Jump to content


Photo

Pushing the CGEM

  • Please log in to reply
4 replies to this topic

#1 kpendlebury

kpendlebury

    Vendor Main Sequence Software

  • -----
  • Vendors
  • Posts: 233
  • Joined: 12 Nov 2008
  • Loc: Central TX

Posted 05 September 2009 - 05:03 PM

Hi All,

Being that the CGEM is a fairly new mount, there does not seem to be a lot of talk about "actual" CGEM weight limits. Of course, the manual states 40 pounds as the limit and I was curious to see what others are actually getting.

I ask mainly because, the setup I am looking at is very close to this limit at 39+ pounds, as follows:

C11, 80mm Stellarvue (piggy back) and various combinations of diagonals EPs and cameras (the heaviest of which comes to a total of 39 pounds).

Any thoughts as to how well the CGEM will function when pushed to its upper limit? Vibration issues? Any veterans of Synta gear know if this will significantly shorten the mechanical life of the mount?

Thanks,
Ken

#2 rmollise

rmollise

    Hubble

  • *****
  • Posts: 15396
  • Joined: 06 Jul 2007

Posted 06 September 2009 - 09:29 AM

Hi All,

Being that the CGEM is a fairly new mount, there does not seem to be a lot of talk about "actual" CGEM weight limits. Of course, the manual states 40 pounds as the limit and I was curious to see what others are actually getting.

I ask mainly because, the setup I am looking at is very close to this limit at 39+ pounds, as follows:

C11, 80mm Stellarvue (piggy back) and various combinations of diagonals EPs and cameras (the heaviest of which comes to a total of 39 pounds).

Any thoughts as to how well the CGEM will function when pushed to its upper limit? Vibration issues? Any veterans of Synta gear know if this will significantly shorten the mechanical life of the mount?

Thanks,
Ken


Shorten the life? No, not as long as you keep things balanced. It will handle an 11 with a guidescope, but I'd suggest some vibration suppression pads under the tripod. Visually, no problem even without the pads. Imaging? I prefer a C8 for imaging anyway. Not only does it not begin to stress out my Atlas (which is, for all practical purposes, the previous model CGEM), I get a wider field as well.

#3 jtaylor996

jtaylor996

    Viking 1

  • -----
  • Posts: 842
  • Joined: 02 Sep 2008
  • Loc: North Texas

Posted 06 September 2009 - 04:59 PM

You'll be fine. I use an Atlas, with a C11, and an 80ED guidescope on an ADM (4" Losmandy D style) side by side setup. Imaging is great, but I do use the vibration pads. It wasn't too bad without them, however (I guess I just had $40 burning a hole in my pocket...).

I never even tried it without the ADM 4" saddle and dovetails. You probably shouldn't either.

I use 3 11# counterweights, and then a magnetic homemade thing I slap on the bottom of the other counterweights (it does dual use on my dob as well), that adds another 7# or so, but out at the end where it counts more. That guy is 2 2.5# small barbell weights epoxied to to 2 90# magnets set next to each other (so I get enough surface area to attach it to my curved dob). I used to use just one of those weights on each of those magnets, and then stack them on the bottom, but the epoxy didn't last the cold last winter on those (the side by side gets more epoxy surface area between the weights, and between the magnets). Lastly, The magnet side that attaches to my dob tube or the bottom cw is coated in silicone so it doesn't scratch stuff (it'll still pinch if you're not careful! 180# of pull with about 7# behind it can be nasty).

I'm sure you don't care about my DIY CWs, but I've never had a reason to describe them to anyone before. I sure like 'em, though. It works a lot better than that fourth 11# CW I would have needed (way up the shaft) to balance things. It's easier to carry for sure!

#4 Lane

Lane

    Soyuz

  • -----
  • Posts: 3586
  • Joined: 19 Nov 2007
  • Loc: Frisco, Texas

Posted 08 September 2009 - 05:51 PM

Jtaylor996 - do you have pictures of that setup by any chance? I want to put my ED80 on the mount at the same time as my C11, but can't decide on piggybacking or side by side. Be nice to see what the side by side looks like when implemented. Plus how do you get both scopes aimed the same direction? Are you using a set of those rings with the 3 adjustment screws? If so, which ones?

#5 KevinUK

KevinUK

    Vendor (DSLR-AstroMod)

  • -----
  • Vendors
  • Posts: 782
  • Joined: 22 Aug 2007
  • Loc: N 51'50 W 00'28

Posted 16 September 2009 - 04:39 AM

From what i've read they recommend not going beyond 1/2 the max payload when imaging, although being a anarchist I break the rule continuously! :lol:

I think if your'e well balanced in both axis, then you could probably push the limit to 3/4 or more of max stated load capacity for imaging.

I have a EQ6 Syntrek ( basically a EQ6 Pro without handset) on which I mount my C9.25 Wo 110 ED, 450D DSLR, various adapter, Meade DSI and have no problems.

:question:...was wondering how my mount compares load wise PEC error wise with the CGEM?

Pricewise?






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics