Hi Francis,
Yes I remember my old school physics. I used a yellow filter for my
first experiment because I happen to have one, it is lighter than my
only other one (Orange), and the write-up from Meade say it is good for
"observing red and orange-coloured phenomena in the belts of Jupiter".
I quite like the results actually.
That is also why I was puzzled that one of my images looked distinctly
blue. See attached image after only simple processing in Registax.
Thanks for the thoughts anyway.
Peter
francis_at_milsom.clara.co.uk wrote:
<em class="quotelev1">> Peter,
<em class="quotelev1">>
<em class="quotelev1">> Remember that when taking photographs a filter transmits its own
<em class="quotelev1">> colour and
<em class="quotelev1">> absorbs other colours to a greater or lesser extent:
<em class="quotelev1">>
<em class="quotelev1">> i.e.
<em class="quotelev1">> yellow absorbs blue
<em class="quotelev1">> magenta " green
<em class="quotelev1">> cyan " red
<em class="quotelev1">>
<em class="quotelev1">> so to enhance a feature, use a colour filter that is opposite the
<em class="quotelev1">> colour of
<em class="quotelev1">> the feature ( red spot - cyan filter).
<em class="quotelev1">>
<em class="quotelev1">> Remember the 'old-days' when photographs used B&W film and yellow,
<em class="quotelev1">> orange or
<em class="quotelev1">> red filters to darken a blue sky to make those fluffy white clouds
<em class="quotelev1">> stand
<em class="quotelev1">> out - use those same principles now with your B&W CCD's to enhance the
<em class="quotelev1">>
<em class="quotelev1">> features you want at the exposure stage.
<em class="quotelev1">> I have attached a colour wheel generated in Photoshop which should
<em class="quotelev1">> help
<em class="quotelev1">> deciding on filter colour v feature colour
<em class="quotelev1">>
<em class="quotelev1">> Francis
<em class="quotelev1">>
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<hr>
<img src="att-5359/Jupiter_Cap04R_.jpg" alt="Jupiter_Cap04R_.jpg">
