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First Light Celestron CPC-800 GPS

Kenny_10_Bellys

By Kenny_10_Bellys
in Member Equipment Reviews

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Kenny_10_Bellys

Kenny_10_Bellys

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Well, after nearly two months since purchasing the new 8" CPC I finally got the weather and time to take it out for first light. With 5 other members of the Scottish Astronomers club I spent last night on the shores of a reservoir south-west of Edinburgh in the darkest skies I've seen in a year. The Milky Way was a clearly visible band crossing through the zenith and dropping to the horizon on either side, with just some skyglow in the east and north from the nearby towns and city to stop us viewing too near the horizon.

The first thing that strikes you about the CPC is its physical size and presence; it's a bulky, imposing sight from any angle with its wide base and two stocky arms grasping that fat OTA. I'd plumped for the 8" version since I figured anything larger would be difficult to lug out to dark skies, but when I saw the thing out of its box on the first day I thought I was going to need a crane to get it to the car. Fortunately the built-in handles on the side and underside of the arms mean that it's manageable enough over short distances, say from the house to the car, but any further would involve more sweating and cursing than I usually enjoy.

Setting up the scope on site was fairly easy, the large tripod with its 2" wide legs and hefty base unit has a locating pin for the base of the scope to assist you. All you do is plonk it on the central pin and spin the base until it clicks into place, then tighten up the three captive screws underneath. It's a very neat and easy design with no nuts or bolts to drop in the dark, and the base even has a bubble level to help with your setup. Power needs to come from a user-supplied power tank through a ridiculously long lead with a standard 12v cig lighter plug at the end, the coils of which I had to kick out of the way under the scope. I could have run it from any car in the car-park without moving the scope.

Once set up and powered on the GPS kicks in and begins to synch, supplying the scope with date, time and position for setting up the goto. Within a minute it was asking me to begin the sky-align procedure, pointing the scope to 3 widely-seperated bright objects in the sky. Unlike the similar Meade system you dont have to find the stars the system tells you to, you just pick any 3 bright objects yourself. It's a whole lot easier to work with, but having said that it failed the first time I tried and I had to go again with 3 brighter objects before it decided it knew where it was. Once set, the go-to performed consistently throughout the night and would put any requested object within the field of view of a 28mm eyepiece every time. There are many ways to fine-tune the go-to and PEC, but for a first night I was well chuffed with the performance as it was.

First target of the evening was the Andromeda galaxy, since everyone else went to it first as a first object that's relatively easy to find. Unsurprisingly it was a faint fuzzy, the 8" aperture not being up to the task of showing any real lane detail in the disc, but comparision with the 6" and 5" scopes next to mine showed that the central core area was brighter and more defined in the CPC. Next target was the Ring Nebula, never much more than a large star in my old 3" and 4" scopes, but through the 8" CPC it was a clearly visible green ring nebula! Cranking up the magnification made it larger but no clearer, and the central star eluded all attempts at seeing it. The real showstopper however was my first view of the Hercules Cluster through the new scope. Looking through the 5" showed a poorly defined area with few stars, almost a nebula, and the 6" resolved more stars and showed it more like a cluster. Through the 8" however it was like a photograph, stars resolved practicallly to the core and eliciting oohs and aaahs from everyone who looked at it. At the end of the day the dew ended up overpowering the scope and dew-shield, ending the session after 2.5 hours.

Optically the 8" CPC is the best scope I've owned, although that may not be saying a lot. Collimation was very slightly out, but given that I had to drive 45 minutes to the dark site with it wobbling on the passenger seat of my car held only with a seatbelt I'm amazed it was no worse. The focusing system could be a bit tighter, but I was able to get sharp focus easily at all but the highest magnifications. I think a set of Bobs Knobs will have to be ordered if I'm to continue transporting it in such an undignified manner, the collimation wont stand for it. All in all I was very impressed with my new toy, it certainly laughs in the face of my old Meade ETX when it comes to ease of use and sheer resolving power, but it doesn't come cheap. After last night I think it was worth it, but your mileage may vary.

Pros:

Easy to set up

Excellent Go-To system

Very steady tripod & mount

Controller has its own cradle on the arm, very handy

Cons:

Good grief its big

power light on scope too bright, had to cover it

not cheap

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Kenny_10_Bellys

Kenny_10_Bellys

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I agree, reviews and opinions really make choosing a scope more of an informed choice than a simple 'check the specs' excersize. Last night was my first night out with a group of fellow astronomers and the chance to actually check out 5 other setups in the same place on the same targets really opens your eyes. There was a Celestron 130SLT, Nexstar 6SE and an Orion 8" Newtonian set up right next to mine, and I got to see some of the strengths and weaknesses of all the scopes. First and foremost was the old 'aperture is king' bit, which really is true. I didn't think there would be a significant difference between a 5, 6 and 8 inch scope in terms of resolution, but you have to see it to believe it. I think I need a 32" Obsession now...

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gary1968

gary1968

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Great report Kenny, and your right, it was good to get my SLT next to bigger scopes and compare the differences. The views through your CPC were amazing. Cant wait 'till our next session, Paul might even have the 12" dob he wants... ;)

Gary

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barkis

barkis

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Well done on describing your first time out with your new baby Kenny. you must have had a frustration build up having waited two months to get into action. Once you become very familiar with her, she'll do you proud, it's a very fine instrument. What won't show with the mirror and eye, will change dramatically when you stick a camera in there. And then we look forward to images as good as your first light report.

Looking forward to what comes next.

Ron. ;)

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  • 13 years later...
284mnc7

284mnc7

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Nel 2009 comprai il Celestron CPC 800 xlt gps, (ottimo telescopio) ho messo su questo sito delle foto, con una webcam (Lifecam cinema 720p) modificata per astrofotografia, la webcam ha buone prestazioni, uso SharpCap 2.9, (non sono molto bravo sono un principiante) il mese scorso ho comprato una ZWO ASI 385 colore 

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