris. I've used both the Astrodon and Chroma filters and both perform exceptionally well. Chroma is easier on the wallet when you move to larger filters.
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