375 replies to this topic

[drprovi57]

Better learn to work on focusers also as mine had more image shift than a sct.

Agree on focusers.. I have a spare FT3.5” focuser that I would probably used to replace the original focuser.  However, first I need to find a used 7” Meade 

[CHASLX200]

Agree on focusers.. I have a spare FT3.5” focuser that I would probably used to replace the original focuser.  However, first I need to find a used 7” Meade 

More 7" Tecs by heck pop up. I would love another shot at a 7" ED but would have to be local and work right and stay right.

[KerryR]

Ron, thanks for taking so much time and effort to post your process, experience, and observations. Extraordinarily helpful stuff!

[RKeating]

Agree on focusers.. I have a spare FT3.5” focuser that I would probably used to replace the original focuser.  However, first I need to find a used 7” Meade 

My focuser was easy to disassemble and regrease. I changed the small diameter Meade knobs out with some larger aluminum knobs I already had. It's not a FeatherTouch, but focusing is much easier.

[KerryR]

When I was doing my first rounds of battle with my 127's several years ago, I got a Moonlit retrofit. While I liked the functionality of the Moonlite, I didn't like it's weight and bulk. I ended up putting the stock focuser back on the scope after some tweaks. I actually like the stock focuser- it's (now) smooth, precise, very nicely baffled, very minimal (if any) image shift, and I like it's looks better than the behemothic Moonlite retro, though I miss the fine focus feature, which, luckily isn't super critical at f9. Luckily, the stock focuser is already well aligned to the center of the objective, so I don't really need the collimation feature of the Moonlite.

[152ED]

Some words of encouragement for anyone wondering why the fuss about large old ED refractors (even the Meades):

 

Seeing was 6 falling to 4 last night and I had all three scopes on Jupiter and collimated (152ED, 10" f/5 GSO mirrored custom dob, 12" LX200 EMC).

 

Red spot front and center, visibly rotating off the edge.  6" ED gave a crisp view as always with that "refractor glow" that I can't describe.  Like it's 3-d and made of glass!  12" LX200 showed it much brighter and whiter with a lot of difficulty showing the spot, but gave a great view in the split seconds when the seeing settled down.  10" (with a 25% C.O.) showed a similar view with more "color" to the planet and almost as much detail, with diffraction streaks up and down, and left and right from the spider. 

 

All scopes showed the detail at times but the 6" f/9 ED Meade was on another level.  Good refractors work in almost any conditions!

[BigC]

Just won an auction for the Meade 102ED APO/EMC.

[zjc26138]

Just won an auction for the Meade 102ED APO/EMC.

Congrats!  I owned one for several years and it was a great scope. I regret selling it.

[deSitter]

Just won an auction for the Meade 102ED APO/EMC.

Did it come with the mount and CDS 1697 go-to?

 

If it comes with a massive 18v power brick, that thing is total junk and should never be used with digital equipment. It's fine for brick and mortar DC so to speak.

 

-drl

[RichA]

The trio of nylon screws around the front element is all I did to my 152ED back in 2000 and it has needed very little attention over the years to keep the images (and star test) almost perfect. 

 

The back element is very delicate glass and the edges are very thin, which is why I didn't do anything to it other than some thin cardboard shims.  The 127 cell might not even need this if it's already a tight fit.  Just the upper nylon screws.

 

When I recently finished my "scope shed" (observatory) and set up the 152ED again after being in storage for 10+ years, and many road trips before that, the scope only needed 1/8 turn in one of the nylon screws to get it back to perfect.  Took about 1 minute on a bright star.

 

I highly recommend doing nothing to the back lens, in your case.  That lens is very easy to damage.

Such a simple little fix, yet the Meade guys didn't think of it, OR, the asthetics of the solution "didn't work" in their design.

[BigC]

Total cost with tax and shipping $390.

No mount.Has finder and diagonal and tube rings.

Have compatible mounts LXD55 ,Celestine AVX.

[KerryR]

Total cost with tax and shipping $390.

No mount.Has finder and diagonal and tube rings.

Have compatible mounts LXD55 ,Celestine AVX.

I think that's a great price. I payed wayyyyyyyy to much for my 127 20ish years ago, having not done my homework and being unaware of the issues some were prone to.

 

Very importantly, if you do see an issue (on-axis astigmatism, and/or on-axis coma, and/or on-axis lateral color dispersion), don't apply excessive torque to the lateral grub screws- in case you missed it in the discussion above, these contact a thin aluminum lens spacer, and I've seen them deformed and broken. They're extremely critical, and it'd be very difficult to find a suitable replacement. If those lateral screws are going to fix anything, they'll take incredibly little movement and torque to do so. This assumes the 4" versions are constructed similarly to the bigger versions- I don't know, but I'd expect that to be true, albeit with less sensitivity. (And hopefully you don't have an issues with yours in the first place! Fingers crossed!)

 

I've only looked through one of the 4" versions, and it showed lateral color dispersion and on-axis coma. The owner just assumed it went with the territory for the price, and didn't particularly care, but I bet the scope could have performed much better with some tweaks. For my 127, the difference between slightly out-of-alignment and well aligned is the difference between a "DSO only scope" and a "solid planetary and double-star performer".

Edited by KerryR, 22 March 2025 - 12:12 PM.

[152ED]

Such a simple little fix, yet the Meade guys didn't think of it, OR, the asthetics of the solution "didn't work" in their design.

I'm pretty sure the engineers wanted it in the first place but the marketing dept. and bean counters said no.  Who would buy a 7000 dollar apo if they had to tweak the collimation?  Totally beneath the dignity of high end refractors!

 

Last night when looking for Mars without a finderscope in the 152ED, using just a 20 widescan, I stumbled on NGC 2392, a very weird little planetary nebula.  Thought it was a distant glob until it wouldn't resolve in my 12".  Tried it again with a skyglow filter and sure enough, it's a planetary.  Had to move west a few mintues in RA to see the faint open cluster NGC 2420 to make sure I wasn't just lost in space.  Both looked really nice!

 

Was finally able to put that 4mm GSO plossl to use on Jupiter, as seeing was flashing 7ish at times.  Nice nice large view with much detail in the two main bands and little stuff in between.  Mars still barely shows the ice cap, but it's really tiny  now.  This scope never quits!

Edited by 152ED, 22 March 2025 - 11:23 PM.

[Jay_Reynolds_Freeman]

Who would buy a 7000 dollar apo if they had to tweak the collimation?  Totally beneath the dignity of high end refractors!

Lol, who would buy a 7000 dollar APO if it wouldn't hold collimation and they had to send it back to the factory to get it fixed?

 

Clear sky ...

[saemark30]

It takes a brave soul to drill and tap holes in a lens cell and collimate it yourself. Much more so for a $7000 refractor with delicate ED element. 

Edited by saemark30, 23 March 2025 - 09:46 AM.

[KerryR]

Over the past several days, I did an experiment with my 127.

 

I put the Moonlite I had on the scope previously, but had removed, back on the scope and very carefully aligned it using it's collimating feature. I disassembled the cell and elements. I found that I could take up the slack between the elements and the cell walls with 3 strips of Scotch tape at 120deg, creating a snug fit, yet not so snug as to make getting the elements back into the cell problematic. I stacked the elements, aligned the orientation/wedge marks on the glass edges, and applied one strip of Scotch tape spanning all three parts- the rear element, aluminum space, and front element- in order to prevent them from rotating relative to one another when the retaining ring (and it's rubber spacer) is tightened gently down-something I had observed happening in the past, which might have served to cancel some of the wedge compensation. I turned the radial grub screws so that they were flush with the inner wall of the cell. I put the stack in the cell, which now fits snuggly, and just barely tweaked each grub screw, just to contact with the spacer. I then very carefully collimated the objective with a cheshire, using the trick of placing a strip of tape over 1/2 the Cheshire opening to create opposing half-circles in the return beam. No further adjustment to anything after this point.

 

So far so good- no on-axis aberrations on four nights of Jupiter and Mars observing, moving the scope in and out of the house, along with "normal" bumps and jostling of the ota. Things have stayed put, which is a first for this scope in the 20 or so years I've had (and avoided) this scope.

 

I think I may be able to avoid drilling and tapping, but more time will be needed to verify the outcome.

[152ED]

It takes a brave soul to drill and tap holes in a lens cell and collimate it yourself. Much more so for a $7000 refractor with delicate ED element. 

Mine was only $2100 back in 1999 or thereabouts.  You can chip the back lens with metal setscrews (I tried, and found out).  Scope still gives awesome images!

 

The cell itself is super-tough and very well made, but needs the three setscrews added for it to be finished.  It's like someone designed a Ferrari engine and didn't make any provision for adjusting the valves.  Nonsense!

[deSitter]

Mine was only $2100 back in 1999 or thereabouts.  You can chip the back lens with metal setscrews (I tried, and found out).  Scope still gives awesome images!

 

The cell itself is super-tough and very well made, but needs the three setscrews added for it to be finished.  It's like someone designed a Ferrari engine and didn't make any provision for adjusting the valves.  Nonsense!

I got my 127ED for $1600. I only wanted a 40lb class mount but not an Atlas, not a GM, nothing fit my bill but the old Meade LXD650, which was way overbuilt for those wimpy refractors. I got my scope as a bonus - had no intention of buying an ED refractor - but something just sang to me about the scope. It sang the song of its ancestors. Became an absolute prized possession when it revealed detail on Ganymede.

 

Still have never gone near the objective in 8 years. It really needs a bath.

 

-drl

[shootnstarz]

I bought the very last 178/750 Meade sold, 2005. Yes, it had some issues and I'll refrain from expounding on it and the LXD750 but suffice to say it's working flawlessly thanks to Dr Clay coming to bat for me. I have really enjoyed this impressive scope, many hobby astronomers said it was the best view of Saturn they're ever seen. I'm getting old now at 70 and wrestling that beast around is tough. At least I have a 127ED/LXD650 and a 102ED/AVX that are easier to handle.

[deSitter]

I bought the very last 178/750 Meade sold, 2005. Yes, it had some issues and I'll refrain from expounding on it and the LXD750 but suffice to say it's working flawlessly thanks to Dr Clay coming to bat for me. I have really enjoyed this impressive scope, many hobby astronomers said it was the best view of Saturn they're ever seen. I'm getting old now at 70 and wrestling that beast around is tough. At least I have a 127ED/LXD650 and a 102ED/AVX that are easier to handle.

One of these days I'll have a 750. I love these mounts. My 650 carries a 40lb OTA easily. I actually like the go-to system. Mine works perfectly after 31 or so years.

 

-drl

[deSitter]

I bought the very last 178/750 Meade sold, 2005. Yes, it had some issues and I'll refrain from expounding on it and the LXD750 but suffice to say it's working flawlessly thanks to Dr Clay coming to bat for me. I have really enjoyed this impressive scope, many hobby astronomers said it was the best view of Saturn they're ever seen. I'm getting old now at 70 and wrestling that beast around is tough. At least I have a 127ED/LXD650 and a 102ED/AVX that are easier to handle.

My 650 mount has a Dr. Clay badge - apparently he tuned it up at one time before I owned it. He did a great job.

 

-drl

[RogerRZ]

I have my 178 on a CGE, that coincidentally was supercharged by Dr. Clay. Works like a charm, and the next step above this would be expensive, as in some large Tak or AP. 

[CHASLX200]

I have my 178 on a CGE, that coincidentally was supercharged by Dr. Clay. Works like a charm, and the next step above this would be expensive, as in some large Tak or AP. 

MY AP 800 would do it easy. Never knew this was on it. But what i think is steady and others think is another ball game.  I am very picky about solid mounts.

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[BigC]

Well folks,good news  and bad.

Scope wrapped in a dozen layers of  bubble  wrap, cushioned further by that machine  punched  cardboard inside a carton. 

Lens appears  clean no clams.

Two finder pointing  screws broken. Finder needs eyepiece. 

PINION SHAFT  BENT! Will need to remove and possibly  can straighten. 

First light will be delayed. 

[KerryR]

Well folks,good news  and bad.

Scope wrapped in a dozen layers of  bubble  wrap, cushioned further by that machine  punched  cardboard inside a carton. 

Lens appears  clean no clams.

Two finder pointing  screws broken. Finder needs eyepiece. 

PINION SHAFT  BENT! Will need to remove and possibly  can straighten. 

First light will be delayed. 

The pinion shaft on my 127's stock focuser was bent when I got it as well. It was easy to straighten: I removed the pinion shaft and placed it on the machined-flat surface of my bench vice. Rolling it back an forth, it was easy to feel the bend. Taking care to protect the pinion gear, I was able to tap the shaft gently with a small hammer until it rolled smoothly on the surface. Problem solved, and the focuser worked great. I've gone back and forth between it and a Moonlite retrofit focuser, eventually settling on the Moonlite for it's ability to collimate. Otherwise, I actually really liked the fit, finish, and machined baffling of the stock focuser. Sometimes I'm tempted to modify it to make it collimateable and re-install it because I like the way it looks better than the massive and sort-of-out-of-place Moonlite.