From: "milton_aupperle" <milton@outcastsoft.com>

Date: August 31, 2009 11:23:34 AM MDT

To: Astro_IIDC@yahoogroups.com

Subject: Re: Colour Jupiter from Ray

Mark;

If your problem wasn't "dark image" then why use the binned or Histogram stacking suggestions? They were for a specific case where the image capture was too dark.

All image processing and stacking is GIGO based (Garbage in  = Garbage out) and you can't turn a pig's ear into a silk purse.

Until you address the fundamental issue your having (i.e. no polar alignment so the image drifts completely outside the FOV in seconds), your never going to get any good results.

Lastly, moon brightness will have zero affect on imaging Jupiter. On nearly full moon nights is when I do most of my guiding and alignment testing, as DSO's imaging is basically impossible (except if your doing narrow band H Alpha).

HTH..

Milton Aupperle

--- In Astro_IIDC@yahoogroups.com, Mark Gaffney <markgaffney@...> wrote:

Hi Milton,

My problem evidently isn`t darkness of image. I just tried the  

suggestions you`ve given Ray & I`m not getting a satisfactory result.  

My Jupiter in the movie is riding right up in the top left & is partly  

under the red border area. Here`s a jpg version of the stacking result  

from the other night;

I was lucky to get even this on the night I did it. I`d have tried  

again tonight but I was busy with other things & the moon was rather  

bright...It`s about to slip behind some trees I have to the west right  

now..

Mark.

On 01/09/2009, at 2:08 AM, Milton Aupperle wrote:

Hi Ray;

The "Curves" he's referring to is a post capture tool in PhotoShop,  

very similar to "Curves" in the Image Processing part of Astro IIDC  

(see page both 58 and 59 of the Astro IIDC Manual). Both are used to  

stretch the image in a non linear way.

As Allan pointed out, you can use the Gamma to change the  

brightness / contrast to some degree, butt IMHO your better off  

adjusting the image brightness (longer exposure,  more Gains /  

Brightness or binning 2x2) to decent levels (likely the brightest  

part of the image being 60% or higher of the image brightness).

Achieving proper brightness when your sitting in the dark can be  

challenging, however there is a live tool in Astro IIDC to determine  

if your hitting the correct brightness before you take an image.  

Read the sections for "Saturated Pixel Cutoff Limit: xxx (0 to  

255)." on page 71 and then "Show Saturated" on pages 82 and 83.

Quote from page 83:

Note that you can also use this to make sure your targets have  

sufficient brightness when  imaging. For example, say you were  

imaging saturn and wanted to make sure that the disk and  rings are  

at least 50 % brightness. If you set the Cutoff Limit to 128  

(128/255 is ~50%) , then as  you adjust your exposure time or gain  

sliders you will be able to see the rings  and disk will just  start  

to turn red. Then you know that your getting at least 50% brightness.

Also for stacking, you can likely improve the stacked images and get  

something better out of them by using these two things when stacking.

In the "Stacking Options.." window:

1) Check mark "Histogram expand brightness of all frames used for  

pixel alignment." (explained on page 35 of the manual)

This was specifically designed for cases where you have to under  

exposes the movie or you need to use the darker portions of the  

movie for finding good alignment features.

2) Check mark  "Bin Frames 2x2 and auto subtract background before  

stacking." (explained on page 37 of the manual)

This can be used to amplify faint DSO objects and can be useful If  

you have really dark planetary images.

Lastly, for darker planetary bodies or if I need to shoot with  

higher frame rates, you may want to consider using "Binned 2x2  

Monochrome" for the ""Camera Display Format" pop up menus (see pages  

76 and 77 of the manual). I have used it under poor skies to image  

Saturn :

http://www.outcastsoft.com/AstroImages/Saturn20090502MJA.jpg

at much higher frame rates than I would have normally and got  

something out of a bad night:

HTH..

Milton Aupperle

On 31-Aug-09, at 6:33 AM, Ray Byrne wrote:

Hi Guys,

On Saturday/Sunday I took some movies of Jupiter in pretty bad seeing

but actually better than the last few weeks. Out of them I got one OK

result which I've posted in the photos section on our site. When I

came to do the colour processing (it was in the small hours) I got

muddled-up somehow and and kept getting a mono result. Frustrated and

impatient I sent the LRGB set to my mate Mick Hyde to do the colour

bit for me which is the result you'll see.

Now he uses the same gear as me but being a PC/Windows guy uses the

K3CCD Tools/ Registax combo for capture and processing and remarked

that my LRGB set were very dark. To quote Mick he said " Ray, There

you go. The images were very dark though, I had stretch them with

curves in PS. I think you need to check your histogram whilst

capturing and boost the gain a bit."  Two things about this what  

would

be the equivalent in Astro IIDC of the histogram he's referring to?

and should a fiddle with the gain? As regards the gain I always keep

that set to 1.00 and use brightness instead, but of course the more

you increase the brightness the noisier the resultant image is it

seems, should a adjust the gain? Here are reduced sized files before

processing in PS:

(actually this is the first time I've seen them in daylight they are

very dark)