Baader 3.8 filter

Use this section to discuss "standard" Baader/Coronado/ Lunt SolarView/ Daystar, etc… filters, cameras and scopes. No mods, just questions/ answers and reviews.
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DSobserver
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Baader 3.8 filter

Post by DSobserver » Sun Jan 29, 2017 10:39 pm

hello

I'm looking to buy a new WL filter for my new MAK

Do you know if 3.8 density baader filter can also be use visually adding ND filters?

thanks

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robert
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Re: Baader 3.8 filter

Post by robert » Mon Jan 30, 2017 12:06 pm

I think so. I use ND3.8 Baader film and ND5.0 as well. A Herschel wedge on its own has the effect of ND2.0 so a 1.25" ND3.0 filter makes it viewable by eye, it becomes ND5.0. You need ND1.2 which could be at the eyepiece end of the setup to get into visible range.
It is a logarithmic measure so ND5.0 is 1/100,000th of the intensity, and ND1.2 is 1/16th of the intensity and ND3.8 is 1/6300th and ND2.0 is 1/100th.
Hope that helps
Robert
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Montana
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Re: Baader 3.8 filter

Post by Montana » Mon Jan 30, 2017 12:17 pm

That's very interesting to know, thanks Robert :)

Alexandra

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DSobserver
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Re: Baader 3.8 filter

Post by DSobserver » Mon Jan 30, 2017 1:00 pm

Thanks!

With new cams, does it still really make sense to buy a 3.8 density???

Just found practical tip by Teleskop-Service:

With 150mm apterture and bigger, the Solar Continuum can be combined with the visual filter foil for visual purposes. With smaller apertures, the image becomes too dark. Here, we recommend the combination with the photographic filter foil and a moderate neutral density filter with 12.5% transmission and an UV/IR cut filter.

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robert
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Re: Baader 3.8 filter

Post by robert » Mon Jan 30, 2017 1:22 pm

DSobserver wrote:
Mon Jan 30, 2017 1:00 pm
With new cams, does it still really make sense to buy a 3.8 density???
You are right about this. I use a ND3.8 and a Continuum (a greenish narrow band filter) for imaging and it only just gets to the shortest exposure time on a PGR Chameleon, but that is good for imaging granulation. Without the Continuum filter it is just over exposed. I also use UV/IR cut for imaging as it helps and for viewing for general safety.

So you could get either ND3.8 or ND5.0 but if you get ND3.8 you may need a Continuum filter for imaging as well
Robert
images and animations http://tinyurl.com/h5bgoso
2018 images https://www.flickr.com/photos/69734017@ ... 1234171714
2017 images http://tinyurl.com/gvk9k3k
ED80. SW200. Celestron-150mm-PST mod
LS60PT-LS60F-B1200. B600-Cak. PGR-Ch3-IMX265

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