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No, it is not necessarily contradicted. Images of planetary nebulae can be processed in ways which do not present the same level or shade of color detail which the eye sees. You might want to check out the following narrow-band images of NGC 1535, as the H-alpha one shows that there is definite H-alpha emission:

http://astro.uni-tuebingen.de/cgi-bin/uncgi/pn?file=n1535&name=NGC+1535

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Everything might be... However how *strong* is that H-alpha emission? Could one see anything there with a H-alpha filter?

Whichever Nebula will have "some" amount of H-alpha emission (including the ears of M27), the point is how faint? is that enough?.
The fact is that 1353 is (as far as I know) by large dominated by OIII; add that the eye is 10 times more sensitive to OIII than H-alpha....
In my opinion you are trying to keep alive a dead theory. Anyway we will see if your hope survives the H-alpha filter. BTW no clear weather this week end. Hope for next.

PS I see here that the distributions of H-alpha and OIII have very similar patterns. Thus the ration Ha to OIII is *the same* all over the nebula and it *must* have the same color either green, if OIII wins, gray if OIII and Ha balance, red if Ha wins (in fact it is green). There are no regions where Ha is strong and OIII weak.
http://astro.uni-tuebingen.de/cgi-bin/uncgi/pn?file=n1535&name=NGC+1535

Here is Ha:

Here is OIII;


and here is the difference Ha-OIII (fringes are *not* dominated by Ha).

Edited by Mauro Da Lio (12/08/07 04:50 PM)

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