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CPC 8

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#1 StarsAbove

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Posted 09 September 2005 - 05:45 PM

I just purchased a CPC 8. When I mount the scope on the tripod
I hear a clinking sound and something is rolling around whenever I tilt the scope. It sounds like it's coming from the base. The scope is working fine. I emailed Celestron and they said, not good, send it in for repair. I called the vendor and they said it's a bearing in the fork arm (at least it was on NextStar models) that's used in the find north process. Anybody else hear this noise whenever they tilt tilt the OTA?

Thanx much for your input.

#2 jrcrilly

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Posted 09 September 2005 - 06:38 PM

The NXGPS series scopes did have a level detector that consisted of a small bearing ball rolling in a track. I don't think the CPC would require that, but I haven't examined one closely.

#3 StarsAbove

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Posted 10 September 2005 - 07:19 AM

Thanks. It's too bad Celestron support doesn't seem to know about this. But it sounds exactly like your description, like a bearing in a track. I guess I'll avoid sending it back to Celestron unless something malfunctions.

#4 Patrick

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Posted 10 September 2005 - 09:50 AM

John,

The CPC does include GPS.

Patrick

#5 andersee

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Posted 10 September 2005 - 11:57 AM

There is a tiny bubble level built into the top of the CPC 800 tripod. Of course, the CPC alignment mechanism means that checking whether you are level is not especially important. Regardless, the built-in level (consisting of some liquid with a bubble in it) is perfectly silent. My CPC 800 makes very little noise, even when slewing at maximum. There is certainly no 'clinking' sound, nor sound as if something were rolling around. Bummer! :bawling: You definitely need to send that puppy in for repair.
-Erik

#6 jrcrilly

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Posted 10 September 2005 - 03:48 PM

John,

The CPC does include GPS.

Patrick


Yes - and if it has the "GPS align" mode as a menu option then it will need to have a level sensor. I'm not sure it has that alignment mode. If it does have that alignment mode, I don't know whether it uses the same level sensor as the NXGPS models. I hope to get a good look at a CPC soon.

#7 andersee

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Posted 10 September 2005 - 04:29 PM

There does not appear to be any sort of level sensor in the CPC.

Checking my CPC 800, there is no "GPS align mode" as a menu option or otherwise. After power on, you first select your desired align mode, i.e. 'SkyAlign', 'Auto Two Star', etc, and then press 'Enter'. The GPS then links up to determine the time and your current position. Per the instruction manual for the CPC 8, a level tripod is helpful for SkyAlign, presumably since it has to guess which three stars you just pointed at. For the other alignment methods, it does not appear to matter in the least whether the tripod happens to be level or not.

About a week or so ago I had gone out to the middle of nowhere Utah, which is fortunately not very far from my home :) the sky was cloudless and basically as dark as it gets. I setup on top of a little hill with a great view of the universe. Given the rocks and cactus and whatnot underfoot, my tripod was pretty far off from level. I did an Auto Two Star align and goto worked just as well as when I align on the perfectly level patio in my back yard.
-Erik

#8 jrcrilly

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Posted 10 September 2005 - 04:35 PM

There does not appear to be any sort of level sensor in the CPC.

Checking my CPC 800, there is no "GPS align mode" as a menu option or otherwise.


That makes sense. The level detector was used in the GPS align mode, which violated Meade's "North and Level" alignment property. It didn't have anything to do with tripod head levelling, but was instead a method of establishing the initial attitude of the optical tube. Celestron came up with Sky Align to get away from that problem; that mode doesn't depend on an initial OTA attitude.

#9 spaceydee

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Posted 10 September 2005 - 04:41 PM

I did have a problem with my first Nexstar8i. I don't know from your description if it is a similar problem or not. When I raised up my N8i when I first purchased it something was rattling around in the base. After I had it for about 2 days it malfunctioned - it would stop while rotating as if it were stuck. I was lucky enough that the vendor took it back for an exchange.

#10 StarsAbove

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Posted 10 September 2005 - 07:09 PM

Well, the mystery has been solved. Rather than spend mega bucks sending a brand new scope back to Celestron, I decided to open up the base that the fork arms attach to. I removed the gray plastic cover and found a 1/2 inch long by 1/4 wide steel pin rolling around in the base. Obviously this was not by design. After looking around for a few minutes I found where it came from, the base where the fork arm connects to.
Unfortunately it cannot be put back from that side of the arm because of the angle of the base at that point. It will apparently only fit in from the other side of the arm which would mean I would have to remove at least the cover to the arm. After checking that out for a few minutes I decided it was not worth the risk. I cannot see any purpose for this pin other than to block a hole at the base of the plate where the arm connects. The arm is solidly attached to the base with 4 bolts so there is no worry there. The pin just fills up a hole among those 4 bolts. Everything is back together and working fine.

#11 Rusty

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Posted 10 September 2005 - 08:05 PM

Most likely it's an alignment pin, and wouldn't be needed unless you disaasemble that arm. Hang onto it...

#12 CarlD

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Posted 16 September 2005 - 08:06 AM

Good to hear that you have located the problem. (noise).... I have now had my CPC for abt 3 weeks now and have not experienced any problems so far. I did notice when slewing the higher Rate(9) it would be a bit noisy, but If I slew at a 3 to 6 Rate, no noise at all.... I too am a beginner and the folks here on CL have just been super and willing to help anytime....

Would you be willing to exchange your experiences with using your scope and various eye pieces that you may use, filters, and so on ???

Enjoy the Scope and Welcome to Cloudy Nights....

Carl

#13 StarsAbove

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Posted 16 September 2005 - 09:48 AM

Carl,

Check out my review of the scope so far on the NexStar GPS / CPC Telescopes forum.

David


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