asaint
Carpal Tunnel
Reged: 04/25/03
Posts: 2021
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14.5" Mag 1 Instruments Portaball
Edited by jrcrilly (10/24/06 10:15 PM)
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Todd
Pooh-Bah
Reged: 02/23/04
Posts: 1381
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The Portaball's really are an ingenious scope. I feel fortunate that I was able to get a 12.5" at a good price last summer.
You'll enjoy having the tracking platform. As you've seen, the Portaball's do move smoothly, even at high powers, but a platform makes it even more enjoyable.
You'll be loving that scope for a long time!
Todd
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erik
telescope surgeon
Reged: 01/30/04
Posts: 24019
Loc: Hawaii 19 N lat -155 Long.
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nice article! it's amazing how portable those scopes are, guess that's why they're called "portaball's"! seriously though, beautiful scope! 
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-Erik Wilcox
Homebuilt 16" Truss Dob
SV 80mm ED Nighthawk NG on M1 ALT/AZ
Nikon Prostaff 65mm spotter on Trekpod
Konusvue 20x80 binos/Peterson pipemount
Orion 10x50 binos
Homebuilt 80mm f/5 refractor
Mirador 60mm f/12 1960's refractor
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wes
scholastic sledgehammer
Reged: 11/13/03
Posts: 977
Loc: Oklahoma
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Hi,
After reading the article on the 14.5 Portaball It occurred to me that the Portaball might be the perfect scope to hand
track and image the ISS, it's unlimited range of motion might be great for tracking the ISS, maybe the owner of
Portaball scopes will loan me one to test out 
Thanks,
Wes Higgins
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square_peg
Postmaster
Reged: 03/26/04
Posts: 23950
Loc: Maple Valley, WA
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Great article and great scope. I dream of one day owning a Zambuto mirror. The bad news; $6652 with the Quik Finder and all other optional accessories.
http://www.mag1instruments.com/14orderform.html
Maybe I'll find out where Jarad goes star partying and follow him around like a groupie! 
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Tom (Pegster)
DSH-8 (GSO Dob)
15x70 Oberwerks
SVP 100 f/6 achro
WO 66 Petzval
Sears Discoverer EQ 60/900
8x42 Regals
History is Philosophy teaching by examples.
Thucydides
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RGM
professor emeritus
Reged: 09/15/03
Posts: 643
Loc: Burks Falls, Ontario, Canada
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The feature I like the most is the ability to rotate the focuser to the most comfortable observing position. Great article, now must go out and buy some lottery tickets.
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Bob
Tak FS78
C8 SCT XLT ASGT
10" LightBridge
Denk Standards and Power Switch diagonal
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Daniel Mounsey
Vendor - Woodland Hils
Reged: 06/12/02
Posts: 2880
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Great scope, the only thing I don't like is that the curved spider is too thick at a 1/8". On Jupiter you can't help but see a halo of light around the limbs.
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Jarad
Post Laureate
Reged: 04/28/03
Posts: 3858
Loc: Atlanta, GA
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Quote:
Maybe I'll find out where Jarad goes star partying and follow him around like a groupie!
Wow, my first Porta-Groupie....
Jarad
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Jarad
Post Laureate
Reged: 04/28/03
Posts: 3858
Loc: Atlanta, GA
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Quote:
After reading the article on the 14.5 Portaball It occurred to me that the Portaball might be the perfect scope to hand
track and image the ISS, it's unlimited range of motion might be great for tracking the ISS
I actually tried this - we had a nice pass of the ISS right by Jupiter last month. Unfortunately, it moves so fast it was really hard. I got a quick glimpse of it, but couldn't keep it in the field. I think you'd really need a computer diven scope with a pretty high slew speed to catch it (and really precise coordnates of your observing spot).
Jarad
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jack savard
sage
Reged: 05/26/04
Posts: 475
Loc: quebec canada
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soory for my ignorance
but how this ball are fix
how this ball move
it is not easy for me to figure how it work may be add some explanation about that is good also
thank for the effort
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nobody made it I AM INTEREST
46,49 N 71,14 O Québec canada 2\L100 2\D100 0\S100
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Anonymous
Unregistered
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Hello,
I own a three years old 14.5" PB. There are some little difference, mine as a bigger mirror cell for example.
Jarad, do you know if your secondary has an offset ? if no, when you look in a cheschire for example, do you see all the primary (in mine I don't see the bottom of the primary in the secondary) ?
I try to track ISS with the portaball, not so difficult with a 26mm (80x) but I think it's necessary to use a filter if you want observe some detail or an higher magnification (but the tracking will be more difficult)
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Jarad
Post Laureate
Reged: 04/28/03
Posts: 3858
Loc: Atlanta, GA
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Quote:
but how this ball are fix
how this ball move
it is not easy for me to figure how it work may be add some explanation about that is good also
The ball is not "fixed" - it sits in the base ring. It is moved by hand, and just swivels in the ring (like a ball-and-socket joint). It is held in place in the ring by gravity, and in place angle-wise by friction. It takes about 3 lbs of force at the UTA end to move the scope (a bit less to mvoe down, a bit more to move up, depending on how it is balanced).
Jarad
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Jarad
Post Laureate
Reged: 04/28/03
Posts: 3858
Loc: Atlanta, GA
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I have sent you a PM on this issue.
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Jarad
Post Laureate
Reged: 04/28/03
Posts: 3858
Loc: Atlanta, GA
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Quote:
Great scope, the only thing I don't like is that the curved spider is too thick at a 1/8". On Jupiter you can't help but see a halo of light around the limbs.
I am not sure how big an issue this really is. I mean, even if you had a perfectly thin vane (0 thickness), they would only look that way perfectly on axis. A 0 thickness vane with 2" width would seem to be 1/8" thick when viewed a bit less than 4 degrees off-axis (or if misaligned by 4 degrees, which isn't much). Even 1 degree off-axis, it will add 1/28th of an inch (and again, aligning the spider vanes to better than 1 degree isn' trivial). That's why some people prefer wire spiders.
Since we can't get 0 thickness vanes, lets say you use .05" spring steel. At 1 degree off-axis, add 0.035, so you're up to 0.085", a bit more than 1/12". Two degrees off, you're up to 0.12", almost 1/8".
So, while I agree that thinner is better, there is a practical limit to how thin you can make a vane, and a non-wire vane will look thicker off-axis. Given all this, I don't think the thickness of these vanes is a critical issue.
FWIW, Peter chose this material and thickness because it is very light (weight for balance is critical), and because it it dampens vibration very well. Even thiner steel vanes would have added significant weight over these, and thin spring steel is, well, springy...
Jarad
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Dave Mitsky
Postmaster
Reged: 04/08/02
Posts: 6281
Loc: Pennsylvania, USA
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I've tracked the ISS and other satellites without undue difficulty using conventional Dobs. The Portaball has the smoothest action of any alt-azimuth telescope that I've used. I once tracked a NOSS pass with a 10" Portaball quite easily.
Dave Mitsky
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Chance favors the prepared mind.
De gustibus non est disputandum.
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Daniel Mounsey
Vendor - Woodland Hils
Reged: 06/12/02
Posts: 2880
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Hi Jarad,
I hear what you're saying, but the reason I know there is a difference is because I've compared them side by side and it's very noticible and it hurts the contrast. I took my 12.5" F-5 Starmaster using just a standard straight four vane Novak spider and even the Novak was producing finer contrast at the limbs. In my partners 12.5" F-5 Portaball, it was really obvious that the thickness of the curve was causing a bright glow around planets. My partners Ed Grissim and John Pons use really thin material for their curves and they beat all of these scopes on pure unsaturated image quality without these halos of light seen around the limbs. I realize the 14.5" has a larger area and thus the spider may not hinder it as much as the 12.5" but until one sees through a thinner vane it's hard to convince people that there is actually a difference. I've tested some really nice curves and they literally kick ..... but it's gotta be done right or else. I see so many observers make a issue out of the top heavy weight of the Portaballs and my partners never has such problems.
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Brian M
sage
Reged: 07/12/04
Posts: 365
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So, what kind of aperture does it take to observe some level of detail on the ISS or Shuttle? Does anyone here image or try to image satellites? I take it an 8" will just resolve a bright dot, more or less, and we are talking about serious aperture here?
Regards,
Brian M
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Jarad
Post Laureate
Reged: 04/28/03
Posts: 3858
Loc: Atlanta, GA
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I have seen shots of the ISS and Space shuttle through an 8" which clearly showed the solar panels of the ISS and the wedge shape of the shuttle. Certainly, it's bright enough to see in any aperture. The hard part is tracking it.
Jarad
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wes
scholastic sledgehammer
Reged: 11/13/03
Posts: 977
Loc: Oklahoma
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Quote:
Quote:
After reading the article on the 14.5 Portaball It occurred to me that the Portaball might be the perfect scope to hand
track and image the ISS, it's unlimited range of motion might be great for tracking the ISS
I actually tried this - we had a nice pass of the ISS right by Jupiter last month. Unfortunately, it moves so fast it was really hard. I got a quick glimpse of it, but couldn't keep it in the field. I think you'd really need a computer diven scope with a pretty high slew speed to catch it (and really precise coordnates of your observing spot).
Jarad
Jarad,
It is difficult to hand track and image the ISS but it can be done, here is my latest image of it taken on 07/09/04
with a 14.5 Starmaster Dob and DMK Firewire camera.
I think the Portaball would be easier to hand track with.
Thanks,
Wes
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Jarad
Post Laureate
Reged: 04/28/03
Posts: 3858
Loc: Atlanta, GA
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Nice shot! I never meant to imply that it can't be done, only that the tracking is the hardest part. An 8", or obviously a 14.5" from your picture, is plenty of aperture.
Jarad
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