13 replies to this topic

[Chris MN]

When I was in my late teens in the late 70's, I was gifted a complete Edmund 4.25" Palomar Jr.  From that I built, with commercially available parts, a 6" (Coulter mirror, E&W secondary), f/8 reflector.  Great scope.  From there, I succumbed to the C8/SCT's and sold the 6".  Been using SCT's ever since.

 

Enter this past week. A local ad caught my attention for a Meade 628.  Local ads for decent telescopes are rare in my area.  And as everyone knows, shipping/insurance costs for older, complete reflector telescopes are almost as much as the telescopes are worth. So I felt compelled to at least check this one out.  The current owners did not know much about it or even much about astronomy.  I asked them how they got it.  Apparently, a neighbor (that they didn't really know) left this out for the trash guy to pick up.  They asked if they could take it (rather than the trash guy) and the owner agreed.  Current owners have had it for a couple years but never got into astronomy.  Now they just wanted it gone to free up space and get some holiday cash. The 628 looked to be complete and to my surprise, even had the original owner's manual (copyright 1980).  I peeled off some cash and the 628 was coming home with me.  Now after 40+ years, I had another reflector.

 

Cosmetically, it is dirty and as you can see, the tube has some paint missing. However, the tube is not cracked or damaged and seems to be structurally sound.  I have not pulled the mirror out yet but sure seems clean as well as the secondary so the tube may have had the covers on it most of the time.  Collimation seems to be pretty good but I have not had it under the stars yet.  Finderscope objective is very dirty.  Focuser seems to work just fine as well as the drive.  Mount motion is smooth.  Whole thing is going to get a good cleaning.

 

So I have a couple of initial questions for the 628 owners out there:

 

1. Did the inside of the cradle rings have some sort of felt or padding?  This one has nothing but some duct tape to protect the tube.

2. I know these came with a 25mm and 9mm as standard accessories. This one has two different styles of the "MA" line of eyepieces.  Did Meade do that and, if so, does it help to date this unit?

3. Underneath the end tube ring is the number "371".  What does this mean?

 

 

Even though I use SCT's, I felt this one needed a good home.  From what I read, these are generally decent telescopes.

 

Or maybe I'm trying to relive my childhood as I could never afford one of these at the time......

 

 

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[highfnum]

a scope worth saving as long as mirror is in good shape

[DouglasPaul]

What a awesome deal to come across.

[apfever]

1. Did the inside of the cradle rings have some sort of felt or padding?  This one has nothing but some duct tape to protect the tube.

2. I know these came with a 25mm and 9mm as standard accessories. This one has two different styles of the "MA" line of eyepieces.  Did Meade do that and, if so, does it help to date this unit?

3. Underneath the end tube ring is the number "371".  What does this mean?

 

Even though I use SCT's, I felt this one needed a good home.  From what I read, these are generally decent telescopes.

 

Or maybe I'm trying to relive my childhood as I could never afford one of these at the time......

1. Yes. These had a thin lining more like tape than felt. It was black, very thin, like tape with the top side a fine fiber coating. It did not have any cushy thickness associated with stick on felt. It was an actual stick on lining meant for the purpose of being protective and allowing some sliding like rotating the tube. I have found it on other scopes. A stick on flannel cloth would be comparable.

 

2. Yes, then No. I have these eyepieces in at least two versions. Changes like this are common during production runs of many eyepiece series. Knowing this forum I wouldn't be surprised if some one knows a narrow time when they went from blue/white top print to side print to something else. I wouldn't hold my breath on it though.

 

3. Interesting. I just pulled the top ring off a 628 OTA and found a small "87" and a small "47.9" underneath. The 47.9 would be the focal length (inches) of the mirror, no idea what the 87 is.  I tried to remove an 826 ring but it was stuck on too hard - so far. It looks like the workers used the area to put assembly notes for that particular scope. Vintage Japan refractors often had matching red print on an OTA and an accessory to match a hand drilled mounting or to match a specific optical location. These still comes up in discussion because Japanese workers often used a poetic reference to the parts and pieces that is still open for interpretation. Fun stuff when you take off a part and find the writing underneath. No idea what 371 means. 

 

They Are generally decent telescopes. Maybe you Are reliving some childhood. Nice match.

Edited by apfever, 27 November 2024 - 03:09 PM.

[Chris MN]

Here is a pic of the "371".  No other numbers on the OTA (I pulled off the back one too).

 

Thanks for the responses so far!  Great info!

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Edited by Chris MN, 27 November 2024 - 03:29 PM.

[apfever]

No idea, most likely an assembly number. Maybe a single assembly designation for a set of parts. I tried a few inch and metric conversions for common measurements and didn't a good match. Open forum on this one. 

[Chris MN]

And now the all important primary mirror! Doesn't look too terrible however I haven't seen a reflector mirror in 40+ years so I'm not 100% sure what to look for. Just looks dusty.  The small linear "blob" near the bottom appears to be something on the mirror (used a 8x loupe to inspect).  Hopefully a good cleaning will remove it. Now I have to learn how to clean a primary mirror.

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[Chris MN]

The linear blob just brushed off!  After gently brushing off the mirror, looks like it just needs a gentle cleaning.

 

On the mount, with the OTA off, movement of the Dec axis seems awfully stiff similar to old, stiff grease.  Is it possible to regrease that Dec axis?  I've searched and can't find anything on how to disassemble/regrease the mount (or at least my search wasn't successful).

 

Do these mounts use bushings or bearings?

[apfever]

They have plastic Top Hat type bushings on each end of the DEC housing. Very straight forward.

Remove everything off the saddle including the rings if possible.

Remove the lock knob in the middle of the DEC housing.

Remove everything off the shaft including the setting circle.

You should be able to see the bottom bushing, the brim part of the 'top hat'. 

 

Every divot and ding on the shaft from counterweights and set screws can snag in the bottom bushing as you pull the saddle up.  You can raise the DEC shaft just a little then try to work the bushing out with the shaft as you push the shaft back in. See if you can work the bottom bushing out and remove it. If the bushing is stuck, and you have bad divots in the shaft, you might have to file down the damage on the shaft.  The top bushing can come off with the shaft.  Keep track of which bushing is top and bottom.

 

Meade set bushing clearance by peening inside the housing bore. Sometime these are just tight. You can sand or file the peening ridges down to adjust.  I've had a few of the 826 and Starfinder GEM mounts set way too tight from the factory.  (Starfinder GEM is the same construction and the model that followed the 628 mount)  I had one so tight from the factory that the drive could not turn the DEC shaft even with the clutch tight, it was bound. The original owner barely used it and sold it, the second owner gave up on it. I had to run a sanding drum down the bore to reduce the peening marks pushing on the bushing. 

 

I have a string on the Starfinder that shows the DEC work, same as the 628.  

Here is the LINK to the shaft repair entry. You might want to scan the whole string while there. The 628 is mostly a simplified version of the Starfinder GEM.

Edited by apfever, 29 November 2024 - 10:11 AM.

[NinePlanets]

You have a very nice telescope in the 628. I used to retail them circa 1980. At that time, the included MA25 and MA9 eyepieces had blue and white letters on top.

 

If memory serves, there are plastic bushings in the mount. Either way, be sure to de-rust the dec shaft before pulling it.

 

There is nothing wrong with that mirror. Clean and enjoy. I never saw a bad Meade Newtonian.

 

The black vinyl dust caps not sold by Meade, I forget the name of the outfit who sold them.

 

There is a fellow here on CN who used to work at the Meade manufacturing facility in California. He might chime in soon. I suspect the 371 is a serial number.

[apfever]

 

There is nothing wrong with that mirror. Clean and enjoy. I never saw a bad Meade Newtonian.

 

This is very interesting. There are others that state they never had a bad Meade Newt from this time period. I never had a bad one. All of us having had many personally. No doubt the dogs exist but apparently not much. General consensus from many forum discussions (frequent here) is that Meade had above average QC during this time, mostly when they had in house optics production.    

[Chris MN]

Thanks for the info on the mechanicals.  I did loosen the set screw on the dec setting circle but it's not moving by hand force alone (I didn't really expect it to move by hand force but had to try).  I'll get that dec shaft cleaned up before I attempt to remove the dec circle/shaft.

 

From the 1982 Meade catalog, looks like those vinyl caps were sold by Meade.

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[NinePlanets]

I was not impressed with the first Meade SCT we got in the store. There were a number of things that should have been flagged by the final QC folks at Meade before shipping. But that was the very first one we got. No doubt those folks were working overtime to get the initial batch pushed out the door. That initial impression soured me toward their SCT's. First impressions count.

[NinePlanets]

 

From the 1982 Meade catalog, looks like those vinyl caps were sold by Meade.

Ah! Good! I stand corrected!

I know we carried another brand of those in the store.