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Portaball - new owner with questions

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#1 mjgillen

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Posted 10 October 2020 - 06:41 PM

Hello fellow Portaball owner I am the new owner of an older 12.5" f4.8 Portaball and of course I have a few questions. First light will be in a couple of hours :-) The guy I bought this off of said he purchased it used about 15 years ago.

 

1) If there is a manual that covers these questions please point me to it!

 

2) How do I remove the primary? Instructions with photos will help a lot. The fan isn't working and I have 12v from the battery that came with it so I am looking to remove the primary so I can check the wiring and fix it.

 

3) This scope came with a very old JMI focuser that uses metal screws to retain the eyepiece which is not for me. I am looking for a recommendation for a drop-in replacement that is a decent two-speed Crayford-type focuser with brass rings to hold the eyepiece. Needs to handle both 2" and 1.25" eyepieces.

 

4) Anyone have an idea how old this one is?

 

5) Anyone have an idea what mirror is in it?

 

6) Looking for a recommendation on recoating service. I live in So Cal.

 

7) Is there a Portaball user group, website, forum for us owners? I know the Mag-1 site is down and he's really really really busy.

 

Thanks guys! Can't wait to try it out, take it apart, fiddle about.

 

Clear skies,

Michael

 



#2 areyoukiddingme

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Posted 10 October 2020 - 06:57 PM

Hello fellow Portaball owner I am the new owner of an older 12.5" f4.8 Portaball and of course I have a few questions. First light will be in a couple of hours :-) The guy I bought this off of said he purchased it used about 15 years ago.

 

1) If there is a manual that covers these questions please point me to it!

 

2) How do I remove the primary? Instructions with photos will help a lot. The fan isn't working and I have 12v from the battery that came with it so I am looking to remove the primary so I can check the wiring and fix it.

 

3) This scope came with a very old JMI focuser that uses metal screws to retain the eyepiece which is not for me. I am looking for a recommendation for a drop-in replacement that is a decent two-speed Crayford-type focuser with brass rings to hold the eyepiece. Needs to handle both 2" and 1.25" eyepieces.

 

4) Anyone have an idea how old this one is?

 

5) Anyone have an idea what mirror is in it?

 

6) Looking for a recommendation on recoating service. I live in So Cal.

 

7) Is there a Portaball user group, website, forum for us owners? I know the Mag-1 site is down and he's really really really busy.

 

Thanks guys! Can't wait to try it out, take it apart, fiddle about.

 

Clear skies,

Michael

Welcome to the club! I'll attempt some answers . . . 

 

1. I have a manual, and I may be able to take pictures and email it to you. But suspect you'll do better just getting answers on here. For example, the collimation instructions are off, and the older scope shipped with center dotted secondaries--which actually puts collimation off from optimum. In any case, PM me . . . 

 

2. Primary is a little bit of a bugger first time--harder to get in than out. If yours is the same as mine (I'm circa 2003 I think), then you'll find three aluminum strips that come out of the bottom of the cell, and that are screwed into the top-mounted bolts.

 

Remove the three collimation screws, and the whole cell will drop to the bottom of the sphere. Rotate the cell a few degrees, and lift it out.

 

3. I don't know what the mounting situation will be with that focuser, so best to hear from someone who has done that.

 

4. Sounds like older than mine, so at least earlier than '03. 

 

5. I assume most have Zambuto mirrors, but F5 was what I thought was standard. If it is Zambuto, you'll see etching on the primary that identifies it clearly.

 

6. Carl Zambuto re-coats his mirrors, so if it is his I'd try him. But Ostahowski does coating, and I think is quite near.

 

https://www.ostahowskioptics.com/

 

7. No idea, but here seems about as good as you can do as you'll find several owners, as well as people who know the owner personally.

 

Good luck!



#3 mjgillen

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Posted 10 October 2020 - 07:36 PM

Thanks for the reply Scott!

 

I'll try removing the primary tomorrow. Going to take a peek at Jupiter in an hour or so...

 

I think that the new Portaballs are shipping with the Feather Touch LW which is $565 yikes! I'm going to call JMI on Monday and see if they can retrofit this focuser for what I need. Can't hurt to ask...

 

I'll inspect the mirror when I take it out. My top piece says 12.5" f4.8 so that might be an indication of its date of manufacture and what mirror is inside. The seller thought it might be a Wilkinson mirror...

 

Thanks for the recommend on the re-coat.

 

I'm sure I'll have more questions later.

 

Michael


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#4 Bill Jensen

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Posted 10 October 2020 - 08:40 PM

I owned one of the "original" 12.5 f/4.8 P-balls. It had an aluminum ball, with a seam around the ball. It had a Galaxy mirror, if I recall correctly.   Pete Smitka  (RIP) changed to the fiberglass ball with holes in the ball to facilitate cooling, and eventually used Zambuto mirrors for his source. There used to be a Mag1 yahoo group, but when yahoo shut those down, I don't know if it shifted to the i.o groups that sprang up in their place. If your ball is aluminum, it is the first generation of that scope. I owned mine in the 1990s. 

 

Pete's electrical systems were...a challenge .  (I also owned a 10 and an 8 inch P-ball and they all had some electrical issues of some sort)). If you get a hold of Dave Jukem, the current owner of Mag1, by phone, he will be able to support some of your questions and concerns, and perhaps provide some upgrades. 

 

if you take some measurements of the holes for the focuser, you may find a slightly cheaper alternative at Moonlight as opposed to the Feathertouch, but the FT focuser is pretty sweet. 

 

The scope itself was robust, and easy to use, especially overhead where normal dobs run into Dobson's hole. 

 

When the movements on the ball became a bit too stiff, a very small amount of turtle wax improved things on the aluminum ball. I really didn't have any issues with the fiberglass balls on the 8 or the 10. 

 

If you have some balance issues with heavier eyepieces, a beanbag weight can work well, even placed inside on the bottom of the ball. 


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#5 mjgillen

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Posted 10 October 2020 - 08:51 PM

Thanks Bill. My ball is fiberglass, not aluminum. Although it has some dents in it?

 

Thanks for the advice on measuring the holes on the focuser. We shall see what the Universe has in store for me in that respect.

 

I'm pretty handy electrically so not worried about fixing the fan problem. A quick look and its simple wiring. Just need to pop off the primary and trace the fault.

 

Just took a look at Jupiter even though sunset was only moments ago. Mirror seems nice. I don't want to scratch the barrels on my Nagler so I'll just use some cheapo eyepiece I have lying around for terrestrial with my TV-85. Can't want to get a good focuser and get the mirror recoated... this thing will shine!

 

Michael



#6 Bill Jensen

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Posted 10 October 2020 - 09:00 PM

Michael, that means that your scope is a more recent vintage, and if it is a Zambuto, a gem. 

 

you may have already read this article 

https://www.cloudyni...struments-r1556


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#7 mjgillen

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Posted 10 October 2020 - 09:08 PM

Thank you Bill I had not found that article yet. Will give it a detailed read now...

 

Michael



#8 Jon Isaacs

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Posted 11 October 2020 - 08:38 AM

Michael:

 

Is your JMI focuser a single speed or a two speed?  The two speed DX-1s are a bit odd in that one side is the coarse focus and the other fine focus but they are very good Focusers and long lived.  The single speeds are good Focusers too,.

 

The metal screws can be replaced with nylon screws.  The stock screws are 6-32s, I retap the holes to 8-32 because the 6-32s are a bit small.  You may loose a bit of inward focuser travel.  I'm not sure about that. My two JMIs are in the high desert and I won't see them until tonight or tomorrow.

 

I also use a different 2 inch to 1.25 inch adapter. 

 

JMI had their new series which used the same mounting holes, I'm not sure if they still ,make them.

 

If you do buy a new focuser, watch the weight and racked in height. JMIs are low profile and Portaballs are sensitive to balance.

 

Jon 



#9 mjgillen

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Posted 11 October 2020 - 08:43 AM

Thank you Jon much appreciated. I will do as you say and report back here.

 

Michael

 

<edit>

 

Jon, appears to be a single speed focuser. I tried both knobs they seem to move it the same speed. I agree seems like a decent focuser will give it a go for a while. Thank you for the suggestion on using a different adapter I have a couple of those that will work and they are the compression type so my concerns have disappeared with this focuser. Once I get the mirror cleaned and collimated I'll try my good eyepieces and report back.

 

Thanks again!

Michael


Edited by mjgillen, 11 October 2020 - 09:20 AM.

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#10 mjgillen

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Posted 11 October 2020 - 08:44 AM

Had first light with the Portaball last night and it looks good. I believe its way out of collimation however could still see pretty good. So the goal today is to clean the primary, fix the fan, and collimate for another viewing session tonight. So I took the primary out so I could work on the fan and I have a few questions for those that know.

Here's a photo of the massive 2" mirror. My question is how should I proceed to take things off the primary. Looks like I could undo three screws that are holding the primary's holder to it and that should be all I need however it also looks like the cell holder has some adhesive to the mirror as well. Once I get the mirror off I can look for any manufacturer's markings.

 

Also, my Portaball IS aluminum. So still trying to date this thing.

 

Thanks for all the help guys!

Michael

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Edited by mjgillen, 11 October 2020 - 08:46 AM.


#11 mjgillen

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Posted 11 October 2020 - 08:47 AM

more photos...

 

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#12 mjgillen

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Posted 11 October 2020 - 08:47 AM

last one

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#13 mjgillen

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Posted 11 October 2020 - 10:16 AM

Figure by J C Wikinson #MAG1-2 F.L. 59.3" inscribed on the bottom of the mirror smile.gif


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#14 Bill Jensen

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Posted 11 October 2020 - 10:29 AM

Michael, 

based on this (among other) threads, you may want to reach out to GeneT, who I believe currently owns the same vintage P-ball as yours. 

https://www.cloudyni...der-portaballs/

 

That said, I recall that Pete used some sort of RTV , similar to what Aurora Precision uses on their cells, 732 Dow silicone 

https://www.aurorap.com/az-mirror-cell

 

Sorry my memory about the internals is limited, as I have not owned the scope for decades. 



#15 mjgillen

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Posted 11 October 2020 - 12:28 PM

Thanks I contacted Gene. He says the mirror is glued onto the cell so quite the project to separate the two and then reglue. I'll skip that part and just clean it with a spray bottle.

 

Michael


Edited by mjgillen, 11 October 2020 - 01:13 PM.


#16 Jon Isaacs

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Posted 11 October 2020 - 01:38 PM

Thanks I contacted Gene. He says the mirror is glued onto the cell so quite the project to separate the two and then reglue. I'll skip that part and just clean it with a spray bottle.

 

Michael

Myself, I would clean it the normal way with it in place and just make sure everything dries out.  I would remove the electronics box.  

 

I use this technique:

 

https://youtu.be/9Y8xFnXFVGQ

 

Jon



#17 areyoukiddingme

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Posted 11 October 2020 - 03:17 PM

Seems you are a morning guy, so you've probably figured this out. . .

 

The side mounted battery should be pretty easy. Mine was similar and just held on by one or two bolts.

 

If all you are doing is replacing the fan, the primary should stay mounted with the RTV in place. You'll only want to take that off to prepare for a recoating.

 

The fan should also be easy to follow with a couple of wires leading underneath, and four screws holding in place in a hole under the mirror.


Edited by areyoukiddingme, 11 October 2020 - 03:21 PM.


#18 areyoukiddingme

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Posted 11 October 2020 - 03:26 PM

Here's a picture of my wood cell with primary removed. Similar to yours it seems, but not identical.

 

Hmm, it may have been necessary to remove the primary to get at the fan. Is that what you are finding?

 

If that's the case with yours, you'll find that you'll most likely need to undo the cell mounts under the primary. They'll stay glued onto the primary as you lift it off the cell.

 

But there's also the problem of the side mountings. You could undo those, possibly, but you may need to get the RTV off.

 

If that's the case, you'll need floss. And it'll be 24 hours or so before you are back in business.

 

PB cell.jpg



#19 mjgillen

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Posted 11 October 2020 - 04:36 PM

Thanks Scott!

 

No I am not going to remove the mirror from the cell holder looks to hard. Your setup slightly different than mine however similar. I did a quick clean with a spray bottle and that's good enough for now it really needs a recoat so I will remove it completely then. I have an email into a recoating company to see when I can send it in etc etc. Gonna try it under the stars again tonight sans collimation tools so will have to eyeball it using the star method. Should be good enough.

 

I have the fan working outside the ball so next I will put the mirror+cell back into the ball and see if the fan still works when connected to the ball wiring. If not I can debug it I'm OK with electrical. Charging the battery now with my Optimus-6.

 

 

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#20 Don W

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Posted 11 October 2020 - 05:02 PM

Jerry Wilkinson worked for Galaxy Optics and his work is very highly regarded.



#21 areyoukiddingme

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Posted 11 October 2020 - 05:09 PM

Might just be the old lead acid battery is needing replaced.


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#22 areyoukiddingme

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Posted 11 October 2020 - 05:19 PM

Also, sounds like collimation is the next consideration?

 

What tools are you working with? If you don't have much experience with that, fire away, I'm sure someone here will give you a good suggestion to get it in the ball park.



#23 mjgillen

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Posted 11 October 2020 - 05:35 PM

The seller said he just replaced the battery (it looks new) however he did not have time to charge it. I got a Mag-1 charger for it will give it a try later after I verify that the rest of the electrical is working. There's not much electrical on this... just the fan and an LED (not really sure why there's an LED but whatever).

 

I'll be fine collimating. This is my third DOB.

 

Thanks for all the advice!

 

Michael



#24 mjgillen

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Posted 11 October 2020 - 06:10 PM

Got it put back together and the fan works yay!

 

 

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#25 peleuba

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Posted 13 October 2020 - 03:56 PM

Nice to see these old Portaballs get fixed up and put back into service.  These are the finest visual-only telescopes in their aperture class - DSC's not withstanding.

 

The OP has version 1.0 of the wooden mirror cell.  Scott (areyoukiddingme) has version 2.0 of the cell, still made from wood.  The mirror, as has been determined, was sourced from Galaxy Optics and should be terrific.

 

Choose a coater wisely.  There are only a small handful of coaters that I would choose today to recoat my glass.

 

The more recent cells, from the mid-2000's or so, are now made from anodized aluminum.  All the cells, regardless of materials work.  The OP has a full thickness mirror which does not require a complex mirror cell.  Peter could make the wooden cells himself, so he did.  When the move to thinner mirrors occurred, a floatation system with spherical bearings was used.  It was easier to have Dave Jukem make the cells out of aluminum because at the time he was providing most of the other parts to Peter for the scopes.  Silicone RTV is fine to use and is needed to hold the mirror in place on the cell.  Only very small amounts of silicone are needed.  I've attached several mirrors and have used clear GE silicone with great results.  There is no need for a boutique, hard to source, brand of silicone.   

 

As is commonly known on the Smitka-era Portaballs, the electrical system can be a headache to troubleshoot.  This is because no two scopes were wired exactly the same.  The good news here is that this Portaball does not appear to have the "upper-electrical package" as it was an optional upgrade during the early years.

 

A couple of upgrades I would consider making:  (1) Improved Truss Tube Connectors for the sphere.  (2) Replace the secondary mirror as its most likely geometrically center-dotted which is wholly unnecessary and hinders effectively centering the secondary mirror optically under the focuser.  Plus you can get a supremely accurate secondary that may not have been available back in the day. 

 

These are simple, well made telescopes that move like a dream.  I use one on an EQ Platform and its the one telescope that I will never let go of.  A good friend of mine, who may be reading this, has both models of the PB8 - the F/5.5 and F/6.   They are potent observing packages.  


Edited by peleuba, 13 October 2020 - 03:59 PM.

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