Jump to content


Photo

C11 Is Very Shakey On It's New Pro HD Wedge

  • Please log in to reply
7 replies to this topic

#1 JayTee

JayTee

    Lift Off

  • -----
  • Posts: 18
  • Joined: 06 Dec 2012
  • Loc: Portland, OR, USA

Posted 13 April 2013 - 10:05 PM

A question for all the wedged CPC 1100 users out there,

After my second night using my CPC 1100 on the Celestron Pro HD Wedge, I have noticed that the scope is noticeably less stable, ie a lot more shakey. When the scope is mounted on just the tripod in Alt-Az mode, I could literally rest my head against the scope and it would barely notice, a tiny shake with immediate dampening.

Now with the scope on the wedge, even when I back off from the eyepiece there is still a pronounced shakiness that eventually dampens out if I hold perfectly still, but my slightest move causes it to shake again.

Has anyone else had this same observation/problem on the stability of the CPC 1100 on the Pro HD Wedge?

The wedge is mounted correctly and securely to the tripod, as is the scope to the wedge. All wedge adjustment bolts are also tightened securely.

After studying the new position of the scope on the wedge, I can see that the vibration is most likely cause by the "moment arm" (as measured from the tripod pedestal) is longer and has a different direction gravity vector (in relation to the Az axis), certainly these two factors add to the lower stability.

This could be very disturbing for my upcoming sojourn into serious AP. Any and all opinions are welcome. Thank you.

Clear and steady skies,
JT

Attached Files



#2 Kraus

Kraus

    Apollo

  • -----
  • Posts: 1145
  • Joined: 10 Mar 2012
  • Loc: Georgia.

Posted 14 April 2013 - 12:07 AM


No wedge is without vibration of some sort. My LX-200 is mounted on a standard wedge. I use cables attached to cement ground anchors to minimize vibration. But then, I don't take photographs. I strictly observe. I recommend going with a permanent mount.

#3 Vagus

Vagus

    Lift Off

  • -----
  • Posts: 18
  • Joined: 02 Apr 2011
  • Loc: Ontario, Canada

Posted 14 April 2013 - 10:58 AM

I had a similar problem with my LX200 on a Mitty wedge. I ended up selling the wedge, deforking the OTA and mounting it on a GEM.

#4 Footbag

Footbag

    Fly Me to the Moon

  • *****
  • Posts: 5743
  • Joined: 13 Apr 2009
  • Loc: Scranton, PA

Posted 14 April 2013 - 11:06 AM

Coming from the older version of the wedge to the HD Pro, I saw a big improvement in stability. I do remember having about a 2 sec dampening time after tapping it.

#5 barbarosa

barbarosa

    Viking 1

  • -----
  • Posts: 863
  • Joined: 11 Apr 2010
  • Loc: "lamorinda", CA

Posted 14 April 2013 - 02:31 PM

JT, I am seriously considering this wedge for visual and video and on a pier. If I understand your post you see vibration caused by your movement near the tripod and not by any direct contact with the OTA/mount/tripod. I have some probably unhelpful questions.
Is the wedge in the low or high latitude position?
What surface are you on?
Did you balance or consider balancing the mount to compensate for the different weights of the left and right arm?
Anti-vibration pads? I also have a question that won't help you but might help me. How much higher does the wedge raise the scope with the OTA horizontal? What is your latitude?

I really do hope that there is a solution for the vibration.

Good luck and thanks.

#6 JayTee

JayTee

    Lift Off

  • -----
  • Posts: 18
  • Joined: 06 Dec 2012
  • Loc: Portland, OR, USA

Posted 15 April 2013 - 01:10 AM

Barbarosa:
Thought I'd post an "I'm working on the answers" notice. It's a little more complicated than initially laid out. Check back tomorrow.
JT

#7 Patrick

Patrick

    Voyager 1

  • *****
  • Posts: 11266
  • Joined: 15 May 2003
  • Loc: Franklin, Ohio

Posted 15 April 2013 - 09:00 AM

Back when Celestron came out with their new HD wedge, I wondered how well it would work. There was a lot of hoopla and fanfare over the new design. At the time I had a Mitty wedge which was a very beefy wedge capable of actually holding my CPC1100 without much vibration to speak of. The Celestron wedge is several hundred dollars less than the Mitty. My gut feeling has always been that the Celestron HD wedge would be fine for an 8" CPC, marginal for the 9.25, and probably not acceptable for the 11". You are confirming that.

I know that does not help you right now, but if you're seriously interested in AP with the CPC1100 and it's as bad as you describe, I would send the wedge back for a refund if you can and get a Mitty wedge from OPT. You will not be sorry.

At any rate, that's my take on it. I hope things work out for you.

Patrick

#8 JayTee

JayTee

    Lift Off

  • -----
  • Posts: 18
  • Joined: 06 Dec 2012
  • Loc: Portland, OR, USA

Posted 23 April 2013 - 04:12 AM

Finally had a clear night to mess with this new mounting configuration (the Pro HD Wedge). As it turns out the scope is more susceptible to shaking, BUT after I tuned up the mount by changing the CG (moved the side plates in relation to the wedge plate) and switching where the wedge handle sits in relation to the tripod leg, and making sure all 6 azimuth plate screws were secure, it only shakes a little bit then calms right down. When left untouched the scope is back to rock solid and guides very smoothly.

I do have a confession to what appears to be a lapse in common sense. Right now my scope and I live in a house on a very small lot. I have no front yard or driveway and only a back deck. Yes I said deck, BUT without the wedge in the Alt-Az configuration the scope never moved, I could rest my head against it, I could put one hand on the tripod leg to steady my eye over the EP and the scope did not move. So I didn't expect the wedge would be so sensitive to this type of surface, but apparently it is. Tonight I had it on a solid concrete patio and it behaved as it should. Big sigh of relief.

Clear steady skies,
JT






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics