From: "Eric" <eddot1103a@mindspring.com>

Date: July 24, 2006 10:00:13 PM MDT

To: <Astro_IIDC@yahoogroups.com>

Subject: Re: [Astro_IIDC] Re: stacking and histogram questions

Hi Milton,

Yeah, I know the feeling about slow speeds as I related before.  Must switch to DSL or something soon. 

Thanks for the advice.  The biggest problem I've been having is that most of the movies I recently captured were all too dark.  During post-processing, I have to readjust the histogram quite a lot to get the brightness back to normal.  No doubt this is causing a lot of problems.  I'm not entirely sure how to properly read the histogram as movies are being acquired.  As I mentioned, if I increased gain too much, the histogram would appear jagged.  I would then reduce but this made everything dark come to find out later. 

Eric

----- Original Message -----

From: Milton Aupperle

To: Astro_IIDC@yahoogroups.com

Sent: Monday, July 24, 2006 11:06 AM

Subject: [Astro_IIDC] Re: stacking and histogram questions

Hi Eric;

I'm on vacation, communicating via a 2600 baud modem, so getting
e-mails is a major pita.

Astro IIDC will reject frames if they exceed the matching tolerance
that you specify. Even if you pick 0% (ie all frames) of the
histogram, it may still reject frames that simply don't match based on
your tolerance setting.

Part of the issue sounds like you have your gains cranked all the way
up. So when it trys to match up one frame against another it may wind
up just matching noise for low contrast areas.

I'm working on changes to selectively allow smoothing of the images
before doing sharpness and alignment (likely a 1 or 1.5 pixel radius
gaussian blur) which should drop the noise level a lot and remove the
noise.

HTH..

Milton Aupperle

--- In Astro_IIDC@yahoogroups.com, "Eric" <eddot1103a@...> wrote:
>
> Hi,
>
> During my laborious processing of various streams, I notice that
IIDC sometimes doesn't stack all of the frames I originally picked.
This has happened for both lunar and planetary sessions. I noticed
with Jupiter that I had to prealign in KIS first before IIDC would
accept all of my hand picked frames. With the moon, if I try
prealigning first, in IIDC it doesn't align them well at all
presumably because KIS allows the black edges to remain if it realigns
a frame. Is there anything I can do in IIDC to get all hand picked
frames stacked? I've had confidence at 0 (because they are hand
picked) and I have tried various matching, but still a certain number
of frames are excluded.
>
> I'd appreciate any histogram suggestions. Maybe because my monitor
was incorrectly adjusted, not sure, but a lot of what I captured
recently came out with very low gains, to the point where I have to
significantly adjust the histogram of the final stack. During
capture, I had the histogram enabled and adjusted gain until the curve
was "pure" without jagged lines. If I continued to increase gain, I
would get a jagged histogram but not saturated. Can I risk running
the gain where the histogram shows jagged lines and what do the jagged
lines (within the histogram curve itself) indicate? Not talking about
saturation here, just an "impure" looking histogram during capture.
>
> Sorry for the long questions, but appreciate in advance any
suggestions for the above.
>
> Thanks,
> Eric
>