celestron cpc 11" what addons to get?

[mickjfawcett (MICK)]

gday everyone

well i bit the bullet and purchased a Celestron CPC GPS 11" and having just had my first use of it, i found it absolutley fantastic

my question is what other eye pieces / filters are people using with this size of scope. or what do people reccomend

im currently using a 2" diagonal with 32mm 1 1/4" eye piece and was thinking about getting 2" eyepieces instead but not sure of the best sizes. (ie would a 11mm televue be to much mag for saturn viewing?)

how much viewing difference is there between the 2" and 1 1/4"

i am looking at 1 set up for planets and 1 for nebula ect.

i would spend up to $200 per piece.

i dont want to buy heeps of stuff but just a couple of addons to help with the learning process. from all the reading ive done the UHC filter seems to be a great addition to nebula viewing

anyway any assistance would be fantastic

[Rigel003 (Graeme)]

Hi Mick
I've had an 11" Celestron Nexstar for 3 years and used a CPC too for a short period this year - they're optically identical. Because of the long focal length of the instrument, you'll find the problem is in getting low powers and wide fields.

A 32mm eyepiece isn't much good in a 1 1/4" size as the narrow barrel size limits the field of view. You need to go for a 2" eyepiece, at least for your lowest power - it'll make a world of difference. I'd highly recommend the Andrews 30mm 2" 80 degree at $150. Poor man's Nagler with pretty good quality, decreasing somwhat towards the outer edge but I'm very happy with mine and use it a lot.
http://www.andrewscom.com.au/site-section-10.htm
This will give you a lowest power of 93 with nearly a 1 degree apparent field of view. You'll feel like you were looking down a drainpipe before.

If you can afford it, try to select wide field eyepieces for your shorter focal lengths too. I have 27mm and 19mm Panoptics, and 14, 10.5 and 7mm Pentax XLs with about 70 degree fields. The 10.5 produces 270x with a 1/4 degree field and only on rare occasions will the atmosphere allow you to use anything shorter than this. There are cheaper alternatives in other brands. The fairly new William Optic UWANs (ultra wides) have been getting excellent reviews - there is a 16mm with 80 degree field for about $260 which would be great with this scope.

If you can afford the 2" version of a UHC filter, it can be screwed into the 2" diagonal and serve for all your eyepeices.

[Harb]

G'day Mick, and hi Graeme, the CPC is going well,

Mick , I would recomend the very first thing you get, is a dew shield and maybe even a cheap orion dew zapper.........
Dew as I have found can be the most frustrating thing with a SCT.
I also have fitted mine with a counter weight assembly, so I can balance the load of my imaging stuff a bit better.
I have also fitted a Celestron motorised focuser and also a Williams Optics Crayford type 10:1 focuser as well.......

cheers
John

[mickjfawcett (MICK)]

thanks for your help guys

im going to take up all 3 suggestions and cant wait to try them out. (30mm, uhc filter and dew zapper)

just wondering as well what setup you guys use for viewing planets with the 11".

[sejanus (Gavin)]

mick i had a great view of saturn and it's moons with my 8mm hyperion, this is the guy ;

http://www.myastroshop.com.au/produc...asp?id=MAS-243

note though that an 8mm on the CPC is 350x, which is rather extreme and i think i was lucky in terms of atmosphere conditions that morning (at 3:30am i think!).

I'm not really an expert on them though so other people may have better suggestions. If you swing past my house one night when it's clear you can borrow it to give it a try. I also have a 11mm televue and a 3x williams optics barlow you could try.

I'll tell you what, you give me your Evo on a dirt track for a few hours and you can have the 8mm haha