From: "Tim" <tjp314@pacbell.net>

Date: September 13, 2005 5:13:14 PM MDT

To: Astro_IIDC@yahoogroups.com

Subject: Re: Binned color?

Milton:

Hm... very interesting. I tried to do a search on "subframe" in the manual, but got no

responses. "Window", not surprisingly, gets too many responses!

But my question now is: If I get one of the megapixel CCD Scorpion cameras, can I take

advantage of the smaller pixels and keep the frame rate up by windowing a subframe of

the ccd for aquiring video? Unless the specs change, the Scorpion isn't available with a

640x480 CCD color chip, just a B&W chip at that size (but with 9.9 micron pixels!) and

megapixel color ccd chips with smaller pixels (in the 4-5 micron range)

Sorry if this is somewhere in the manual but I missed it (I'm one of those RTFM guys you

meet from time to time).

-Tim.

--- In Astro_IIDC@yahoogroups.com, Milton Aupperle <milton@o...> wrote:

Hi Tim;

On 13-Sep-05, at 8:47 AM, Tim wrote:

Milton:

In making my decision on whether to order a Scorpion so I can

remove the IR filter without

voiding the warranty, I'm faced with a wide array of CCD and CMOS

chip choices.

If your going for DSO's, get the biggest pixels you can afford.

If your going for Lunar/Planetary get smaller pixels - but the more

pixels, the less sensitive each one is as it has reduced surface area.

On the

Astro IIDC website, it says:

"Supports display and capture in color, monochrome, binned 2x2

color, binned 2x2

monochrome and individual red, green or blue color channels modes."

I thought the color information got lost when binning color chip

cameras. If it isn't in Astro

IIDC, does one get the benefit of the increased sensitivity of the

binned pixels?

Where there is a will, there is a way.

On page 30 of the Astro IIDC manual is the description of ""Binned

2x2 Color"". I copied it for you below.

"Binned 2x2 Color" is only available for color cameras. Essentially 4

adjacent pixels are forward

summed to together to calculate a luma value. Then the red, two green

and blue colors of those

four adjacent pixels are used to calculate the LRGB for it. It

increase images brightness by up to

400%, however the result is a 50% drop in image resolution. It tends

to increase the Green color

of the image too, which means you need to increase the Red and Blue

gains to balance it.

Additionally the amount of calculation going on extracts a fairly

hefty toll on CPU and with a G4

733 MHz single processor, you will barely be able to run at 8 frames

per second

HTH..

Milton J. Aupperle

President

ASC - Aupperle Services and Contracting

Mac Software (Drivers, Components and Application) Specialist

#1005 - 815 14th Avenue. S.W.

Calgary Alberta Canada T2R0N5

1-(403)-229-9456

milton@o...