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Askar C1/C2 vs D1/D2 filter set... which one??

ZWO ASI533MC William Optics Redcat 51 Filters Acquisition Deep Sky
3 repliesā€¢305 views
peng155 avatar
peng155 avatar
Hello Folks,

I have a question about Dual band filtersā€¦. I currently shoot OSC, thinking about maybe going to mono, but that won't be very soonā€¦
I'm getting ready to pull the trigger on getting the ZWO ASI2600MC-Pro for the larger APC-C sensor.

I'm curently shooting with a ASI533MC-Proā€¦ I've been using the ZWO Duo-Band filter (OIII/Ha) for all of my DSO imaging on my Redcat 51, and
Celestron C6 Hyperstar..

After viewing some Youtube vid's I learned that the f2 focal ratio of the Hyperstar causes band shift of the incoming light, which may or
may not work with the ZWO duo-band..

I just got a IDAS NBZ-II Dual Band filter that has a narrower BW than the ZWO, and works with the faster focal ration of the hyperstar and
RASA type scopes.. I also saw that Askar makes a set of filters that allows the images to be merged for a Hubble Pallet color image

Askar makes two versions C1/C2 and D1/D2.. The C1/C2 has a BW of 15nm for Ha and SII, and BW of 35nm for OII and cost $189
The D1/D2 has BW of 8-9nm for Ha and SII, and a BW of 6-7nm for OIII and it cost $549, Over twice as much as the C1/C2 versionā€¦.

I'll be using either the C1/C2 or D1/D2 versions on my Hyperstarā€¦ The question I have is, Would the narrower BW of the D1/D2 filter set make
that much of an improvment in my light frames? Most of my imaging is from my backyard, just outside of the city limits.. The Light Pollution map
classifies my location as Bortle 6

Thanks
Helpful
Oscar avatar
Oscar avatar
IMO,

I think it's risky to use any of those with the Hyperstar (besides the IDAS)

the IDAS was especially designed for fast systems

if you want SII, I can only recommend getting an Astronomik MaxFR SII

I may not be remembering if there is a fast FR dual band OIII/SII filter, but if there is, I'm sure someone will point it out

and yes, narrower filters will give you better contrast; the narrower the better
Alex Nicholas avatar
Alex Nicholas avatar
D1/D2 are SIGNIFICANTLY better than C1/C2, however, you will get bandpass shift using them on a hyperstar or rasaā€¦

I'm in bortle 5 and the difference between my d1 and the c1 I used to use is wild.
peng155 avatar
peng155 avatar
Thanks for the inputā€¦. I spoke with the folks at Starizona, and they suggested that I go with the Antlia Triband RGB filter to go along with the IDAS NBZ-II for the Hyperstar rig.. So we'll see how this all works out when the new filter arrives