From: Milton Aupperle <milton@outcastsoft.com>

Date: April 25, 2010 7:08:27 PM MDT

To: Astro_IIDC@yahoogroups.com

Subject: Re: [Astro_IIDC] First Light 80mm PST


Hi Alan;


If you have movies that show this behavior with stacking, put them on a CD or DVD disk (uncompressed, original footage only), send them to me and I'll have a look at them.


I don't have access a PST scope, so I have no movies like that to work with.


And the big problem that I've seen to date form the sample images I've seen is that the frames usually are very low contrast, except for the edges. Using Histogram expand option (see "Histogram expand brightness of all frames used for pixel alignment." on page 35 of the Astro IIDC manual) when stacking may help.


HTH..


Milton Aupperle



On 25-Apr-10, at 12:42 PM, Alan Friedman wrote:



Hi Ray,


In my experience, it can be very difficult to get accurate alignment and stacking using chromospheric details on a spotless sun... especially so if transparency is poor and the details even lower in contrast than under a cloudless sky. To my eye, these two pictures look very soft and somewhat overprocessed while trying to bring greater contrast to the detail. 


I would suggest scanning through the movie to locate a sharp frame. I usually do this with a copy of Quicktime Pro v.7. You can select and copy a single frame and paste it into a new document in Photoshop. Apply a gaussian blur (1.0 pixel radius should work well) and then unsharp mask. The result might be a bit grainy depending on your capture settings, but it will show you the potential of your data. If it looks a lot sharper than your stacked image, the stacking process is not working out well. I often use single frames to create solar images. My blue sun was made from two individual frames - also a day of very low activity and high turbulence. The sun provides enough light that the individual frames should have a nice signal to them - stacking may not be needed at all.


I've seen a lot of very fine images from PSTs with this modification - keep at it!


Apologies to Milton and Alberto for not commenting on your recent posts and the new version of Astro IIDC. I've been very busy with travels and work... hope to have time to get back to my night job soon!


best wishes,

Alan





On Apr 25, 2010, at 8:22 AM, Ray Byrne wrote:

Hi Group,

I've just got a conversion kit to make my 80mm Apo into effectively an
80mm PST. I did my first imaging session with it yesterday and have
uploaded 2 shots to the files section. The sky had milky thin cloud so
no prominences I'm afraid although there is a spikule to be seen in
one of the shots. This particular shot has an active region which is
what was the explosive prominence that was seen last week I think. The
other shot has another active region just coming into view on the
Solar limb.

These images are a bit wooly but I'm sure this is down to the poor
transparency I also need to experiment with processing as this is a
different subject than normal any input from Alan would be appreciated.

ATB

Ray






Milton J. Aupperle

President

ASC - Aupperle Services and Contracting

Mac Software (Drivers, Components and Application) Specialist

#1106 - 428 Chaparral Ravine View SE.

Calgary Alberta T2X 0N2

1-(403)-453-1624

milton@outcastsoft.com

www.outcastsoft.com