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Porta ll Mount Head and CG-4 Tripod

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#1 Gary Riley

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Posted 30 November 2012 - 10:12 PM

Will the Vixen Porta ll Mount head fit on a CG-4 tripod, the one with the 1.75 inch stainless steel legs? I have the CG-4 EQ and tripod and was thinking about getting the Porta II mount head to use on it sometimes with my 4 inch f/9.8 refractor.

Gary

#2 Locoman

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Posted 30 November 2012 - 10:53 PM

I can't tell you if the Porta ll head will fit on your tripod but I can tell to about my experience. I have the celestron 102 gt F/9.8 refractor and I have the Vixen StarGuy that is the Porta ll with the Hal-130 heavy duty tripod. I tried the 102 refractor on it and it was very very shaky. The StarGuy handles my C6 sct, ST120 and my C6-N just fine but the longer tube refractor was unsatisfactory. It would take 8 to 10 seconds to dampen down. I can mount the slt mount head that came with the 102 gt onto my Hal-130 tripod and the 102 refractor is pretty steady with about 2 to 3 seconds of damping time. So its not the tripod, its the Porta ll mount head that can't handle the longer tube. My other scopes weigh more than the 102 refractor but they are a lot shorter in length. So I would think you would get the same results using the EQ 4 tripod.

#3 Gary Riley

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Posted 30 November 2012 - 11:49 PM

Thanks Locoman for your reply. The refractor mounted to the CG-4 EQ is a pretty stable system with vibrations dampening out in approx. 2-3 seconds. Just thought I would check around and see what others have experienced before investing money into it.

Thanks again,
Gary

#4 beatlejuice

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Posted 01 December 2012 - 02:23 AM

Gary, the AZ post will probably be in the way, but I got the SVP mount extension from Orion and was able to mount the AT Voyager on top because the post of the mount extension unscrews just for that purpose I presume. A very stable Alt-AZ setup with ability to now keep the CG4 legs permanantly retracted. If the screw size of the Porta II matches the CG4 screw size this would work for the Porta as well.

Eric

#5 Locoman

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Posted 01 December 2012 - 09:38 AM

I have installed on my porta ll the "Manny's dove tail saddle" and so when I used my 102 f/9.8 refractor on it I had to use rings and an 8" dove tail bar because of where the dove tail bar that is attached to the scope made it side way's with the focuser sitting vertical. If I take off the Manny's saddle and use the scope with out it maybe it would be more stable. :question: I'll have to give it a try to see!

#6 Locoman

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Posted 01 December 2012 - 03:16 PM

I got my StarGuy out with the Manny's saddle and pan handle still installed.I attached my 102 F/9.8 refractor with a 9mm eyepiece and focused on a tree limb about 75 yards away. I gave it a good tap on the tube and timed the damping time which was about 9 to 10 seconds. I did this several times with the same results. I then took off the Manny's dove tail saddle with the panhandle and attached the dove tail saddle as it came stock. I attached the 102 refractor and focused on the same tree limb and gave the tube a good tap and to my surprise it dampened in about 4 seconds. I did this three or four times with the same results. To assure myself I put the Manny's saddle back on and off and received the same results. I know this test wasn't under dark skies using stars but I was surprised that the Manny's saddle would result with twice as much shakiness. If the clouds clear tonight I will take it out and test it under the stars. Needless to say I didn't realize this. I would like to know if anyone else who has the Manny's saddle and pan handle installed noticed this! :foreheadslap:

#7 Locoman

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Posted 01 December 2012 - 08:42 PM

The clouds cleared and I got to use the mount without the Manny's saddle and it was more usable. Damping times were about four seconds when I tapped the tube and around two seconds while focusing and adjusting the slo mo controls. I guess the mod puts the scope farther out away from the mount head so that makes it less stable.

#8 Gary Riley

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Posted 01 December 2012 - 11:57 PM

Thanks everyone for your replies! Still pondering it over.

#9 Locoman

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Posted 02 December 2012 - 12:02 AM

Here's a pic of my 102 on the StarGuy.

Attached Files



#10 Chucky

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Posted 02 December 2012 - 06:52 AM

<< I guess the mod puts the scope farther out away from the mount head so that makes it less stable. >>

As the saying goes -- If it ain't broken, don't try and 'fix' it.






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