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FXDX
member


Reged: 03/29/13

Loc: Good old Europe
Horrible tracking - what´s wrong with my CPC?
      #6066418 - 09/06/13 03:42 PM

hi folks,

after some months i went out again with my cpc9.25 yesterday and today and made bad experience in tracking. i made successfull auto two star alignment with a 26mm crosshair ep using arcturus and deneb. but after finsihing with deneb and pressing enter again the scope did not slew deneb correctly into ep-center but put the star far out of crosshair, nearly out of the field. furthermore the star is moving slowly trough the ep from rigth to left and at the end leaves ep at all.

today i made sky align procdure twice (with deneb, vega and arcturus) and it failed twice! "not matching with internal data..."
made successfull auto two star alignment then but had the same problems as yesterday night (moving objects...).

what´s wrong with my scope? why does it not keep obejects in center?
in spring i was rather happy with tracking. tracking rate is ok (siderial) and local time is correct. should i do a reset? any idea?

thanks for your help and advice!

holger


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brianb11213
Postmaster
*****

Reged: 02/25/09

Loc: 55.215N 6.554W
Re: Horrible tracking - what´s wrong with my CPC? new [Re: FXDX]
      #6066466 - 09/06/13 04:12 PM

Clutches reasonably tight? Tube somewhere close to balanced? Good contact on power supply plug & socket? Battery not close to being totally discharged (if not using a mains power supply adapter?)

Another point: if you have a GPS unit on your scope & don't use it for a long time there is an internal battery which discharges & this can confuse the GPS. The solution to this is, every three months or so if you don't use the scope, connect the 12V power supply to the scope but leave it switched off at the power switch, for 12 - 24 hours. If you use the scope regularly the internal battery will trickle charge whilst in use (but will take 12 - 24 hours to do so if it becomes discharged).


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FXDX
member


Reged: 03/29/13

Loc: Good old Europe
Re: Horrible tracking - what´s wrong with my CPC? new [Re: brianb11213]
      #6066508 - 09/06/13 04:35 PM

thanx brian,

but the time was correct and tracking does not depend on gps. right? will keep the scope hooked on the car battery over night. hope it helps.
(unbelievable that when connected to a power supply whilst a session gps would not work correct...).

clutches were tight, yes. obviously no mechanical problem though.

h.


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cn register 5
scholastic sledgehammer


Reged: 12/26/12

Re: Horrible tracking - what´s wrong with my CPC? new [Re: FXDX]
      #6066565 - 09/06/13 05:19 PM

When people at my Astro Sociey complain about poor tracking I ask if they have aligned using an equatorial mode. Our scope is on a wedge and doing an Alt Az alignment gives very poor tracking.

No idea if this is relevant but it's easy to do.

Chris


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Sorny
professor emeritus


Reged: 03/15/12

Loc: Southern MN
Re: Horrible tracking - what´s wrong with my CPC? new [Re: cn register 5]
      #6066593 - 09/06/13 05:38 PM

Factory resets can "fix" goofy errors, if you've made sure power isn't the issue. Maybe spread the power pin a tiny bit as insurance on a tight fit (assuming the battery wasn't low).

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FXDX
member


Reged: 03/29/13

Loc: Good old Europe
Re: Horrible tracking - what´s wrong with my CPC? new [Re: Sorny]
      #6067230 - 09/07/13 04:09 AM

ps: may be i have too many high trees around my scope at the moment and gps is not linking correctly. but why is tracking velocity too low, are objects slowly moving out of the ep?

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Larry F
Carpal Tunnel
*****

Reged: 05/24/04

Loc: Westchester, NY
Re: Horrible tracking - what´s wrong with my CPC? new [Re: FXDX]
      #6067317 - 09/07/13 07:27 AM

It thinks it's somewhere else. Do a factory reset. I've seen this cure similar problems in friends' scopes.

Charge up the GPS battery by plugging the scope into a power source, no hand control, power switch on (not off), leave at least 24 hours.

Reload your time zone information, check tracking mode (alt/az vs. equatorial), scope level, clutches tight. Wait for it to link to GPS, even if it takes 45 minutes, then do your alignment.

Make sure power supply is giving full voltage if you are using a battery.


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FXDX
member


Reged: 03/29/13

Loc: Good old Europe
Re: Horrible tracking - what´s wrong with my CPC? new [Re: Larry F]
      #6067358 - 09/07/13 08:13 AM

thanx larry,

will consider your advices. what i am wondering about is that hyper fast gps linking my scope does...

i will also try alignment without gps using correct local position and time.


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FXDX
member


Reged: 03/29/13

Loc: Good old Europe
Re: Horrible tracking - what´s wrong with my CPC? new [Re: FXDX]
      #6067369 - 09/07/13 08:25 AM

BTW: can anybody explain the correct gps linking procedure?

after selcting the alignment modus the HC shows "waiting for GPS ... UNDO for leaving...ENTER to confirm..." while the local time is shown.

HOW do i have to act at THIS step of alignment? what does ENTER confirm? linking procedure oder leaving GPS linking?

a stupid question perhaps but i never was sure about what ENTER or UNDO occures...


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SporQ
member


Reged: 09/03/13

Loc: Indiana, USA
Re: Horrible tracking - what´s wrong with my CPC? new [Re: FXDX]
      #6067453 - 09/07/13 09:42 AM

Enter will last location it has in memory. Just start it up and let it sit until it is ready and has found it's position.

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MikeBOKC
Post Laureate
*****

Reged: 05/10/10

Loc: Oklahoma City, OK
Re: Horrible tracking - what´s wrong with my CPC? new [Re: FXDX]
      #6067514 - 09/07/13 10:17 AM

Let the GPS do its thing until AFTER it displays the first alignment star choice. At that point it is telling you it has a full lock and knows where it is.

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AhBok
professor emeritus


Reged: 12/02/10

Re: Horrible tracking - what´s wrong with my CPC? new [Re: FXDX]
      #6068475 - 09/07/13 08:25 PM

Were Deneb and Vega nearly overhead? Stars too near the zenith and spaced as closely as Deneb and Vega do not make good alignment stars. This can cause SkyAlign failure and poor GOTOs regardless of alignment mode. This time of year, stars like Fomalhaut and Caph make good alignment stars.

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FXDX
member


Reged: 03/29/13

Loc: Good old Europe
Re: Horrible tracking - what´s wrong with my CPC? new [Re: AhBok]
      #6068871 - 09/08/13 03:35 AM

yes, nearly overhead. but the distance to arcturus is reasonable i think. nevertehless i will avoid those stars in the future...

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cn register 5
scholastic sledgehammer


Reged: 12/26/12

Re: Horrible tracking - what´s wrong with my CPC? new [Re: FXDX]
      #6068887 - 09/08/13 03:55 AM

Quote:

BTW: can anybody explain the correct gps linking procedure?

after selcting the alignment modus the HC shows "waiting for GPS ... UNDO for leaving...ENTER to confirm..." while the local time is shown.





It's doing what it says, waiting for a GPS link. The GPS module has a built in clock so it knows the approximate time. This helps it find the satellites.
Once it has found one satellite it can update it's local time but it needs at least three satellites to get the position.

If you wait then the GPS should link and the HC will move to the next step by itself.

Turn it on, get to the the waiting for GPS stage and do something else, like fitting the visual back diagonal, and reticle EP while it sorts out where and when it is.

Chris


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A. Viegas
Pooh-Bah
*****

Reged: 03/05/12

Loc: New York City/ CT
Re: Horrible tracking - what´s wrong with my CPC? new [Re: FXDX]
      #6068977 - 09/08/13 07:48 AM

If you are using alt-az I highly recommend downloading this app for your IOS (Iphone, ipad) device, Alt-Az align it will give you the best alignment stars for your specific time and location. The advice about GPS linking is correct, but be aware if your GPS battery is low or the scope has lost its satellite ephemerides it can take a while... In the past i have turned on the CPC at 6pm and just left it turned on until it was dark at 8:30pm... By then after dinner it had found all the satellites... Lastly, check your tracking rate... It should be sidereal, Not lunar or solar... You can find the tracking rate by pressing the menu button...

Good luck

Al


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FXDX
member


Reged: 03/29/13

Loc: Good old Europe
Re: Horrible tracking - what´s wrong with my CPC? new [Re: A. Viegas]
      #6069032 - 09/08/13 08:33 AM

thanx to all! i will check under next CS...



Edited by FXDX (09/08/13 08:38 AM)


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SporQ
member


Reged: 09/03/13

Loc: Indiana, USA
Re: Horrible tracking - what´s wrong with my CPC? new [Re: A. Viegas]
      #6069050 - 09/08/13 08:48 AM

After you get done with going through all these suggestions and you still see bad tracking, loosen your Az clutch and see how it feels when you rotate the scope. That is a lot of friction to overcome and it is a wonder it tracks at all.

The CPC uses a taper bearing on it's pivot axis, but this bearing simply loads itself against the ball bearings in the outside ring of the base, so the preload setting is quite critical. Your telescope was probably built by workers working 12 hour days who want nothing more to just go home, so you can then figure that into quality control.

There is excellent info in this forum and I learned how to improve my CPC very much, but then I like to tinker... It now runs much better than when I bought it.

Best of luck to you.

Cary


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FXDX
member


Reged: 03/29/13

Loc: Good old Europe
Re: Horrible tracking - what´s wrong with my CPC? new [Re: SporQ]
      #6069151 - 09/08/13 09:46 AM

thanxs cary! any link to that info?

holger


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FXDX
member


Reged: 03/29/13

Loc: Good old Europe
Re: Horrible tracking - what´s wrong with my CPC? new [Re: FXDX]
      #6069262 - 09/08/13 10:45 AM

first tiny success in my living room!

go to approach was set to "positive" in ALT but to "negative" in AZM what does not match with my preferred alignment movings which strictly are "up" and "right" keys on HC. no doubt anymore why the scope did not catch a just centered object after pressing "enter" again...

(i am wondering how this happend as i am sure both were set once to positive. very strange...).


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FXDX
member


Reged: 03/29/13

Loc: Good old Europe
Re: Horrible tracking - what´s wrong with my CPC? new [Re: FXDX]
      #6074639 - 09/11/13 09:20 AM

correction: positive ALT and negative AZM was/is still correct. this setting guarantees scope slewing down and to right at the end of slewing what correlates with up and right keys when centering.

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