[AZ-Observing] Re: Mars Is Not "Too Bright"
- From: Jeff Hopkins <phxjeff@xxxxxxxxxxx>
- To: az-observing@xxxxxxxxxxxxx
- Date: Fri, 12 Sep 2003 11:00:31 -0700
Jack Jones wrote:
>I wonder if that's what it mostly is then. When an aperture mask is used on
>a large telescope the view is usually improved because on par large mirrors
>are just not that great. Cutting off the edge and bad parts of the mirror
>would give a surprising improvement, esp. on planets. At star parties you
>continually hear from light bucket owners 'well the seeing isn't that great
>right now'. It's amazing how quickly the seeing improves in the time it
>takes to walk to another telescope.
>
There are aperture masks and there are aperture masks. The big
advantage I have heard about is using an off axis aperture mask on a
large scope so that you have a clear view with no obstruction due to
the secondary and secondary supports.
I have tried a 5" round opening off axis mask on my 13.1" DOB, but
really did not see any improvement. Using a full aperture mask would
seem to just reduce the resolution and light grasp.
Jeff
--
Jeff Hopkins
HPO SOFT
**************************************************************
Phoenix, Arizona Atlanta, Georgia
7812 West Clayton Drive 12170 Boxwood Circle
Phoenix, AZ 85033-2439 U.S.A. Alpharetta, GA 30005 U.S.A.
(623) 849-5889 (Fax) (770) 619-3322 (Phone/Fax)
www.hposoft.com dataman.home.mindspring.com
4th Dimension Developer
FileMaker Pro Expert
BASIC/C/C++ Programmer/Web Site Developer
--
See message header for info on list archives or unsubscribing, and please
send personal replies to the author, not the list.
Other related posts:
