From: Mark Gaffney <markgaffney@mac.com>

Date: July 3, 2008 9:42:14 AM MDT

To: Astro_IIDC@yahoogroups.com

Subject: Re: [Astro_IIDC] Re: IR/UV filter...

Thanks Milton, I finally got the finder bracket screws from Extravision in Brisbane. They`re the Celestron importers for Australia. I found there`s another adjustment ring on the opposite end to the eyepiece on the 9x50 finder which I was missing at first. So I can finally get things in the centre of the cross-hairs. The FWHM/HFD rings in Astro IIDC may be of some help too when I manage to centre a star. I`ve had the camera out on successive days testing on trees with the different scopes. I found there`s too much sunlight coming down the tube for the camera to handle with the 10" whereas the 4" is perfectly OK. I may have been having trouble getting things into focus with the 10" also as I can find no terrestrial objects over about 200 metres distant. Mark.

On 03/07/2008, at 10:47 PM, Milton Aupperle wrote:

Hi Mark;

No it wouldn't cause that. It primarily blocks off infra red light

which causes color balance issues (mainly lunar / solar, but Planetary

too like Jupiter) and also improves sharpness as IR light comes into

focus at a different point than visible light.

Usually when you can't find objects it's because the finder and the

camera / scope are not pointing at the same place. The small field of

view at prime focus with most scopes allows for very tight tolerance

in alignment. After I remove the coverings on my scope, I usually have

to re-adjust the Finder scope so that the finder and camera point to

the same object. I usually do this right before dusk and site them in

on a dsitant terrestrial object.

HTH..

Milton Aupperle

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

Hi Milton & others,I`m wondering if the lack of the above filter on

my IS DBK 21A F04.AS

would be affecting my ability to acquire stars in the camera window

of Astro IIDC. I`ve tried a

couple of times with my NexStar 4SE (as it`s easier to set-up) but

haven`t had any success

with more difficult objects. I`ll have to have another go with

Jupiter as I acquired it 2-3

months ago although quite overexposed with little chance it seems of

adjustment. Now that

my Firewire port has luckily started working again I can devote some

funds to a Baader filter

by the end of the month! Mark.

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