Replacement Saddle for Vixen Porta Mount

[scarp15]

I would like to follow on from a thread in the review section started in 2015 by Jabeoo1, ADM saddle, an upgrade for a porta mount.

I am considering replacing the saddle on my PortaII mount and have looked into some alternatives. The reasons for wishing to replace are primarily that I dislike the two tightening bolts that tend to scratch and wobble a little when being tightened. Also when assembling my frac into the saddle, it will not always align snugly and the fairly poorly engineered bolts seem to make this worse.  The existing saddle with care does function OK, but there are clearly better alternatives out there. 

Based upon the review and further discussions with James, the ADM (VSAD-TAK8) is a very credible improvement and upgrade. The tapered uniform fit may also eliminate any small trace of vibration that the stock saddle might cause. If using more than one scope on this mount or considering potential future scopes / mounts, then investing in an ADM is completely logical. In my circumstance, I use a compact TV76, attached to the mount with a 7" Revelation Dovetail bar.  As I mainly use heavy 2" and particularly low power EP's, I position the scope relatively forward on the mount and with the tension biting, this facilitates good balance.  The projection of the (6" overall length) ADM saddle actually crosses over the focusing wheel.  I could perhaps move the scope back a little, but I would have to adjust and tighten the tension yet more which I do not really want to do.

Not entirely though ruling this option out, I am also looking at another alternative, a Berlebach Dovetail Clamp with Pressure Saddle. This unit is much more compact, matching the profile of the porta housing mount. Since it comes from Berlebach, it will be very well engineered and looks to be functional and secure (there are a few short reviews). I am in the process of enquiring, but it appears to be compatible with fitting to a Porta Mount. It has however only one locking bolt, but looks better tailored to fit a vixen dovetail bar and will be a marked improvement over the stock version.

Have you considered or have undertaken replacement of a stock Porta Mount Saddle and do you have any opinions on these two models or any further alternatives suggestions?

Below is a picture of my frac on the mount and a template I made to match an ADM saddle.

 

 

[scarp15]

Just to conclude this thread for anyone who is reading and thinking on similar lines.

Except for the ADM (VSAD TAK-8), there are no other alternative replacement saddles, that I am aware of, for a porta mount. There was, profiled on Cloudy Nights back in 2013 an ADM DV series saddle - DVPA - Porta mount, which was a compact, one locking bolt version of the standard saddle, complete with two specific fixing bolts. It looks like this is no longer in production. The Berlebach adapter, which I have mentioned is not compatible with bolt size (M6 in which M8 is required).

[dobbie]

Hi scarp , I have the same set up a tv76 and a porta 2 mount , I am interested in the dovetail fitting you use , do you have a photo of it? . As for the saddle I don't have a problem with balance as I only use 1.25 eyepieces at the moment  and I use the televue dovetail which fits perfectly in the vixen saddle , I also have a ADM saddle which I use on my ayo ako mount never thought of putting it on the porta mount but might give it a go to see if in future I might have to move the scope forward to balance it .Regards John.  

Ps I will add photos of mine and the porta mount/saddle  .

Edited February 26, 2017 by dobbie

[iPeace]

On 2/19/2017 at 20:29, scarp15 said:

Not entirely though ruling this option out, I am also looking at another alternative, a Berlebach Dovetail Clamp with Pressure Saddle. This unit is much more compact, matching the profile of the porta housing mount. Since it comes from Berlebach, it will be very well engineered and looks to be functional and secure (there are a few short reviews). I am in the process of enquiring, but it appears to be compatible with fitting to a Porta Mount. It has however only one locking bolt, but looks better tailored to fit a vixen dovetail bar and will be a marked improvement over the stock version.

These are absolutely lovely. Haved used them to hold a TV85 to an Ercole; should do you fine.

EDIT: sorry, only now do I read that the bolt size is wrong. My sincere apologies.

Edited February 27, 2017 by iPeace

[iPeace]

TS do a nice one - see pic:

[Racey]

7 hours ago, iPeace said:

TS do a nice one - see pic:

Mike, might I enquire as to where you sourced the "tripod extension pier" (between tripod and mount) please ? 

[iPeace]

1 minute ago, Racey said:

Mike, might I enquire as to where you sourced the "tripod extension pier" (between tripod and mount) please ? 

Sure, give me a few minutes, I'll get back to you.

[iPeace]

29 minutes ago, Racey said:

Mike, might I enquire as to where you sourced the "tripod extension pier" (between tripod and mount) please ? 

PM sent.

[scarp15]

15 hours ago, dobbie said:

Hi scarp , I have the same set up a tv76 and a porta 2 mount , I am interested in the dovetail fitting you use , do you have a photo of it? . As for the saddle I don't have a problem with balance as I only use 1.25 eyepieces at the moment  and I use the televue dovetail which fits perfectly in the vixen saddle , I also have a ADM saddle which I use on my ayo ako mount never thought of putting it on the porta mount but might give it a go to see if in future I might have to move the scope forward to balance it .Regards John.  

Ps I will add photos of mine and the porta mount/saddle  .

Hi Dobbie, I look forward to a picture of your porta mount / saddle configuration. My dovetail fitting is the 7" Revelation - Synta CNC Dovetail, which has a 5" rail very suited for fitting the TV76. Purchased from Telescope House, where it is still listed, but currently I think  out of stock, I will see if I can get some pictures later.

I have a ADM adapter incoming. Ordered through FLO, who have been very helpful, the ADM - DVPA TAK -D dovetail plate adapter, which is 4" wide and with one locking knob, is compatible with the spacing and bolt size on the mount head. I will report more on this when received. Some pictures show this with a T-Bar, it however has the standard locking knob and can be best seen on the ADM website.

[dobbie]

hi scarp i have had a play around with the saddle combo's, and i have solved the tv76 balance problem, swap the saddles.. i might make this a permanent solution .with the adm saddle i can move the tv76 forward and if i fit a dovetail it will go forward even more .the televue/vixen dovetail that i have wont allow me to do this as it has two end flanges that protrude out . 

the balance was spot on with the focuser racked out and a 2" diagonal and 2" ep  as you can see from the photos .i need to find a pic of that dovetail you use . john . 

ps the porta saddle fits my ayo bonus!!

[iPeace]

3 minutes ago, dobbie said:

 

Love that scope.

[dobbie]

Hi I peace... yep it's a beauty..

[Helen]

46 minutes ago, dobbie said:

hi scarp i have had a play around with the saddle combo's, and i have solved the tv76 balance problem, swap the saddles.. i might make this a permanent solution .with the adm saddle i can move the tv76 forward and if i fit a dovetail it will go forward even more .the televue/vixen dovetail that i have wont allow me to do this as it has two end flanges that protrude out . 

the balance was spot on with the focuser racked out and a 2" diagonal and 2" ep  as you can see from the photos .i need to find a pic of that dovetail you use . john . 

ps the porta saddle fits my ayo bonus!!

Nice set ups 

A couple of questions if you don't mind... Is that a Horizon tripod you are using for the vixen?  If so how have you attached it?  And secondly,  what is the extension under the (rather lovely, drool!!) AYO?

Thanks

Helen

[dobbie]

hi helen you have a keen eye... it is the horizon  tripod and its a vixen tripod adapter from flo.. take the old one and replace it with this . 

the tripod extension is from astro macanic from ab&s he's on there small ads. its 10" tall more manageable than the skywatcher ones .. but at £130 a tad expensive  hope that helps helen .. john 

[Helen]

2 minutes ago, dobbie said:

hi helen you have a keen eye... it is the horizon  tripod and its a vixen tripod adapter from flo.. take the old one and replace it with this . 

the tripod extension is from astro macanic from ab&s he's on there small ads. its 10" tall more manageable than the skywatcher ones .. but at £130 a tad expensive  hope that helps helen .. john 

Thanks John   A friend has a horizon, but for me the head is the weak point (the tripod is robust and easy to use).  Combining with a nice porta head would be attractive.  

Helen

[scarp15]

Hi again John, here are a couple of pictures.

 

[dobbie]

Hi scarp, yep that's looks the job will have to have one of them thanks for the pics 

John. 

[scarp15]

There was also a similar profile ADM Vixen type dovetail bar that would fit if still available though more expensive. How is your ADM saddle for clearance with the TV76 to operate the focusing wheel?

[dobbie]

hi scarp it just misses the saddle so can go forward right up to the limit where the focusing wheels would touch the mount . 

john.

[John]

On 28/02/2017 at 11:42, scarp15 said:

Hi again John, here are a couple of pictures.

 

I use that sort of approach for all my fracs. It's dead useful to be able to simply slide the OTA back and forth as needed. You just need to put a supporting hand under the OTA as you loosen the DT clamp, for security.

 

Edited March 1, 2017 by John

[scarp15]

My ADM clamp arrived today, unfortunately the supplied bolts are the smaller M8 type. The fixing holes compatible with the clamp are the larger type on a horizontal plane on the mount head. Would anyone be able to confirm this bolts spec please and if possible where I could obtain from?

 

[Davey-T]

Those ones you have already look like M6 so you may need M8, loads on EBay

Dave

[scarp15]

Yes I think that you are right Dave, so M8 cap head hexagon screws, cheers.

[scarp15]

I have fitted the ADM (DV) Dovetail Adapter to the porta mount head. The fixing bolts as Dave had suggested were easily and very promptly sourced via ebay at negligible cost (£1.79 for a pack of four). The 12mm length is in keeping with the supplied bolts, I would expect that 14mm will also fit.

http://www.ebay.co.uk/itm/111886065887?_trksid=p2060353.m2749.l2649&var=410851258986&ssPageName=STRK%3AMEBIDX%3AIT

The clamp works very smoothly and grips the dovetail bar very securely and I consider that this is a worth while upgrade for consideration for porta mount users. Here is a picture of the newly fitted saddle and with the mount dressed up.

 

[robbymain]

On 19/02/2017 at 19:29, scarp15 said: I dislike the two tightening bolts that tend to scratch and wobble a little when being tightened. Also when assembling my frac into the saddle, it will not always align snugly and the fairly poorly engineered bolts seem to make this worse

That's interesting to read as I've just taken delivery of a Porta 2 and the Dovetail Clamp Knob and Safety Screw are very sloppy fits - almost as if the threaded holes are a size bigger than the shafts... Definitely expected higher quality engineering for a mount that cost nearly £300!