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Astronomik 6nm vs Baader 4.5nm

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#1 amajed172

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Posted 21 May 2019 - 09:28 AM

Hi, I'm thinking of getting ether:

 

Astronomik L-RGB Typ 2c Color filter + NB Ha OIII SII 6nm

 

OR

 

Baader LRGB CCD Filter set + Ultra Narrowband Ha 3.5nm OIII SII 4.5nm

 

 

what do you think I should get?

both sets almost the same price.



#2 happylimpet

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Posted 21 May 2019 - 10:34 AM

What equipment will you be using them with? 


Edited by happylimpet, 21 May 2019 - 10:34 AM.


#3 amajed172

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Posted 21 May 2019 - 10:36 AM

What equipment will you be using them with? 

ASI1600MM-C Pro + 7 Pos EFW

 

EdgeHD 8"

Esprit 100ED

 

 

Thanks



#4 happylimpet

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Posted 21 May 2019 - 10:46 AM

And how bad is your light pollution?!



#5 amajed172

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Posted 21 May 2019 - 10:51 AM

And how bad is your light pollution?!

Sorry for that.

Class 4 Bortle.


Thanks

#6 happylimpet

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Posted 21 May 2019 - 11:04 AM

Well after all those questions, I dont have any profound wisdom.

 

However I would be tempted to get the 6nm myself  (or another wider one) for the Ha at least as

 

1) your LP isnt too bad so you dont need ultra narrow and

2) wider transmission allows you to image HII regions (the pink splodges) in galaxies to higher redshifts. People often forget about this with narrow bandpass filters.



#7 amajed172

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Posted 21 May 2019 - 11:20 AM

Well after all those questions, I dont have any profound wisdom.

 

However I would be tempted to get the 6nm myself  (or another wider one) for the Ha at least as

 

1) your LP isnt too bad so you dont need ultra narrow and

2) wider transmission allows you to image HII regions (the pink splodges) in galaxies to higher redshifts. People often forget about this with narrow bandpass filters.

Well, I see a lot of people trying to get Astrodon 5nm and 3nm I don't think they all live in a red zone right? so I figured maybe a 4.5nm is good too.



#8 RogeZ

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Posted 21 May 2019 - 05:27 PM

I have the Astronomiks and they are fantastic.

The Baaders are new and I have no idea how good the AR coatings are. I have used the 7nm and 3.5nm as well and they are good but tend to create reflections.
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#9 amajed172

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Posted 21 May 2019 - 05:35 PM

I have the Astronomiks and they are fantastic.

The Baaders are new and I have no idea how good the AR coatings are. I have used the 7nm and 3.5nm as well and they are good but tend to create reflections.

Nice, do you see any halos when using the Astronomiks? especially when using refractor?



#10 RogeZ

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Posted 21 May 2019 - 06:54 PM

Nope. The astronomiks are halo free on every scope i have use them.
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#11 Stelios

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Posted 21 May 2019 - 07:16 PM

Nice, do you see any halos when using the Astronomiks? especially when using refractor?

I have halos on bright stars with my Astronomik Sii filter. The other two just display the micro-lensing effect of the ASI1600. 

 

I think there's some variability--I may well have got a lemon in the Sii. 


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#12 entilza

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Posted 21 May 2019 - 08:33 PM

I have halos on bright stars with my Astronomik Sii filter. The other two just display the micro-lensing effect of the ASI1600.

I think there's some variability--I may well have got a lemon in the Sii.


I get that too on my Sii on bright stars but I get more of the microlensing qlmost like a plus sign on the Sii. Its the 1600 camera on bright stars.. A slight desaturation tool helps touch that up.
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#13 amajed172

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Posted 22 May 2019 - 03:23 AM

Nope. The astronomiks are halo free on every scope i have use them.

 

 

I have halos on bright stars with my Astronomik Sii filter. The other two just display the micro-lensing effect of the ASI1600. 

 

I think there's some variability--I may well have got a lemon in the Sii. 

 

 

I get that too on my Sii on bright stars but I get more of the microlensing qlmost like a plus sign on the Sii. Its the 1600 camera on bright stars.. A slight desaturation tool helps touch that up.

Maybe Halo in Sii only is not big of a deal, are they all parfocal as advertised? can I really focus using L and image with NB without issues?



#14 Stelios

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Posted 22 May 2019 - 11:48 AM

Maybe Halo in Sii only is not big of a deal, are they all parfocal as advertised? can I really focus using L and image with NB without issues?

They (Astronomik) are much closer to parfocal than ZWO filters (at least the 1st generation) are.

 

With my Rigel driving a Feathertouch, I had Oiii focus at Ha -10 and Sii at Ha + 10. However Ha was Lum -24. You could try these offsets, measure your own (not all copies will focus exactly the same) or you can refocus.

 

IMO, a 10 tick change (36000 ticks total range) is close enough to not merit refocusing. A 24 tick change is marginal, and yes, you could get away with it.

 

However, this assumes that temperature is constant. As this is likely untrue, you should probably be frequently refocusing anyway, unless you have temp compensation dialed in.


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#15 amajed172

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Posted 22 May 2019 - 03:38 PM

They (Astronomik) are much closer to parfocal than ZWO filters (at least the 1st generation) are.

 

With my Rigel driving a Feathertouch, I had Oiii focus at Ha -10 and Sii at Ha + 10. However Ha was Lum -24. You could try these offsets, measure your own (not all copies will focus exactly the same) or you can refocus.

 

IMO, a 10 tick change (36000 ticks total range) is close enough to not merit refocusing. A 24 tick change is marginal, and yes, you could get away with it.

 

However, this assumes that temperature is constant. As this is likely untrue, you should probably be frequently refocusing anyway, unless you have temp compensation dialed in.

I do have an auto focuser and a temp sensor too, I do plan on focusing every 1 degree change in temp, but I do not want to refocus using a NB filter, it will be faster to refocus using Lum filter, that's why I want parfocal filters.

 

 

Thanks



#16 HydrogenAlpha

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Posted 23 May 2019 - 06:39 AM

Another benefit of narrow bandwidths are reduced star sizes, which allows greater emphasis on the nebula, as well as resistance to moonlight (a very important point). 

 

However, you cannot use fast telescopes with very narrow bandwidths, as you'd be wasting useful aperture. Even with a special bandpass preshift, my 3nm filters only work down to f/4 at best (despite claims by the manufacturer that it will work till f/3, the math says otherwise). Without the bandpass preshift, which is the default, any system working faster than around f/5 for a 3.5nm filter will be wasting useful aperture. 

 

I live in a bortle 8 zone, so 3nm filters (especially for OIII) are almost a necessity. However, this means I wouldn't be able to use some of the very nice f/2.8 astrographs (or fast telephoto lenses) out there. 


Edited by HydrogenAlpha, 23 May 2019 - 06:41 AM.


#17 amajed172

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Posted 23 May 2019 - 06:45 AM

Another benefit of narrow bandwidths are reduced star sizes, which allows greater emphasis on the nebula, as well as resistance to moonlight (a very important point). 

 

However, you cannot use fast telescopes with very narrow bandwidths, as you'd be wasting useful aperture. Even with a special bandpass preshift, my 3nm filters only work down to f/4 at best (despite claims by the manufacturer that it will work till f/3, the math says otherwise). Without the bandpass preshift, which is the default, any system working faster than around f/5 for a 3.5nm filter will be wasting useful aperture. 

 

I live in a bortle 8 zone, so 3nm filters (especially for OIII) are almost a necessity. However, this means I wouldn't be able to use some of the very nice f/2.8 astrographs (or fast telephoto lenses) out there. 

Nice, so I guess the 4.5 OIII and SII are good for f5.5 and f10 (my two telescopes)

 

I do want smaller stars. does make the picture look nicer.

 

 

Thanks


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