Here is the place to talk about all those equipment(Telescope, Mounts, Eyepieces, etc...) you have. Not sure which scope/eyepiece is best for you? Trash it out here!
jiahao1986 wrote: but it returned unfixed, now the field of view through the C8 is a cigar or spindle like shape (they must have glued the secondary off-centered...)
Spindle-shaped? It is unlikely that the secondary is excessively 'glued off-cnetred'. The secondary is mounted in a hole in the corrector plate. It can't move too much. My guess is that the baffle is tilted. The baffle is tubular. You can imagine looking thru a tilted tube. The FOV will be spindle-shaped.
From your description of the 6" reflector, it would be easier to get a Skywatcher 6" F5 relector OTA as replacement.
Canopus Lim wrote:Perhaps the 6" Reflector focuser can be replaced with a proper crayford/ R&P focuser. Maybe the 1.25" Orion helical focuser can be used too.
I don't thinks the focuser can be replaced as the only arm holding the secondary is connected to the focuser...
Canopus Lim wrote:Perhaps the 6" Reflector focuser can be replaced with a proper crayford/ R&P focuser. Maybe the 1.25" Orion helical focuser can be used too.
The old celestron C6 is a bit like the current Vixen 6" reflector; they used a sliding focuser and not the common rack and pinion or crayford.
I have the same slide type focuser. My Vixen R135S is the same series as your C6 Newtonian (nyp also has one!). The focuser cannot be replaced. If you don't mind, I can try to do the collimation for you.
Get some padded scope bags from Orion also. They are handy and reduce greatly the damage due to bumps.
I would recommend GOTO considering the knowledge of students. (Its is actually bad to teach astro by GOTO. But you don't want every session to be just viewing planets, moon and starclusters and nebula, you would want them to try galaxies (at least 8")) Most students just want to see things in astro, so if you teach them star hopping, then it might turn them off.
CG-5 GOTO mount is ok for tracking and GOTO, and it is versatile enough for you to do more serious stuff. Btw as far as I know, C8 is the lightest 8" scope, C8 Newtoniain is heavier than C8 SCT.
Btw, SCT can be collimated into a rough position first in daytime, then collimate under the stars, otherwise, if it is far out of collimation, it will take ages for you to collimate under the stars.
Thanks again for you guys' help. Another thing is that our accessories are also out-dated and in bad condition, we cannot spend all the budget for the new scope, so a Nexstar 8SE is not possible, besides, we already have a C8.
Now I think we need to send the C8 back for another repair to see it's fixable, then decide whether to buy a new scope or buy a new mount plus accessories.
jiahao1986 wrote:Thanks again for you guys' help. Another thing is that our accessories are also out-dated and in bad condition, we cannot spend all the budget for the new scope, so a Nexstar 8SE is not possible, besides, we already have a C8.
Now I think we need to send the C8 back for another repair to see it's fixable, then decide whether to buy a new scope or buy a new mount plus accessories.
Again thank you all for the help!
Jia Hao
Go with Nexstar 6SE then. Trust me, I run an university astro club before and I can see what are your contraints especially on manpower and technical expertise. If I have a club and i have your budget, the 6SE will be the scope to get.
Just remember that in a club observation session, people who come do not want to be bored seeing you setting up, busy collimating or busy searching for objects. While some of you may be enjoying all these processes, most students who come just want to see what's in there. Once you bored them, that's the last time you will see them again. So an easy to setup scope, easy to maintain, generally compact with a tracking and GOTO function will give awe to most of these students. You also need not worry who should be in charge of "pushing the scope" (in the case of non-tracking scope) for them or who should do all the hunting of objects.
I agree with VinSnr on the people getting bored part. The new students always get bored fast.. The real core group who are interested will not really mind any scope above 6", as long as they get to use the scope. It's a good balance. Anyway, I've been to NTU astro before, every session need to lug the astro equipment through a quite narrow (in my memory) corridoor. Bigger stuff = higher chance of knocking too. And requiring more people to handle, not that you have a lot of people to help to start with.
Stargazing ... is an excuse to stay up past bedtime that never fails!
