My strange Skytee Porta ii Hybrid - now with pics

[digital_davem]

I have my new mount set up. 

It's a skytee 2 fitted to the tripod top plate from the porta, a piece of steel tube and a long 10mm threaded rod acting as a pillar extension, the aluminium legs of the porta tripod replaced by home made wooden ones, and the standard skytee dovetail clamp replaced with the larger two bolt dovetail clamp from the porta!

My telescope is a refurbished and modded Prinz 660 3" long tube refractor with all modern accessories and a new metallic red paint job.

It will now be set to be 100% wet and cloudy for the next 3 months..

 

Dave

 

[John]

Sounds interesting Dave - I'd love to see a photo !

[digital_davem]

2 minutes ago, John said:

Sounds interesting Dave - I'd love to see a photo !

Will do tomorrow.

p.s.

Is it just me or has the forum styling changed. The text is about half the size it was yesterday (8pt?) . Can't see any settings I might accidentally have changed...

[digital_davem]

[Stu]

Ingenious . Looks just the job for that OTA. Your pillar extension looks very much like one I put together a while back which works very well. You'll have fun with that setup.

[iPeace]

This is what it's all about. Great stuff.

[digital_davem]

14 minutes ago, Stu said:

Ingenious . Looks just the job for that OTA. Your pillar extension looks very much like one I put together a while back which works very well. You'll have fun with that setup.

Do you recognise that bit of carbon wrap, Stu? You should :-)

 

[Stu]

9 minutes ago, digital_davem said:

Do you recognise that bit of carbon wrap, Stu? You should :-)

 

Ah yes, I thought there was something familiar about it  

[Paul73]

The price of pretty simple bits of Astro related metal is, IMHO, truely offensive.

Great to see that you're beating the system!!!

It always goes a bit wrong when I try. But, I do have a heafty bit of threaded rod as a counterweight bar on my trusty Sky Tee!

Paul

[Ricochet]

Not what you were trying to show but I like your finder shoes on tube rings. 

[Racey]

Interesting, great minds and all that...

Inspired by a "PM exchange" with Stu I'm part way through gathering the bits to construct one myself. I've gone with a hefty piece of aluminium tube to sit on top of either my Carbon Gitzo Travel tripod or the tripod that came with our AVX. 

All I'm waiting on is my Laser cut "washers" to form top and base plates. 

"Come on Postie... Run, Run, ?"

[digital_davem]

25 minutes ago, Ricochet said:

Not what you were trying to show but I like your finder shoes on tube rings. 

The tubes rings were a £10 for the pair and I had to drill the shoes but only took a few seconds.  Also covers up the dings in the paintwork where I dropped the tube a couple of times :-(

[digital_davem]

Good time for a warning actually. If you decide to repaint a tube and use a polishing machine for shining it up make sure, the tube is properly secured. When the spinning polishing pad meets an unsecured metal tube be prepared to watch your precious telescope disappearing rapidly over the horizon...New paint and all...

[Swoop1]

What timber did you use to build the legs of the tripod?

[digital_davem]

4 hours ago, Swoop1 said:

What timber did you use to build the legs of the tripod?

It was just some cheap softwood from home base. The legs were an experiment , just knocked together crudely but they work well enough I'm wondering whether it is worth the effort to redo them with fancy wood. 

 

[Swoop1]

So, did you replace basic aluminium legs?

is the stability and vibration damping an improvment?

[digital_davem]

7 hours ago, Swoop1 said:

So, did you replace basic aluminium legs?

is the stability and vibration damping an improvment?

Yes.

The aluminium legs are lightweight but weak with a telescoping action secured by a screw clamp plus they attach to the tripod top plate/spider with bolts that go through plastic end pieces.  My DIY legs are not height adjustable but single lengths of wood from top to bottom. The side pieces of each leg are glued and screwed into wooden blocks that make up the centre of each leg. This leads to a heavy and stiff set of legs despite the soft wood used.

It is difficult to mount a long tube refractor, even if it isn't that heavy. The long tube gives a big lever action that means the slightest vibration causes considerable movement of eyepiece and objective.  I started off using a photo tripod and it was wobbly. The porta ii was an improvement, even more so on the wooden legs.  It was perfectly steady if you were just looking through but focusing still caused movement. The jiggling vibration took maybe 7 secs to calm down after every touch and made focusing tricky.

I was hoping the Skytee would make it rock steady. My brief foray so far suggests it is a massive improvement but it is not rock steady. Touching the eyepiece with a 100x lens in cause noticeable movement in the field of view but only for about a second which is manageable. There are still a few things I have to play around with:  adding a spreader to the tripod, adjusting the skytee tension, using the counterweight. 

 

[Swoop1]

Ok. Thanks for the answers.

I have the standard alloy tripod for my 150P Newtonian on an EQ3/2 mount. Swapping the legs out for wooden ones is a DIY mod I would consider as an improvement.

[digital_davem]

11 hours ago, Swoop1 said:

Ok. Thanks for the answers.

I have the standard alloy tripod for my 150P Newtonian on an EQ3/2 mount. Swapping the legs out for wooden ones is a DIY mod I would consider as an improvement.

I have a 130p on an Eq2.  With the legs at their shortest, I find it fine when seated. It's nothing like the challenging of keeping a f/16 long tube achromat steady. Is the 150p so much wobblier?

[Swoop1]

The 150P isn't fantastically unstable. It does have its moments however. It is more that I feel the alloy legs of the tripod are not the strongest of things.

I observe from standing at the moment so have to extend the legs slightly. I suppose it might help if I fixed the accesory tray to the tripod when i deploy it. The reason I don't is that I cant store the tripod with the legs fully deployed, i have to half fold them to fit them into a gap.

[Louis D]

On 3/3/2017 at 15:48, digital_davem said:

Yes.

The aluminium legs are lightweight but weak with a telescoping action secured by a screw clamp plus they attach to the tripod top plate/spider with bolts that go through plastic end pieces.  My DIY legs are not height adjustable but single lengths of wood from top to bottom. The side pieces of each leg are glued and screwed into wooden blocks that make up the centre of each leg. This leads to a heavy and stiff set of legs despite the soft wood used.

It is difficult to mount a long tube refractor, even if it isn't that heavy. The long tube gives a big lever action that means the slightest vibration causes considerable movement of eyepiece and objective.  I started off using a photo tripod and it was wobbly. The porta ii was an improvement, even more so on the wooden legs.  It was perfectly steady if you were just looking through but focusing still caused movement. The jiggling vibration took maybe 7 secs to calm down after every touch and made focusing tricky.

I was hoping the Skytee would make it rock steady. My brief foray so far suggests it is a massive improvement but it is not rock steady. Touching the eyepiece with a 100x lens in cause noticeable movement in the field of view but only for about a second which is manageable. There are still a few things I have to play around with:  adding a spreader to the tripod, adjusting the skytee tension, using the counterweight. 

 

Try putting Sorbothane pads under each tripod foot.  My photo tripod now settles in under a second instead of 3 to 4 seconds.

[Daz69]

I thought of doing wooden legs on my tripod, but I would use beech or oak. It'll be heavy, but the weight should help stability.

[digital_davem]

Had a brief outing in the garden last night before it clouded over. Seems to be quite a lot of movement in both axes of the Skytee.  Even with everything clamped up tight, if I grab the eye piece and wiggle it, the objective end wobbles up and down about an inch! Not smooth movement but simple slop.

I know the Skytee has a bit of a reputation of being quirky but is this just an adjustment issue or should I be thinking of returning it for replacement?