From: Mark Gaffney <markgaffney@mac.com>
Date: July 4, 2008 11:37:39 AM MDT
To: Astro_IIDC@yahoogroups.com
Subject: Re: [Astro_IIDC] Re: IR/UV filter...
Hi Tim, I did look into these focusers at one stage but postponed the whole operation indefinitely; http://www.focuser.com/cgi-bin/dman.cgi?page=category&plugin=dstore.cgi&category=3 They are compatible with my 10" scope & can be operated on a Mac via the DC Servo drive based motor; http://www.focuser.com/cgi-bin/dman.cgi?page=motorfocus , with a FCUSB device from Shoestring Astronomy & this software;http://www.stark-labs.com
I even bought the FCUSB device & cables at the time! Milton directed me to the software & FCUSB. Mark.
On 05/07/2008, at 2:36 AM, Tim wrote:
Mark:
I personally hate spending money on stuff without knowing what my
problem is first, so I try to rig up easy ways to find out.
if you get an out of focus image, at least, and the closest to focus
is with the draw tube all the way out, one thing you can try is
loosening the set screw holding the camera in place, and carefully
pulling the camera out while watching the image on the screen, to see
if it gets sharper. If it does, you could use an extesion tube to
reach focus. If you can't reach focus with the focuser racked all the
way in, then you either need a lower profile focuser than the one you
have, or move the primary mirror forward up the tube (depending on
the way it's mounted, this might be easy or difficult).
-Tim.
--- In Astro_IIDC@yahoogroups.com, Mark Gaffney <markgaffney@...> wrote:
Hi Milton, Here`s the scope;
I was wondering if something like this might work;
http://www.myastroshop.com.au/products/details.asp?id=MAS-347
I`m not getting any image of a star at all at present inside the
FWHM/HFD rings? I`ve taken moon images with both scopes, the 4SE is in
the background of the picture. Mark.
On 04/07/2008, at 11:47 PM, Milton Aupperle wrote:
Hi Mark;
On 3-Jul-08, at 8:24 PM, Mark Gaffney wrote:
Hi Milton, seems shifting the camera/nosepiece inside the eyepiece
holder won`t work for trees in the sunlight through the 10". Too much
light for the camera without a filter perhaps?
Most likely yes, especially since sunlight has a lot of infrared
light in it too.
I can bring the 20mm
eyepiece into focus on nearer objects this way though. Mark.
The puzzling thing to me is that you did shoot some lunar images
previously, which seemed to be pretty close to focus. Or was that
taken with a different Telescope than this one?
I believe your 10" is a newtonian, right? If you put a bright star
in the field of view you twist the focus knob back and forth, you can
usually see the star go from larger diameter (out of focus larger
FWHM/HFD values) to smaller diameter (smaller FWHM/HFD values) and if
you continue twisting it then it once again becomes a large star
again.
If your not seeing that sort of behavior, the 10" might not have
enough travel distance on the focuser then, either in or out to bring
it into focus.
HTH..
Milton Aupperle
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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