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

Date: June 25, 2005 2:25:56 PM MDT

To: Astro_IIDC@yahoogroups.com

Subject: Re: a couple of questions

Milton:

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

The IR filter on the UniBrain and every other FireWire Web camera

I've seen is on the back of the screw out lens. So once you remove

the lens, you have lots of IR hitting the CCD. I showed the

difference that this can make for color balance on page 37 of the

manual.

This is interesting! I'll have to take a look at it again. My 3com (USB) camera has a small

square filter right in front of the CCD. When I got the camera, it had been mishandled (the

case was cracked around the tripod screw, and I almost returned it), and the filter had

slipped such that I got a half filtered, half unfiltered view when I first tried it on Jupiter.

What was interesting was just how much light that filter blocked (it had a medium blue

color to it). So, I took it out and used an astro IR cut filter instead, screwed into the

webcam adapter.

My ToUcam Pro also has an IR filter right ahead of the CCD.

And the Aplux. It's a small square filter that fits right in front of the CCD in a recess in the

lens mount (the one that's 8mm)... I'd forgotten this. It's in a drawer with the lens mount,

which I'm not using at the moment. And since I don't have it in place, no WONDER I'm

getting Purple Jupiters! h'DOING! I should put it back, since I can't use the webcam

adapter and its filter thread mount on the scope.

Again, I don't know whether this configuration is typical of the plastic case-mounted fire-

i's, or just the Aplux version. So, your mileage may vary.

-Tim.

P.S. Milton, I've been reading the help file, and learning as I go! Love it!!!

For the Unibrain's, I bought a 15 mm square Glass IR filter for about

$25 US (after customs, taxes shipping fees it was $65 CDN) form

Edmund Optics and then have it mounted in my C-Mount to M42 adapter

so I can use it with multiple cameras. For lunar or solar images,

it's frankly necessary to get good color saturation and avoid loss of

focus too.

I have a Lumicon focal reducer that I bought for DSO imaging with a

Meade DSI Pro that I

also recently purchased. I don't use it with the webcams, though,

as they're strictly for

planetary imaging (for me). I did experiment with the fire-i on

M13 with the focal reducer

on my C9.25 at f/5, though, and couldn't see anything at all. But

I didn't spend a lot of

time trying to refocus, and that may have been the problem.

I use a MOOG focal reducer and by increasing the distance from the

CCD to the back of the Focal Reduce to about 100 mm, my MAK 127 mm

aperture / 1540 mm focal length scope has an effective focal length

of 550 mm. There is some vignetting and light fall off on the edges,

but it does give me a decent FOV 0.49° x 0.37° with the Flea 1/3" CCD

and 0.37° x 0.28° for the Unibrain type 1/4" CCD's. And the shorter

the focal length, the less stringent you have to be for tracking too.

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...