From: Alan Friedman <alan@greatarrow.com>

Date: June 22, 2005 9:08:13 AM MDT

To: Astro_IIDC@yahoogroups.com

Subject: Re: [Astro_IIDC] Solar Images Posted

Hi Milton -

Very nice images!!

I also need a filter to attenuate the light level using the DMK camera with Baader white light filter material. I've experimented with a number of wavelengths including the Baader solar continuum in the green, 45nm HAlpha and near IR. I found that as with planetary imaging, the streams taken in red light suffered much less from atmospheric effects than those taken at shorter wavelengths.

best wishes -

Alan

On Jun 21, 2005, at 10:02 PM, milton_aupperle wrote:

Hi folks;

I was trying to chase down some tracking issue in Astro IIDC 2.01.00

(hopefully released tomorrow) using the sun limb as my target, so I

also recorded a few gigabytes of video of sunpsot groups 780 (central)

and 779 (on the limb and gone from view tomorrw). They are in the

Files -> Solar folder. This was my firtst attmept at shooting the sun too.

I had to use a wratten 25A filter because I could not run the Unibrain

color camera any lower  exposure time than at 0.3 milliseconds with

gains at near zero. With it on, I could asjust the gain a little bit.

I also discovered that you can really improve the contrast and detail

level of your solar images using the "Histogram Expand" option in

Astro IIDC. Unfortunately I didn't record any images with it off for

comparison sake, but basically you could just make out that their were

some low contrast dark blotches visible on the suns disk. With it on,

the sunspots are black, and the granulations and flocculae / phlages

stick out like a sore thumb - as shown in the images.

TTYL..

Milton Aupperle

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