db-astro.org

justanotherpete · Joined: 07 Sep 2007 Posts: 27 Location: Rosyth

Was trying to think of a way to reduce the brightness of the solar disc in my PST to make prominences etc at the limb stand out more and came up with this:

Take one of these filters (nearest I could find to plain glass):

http://www.rothervalleyoptics.co....trast-booster-1-25-inch_d499.html

Then attach to it centrally a small circle of black card / paper / insulating tape that's approximately or slightly less than the diameter of the sun's image in the eyepiece (probably some trial and error would be needed here).

Then viola! An occulting disc filter that screws into the eyepiece you are using with your PST; most of the sun is obscured except for the limb so perhaps prominences would be more visible?

Just wondered if anyone had any thoughts on whether this might work?
Thanks
Pete

astrogeorge · Joined: 25 Oct 2007 Posts: 77 Location: Kirkcaldy

Hi,
As far as I'm aware using colour filters with your pst makes no difference. There for i would just buy something like the meade moon filter.
_________________
Celestron C100ED-R, Meade LX200 10" & Series 5000 80mm Apo, Coronado PST
EQ6 Pro with GPS
Meade Series 4000 Eyepieces & 2x Apo Barlow
Tele Vue 4x & 5x Power Mate
Meade DSI Colour & DSI II Pro, Image Source DBK 21, Canon Eos 400D

Cosmic · Joined: 12 Jun 2008 Posts: 190 Location: Dunfermline

Pete
All i know about black spots is what I read in Treasure Island Smile

however seems like a goer so why not try it and report back to us.
Bests of luck
Cosmic
_________________
Meade LX90 UHTC 8" SCT
Celestron Nexstar 5SE SCT
Mintron MTV-12V6HC-EX ccd video cam
15x70 Astro Binoculars 10x50 Binoculars
When I was a child I had a dream......now I own a telescope ....it's no longer a dream.

justanotherpete · Joined: 07 Sep 2007 Posts: 27 Location: Rosyth

Thanks for the suggestion George - I'll look into that Smile

Solar B · Joined: 07 Dec 2006 Posts: 138 Location: Dalgety Bay

Hi Pete

You should be able to De-tune the Etalon away from surface
detail and towards Limb,i have used variable Pol filters
in the past with PSTs which do improve contrast a bit on
the surface,for ulitimate PST views a Double stack filter
is required,this is great for surface and limb,proms can take
on more of a 3D affect.

Brian

_________________
" Gentlemen only ever use Refractors "