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ZWO LRGB filters parfocal?

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4 replies to this topic

#1 Marco 104

Marco 104

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Posted 12 November 2019 - 09:04 AM

Hi, anyone knows or has tested the (31mm) ZWO LRGB filters that come along with the EFW package in order to confirm if they are parfocal?

 

How do the NB ones do compare to each other and to the LRGB?

 

Thanks

Marco

 



#2 Astrodymium

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Posted 12 November 2019 - 10:33 AM

I believe that the LRGB ones are parfocal, but if you have a doublet you'll need to refocus for each one.

Edited by Astrodymium, 12 November 2019 - 10:33 AM.


#3 Marco 104

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Posted 12 November 2019 - 11:43 AM

Thanks



#4 rgsalinger

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Posted 14 November 2019 - 07:32 PM

They may be advertised as par focal but there can be variations between sets of filters. The only way to be sure is to run some tests and see what's what. Even triplets may have enough CA to merit refocusing.

Rgds-Ross



#5 Achernar

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Posted 14 November 2019 - 08:13 PM

Hi, anyone knows or has tested the (31mm) ZWO LRGB filters that come along with the EFW package in order to confirm if they are parfocal?

 

How do the NB ones do compare to each other and to the LRGB?

 

Thanks

Marco

Mine are, but I am using them with my SCT.

 

Taras




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