FS: Skywatcher 127 Mak Cass

yanyewkay · Post by **yanyewkay** » Thu Apr 05, 2007 9:46 am

don't worry guys, the scopes a hefty investment for me. i won't be disappearing from under the night skies for a long time.

Scope is still for sale!!
Willing to throw in my DIY laser pointer holder for it as well

alvinsclee · Post by **alvinsclee** » Fri Apr 06, 2007 6:00 am

Airconvent wrote:... As a rule of thumb, you need to increase the aperture diameter by 50% to see improvement. Hence to upgrade from a 5" scope, the next option is 8"...

UK,
I generally agree with Airconvent on this rule-of-thumb. Based on photometric principle on the factor of square root of 2 (which is around 1.4142), it would be better to have at least 41.42% increase in aperture to perceive a doubling of light capture.

Our sensory nerves exhibit logarithmic response (intensity of sensation and magnitude of stimulus is related by "Weber-Fechner rule")... in the case of visual response, doubling is needed each time to generate significant noticeable differences. That's why lens stops increase by factor of 1.4 (that is... f1, f1.4, f2, f2.8, f4, f5.6, f8, f11, f16, f22, f32).

By the way, if you do disappear from under the night skies, I know I can find you in daytime chasing treetop butterflies with that scope ...

Up for a good scope (this same Mak 127 model would have been my first scope, if I had not been subsequently tempted by the ED refractor shown in my avatar).

yanyewkay · Post by **yanyewkay** » Fri Apr 13, 2007 12:13 pm

still available

yanyewkay · Post by **yanyewkay** » Fri Apr 27, 2007 1:41 am

still for sale

yanyewkay · Post by **yanyewkay** » Fri Apr 27, 2007 10:54 pm

*SOLD* to a nice gentlemen!!

swimaniac · Post by **swimaniac** » Fri Apr 27, 2007 11:43 pm

Thanks for showing me the basics.

My very first scope.

Now to join a group and learn more.

Anybody around the East Coast area, specifically around Bedok Reservoir?