I am a newbie to astro

Quasar · Post by **Quasar** » Wed Oct 08, 2003 8:06 pm

Hmmm... maybe first of all, let's get a few things straight, the angle 45 deg or 90 deg is simply the angle at which the diagonal diverts the light, 45 deg bends the light up 45 degrees for viewing while 90 deg bends it 90 deg for viewing

The comfort wise btw the diagonals is quite relative i suppose, however, the main concern with diagonals is that 45 deg ones are made using prisms and 90 deg ones are both mirrors and prisms. Prisms are easier to make and therefore cheaper, but since they ADD more points of contacts for the light from a scope, most pple think they cause more loss of light (Is there any other reason?) So most astronomical scopes would use mirror, 90 deg diagonals.

Quasar · Post by **Quasar** » Wed Oct 08, 2003 8:12 pm

Okay, here's to help u out, visually

Post by **weixing** » Wed Oct 08, 2003 8:33 pm

Hi,
Normally, 90 deg diagonal is use on the refractor, Maksutov-Cassegrain(MCT) or the Schmidt-Cassegrain(SCT) when it point at a high angle or point at zenith (directly overhead) - the eyepeice is point at the ground, so very difficult to see through it. Newtonian reflector usually don't need to use a diagonal - instead you may need a ladder if you got a "long" tube Newtonian reflector... ha ha

dew · Post by **dew** » Wed Oct 08, 2003 9:55 pm

I'll explain to you slowly with references to *live samples* when you come over ok ? Anybody wants to come over for a free crash course too ? It'll be fun.

hey can i come over too? i'm still trying to understand all the different eps.. although i'm not sure i can make it this sunday.. sam, mind keeping me posted on this? but if i cant go dont change the day because of me.. ill find out more myself during the next csn..

eu-wen

IceAngel · Post by **IceAngel** » Wed Oct 08, 2003 10:00 pm

ooh.. Quasar.. i understand better liao.. hehe.. thanks alot...

dew.. i dunno am i going this sunday, i have to see whether starfirez when free.. coz she also wanna see and learn.. hehe..

harlequin2902 · Post by **harlequin2902** » Wed Oct 08, 2003 10:03 pm

hey can i come over too? i'm still trying to understand all the different eps.. although i'm not sure i can make it this sunday.. sam, mind keeping me posted on this? but if i cant go dont change the day because of me.. ill find out more myself during the next csn..

eu-wen

No problem Eu-wen. So as of now, I'll take it that 3 of you are interested

Will keep all of you posted about it.

harlequin2902 · Post by **harlequin2902** » Wed Oct 08, 2003 10:05 pm

Hm, so I think I'd better start putting together an eyepiece-edu kit for such sessions in the future.

Looking forward to it

IceAngel · Post by **IceAngel** » Wed Oct 08, 2003 10:05 pm

samuel.. i found a date that usually we can go.. maybe 23th Oct.. bcoz is a weekday and devepali unless u r celebrating.. hehe...

Post by **weixing** » Wed Oct 08, 2003 10:13 pm

Hi,
I've post this link on the yahoo! Group before... So post here again for the newbie.
It is actually the lecture notes for the introductory astronomy course offer by The Department of Physics of The University of Hong Kong: "Nature of the Universe I & II'':

http://bohr.physics.hku.hk/~nature/CD/f ... index.html

Hope useful to the newbie...

harlequin2902 · Post by **harlequin2902** » Wed Oct 08, 2003 10:14 pm

Now that's strange. It seems like different local calendars have listed it on different dates. Some indicate 23rd while others indicate 24th. ??