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Vixen Porta II Altazimuth Mount

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#1 meddyliol

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Posted 29 October 2020 - 04:35 AM

Waiting for a Vixen Porta II Altazimuth Mount, ordered from Telescope House. I am wondering whether I have made the correct choice. It seems to have very good reviews generally but is it OK for my Skywatcher Startravel 102. Not sure if the weight would be OK. The tripod seems to be the weak link (as well as the slow motion controls, I have no issue with that as it is easily? sorted). Any info would be appreciated.

 

Thanks

 

Brian confused1.gif



#2 noisejammer

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Posted 29 October 2020 - 04:52 AM

Years back, I used one with my FLT110. This is quite a heavy / high moment 4" but it was marginal until I installed a binoviewer (with light weight eyepieces like the 16T5.) At that point I found it unusable.

 

I ditched the lightweight tripod and replaced it with one I made from maple. This improved things so that the mount was usable but it would still oscillate for a few seconds. On reflection, I could have improved the tripod further but I chose to get a much heavier mount & tripod instead.

 

Overall, I think you'd be much better served by a (used) Quarter Hitch but it might be difficult to find one on that side of the pond. Whatever you select, be conscious that the tripod's torsional stiffness around the azimuth axis is crucial.


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#3 RTLR 12

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Posted 29 October 2020 - 05:34 AM

The mount is rated at 10kg, but I never felt safe with that much weight on mine. I think that 5 kg would be the limit that I would rate it for.  The tripod is definitely a weak point of the mount. I improved my mount’s stability considerably by using on of my CG5 tripods. I do like the mount for light payloads and quick grab n go use.
 

Stan

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Edited by RTLR 12, 29 October 2020 - 05:44 AM.

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#4 Jon Isaacs

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Posted 29 October 2020 - 06:06 AM

Brian:

 

The Skywatcher Startravel 102 is a 102mm F/5 achromat.  The Vixen Portamount 2 will be a fine mount for your scope. It's about the weight and length of an 80mm ED refractor and that's the bread and butter of the Portamount.  

 

I use my 4 inch F/5.4 TeleVue on a Portamount with wooden legs.  The TeleVue weighs 12 pounds and is about 26 inches long, nearly double the weight of your scope.  It's not the ideal mount and if it's windy, high powers are difficult but with your scope, this should not be a problem.

 

I love the mount, I just wish they made a heavy duty version.

 

5976318-NP-101 Boulevard CN.jpg
 
Jon

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#5 Jim Davis

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Posted 29 October 2020 - 07:38 AM

I find no issues with the tripod. It's exactly what I want, something light. It's not a mount for a heavy scope or high magnification. It's a great grab and go mount. I put the pan handle that Agena Astro sells, makes it much easier to control and find objects. That should be a standard feature.


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#6 Jon Isaacs

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Posted 29 October 2020 - 07:57 AM

I find no issues with the tripod. It's exactly what I want, something light. It's not a mount for a heavy scope or high magnification. It's a great grab and go mount. I put the pan handle that Agena Astro sells, makes it much easier to control and find objects. That should be a standard feature.

 

No handles for this guy.. Just gets in the way.  The scope is the handle.

 

Jon


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#7 TOMDEY

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Posted 29 October 2020 - 08:32 AM

I find that the JMI drive makes the Porta 2 great and convenient for solar and lunar imaging. I've collected hundreds of images that way, every clear day for a couple of years when the sun was active. I'll resurrect it for that now. The Lunt 80/80 for H-Alpha and also the TeleVue Genesis 100mm F/5 for white light and CaK. Those payloads are rather heavy, but the mount handles it nicely. Quick, easy, and convenient to swap in the same session, without even losing the tracking.

 

But the stock tripod is deficient. Jon's wooden legs retrofit up there is a great improvement... I'm inclined to do that!    Tom

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#8 Jon Isaacs

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Posted 29 October 2020 - 08:52 AM

But the stock tripod is deficient. Jon's wooden legs retrofit up there is a great improvement... I'm inclined to do that!    Tom

 

 

These are even better but the Portamount is no longer portable..

 

4382689-TeleVue NP-101 on Houston Fearless CN 2.jpg
 
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#9 BlueMoon

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Posted 29 October 2020 - 08:54 AM

I use a Porta II quite a bit with an SW 100ED and I find it works very well. The slo-mo controls are fine but you may wish to install some more flexible cable types. Just take a little time to balance your scope and set the drag. A couple things I did change as "personal preferences". You don't have to do these and the stock Porta II will serve you just fine.

 

If I'm doing high magnification stuff, like splitting binaries, I mount the head on an EQ-3 steel tube tripod (it's a direct bolt-on. No mods needed) like you see in RTLR 12's post above. The stock Porta II tripod is fine at lower magnifications but gets a little shaky higher up.

 

Secondly, if you want to avoid having the Vixen dovetail on your scope pockmarked with mounting and safety screws marks over time (Vanity, vanity, all is vanity), replace the stock saddle with something like a Williams Optics clamping unit: https://williamoptic...tail-plate-90mm

 

I have other mounts, but the Porta II is generally my "grab n go" favorite.

 

Clear skies and be well.


Edited by BlueMoon, 29 October 2020 - 06:06 PM.

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#10 meddyliol

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Posted 29 October 2020 - 11:18 AM

Thanks very much for all of your VERY helpful replies. Mine should be coming tomorrow so will try it with my new 'cheapo' red dot finder as an alternative to my 50mm finder scope.

 

Thanks again

 

Brian



#11 Nippon

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Posted 29 October 2020 - 11:56 AM

From my experience length of the scope is more of a problem than weight. American US Vixen distributors I have seen rate it for 20 pounds but Vixen Japan rates it at 11 pounds. I found mine unusable with the 103mm f/7.7 Vixen refractor. Okay with a rather heavy Stellarvue 80mm f/6 and delightful with my Coronado PST. It is such a nice design I really wish Vixen would produce a Porta DX if you will. A more robust mount of the same design that can handle a typical 4" apo. 


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#12 RazvanUnderStars

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Posted 29 October 2020 - 04:23 PM

I had this mount. One annoyance to be aware of: the slow motion handles kept falling off. Maybe some Loctite would help.



#13 Jim Davis

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Posted 29 October 2020 - 08:26 PM

I had this mount. One annoyance to be aware of: the slow motion handles kept falling off. Maybe some Loctite would help.

Yes, the set screws do not hold them on well. That is a really **** poor design there.



#14 kksmith

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Posted 29 October 2020 - 08:28 PM

I have my Skywatcher 102/F5 mounted on a ES Twilight Nano which is a lighter mount than the Porta II. It works fine for me, but it's at its limit. If my Twilight Nano handles it - the Porta II will easily handle it. My Skywatcher has a 9X50 RACI finder and a Lunt 2 speed Crayford focuser. 

 

Ken




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