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Old 14-04-2024, 04:54 PM
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ASKAR dual band filters

I'm curious about these dual band filters I've seen on AliExpress and Cuiv on YouTube. Ali offers C1 and C2 series whereas Cuiv reviews both.

The difference seems to be in the bandwidth. The C series are broader and consequently less effective at suppressing background light. But they are also quite a bit cheaper.

In each of the C and D, there are 2 filters. One is a Ha/O3 and the second is S2/O3 meaning that by using both, you can extract a double dose of O3 and singles of Ha and S2. That gives you a full SHO palette ��

I would be glad to read any experiences from fellow IISers.

Last edited by pmrid; 15-04-2024 at 11:02 AM.
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Old 15-04-2024, 07:05 PM
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I am waiting for mine to arrive (in 1~2 weeks, "C1").
Then I will post my impressions/results..

Last edited by bojan; 16-04-2024 at 08:41 AM.
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Old 15-04-2024, 11:08 PM
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Me too. I already have a couple of Optalong (Enhance and Extreme) but they are both Ha/O3 so I figure the C2 ought to complement them nicely. No doubt that was your thinking as well.

Fingers crossed!
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Old 16-04-2024, 06:26 AM
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Quote:
Originally Posted by pmrid View Post
Me too. I already have a couple of Optalong (Enhance and Extreme) but they are both Ha/O3 so I figure the C2 ought to complement them nicely. No doubt that was your thinking as well.

Fingers crossed!
My thinking was either Ha only, or Ha/O3, or Optolong Extreme (as I already have L-Pro)..
ASKAR price was determining factor (for something similar to Optolong Extreme) :-)
Yep, fingers crossed.. we can always return the items if they do not live up to expectations.. but then again, my thinking was, this filter simply will help to some extend.. so I decided to try.

Last edited by bojan; 16-04-2024 at 08:42 AM.
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Old 16-04-2024, 10:53 AM
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Just arrived, now I may try to measure the response with my spectrometer setup.
And test with wide field lens tonight if Melb weather permits.. (doesn't look it will).
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Old 22-04-2024, 09:13 AM
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Comparison between just UVIR and C1 filters (C1 is also stack 128x30sec @ISO12800, compared to 32x30sec @ISO3200).
C11+C-FR6.3+Canon 60Da.
C1 suppresses LP (mostly Moon in this case) quite effectively.. definitely a keeper!


ERRATA:
Should have been ASCAR C1, not C2.
Corrected.
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Last edited by bojan; 22-04-2024 at 02:24 PM.
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Old 23-04-2024, 05:49 AM
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Quote:
Originally Posted by bojan View Post
Comparison between just UVIR and C1 filters (C1 is also stack 128x30sec @ISO12800, compared to 32x30sec @ISO3200).
C11+C-FR6.3+Canon 60Da.
C1 suppresses LP (mostly Moon in this case) quite effectively.. definitely a keeper!


ERRATA:
Should have been ASCAR C1, not C2.
Corrected.
Interesting UVIR comparison with the C1 ( I note your correction - not the C2).

On paper the C1 is close to the Optalong L-Enhance (and a host of other dual-bands). When my C2 arrives, I'll try comparing it but lacking any Ha will make it a comparison of little intrinsic value I suppose.
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Old 23-04-2024, 01:04 PM
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..Interesting UVIR comparison with the C1 ....
I used UVIR filter because my modded Canon 60D is sensitive to far IR, so I wanted to reduce this as much as possible.
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Old 23-05-2024, 03:08 PM
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G'day Bojan,
I had an opportunity to give my Optalong L-Enhance a side-by-side comparison with my new ASKAR C2 dual band last night. It was a full moon (minus 1 night) but even so, the results were clear enough.
I imaged using a ASI071MC on a SharpStar 94EDPH (x0.8 reduced).
The absence oh the Ha signal in the ASKAR image certainly brings out the O3 and allows that little bit of S2 to come through as well.

I do not yet have the skill needed to extract the 3 NB bands and combine into a full Hubble palette. That is a task for another day.
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Old 23-05-2024, 03:38 PM
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Yes, those filters certainly battle LP (and Moon), but at expense of star light (which is broadband).
I also tried Optolong L-Pro (which is broader than yours L-Enhance filter) under similar conditions (last month) and the result is here.

Good for milder LP...
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