Re: AW: [APML] M42 & Meteors

[Matt BenDaniel <matt@starmatt.com>]

At 08:23 PM 11/20/2001 +0100, Andreas Roerig wrote:
>Wow, Matt!
>
>Gongratulations to both!
>That's a great shot!
>Your website tells me that it was a single 100min shot at f/6.7. How did 
>you manage to hold the detail in the nebula without totaly burning the 
>core?

http://people.ne.mediaone.net/mbendaniel2/gallery/astro/m42_meteors.html

Andreas,

Thanks!

I had the same question when I saw John Gleason's M42:
http://www.celestialimage.com/page100.html

At f/6.7, it takes a lot of light to burn out negative film. Negative film can capture 8 stops of dynamic range, while slide film can only capture 5 stops. I try to expose long enough to make sure the sky glow is above the film's response curve toe in the corners. That, in conjunction with anti-vignetting, allows use of the entire frame. This M42 image, as with many of my other images, is full frame uncropped.

In addition, I created an unsharp mask to introduce more contrast in the bright central area of M42. I duplicated the background layer, blurred, desaturated, inverted, and curved it, and used the multiply function. A variation of that is covered in detail in Jerry L's article:
http://www.astropix.com/HTML/J_DIGIT/USM.HTM
--
Matt BenDaniel
http://starmatt.com


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