From: Mark Gaffney <markgaffney@me.com>

Date: August 31, 2009 11:43:55 AM MDT

To: Astro_IIDC@yahoogroups.com

Subject: Re: [Astro_IIDC] Re: Colour Jupiter from Ray

Milton, 

Don`t worry! It certainly wasn`t a worry for me-just a couple of minutes work. I thought I`d give it a go anyway. I checked earlier on (in the midst of other things) & alignment stars were barely discernable so didn`t try an "All Star" PA which I`ve been procrastinating over. I guess if I`d set-up the stars would`ve been visible enough through the scope. 

Mark.

On 01/09/2009, at 3:23 AM, milton_aupperle wrote:

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)
> >>
> >>
> >>
> >
> >
> >
> >
> >
>