Re: [APML] Sunspot Picture

["Stuart Heggie" <stuart.j.heggie@sympatico.ca>]

Jerry - that is extraordinary! I feel like I'm falling into the picture as I
stare at it. Beautiful shot! Also, thanks for the processing explanation
(most of which I can pretend to follow, some of which I did follow!).

Stuart
----- Original Message -----
From: "Jerry Lodriguss" <jerry@astropix.com>
To: <astro-photo@seds.org>
Sent: Friday, October 31, 2003 4:44 AM
Subject: [APML] Sunspot Picture


> Hi yall,
>
> I've posted a shot of the two large sunspots that are currently on the
sun.
>
> It's at: http://www.astropix.com/HTML/SHOWCASE/SUNSPOTS.HTM
>
> Although it was taken with a Nikon D1h digital camera, the image
processing
> may be of interest to the few film photographers left alive on this list.
<G>
>
> A series of approximately 300 images were taken manually one after another
> with the camera in anti-mirror shock mode and triggered with the
self-timer
> to reduce vibrations.
>
> The raw images were then imported into Photoshop 7 with the Adobe Camera
> Raw plug-in and were exposure adjusted, contrast increased and sharpened
in
> the ACR module. Because the images were low noise from having been shot at
> ISO 200, noise reduction in the ACR module was set to zero.
>
> All of the images were then opened in Photoshop and enlarged to 200
percent
> and examined for sharpness and the best image was selected.
>
> The image was further adjusted in Photoshop for tonality, and sharpened
> with an unsharp mask of 100 percent, 0.5 pixels and 0 levels. Another
> unsharp mask of 100 percent, 2 pixels and 2 levels was applied. False
color
> was added with a layer in the darken blending mode.
>
> Shooting 300 images was a method of hoping to luck out and get one with a
> moment of especially good seeing. This technique goes back many decades
and
> has recently been advanced greatly with web cams for planetary photography
> where videos are shot at a high frame rate and specially designed software
> selects the sharpest frames and stacks them together to create a low-noise
> image.
>
> In the case of a web cam, the images are relatively low resolution in
terms
> of the total number of pixels, but the resolution of the seeing is matched
> to the image size at the focal plane producing excellent results. In this
> case a larger file size of approximately 3.5 megabytes was produced by the
> Nikon digital camera.
>
> Jerry
>
>
> Photoshop for Astrophotographers - http://www.astropix.com/PFA/PFA.HTM
>
>
>
>
>
>
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>
>
>
>
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