Hi all,
Did some experiments today with my canon unmodded DSLR and my Astronomik CLS LP filter, i was always getting a green tinge on pics which is normal with these filters and then i read here about doing a custom white balance with a piece of grey card and using that for astro use instead of the daylight setting....wow it works check out the results below, stood in a slightly different place to take the pic at the bottom hence the cropped look.
Normal camera and no filter and daylight white balance
With CLS LP Filter and daylight white balance used, this is what all my astro pics come out looking like.... well not a picture of my back garden obviously...LOL
Adjusted Custom white balance with grey card with CLS fitted ...WOW what a difference no green tinge like the middle pic !!
Also this should have been done with the proper colour 18% grey photographic card, and in the sunlight, i did with a piece of card i found and on a dull day, so should be able to get it even better.
There is a slight red channel increase, but isnt that what we want from unmodded DSLR's !!