From: Milton Aupperle <milton@outcastsoft.com>

Date: June 6, 2011 12:17:11 PM MDT

To: Astro_IIDC@yahoogroups.com

Subject: Re: [Astro_IIDC] More solar images from the weekend

Hi Alan;

On 6-Jun-11, at 11:05 AM, Alan Friedman wrote:

A couple of things that can help when it is necessary to work from a single frame:

1. shoot with 0 gain (brightness)

Yes, yes, yes...  High Gain or Brightness = High Noise. Stacking reduces this, but if you can't stack then this is basically your primary means to control it.

2. apply a mild gaussian blur before sharpening (in photoshop) - .6 pixel radius works well for me.

When using Astro IIDC to capture and process data from the solar disk in Ha, it can help to increase the gamma by a sizable amount (1.5 or greater)... this will give the program something to "hold onto" in terms of image contrast for alignment and stacking.

Allan and Jim, have you tried using :

"Histogram expand brightness of all frames used for pixel alignment."

when stacking? See page 42 of the 4.06.00 manual for an explanation.

Depending on what your initial image range is, this will also boost the contrast used for the alignment frames.

Just for kicks, here is what Jim's

http://dl.dropbox.com/u/4852049/SunJune5a.jpg

image looks like when the "Histogram expand brightness" function is applied for selecting image areas for alignment.

http://groups.yahoo.com/group/Astro_IIDC/files/Other/ExpandedSun.jpg

It can really boost the contrast for soft images and give Astro IIDC something "hard" to lock onto.

If you have significant gain noise this will amplify it, so you might want to check mark the

"Gaussian blur the frames used for sharpness estimation & alignment"

item (page 42 of the manual) when stacking.

Here is the difference that will make.

http://groups.yahoo.com/group/Astro_IIDC/files/Other/ExapnadedAndSoftened.jpg

for your your alignment frames.

I haven't had time to work on my data from yesterday, but here is a quick stack from one of the files.

http://www.avertedimagination.com/images/060511_test.jpg

This is my 1600x1200 Scorpion camera with an ROI selection of 600x800 pixels.

Nice preliminary images. Can't wait to see the finals.

Hope some of this helps..

Milton Aupperle