RE: [ccd-newastro] Re: M20
- Looks more like a collimation issue. However, poor collimation is
exacerbated by a reducer, especially one that is out of position, so it
could be both interacting.
author of The New CCD Astronomy
From: carlburton2001 [mailto:carlburton2001@...]
Sent: Wednesday, July 31, 2002 12:13 PM
Subject: [ccd-newastro] Re: M20
I put in in the files section at http://groups.yahoo.com/group/ccd-
newastro/files/M20-try1%20copy.jpg . I'll try and move the reducer
closer to the chip tonight and see what happens.
--- In ccd-newastro@y..., "Ron Wodaski" <ronw@n...> wrote:
> Attachments aren't permitted in the group to avoid the risk of
> you point me to a location on the web where I could get a look at
> If you don't have a web site, you can upload a JPG image to the
> FILES section.
> A generic point about reducers:
> * Reducers have to be located a certain distance from the camera's
> order to work effectively. If they are not at this distance, they
> introduce various aberrations. The faster the reducer, the more
> distance is. Ted Agos makes an adapter for the f/6.3 reducer that
> maintain this distance when working with motorized focusers.
> Ron Wodaski
> author of The New CCD Astronomy
> -----Original Message-----
> From: carlburton2001 [mailto:carlburton2001@y...]
> Sent: Wednesday, July 31, 2002 6:38 AM
> To: ccd-newastro@y...
> Subject: [ccd-newastro] M20
> Hi Ron-
> I took this image of M20 last night. I have been using a f6.3
> reducer with my Van Slyke focuser giving a f-ratio of 4.6. I see
> stars in a circular patern, is this caused by the reducer,
> collimation, or me?
> The image was made up from 6x300 sec RG 9x300 sec B and the L
> channel was of the RGB with a ST-8e.
> Any other sugggestion on the image?
> Carl Burton
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