CLS filter and custom white balance

[PoppaChris]

OK, I know this is truly a concern of BackyardEOS but since it does affect the quality of our images so much, and I am having issues with it I felt I must ask for some help.  Since so many of us use Canon EOS cameras this is a natural audience of which to ask my question.

 

Background: 

I use BYE3.02 premium with a Canon T2i and an off-axis guider with Orion SSAG on a CPC1100. I normally keep a 0.63 focal reducer in place at all times. Due to rampant light pollutionin my area, I have taken the step of using an Astronomik CLS clip-in filter.

 

Question:

DAYLIGHT White Balance with the CLS in place leaves everything with a blue/green cast in my images. I know there is a feature of the T2i allowing for a CUSTOM White Balance. (I found it on the in camera menu.) So my question is: how have any of you produced this custom White Balance?  I assume it would require taking a photo of a plain white surface (like taking a flat) with the CLS in place, But this is where I get lost.  How do I translate that photo into a new White Balance?  

 

Anybody do this yet?

 

 

[admin]

OK, I know this is truly a concern of BackyardEOS but since it does affect the quality of our images so much, and I am having issues with it I felt I must ask for some help.  Since so many of us use Canon EOS cameras this is a natural audience of which to ask my question.

 

Background: 

I use BYE3.02 premium with a Canon T2i and an off-axis guider with Orion SSAG on a CPC1100. I normally keep a 0.63 focal reducer in place at all times. Due to rampant light pollutionin my area, I have taken the step of using an Astronomik CLS clip-in filter.

 

Question:

DAYLIGHT White Balance with the CLS in place leaves everything with a blue/green cast in my images. I know there is a feature of the T2i allowing for a CUSTOM White Balance. (I found it on the in camera menu.) So my question is: how have any of you produced this custom White Balance?  I assume it would require taking a photo of a plain white surface (like taking a flat) with the CLS in place, But this is where I get lost.  How do I translate that photo into a new White Balance?  

 

Anybody do this yet?

 

 

Custom White balance should not matter if you are taking raw images, which I assume you are doing.  But it you really an accurate CWB you should use a grey card.

 

Most staking software won't even read the CWB when stacking raw.  Which one are you using?

 

 

 

 

 

[PoppaChris]

Hi Guylain,

 

I do indeed shoot RAW (CR2) files.  I stack them uising either PixInsight or Deep Sky Stacker (still a novice with Pixinsight).  

 

But as you well know, BYE planetary AVI's are a series of JPEGs and lunar videos can bring a new definition of "Blue Moon".  Mars is no longer the Red Planet.  It's more of a shade of purple. Saturn is also affected similarly. etc., etc.

 

My only recourse is to remove the CLS filter when doing planetary imaging.  Another thing to remember in the field or to worry over when physically digging in the camera so close to the sensor. I'm too fumble-fingered to be doing this all the time.

 

I thought that a custom White Balance would be the answer to this planetary problem.

 

[admin]

Hi Guylain,

 

I do indeed shoot RAW (CR2) files.  I stack them uising either PixInsight or Deep Sky Stacker (still a novice with Pixinsight).  

 

But as you well know, BYE planetary AVI's are a series of JPEGs and lunar videos can bring a new definition of "Blue Moon".  Mars is no longer the Red Planet.  It's more of a shade of purple. Saturn is also affected similarly. etc., etc.

 

My only recourse is to remove the CLS filter when doing planetary imaging.  Another thing to remember in the field or to worry over when physically digging in the camera so close to the sensor. I'm too fumble-fingered to be doing this all the time.

 

I thought that a custom White Balance would be the answer to this planetary problem.

 

 

Oh, yes, planetary. 

 

Canon did not implement Custom White Balance to live view images sadly <_ so i afraid it won help.>

 

Regards,

 

 

[PoppaChris]

Thanks anyway, Guylain.

 

Thinking about it a little more, maybe (I hope) I can do a color correction process in Pixinsight and save it as a custom icon for future use when needed.  I need to learn my way around that software a bit more than my current skill level I'm afraid.

[s3igell]

There is little advantage (and some penalty) to using a CLS (or other LP Filter) for Planetary Imaging.

This is because:

1)  Planets are especially Bright Objects, often emitting reflected sunlight strongly within bands which for terrestrial purposes are blocked by LP Filters.

2)  Planetary Imaging is performed in terms of Very Short Exposure still Exposures or equally short Exposure (high FPS) Video, for which background LP Skyglow will have little time to accumulate on the Sensor.