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Narrowband Filters, does price really matter?

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#1 joeytroy

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Posted 25 January 2021 - 02:04 PM

Ok so now that I understand filters a little more

https://www.cloudyni...nm-for-filters/

 

I am shooting to create the following images that James created using a some filters.

https://www.cloudyni...ith-osc-images/

 

James used the following filters, I choose the 1.25mm versions as I am going to add a manual filter wheel for now with my ASI533 to keep price down

 

L-eXtreme Dual Band 7nm HA/OIII Filter $239.99
Astronomik SII 6 nm CCD Filter $199.95
Total $439.94

 

However thinking about it I thought why not just go with an HA and OIII filter so I can capture just HA, or just OIII from objects. Then I started going down the wormhole of filters and found the following

 

Optolong 1.25" Filter Set with H-Alpha, SII, and OIII Filters
Optolong 7nm H-Alpha Filter - The Optolong H-Alpha 7nm is an extremely narrow emission-line filter that works by allowing a 7nm bandwidth of light, centered on the 656nm wavelength

Optolong 6.5nm SII Filter - The Optolong Sulfur-II 6.5nm Extra-Narrowband Filter transmits a 6.5nm bandwidth of light that is centered at 672nm

Optolong 6.5nm OIII Filter - The Optolong Oxygen III 6.5nm Extra-Narrowband Filter transmits a 6.5nm bandwidth of light that is centered at 500nm
Total $465.00

 

ZWO 1.25-inch H-alpha SII OIII 7nm Filter Set

* About 90% transmission at H-alpha line 656nm (H-Alpha filter).
* About 90% transmission at Sii line 672nm (Sii filter).
* About 90% transmission at major Oiii line 500 nm (Oiii filter).
$369.99

 

Orion Extra Narrowband OIII, SII & H-Alpha CCD Filter Set - 1.25"

The H-alpha filter has a transmission of 90% at the hydrogen-alpha line of 656.3nm and a full width at half-maximum (FWHM) bandpass of 7nm.

And the S-II filter passes light at the 672.4nm wavelength (the Sulfur-II line in the deep red end of the visual spectrum) with 90% transmission and a bandpass also of 7nm.

The O-III filter passes light at the 500.7nm wavelength (the Oxygen-III line) with very high 90% transmission and a bandpass of 7nm.

$349.99

 

Based on what I am reading the are all with in the same wavelength, and all allowing 90% transmission. So does price really matter, or am I just paying for the name?

 

My setup is in my signature and based on multiple websites my Bortles class is 2-4 so maybe call it 3.



#2 PirateMike

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Posted 25 January 2021 - 02:22 PM

I would stay away from the last two on your list. I have no experience using Optolong filters.

 

Have you looked at the Astronomik or Badder filters. They are a little more expensive but well worth the money.

 

They can be bought one at a time to help with spreading out the pain. Start with the Ha.

 

 

https://www.astrobin.../full/xnr4io/B/

 

 

Miguel   8-)

 

.


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#3 OhmEye

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Posted 25 January 2021 - 02:47 PM

It's not the price that matters, it's the quality of the coatings. Higher quality brands may have slightly higher rejection outside the passband or steeper notches, but the main difference is anti-reflection and halos. Unfortunately the filters that tend to not produce halos (especially for shorter wavelengths like OIII) tend to cost more. Pretty much my whole motivation to pay more for filters is to reduce/prevent halos.


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#4 pyrasanth

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Posted 25 January 2021 - 02:48 PM

The choice of OIII filter I consider being of the upmost importance as it is likely to be the only narrow band filter potentially impacted by the moon when it is closer to full- more so than the HA or SII filters.

 

I went for the best OIII filter that I could afford which was the Chroma OIII 3 nm. This is expensive but not as expensive as the Astrodon.

 

I then chose the Baader 3.5 nm HA enforced and the Baader 4.5 nm SII with the eventual aim of replacing those 2 with Chroma brands. However this combination gives me good results.

 

The cheaper narrow band filters tend to have wider bandpasses with the potential to let through more unwanted light and the risk of reflections or halo's but most now guarantee, with mixed results, halo or reflection fee.

 

I suggest you buy the filters one size up from your current sensor real estate so you have some future sensor upgrade room.


Edited by pyrasanth, 25 January 2021 - 02:48 PM.


#5 Cometeer

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Posted 25 January 2021 - 02:55 PM

I then chose the Baader 3.5 nm HA enforced and the Baader 4.5 nm SII with the eventual aim of replacing those 2 with Chroma brands. However this combination gives me good results.

Any halos with that Baader 3.5nm Ha?


Edited by Cometeer, 25 January 2021 - 02:55 PM.


#6 Cometeer

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Posted 25 January 2021 - 02:56 PM

I see little benefit in using SHO filters with an OSC, especially ones that are 7nm wide. With a Ha filter for example, the bayer matrix means that you are only capturing signal on 1 out of 4 pixels. The other 3 out of 4 are only capturing noise. You might as well make use of the other 2 channels (blue and green), and that’s where duoband filters (l-extreme, l-enhance) come in.


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#7 terry59

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Posted 25 January 2021 - 02:59 PM

Any halos with that Baader 3.5nm Ha?

Yes and I've replaced mine with a Chroma Ha filter

 

Edit: I have no haloing with my 8nm filters and the wider bandpass isn't an issue for me


Edited by terry59, 25 January 2021 - 03:00 PM.

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#8 Stelios

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Posted 25 January 2021 - 03:49 PM

I am not going to try to talk you out of Chroma or Astrodon--if your wallet can stand them, these are the best. But if you go that way, you should get a mono camera too.

 

But if not, I strongly recommend the Astronomik. I don't get noticeable halos with my Astronomik Ha.

 

flandhh.JPG

 

Note: I *do* get some halos with the Astronomik Sii (the worst of the three, still pretty good) and the Astronomik Oiii. But the Ha is pretty much perfect. 

 

If the Astronomiks are too much, try the ZWO (the newer ZWO are an improvement over the old). 


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#9 joeytroy

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Posted 25 January 2021 - 03:51 PM

I see little benefit in using SHO filters with an OSC, especially ones that are 7nm wide. With a Ha filter for example, the bayer matrix means that you are only capturing signal on 1 out of 4 pixels. The other 3 out of 4 are only capturing noise. You might as well make use of the other 2 channels (blue and green), and that’s where duoband filters (l-extreme, l-enhance) come in.

Cometeer,

 

Based on that would it be worth to invest in a tri-band filter say something like this since I am doing OSC? Also I assume I should still be able to split out the channel with PI?

 

https://optcorp.com/...ch-triad-filter



#10 JamesTX

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Posted 25 January 2021 - 04:04 PM

I would advise against going the route of getting separate Ha and O3 filters.  With the Ha filter, your green and blue pixels are doing nothing.  With the O3 filter, your red pixels will be doing nothing.  It will work.. but you'll need much more integration time to make it work.  A mono camera is the right tool for that, not OSC.. especially if time is of the essence.

 

A dual band filter like the L-extreme or the one from zwo will capture both Ha and O3 at the same time, this way you are utilizing all of your pixels.  Running a S2 filter will only utilize the red pixels.. so its a sacrifice with that filter.  Using something like the L-extreme at least cuts your loses when compared to a mono camera.

 

A 3 or 4 band filter like the triad has one problem when wanting to do SHO.  It gathers ha and s2 at the same time.  Both Ha and S2 are red.. there is no way to separate them.  You can try to "simulate" the s2 signal which has been done but its not straight forward.. and IMHO the results are not quite as good as standard SHO.  Using a straight s2 filter gets around the limitation, at the cost of some efficiency.

 

Since money is a concern.. I'd recommend getting just the l-extreme now and picking up a s2 later.  The zwo s2 filter is probably fine.  Keep in mind, filters like the l-extreme are basically two filters in one.


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#11 joeytroy

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Posted 25 January 2021 - 07:00 PM

Everyone, thanks a bunch! I am going to roll with the following setup, and to keep it cheaper going to roll with the with 1.25 filters instead of the 2"

 

L-eXtreme Dual Band 7nm HA/OIII Filter - $239.99
Astronomik SII 6 nm CCD Filter - $199.95
Starizona Filter Slider - 2-inch to 1.25-inch Filter Adapter - $25.00
Total $464.94


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#12 va1erian

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Posted 02 February 2021 - 06:30 AM

My question is a tiny bit off topic. Filters seem to be too expensive compared to telescopes, refractors, reflectors, camera lenses. The price of the filter consists of the components: design expense, manufacture expense, novelty premium.

 

So, what is the main component in the today's filters made in China ? Is the manufacture expense really low ? If it is the novelty premium, then I'd expect the price come down in a year or few years for Optolong etc.



#13 joeytroy

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Posted 02 February 2021 - 01:27 PM

Everyone, thanks a bunch! I am going to roll with the following setup, and to keep it cheaper going to roll with the with 1.25 filters instead of the 2"

 

L-eXtreme Dual Band 7nm HA/OIII Filter - $239.99
Astronomik SII 6 nm CCD Filter - $199.95
Starizona Filter Slider - 2-inch to 1.25-inch Filter Adapter - $25.00
Total $464.94

So I figured stop being so cheap and popped for the 2” L-eXtreme and will buy the Sii next.




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