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Can you photograph galaxies with cls ccd filter?

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#1 AstroPepe

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Posted 21 September 2019 - 07:22 AM

Hi smile.gif I am just wondering if you can photograph galaxies using skytech cls-ccd filter with modded camera? laugh.gif

 

Camera i am using canon 1100d modified, 650d stock

Scope: Skywatcher 72ed

Mount: Skywatcher eq2-3 pro

Filters: Cls-ccd


Edited by AstroPepe, 21 September 2019 - 07:23 AM.


#2 sg6

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Posted 21 September 2019 - 07:45 AM

You can but the question is what does the filter block and so passes through to the sensor and therefore what the color changes are for the resultant image.

 

As a galaxy is considered "white" then the blocked wavelengths will not get to the final image. Generally they block the yellow and green area so the galaxy image would lose those and appear red+blue bias.

 

Looking at the box it blocks basically 530nm to 630nm also blocks below 450nm. So conversly passes 450 to 530, then 630 upwards. So images are blue and a bit of green, then red. You lose Orange, Yellow and say half the green. So a galaxy has no orange, yellow and reduced green at the final image.

 

A CLS filter does not block the City Lights, it just blocks the chunk of the spectrun where not city lights are, and it blocks any wavelength in that chunk immaterial of source.



#3 AstroPepe

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Posted 21 September 2019 - 07:59 AM

You can but the question is what does the filter block and so passes through to the sensor and therefore what the color changes are for the resultant image.

As a galaxy is considered "white" then the blocked wavelengths will not get to the final image. Generally they block the yellow and green area so the galaxy image would lose those and appear red+blue bias.

Looking at the box it blocks basically 530nm to 630nm also blocks below 450nm. So conversly passes 450 to 530, then 630 upwards. So images are blue and a bit of green, then red. You lose Orange, Yellow and say half the green. So a galaxy has no orange, yellow and reduced green at the final image.

A CLS filter does not block the City Lights, it just blocks the chunk of the spectrun where not city lights are, and it blocks any wavelength in that chunk immaterial of source.

Thanks for the information :) i was reading Trevors (Astrobackyard) blog and he says it blocks city light pollution: https://astrobackyar...ography-filter/

#4 ChristopherBeere

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Posted 21 September 2019 - 08:20 AM

You most definitely can but the challenge is removing the tint that the filter causes.

 

Depending on your white balance it will be roughly green/cyan. There are videos/tutorials for how to remove it available on the web.

 

Here is one for PixInsight : https://www.star-wat...-in-pixinsight/

 

To get you started the Andromeda galaxy (M31) should squeeze into your field of view with the 1100D + Skywatcher 72.

 

 



#5 RogeZ

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Posted 21 September 2019 - 01:23 PM

A CLS filter does not block the City Lights, it just blocks the chunk of the spectrun where not city lights are, and it blocks any wavelength in that chunk immaterial of source.

This is incorrect. A CLS filter blocks common sources of light pollution and skyglow. A cls-ccd blocks IR and UV as well making it perfect for modded cameras. 

 

Broadband objects lose some light but overall the effect is a net positive. 



#6 AstroPepe

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Posted 21 September 2019 - 05:50 PM

This is incorrect. A CLS filter blocks common sources of light pollution and skyglow. A cls-ccd blocks IR and UV as well making it perfect for modded cameras. 

 

Broadband objects lose some light but overall the effect is a net positive. 

Thank you Roger laugh.gif Yea I was thinking that it can't be true because when I compare my images (filter vs no filter) there is a difference in light pollution.


Edited by AstroPepe, 21 September 2019 - 05:50 PM.



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