9700 replies to this topic

[deSitter]

I couldn’t find a 2 inch adapter for my Meade 826 so I made one. I bought a piece of 2 inch I.D. 2.5 inch O.D. Aluminum pipe. It was a little over 3 inches long. It was about .005 too small I.D. Which is better than too big. I reamed it until it was close then wet sanded until the 2 inch eyepiece and the 1.25 adapter fit. I drilled and tapped the hole for the screw that holds the eyepiece. I filed a notch for the 1.25 adapter. I have read that these came with a two inch extension. My 40mm and Galoc eyepieces I had to pull out of the factory adapter to achieve focus. I had the machine shop cut it 1.25 inches longer than the 1.25 adapter it came with. The also cut the threads. Lastly I wet sanded with 350,500, and 1000 grit sandpaper then used a polishing compound. I may eventually paint it black.

Nice work! This is an ideal candidate for home anodizing, home electrochemistry at its smelly, dangerous best.

 

https://sendcutsend....ng-in-10-steps/

 

-drl

[Kasmos]

R. F. A. is Rich Field Adapter. It came with a focal reducer I'm pretty sure.

It's a nice plastic, Bakelite. And yes machine threads as if it were made of metal.

Some even have brass inserts for the screw threads if you go back far enough.

As time went on the product was cheapened by removing the cast-in brass inserts

and the set screws to center and hold the prism in the housing.

A very good star diagonal that came with the Celestron SCT telescopes, plenty

of them out there for sale.

 

Robert

The exact same diagonal came with one of my C5s and at first I was confused about it being labeled as a R.F.A.

And yes it's the one that came with the R.F.A. kits, but I believe the diagonal itself is the same as two other made in Japan ones ones I have but with the front barrel swapped. They were a .5 Tele-Compressor that came before the .63s. It was suggested to be optimally used with a 20mm Erfle but other EPs would work. I think the downside was the field wasn't flat at the edges.

 

[CHASLX200]

cleaned up the pier to the AP800. Water was just below the counter weight shaft when surge came in.  This pic was taken just after the flood.

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Edited by CHASLX200, 02 November 2024 - 03:12 PM.

[starman876]

cleaned up the pier to the AP800. Water was just below the counter weight shaft when surge came in.  This pic was taken just after the flood.

Ouch, sorry to hear that.  I bet that tool a lot of work to replace the drywall and clean up all the toys. 

[John Huntley]

I've now got my brass Elliott / BC&F 3" F/16 refractor mounted on the Fullerscopes MkIII equatorial. The two seem well suited. Both came from the 63 Farringdon Road, London base of Broadhurst Clarkson and Fuller, the refractor being manufactured in the basement tube works by Ernie Elliott and Gerry Morris around 1992 following the design used for a couple of hundred years before that. The mount, designed and sold by Dudley Fuller, dates from 1985. So neither are really old but they have a "classic" look I feel. The objective in the refractor is by Carton, Japan. 

 

 

 

 

 

 

 

 

 

[CHASLX200]

Ouch, sorry to hear that.  I bet that tool a lot of work to replace the drywall and clean up all the toys. 

May never replace the dry wall.  May just sell as is for around 50k and get out of FL.  More and more hits will just keep getting worse. I see a CAT 5 with gust over 200mph within 10 years hitting just north of me. This is the new normal.

[clamchip]

Today I started on a job I've been meaning to do for a long time, glue the front cell back

on my '75 C8. You can see in the top photo I have accessory bars top and bottom, these 

are holding the front cell on the tube!

The front cell fell off when I brought the scope home after purchasing it and I actually

caught it in freefall !

I was able to 'key' the old cement and get it back where it was, even collimation wasn't far off !

I used it this way meaning to fix it sometime, that time is now!

I don't want to disturb the cell, my plan is to use water thin hot-glue from the inside and

glue the cell in place. The corrector was stuck good, the worst case I've ever dealt with.

I drizzled 91% isopropyl alcohol along the retaining ring gasket and the retaining ring pulled

free quite easy with my special tool. Next I did the same treatment on the corrector gasket

only I used a thinned down popsicle stick to nudge the corrector side to side hoping

to help the gasket wick up the alcohol, and it did, lifting the corrector free from the cell.

While I have things apart I removed the primary for cleaning and lube the mirror carrier and

focusing mechanism. Tomorrow I will go ahead and permanently cement the front cell back on.  

Robert

 

Edited by clamchip, 03 November 2024 - 12:09 AM.

[cavedweller]

I was able to 'key' the old cement and get it back where it was, even collimation wasn't far off !

IMG_2829.JPG

What ink did you use to mark the glass? Will it clean off easily?

[deSitter]

Today I started on a job I've been meaning to do for a long time, glue the front cell back

on my '75 C8. You can see in the top photo I have accessory bars top and bottom, these 

are holding the front cell on the tube!

The front cell fell off when I brought the scope home after purchasing it and I actually

caught it in freefall !

I was able to 'key' the old cement and get it back where it was, even collimation wasn't far off !

I used it this way meaning to fix it sometime, that time is now!

I don't want to disturb the cell, my plan is to use water thin hot-glue from the inside and

glue the cell in place. The corrector was stuck good, the worst case I've ever dealt with.

I drizzled 91% isopropyl alcohol along the retaining ring gasket and the retaining ring pulled

free quite easy with my special tool. Next I did the same treatment on the corrector gasket

only I used a thinned down popsicle stick to nudge the corrector side to side hoping

to help the gasket wick up the alcohol, and it did, lifting the corrector free from the cell.

While I have things apart I removed the primary for cleaning and lube the mirror carrier and

focusing mechanism. Tomorrow I will go ahead and permanently cement the front cell back on.  

Robert

 

post-50896-0-57750300-1681831489.jpg

IMG_2825.JPG

IMG_2824.JPG

IMG_2829.JPG

Why not screws?

 

-drl

[jragsdale]

Tomorrow I will go ahead and permanently cement the front cell back on.  

I'm still surprised these are glued on with how much stress, moisture and temperature these are subject to and how critical SCT collimation is. What's the thermal expansion coefficient of the glue? Wouldn't it be better to drill and tap some radial screws around the perimeter for a long term fix? 

[deSitter]

I'm still surprised these are glued on with how much stress, moisture and temperature these are subject to and how critical SCT collimation is. What's the thermal expansion coefficient of the glue? Wouldn't it be better to drill and tap some radial screws around the perimeter for a long term fix? 

Yes I would make some form-fitting little banana-shaped "shoes" to nestle against the tube wall and spread out the pull stress from the screw.

 

-drl

[Exnihilo]

May never replace the dry wall.  May just sell as is for around 50k and get out of FL.  More and more hits will just keep getting worse. I see a CAT 5 with gust over 200mph within 10 years hitting just north of me. This is the new normal.

So sad all that happened to you, I hope you can move to a better place.

 

You could move to Arizona.

Edited by Exnihilo, 03 November 2024 - 10:10 AM.

[CHASLX200]

So sad all that happened to you, I hope you can move to a better place.

 

You could move to Arizona.

Sure won't be in this country.  Weather has just gone bad everywhere. Just may clean up and sell what all is left in the trunk with all the eyep's and this and that's and the mounts and scopes i have left for very cheap.  

[clamchip]

What ink did you use to mark the glass? Will it clean off easily?

I didn't mark the glass, I just found the exact position of the corrector cell by the fit, the old glue has

a random pattern to it and only fits properly in one position.

 

Robert

[clamchip]

I thought about screws and nuts to hold the cell on, or even just screws and tap the cell, but I could not get

myself to do it, I'm too much of a originality nut.

Celestron eventually did use screws to hold the front cell on, I'm not sure when.

It would be so simple to modify it and use screws, I would have the scope finished in a few hours and it will

never be a problem again. Instead I will cement it and wait for the off gassing to dissipate and then assemble

the scope maybe a week from now. 

 

Robert

[clamchip]

I went ahead and cemented the corrector cell back on and now I have some time to think about what

lube to use on the baffle tube. I can't remember what I used last time, or if I was even happy with my

choice. I wish I could remember the telescope.

There is so little space between the mirror carrier and the baffle tube, I'm reluctant to use a grease. Oil

will probably bleed out into the flat black paint but a spindle oil like I use on my lathe seems a good choice.

I might go with a extremely thin almost undetectable wipe of Super Lube. I can't tell what Celestron used

there's no evidence left, pretty dry in there but water beads up so there's something there.

The fits are very tight in this telescope, maybe this is why everyone likes the old sandcast so much.

I'm hoping someone might know what's best to use?

Robert

 

Edited by clamchip, 03 November 2024 - 02:25 PM.

[cavedweller]

I didn't mark the glass, I just found the exact position of the corrector cell by the fit, the old glue has

a random pattern to it and only fits properly in one position.

 

Robert

In that case, it only leaves the mystery (to me) why I see arrows in your pictures.

[clamchip]

In that case, it only leaves the mystery (to me) why I see arrows in your pictures.

I think I see the arrows!

It must be the reflection from the switch string hanging from my shop light! 

Amazingly this string appears in two of the photos I posted and it does look like an arrow!

 

Robert

[deSitter]

I think I see the arrows!

It must be the reflection from the switch string hanging from my shop light! 

Amazingly this string appears in two of the photos I posted and it does look like an arrow!

 

Robert

You could use soap to mark glass I thought you had done that with the corrector - but the mirror?!?

 

-drl

[clamchip]

This must be the arrow:

 

[clamchip]

I went ahead and cemented the corrector cell back on and now I have some time to think about what

lube to use on the baffle tube. I can't remember what I used last time, or if I was even happy with my

choice. I wish I could remember the telescope.

There is so little space between the mirror carrier and the baffle tube, I'm reluctant to use a grease. Oil

will probably bleed out into the flat black paint but a spindle oil like I use on my lathe seems a good choice.

I might go with a extremely thin almost undetectable wipe of Super Lube. I can't tell what Celestron used

there's no evidence left, pretty dry in there but water beads up so there's something there.

The fits are very tight in this telescope, maybe this is why everyone likes the old sandcast so much.

I'm hoping someone might know what's best to use?

Robert

 

From exhaustive searching today it looks like two choices seem popular:

Super Lube

Dow Corning Vacuum Lubricant

I also learned you must be careful about too much or too little of whatever you use.

Maybe I'll message Celestron Support and see if they can recommended a lube.

 

Robert

[deSitter]

From exhaustive searching today it looks like two choices seem popular:

Super Lube

Dow Corning Vacuum Lubricant

I also learned you must be careful about too much or too little of whatever you use.

Maybe I'll message Celestron Support and see if they can recommended a lube.

 

Robert

Seems like an ideal scenario for graphite dry lube. Apply with fingertip.

 

-drl

[davidmcgo]

If the fit is really smooth and there is no flop you might try it dry.  My 1975 C8 has no grease on the baffle and is about as smooth a focuser as you could wish for.

 

Dave

[Cavs56]

This is the free 6 inch Criterion that was in Cincinnati last week. Pretty bad shape both ends of the tube were damaged, focuser rusted spyder bent and rusted. I decided I wanted to see if I could make it a telescope again. There was room to cut off the damaged bottom of the tube. I cut the damaged part into two pieces discarding the damaged area. Then I used those to clamp the repair on the front of the tube. I filled it with JB weld put wax paper down and used five clamps. It worked great all the pieces went back together. A lot of work, oil and heat. The spyder was a mess. I wasn’t trying to restore it just get it to work. The motor works and it does track. I got it mostly for the mount. The mirrors need recoated. I am happy with how it turned out.

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[deSitter]

This is the free 6 inch Criterion that was in Cincinnati last week. Pretty bad shape both ends of the tube were damaged, focuser rusted spyder bent and rusted. I decided I wanted to see if I could make it a telescope again. There was room to cut off the damaged bottom of the tube. I cut the damaged part into two pieces discarding the damaged area. Then I used those to clamp the repair on the front of the tube. I filled it with JB weld put wax paper down and used five clamps. It worked great all the pieces went back together. A lot of work, oil and heat. The spyder was a mess. I wasn’t trying to restore it just get it to work. The motor works and it does track. I got it mostly for the mount. The mirrors need recoated. I am happy with how it turned out.

If you examine the construction of the spider hub, you will see that the vanes nestle into little bays in the hub. I replaced these on mine with thinner steel bands that came on a clothes dryer carton. You drive out the old vane with a punch, bend a U into the end of a band, nestle that U into the bay, then drive a pin (e.g. a thin nail) between the tines of the U to make the steel expand into the bay. Very secure and the resulting vanes were both very thin and perfectly straight when under tension. I used both inside and outside nuts on the vane lugs to prevent distortion of the tube.

 

Nice save!

 

-drl