Re: Comet 2002-T7 and CA Nebula

Jason Ware <[EMAIL PROTECTED]> wrote:
> Florian wrote:
>> 
>> >Here is a color version of comet 2002 T7 (linear)
>> >with the California Nebula.
>> 
>> Jason... Absolutely breathtaking!! I tried to pick out the Calif neb on 11/22 while 
>> out on the southern Calif desert. I could just barely detect that something was 
>> there. Your photograph is amazing!!!
>> 
>> -Florian.at.stargazing.dot.com

> I have never seen it visually.

This is one of the funny nebulae (in a class with the North America 
Nebula) that is trivially easy to get on film but really hard to
see visually. I got the NA in a 20-second exposure with my 35mm camera's
normal 50mm f/1.8 lens, from my front yard (aimed at Hale-Bopp) on Kodacolor
400, under conditions when the Milky Way was at best a marginal naked-eye
object. Similarly, albeit with a much darker sky, the California nebula
showed up in a similar exposure (also targeted at Hale-Bopp) about
a month later. (The latter is at
http://www.astr.ua.edu/keel/comets/
if you scroll down). The secret is that some color emulsions have
a red layer that is really sensitive right around H-alpha, so you
can recognize these nebulae as red splotches even if the overall
brightness is barely above the sky.

Bill Keel