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This Edmund reflector - A fixer-upper?

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#1 zakry3323

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Posted 22 October 2021 - 07:00 PM

Yesterday I drove 120 miles to save this setup from the dumpster. I'm not sure, but after doing some reading on this forum, I believe that it's an Edmund Super Space Conqueror. 

 

20211022_194801.jpg

 

If anyone can confirm, I'd really appreciate it. 

 

It seems fairly complete.

 

The focuser is a rack and pinion and is actually pretty smooth with only a little backlash. Odd that it's attached spaced away from the tube...seems like that's a great way to let stray light right into the light path. Also interesting is the secondary on a stalk that goes right through the focuser. Seems convenient, but how well collimated can the system be if the secondary is only adjustable in 2 axis? I am concerned about the drawtube- it seems that the tube itself has been cut to be a collet- the 1.25" no-name eyepiece that it came with slides in and out, not without a little torque. I wouldn't want to do that to the barrels of my good eyepieces. 

 

20211021_204737.jpg

 

I removed the secondary, and unfortunately the coatings are mostly gone. 

 

20211021_213611.jpg

 

 

 

 

 


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#2 zakry3323

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Posted 22 October 2021 - 07:01 PM

The cover for the motor popped right up, so I can get a close-up. It seems as though it still runs!

 

20211022_185951.jpg

 


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#3 zakry3323

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Posted 22 October 2021 - 07:02 PM

The worm drive doesn't seem to have any obvious damage, just looking pretty tarnished in spots. 

 

20211022_185722.jpg

 

20211022_185820.jpg


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#4 zakry3323

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Posted 22 October 2021 - 07:05 PM

The primary actually looks pretty good, though I haven't removed it from the tube yet. The tube itself has seen better days, a bunch of extra holes in it. But it does seem to be made of aluminum, which should make stripping, patching, and repainting go easy enough. It also came with two counterweights and a 9x Towa finder. 

 

20211022_185623.jpg

 

I unscrewed the eyepiece and quite a bit of water dripped out. Despite this, I don't see anything growing on the glass. 

 

20211022_190120.jpg


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#5 zakry3323

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Posted 22 October 2021 - 07:13 PM

If it is indeed a Super Space Conqueror - I'm not sure where I should go from here. I've never attempted a restoration on a precision instrument before. A 6" F/8 reflector would be something nice to have though, it could be a mini-planet killer, especially on that GEM with a clock drive. I'm not sure what I would need to make it complete- certainly the mirrors would need recoats, and after reading a copy of a catalogue with the advertised "hand polished to 1/4 wave" for the primary, I'm not sure if it would be worth refiguring/recoating as opposed to simply buying a better 6" mirror. And once the mirror is replaced....well maybe it would be better to update it further, for instance the barrel-eating focuser? Which would necessitate the replacement of the secondary....you see where I'm going.

 

What would you do in this situation? Try to restore the original, or update/replace? 



#6 ngc7319_20

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Posted 22 October 2021 - 07:15 PM

It definitely looks like an Edmund Scientific to me.  My (sobering) comment is that after spending $400 on it you will have a scope worth maybe $200.  So be aware of the economics.  But that said, it might be a very nice scope for all-around observing.  I've used / owned many of the similar Criterion RV-6 scopes and they are really wonderful.


Edited by ngc7319_20, 22 October 2021 - 07:22 PM.

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#7 1939Dodge

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Posted 22 October 2021 - 07:25 PM

It’s an Edmund. I have several. The extra holes in the tube are for the optional solar image screen mount.

 

They are plentiful and very inexpensive for the excellent quality of the optics.

 

Personally, I would clean it up, and USE IT! It’s got plenty of fun left in it. Then after you’ve gotten some time with it, decide if you want to resilver or recoat the mirrors.

 

It may not be worth spending a lot of money, but it sure is fun as designed. Now go out and have fun!


Edited by 1939Dodge, 22 October 2021 - 07:28 PM.

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#8 clamchip

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Posted 22 October 2021 - 08:00 PM

Yes a Edmund Super Space Conqueror.

If it came with the drive the date on the motor cover is  march 1969 and is when the whole

telescope was built, give or take a few months or so.

The diagonal mirror support stalk is to be left alone, unless someone in the past has tried 

or succeeded in bending it, you may need to straighten it and set the mirror platform exactly

45 deg and it will be fine. 

The primary mirror was made and tested by UPCO it's a very fine mirror one of the best to

come out of the era.

You will find everything you need to fully restore your new scope right here in the classic

forum, it is a very popular classic here. For most of the work you need to do any make or

model information will apply, only a few things unique to the famous Super Space Conqueror

and those items will be covered here too.

 

Robert


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#9 YourNotSirius

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Posted 22 October 2021 - 10:08 PM

I agree that it is an Edmund Super Space Conqueror. The motor cover does confirm that the motor was made in 1969 which means this is from that year or 1970. The mount is in excellent shape and they were quite stout and reliable. The drive is very simple and works quite well. It's one of the most easy clock drives to repair and use.

 

The EQ mount is quite strong and will move very freely. When this was made they were still using self lubricating bronze bushings instead of the later junk nylon inserts. The latter were a mess and always wore out. The old man has taken those apart, broached the axle bores to size and inserted bronze bushings into them as replacements. Apparently, in the late 1970s, Edmund was trying to cut costs and went to the cheap and sloppy nylon inserts.

 

The tube is made from seamless aluminum and has a coating that was known as porcelainized. It is very strong and does not scratch as easily as paint or fiberglass. If you need to repair damage to the tube it is not difficult. Many people use automotive paint but, you can just as easily have it anodized to the original color. There are a few coating companies that can still produce the original porcelain type of finish which is much harder and durable than the other two methods. It's a matter of expense that will determine which choice you make.

 

The extra holes on the OTA are for the camera/solar projection screen that was an option for the Edmund Newtonians. I see the mounting bracket there. Hopefully, you got the white screen or, at least the camera bracket. If not, they are easy to find or duplicate.

 

The secondary is in dire need of a new coating. It can be removed but, it's kind of a bugger to remount it. Any coating company will have to remove it from the stalk in order to apply a new coating. If you do have that done it would be well worth the effort and small expense to give the primary a new coating, too. IF the UPCO sticker is still on the back of the mirror you might wish to gently remove it before having if coated. You can then replace it upon its return. Normally, those are sacrificed when the mirrors are given a new coating. UPCO was the optic house that supplied Edmund, Jeagers and Criterion, to name a few. They made very good mirrors which have never let us down. The old man says that some of the ones he has had were far better than the declared 1/4 wave accuracy. He has yet to find one that was any worse than 1/8 and normally 1/10 wave accuracy. They have always been a dead on match for any Criterion RV-6 and others.

 

The focuser does stand away from the tube a small bit but, my old man and I have never had any issues with light intrusion since the amount of space is so small. It really cannot get into the path very easily because any light that does enter will be almost at 90 degrees off axis from the light path.

 

I see that you got both of the counterweights and the shaft that was originally supplied with them. The second CW with that shaft are for balancing the OTA when a camera is mounted upon it. It was supposed to help keep the center of gravity closer to the DEC axis which meant that you would not have to apply excessive force to the clamping knob.

 

The eyepiece that you have is a 1" focal length Kellner model. It and a few other EPs were standard with that telescope. The others would have been a 1/2" fl and f/4" fl Ramsden design accompanied by an Edmund 2x Barlow lens. The tube in the focuser uses light tension to hold the EP in place. The old man says he never noted any major scratches on his EPs from any of the Edmund scopes he has owned. (His first scope was the 4-1/4" f/10 version known as the Palomar Junior.) We have had a number of the Edmund scopes come to us and every one has been an excellent performer because they are simple and well built, unlike some of the "premium" brands from those days! LOL

 

The finder scope is a Towa supplied 6 x 30mm. The objective housing is the focusing mechanism. The cross hairs were made from extremely thin copper wire. We have replaced missing cross hairs in those with either fine copper wire from a very small electric motor or threads from a spider's web. It appears that a previous owner drilled a hole in the tube to install a small light to illuminate the cross-hairs. It can be repaired or used again as you see fit to do.

 

You have rescued a wonderful instrument from the scrap bin and should be commended for doing so. If you wish to restore it completely it will be a simple but, rewarding project. However, you can just clean it up and put it back into use. The others here noted that they really are not worth much because so many of them were sold. Although, our opinion is that they are unsung heroes of the space age. They were not Prima Donna instruments when compared to other instruments from that time period. They were excellent telescopes for short money and were built to be used heavily. They never let any of us down, ever.

 

I kind of ran off a bit there didn't I? LOL That's Okay, the old man would be writing an entire book on this telescope if you let him. LOL

 

We hope that you enjoy your rescue scope. As was noted above, this site has more information and resources for your project than you will ever need. If we can be of assistance in any way just let us know.

 

Clear skies, (whatever those are!)

 

Q


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#10 Star.Monger

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Posted 23 October 2021 - 06:43 AM

Another vote for cleaning it up and using it!  You can always restore it later or sell if you wish to move on.


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#11 zakry3323

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Posted 23 October 2021 - 08:48 AM

Thanks very much folks, I really appreciate confirmation of the model and all your advice! I think that getting it fit for duty should be my first priority, and if I can restore or partially restore it without it becoming a money pit, that should be the way to go. I think it's really interesting and kind of unique, and as it seems to already be in decent working condition, would be a shame to retrofit.  

 

Thank you, NotmySirius, for letting me know about the porcelainized finish. Covering the mount as well as the counterweights, I was really wondering just what the heck it was- it sure is durable! 

 

I didn't get the white solar projection card or the stalk upon which it must reside, but fortunately I do have the attachment bracket, and it seems to be in pretty good shape.

 

20211023_092139.jpg

 

I cleaned out the draw tube and tried it with a few outreach plossls- very happy to say that the excessive tightness seems to be a symptom of the included eyepiece barrel and is not an issue with other eyepieces. In fact, smoothies slide in and are held quite nicely. Those with undercuts aren't held very firmly and can jiggle around a little bit, but seem like they won't fall out under normal use. 

 

20211023_092155.jpg

 

 

I'm excited to get the ball rolling on this project after I return home from camping this weekend. I suppose that my order of operations begins with disassembly and cleaning- maybe in the meantime I can have the secondary sent out and recoated somewhere. The sliding rod/spider is clean and not bent at all, I just wonder how I'm going to get the mirror off of it. It seems that it's affixed with an epoxy, yellowed with age. Would anyone happen to know if I can remove it with heat, or does it require a glass-safe solvent? 

 

 

 

 

 

 


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#12 YourNotSirius

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Posted 23 October 2021 - 10:23 AM

Glad to help.

 

The secondary can be removed by the use of an X-acto knife and patience. Or, you can use a Dremel tool if you have steady hands. I'm certain there are other ways that just don't come to mind right now.

 

The fun part about the focusing tube AND the missing Barlow lens is that they were made from plumbing hardware which is still sold in hardware stores today. All they did was to cut some slots for the tension wings and that was the end of that! I know because I've used that exact hardware to make replacements. LOL

 

The solar projection screen and camera bracket can be found used in the classified sections here or on Astro-Mart on occasion. It's just as easy to make up something though. The support tube that was originally supplied was just regular electric conduit piping which is, again, still available at your local hardware store. Yes. I've used it to make replacements and so has the old man. (Where do you think I learned all of this stuff, anyway? LOL)

 

In case you did not know, those "undercuts" that you have on some of your EPs are where set screws are supposed to land when tightened. They are a form of security so that if then somehow loosen or, are not tightened to a point of contact, they help to prevent the EP from falling out if the focusing unit is turned upside down. That happens mostly with refractors and SCTs where the EPs can be rotated for more comfortable viewing. For the Edmund, just use straight cylinder EPs and you will be just fine.

 

Have fun! I'm going back to the river. I was there all morning catching trout and I'm going back for more. No. We are a catch and release family. We only keep fish that are mortally wounded (a rare event) or if we actually want to have a fish dinner. (Grin)

 

Q


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#13 ccwemyss

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Posted 23 October 2021 - 08:03 PM

One thing to note about this mount is that, when it has the clock drive, you do not use the lock knob on the shaft to hold it in place. The two thumb screws at the back of the drive replace that function. 

 

Also, the little handle at the top of the drive is a kind of slow-motion control. It turns a cam against the two posts, to shift the axis. If you plug it in, and the mount doesn't start turning, it is because the cam isn't pressing on the post. Once the motor turns enough to to engage, it will start moving, but you can avoid the delay by turning the handle.

 

If you take it apart to re-lubricate it (they get very stiff when the old grease dries up), there are a couple of small ball bearings in the cam assembly to keep track of, which always seem to want to roll off to the hardest place to reach them. 

 

In the pressure plate assembly at the back of the drive, there is a thin cork gasket. That often becomes brittle and breaks up. You can get similar gasket material at an auto parts store and just cut out a replacement. 

 

It's unfortunate that the diagonal has lost so much of the coating. You can still use it, but the view will be dimmer. As others have said, the primaries are excellent. Another member, who does a lot of optical work, DAVIDG, has found that the diagonals are an optical weak link in these scopes, and after he has refigured them, gotten better performance. So you might simply look for a replacement of about the same size from a good supplier, rather than getting it recoated. 

 

Chip W. 


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#14 ShaulaB

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Posted 23 October 2021 - 08:14 PM

The pictures gave me a huge smile. I used this scope in the 1980's. It was a hand-me-down from my FIL, who had purchased a C8 and was not using this Newtonian.

I observed the entire Messier list with this scope. Of course, it had to be driven to darker skies on occasion. And planets were very enjoyable. It sits in my dining room now, not much used, but very beloved.
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#15 Myk Rian

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Posted 24 October 2021 - 06:51 PM

I had a 4.25" Polaris Jr. that I gave up. They really are nice scopes.

That eyepiece is probably an original Edmund 1".


Edited by Myk Rian, 24 October 2021 - 06:52 PM.

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#16 YourNotSirius

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Posted 24 October 2021 - 11:21 PM

I had a 4.25" Polaris Jr. that I gave up. They really are nice scopes.

That eyepiece is probably an original Edmund 1".

Yes they were and still are today!

 

That is definitely an Edmund 1" fl Kellner EP. I have one sitting in my eyepiece kit which is on the other side of the room. It's just as good as any other 25mm EP out there today. I like the nice eye relief that it has. Because of acute astigmatism we all need to wear eyeglasses when observing.

 

Q


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#17 zakry3323

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Posted 25 October 2021 - 02:02 PM

Thanks for all of the additional information, it'll come in real handy- especially regarding that cork clutch! I'm planning on disassembling the mount if I can get the OTA to show me something. 

 

To that end, I've taken your advice and rather than sending it for a recoat, I've started this project by ordering a 1.30" mirror diagonal from Antares. 

 

I haven't a guess as to when it may arrive, so in the meantime I thought I'd clean up the OTA. First things first, mirror removal: 

 

 

20211025_141152.jpg

 

After dumping out a few twigs and leaves, I removed the support cell- which was covered in "white rust" from zinc corrosion. I assume what remains in the cell was some kind of pad. It seems to have been compressed for a pretty long while and has an oily residue. I intend to remove it. 

 

20211025_141406.jpg

 

I was hoping to see that fabled "UPCO" sticker on the back, but alas, it's blank pyrex. I've compared it with some of the photos that I've found in other threads here about the Space Conqueror and it does seem to be an UPCO mirror, just lacking a sticker (though not lacking a smear of schmoo where the sticker had once been). 

 

20211025_141525.jpg

 

There is a serial number printed on the mirror: 1127 68 - also an indication on the mirror that it's 6" D 

 

If anyone can help me confirm that it is indeed an UPCO mirror, I'd appreciate it. I intend to give it a soak for a while and see how bad the coatings are. 

 

 

 


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#18 zakry3323

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Posted 25 October 2021 - 02:13 PM

Since there's some interest in the eyepiece, here it is in all its glory: 

 

20211025_141631.jpg

 

It's clearly seen some better decades than the current. Clamshell chip is a bummer.

 

20211025_141644.jpg

 

It seems to fit your assertions about it being the 1" eyepiece it came with originally. I'm not typically confident enough to disassemble eyepieces, but I was curious and this one looked pretty darned simple.

 

20211025_142104.jpg

 

Unfortunately it looks like something was growing in between the mating surfaces of the cemented achromat. Together with the large field lens, this seems to me to be a Kellner design. Can't wait to try it out :) 

 



#19 zakry3323

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Posted 26 October 2021 - 10:50 AM

I'm headed out to Lowe's today for some project supplies, and while I'm at it I thought I might pick up some supplies for the Space Conqueror. I'm going to be looking for some new galvanized bolts for attaching the tube to the saddle (current ones are bent and I can't remove them from the tube, so I'll be snipping them off later) as well as some new nylon-tipped thumb screws for the finder. I'll be looking for something to allow some degraded zinc-coated parts to soak in and remove the white rust, as well as some zinc spray paint to cold-re-galvanize some parts, especially the mirror cell. 

 

While I'm there I might pick up some primer/paint for the tube- if anyone has any suggestions based on what's worked well for them regarding these products, please let me know! 



#20 YourNotSirius

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Posted 26 October 2021 - 11:31 AM

I submit that the photos of the mirror show it to have very degraded coating. It would be best to send it off for a new coating. I have had excellent service from Spectrum Coatings in Florida. We recently restored a Cave telescope for a local school and Spectrum did a fantastic job. They even put a center triangle on it to make aligning the optics easier.

 

If you shop around you should be able to find another secondary on the stalk. They show up on Evil Bay and here every so often. However, you can fit a new diagonal to the stalk. You need to remember to account for the space between the front reflective surface of the mirror and the mounting point on the stalk. Edmund used old prisms with a good flat side to make those secondary mirrors. You will need to measure the distance between the contact point with the flat on the stalk and the reflective surface of the prism and then make a spacer to account for it. Also, subtract the thickness of the new secondary before mounting it. Of course, you could go to the trouble of using a new spider secondary support but, then you would need to measure and drill holes in the tube for the mounting hardware. That can be a bit tricky if you've not done it in the past.

 

Many ATMs and such like to use Rustoleum products. We prefer Krylon for it's consistency in color and quality. Also, we haven't had as many splatters from their products. Then again, nothing beats a good old compressor and spray gun! LOL

 

Definitely use a self etching primer. They come in several colors. Many times, we used to use two colors. One as the initial coat and then a different color AFTER wet sanding. Once the second color was sprayed we would then again wet sand down to the first coat. If any of the second color remained we knew that we had a small low spot that needed to be filled and sanded smooth to match the rest of the surface. We repeated that as many times as required until there were no low spots, or high spot, left. That's what makes a show car class of finish when compared to just spray bombing the tube. LOL It all depends upon just how nice of a finish you want. (Grin)

 

One nice thing about using automotive grade materials is that the enamels are harder and can be covered with several layers of clear top coat which helps to reduce scratches in the color coat. Most hardware store spray bombs do not allow clear coats and if they do, the clear coats don't turn out very well. That's just something to consider in case you really want to go to town on this thing. LOL

 

By the way, a lot of people like to paint the mirror cell flat black. It helps to control random glare and stray light which can get into the optical path. It was an extra step that few manufacturers took, Edmund included. At the time, I don't think that we were as knowledgeable about stray light and it's effects as we are now.

 

FWIW

 

Q


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#21 zakry3323

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Posted 27 October 2021 - 09:30 AM

I submit that the photos of the mirror show it to have very degraded coating. It would be best to send it off for a new coating. I have had excellent service from Spectrum Coatings in Florida. We recently restored a Cave telescope for a local school and Spectrum did a fantastic job. They even put a center triangle on it to make aligning the optics easier.

 

If you shop around you should be able to find another secondary on the stalk. They show up on Evil Bay and here every so often. However, you can fit a new diagonal to the stalk. You need to remember to account for the space between the front reflective surface of the mirror and the mounting point on the stalk. Edmund used old prisms with a good flat side to make those secondary mirrors. You will need to measure the distance between the contact point with the flat on the stalk and the reflective surface of the prism and then make a spacer to account for it. Also, subtract the thickness of the new secondary before mounting it. Of course, you could go to the trouble of using a new spider secondary support but, then you would need to measure and drill holes in the tube for the mounting hardware. That can be a bit tricky if you've not done it in the past.

Thanks, Sirius. I gave the mirror a good soak and rinse with RO/DI water- the coatings really are pretty bad: 

 

20211025_155713.jpg

 

Isn't it nice that it fits so well in the closed cell foam packaging that one of my counterweights came in though? 

 

So, I think what I'll do is send off the primary for a recoat, as well as the original secondary mirror. I'd really like to get a report regarding the primary's figure and the flatness of the secondary, I'll have to check out Spectrum and see if that's a service that they provide. This way if the Antares secondary is a poor or complicated fit on the original stalk (I'd rather not drill the tube and put in a new spider) maybe I can re-adhere the original recoated secondary and use it to good effect. If I don't end up needing it for this scope, I can use the Antares secondary with my 8" newt. 


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#22 zakry3323

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Posted 03 November 2021 - 10:47 AM

I submit that the photos of the mirror show it to have very degraded coating. It would be best to send it off for a new coating. I have had excellent service from Spectrum Coatings in Florida. We recently restored a Cave telescope for a local school and Spectrum did a fantastic job. They even put a center triangle on it to make aligning the optics easier.

 

If you shop around you should be able to find another secondary on the stalk. They show up on Evil Bay and here every so often. However, you can fit a new diagonal to the stalk. You need to remember to account for the space between the front reflective surface of the mirror and the mounting point on the stalk. Edmund used old prisms with a good flat side to make those secondary mirrors. You will need to measure the distance between the contact point with the flat on the stalk and the reflective surface of the prism and then make a spacer to account for it. Also, subtract the thickness of the new secondary before mounting it. Of course, you could go to the trouble of using a new spider secondary support but, then you would need to measure and drill holes in the tube for the mounting hardware. That can be a bit tricky if you've not done it in the past.

 

Many ATMs and such like to use Rustoleum products. We prefer Krylon for it's consistency in color and quality. Also, we haven't had as many splatters from their products. Then again, nothing beats a good old compressor and spray gun! LOL

 

Definitely use a self etching primer. They come in several colors. Many times, we used to use two colors. One as the initial coat and then a different color AFTER wet sanding. Once the second color was sprayed we would then again wet sand down to the first coat. If any of the second color remained we knew that we had a small low spot that needed to be filled and sanded smooth to match the rest of the surface. We repeated that as many times as required until there were no low spots, or high spot, left. That's what makes a show car class of finish when compared to just spray bombing the tube. LOL It all depends upon just how nice of a finish you want. (Grin)

 

One nice thing about using automotive grade materials is that the enamels are harder and can be covered with several layers of clear top coat which helps to reduce scratches in the color coat. Most hardware store spray bombs do not allow clear coats and if they do, the clear coats don't turn out very well. That's just something to consider in case you really want to go to town on this thing. LOL

 

By the way, a lot of people like to paint the mirror cell flat black. It helps to control random glare and stray light which can get into the optical path. It was an extra step that few manufacturers took, Edmund included. At the time, I don't think that we were as knowledgeable about stray light and it's effects as we are now.

 

FWIW

 

Q

Thank you for all this helpful information! 

I called Paul over at Spectrum and he's willing to recoat the primary and secondary for me for a very reasonable price. I intend to send it off today. 

 

I've received a 1.30" from Antares just the other day and as predicted, the major axis is too long to accommodate the stalk without adapting with an additional spacer and accounting for thickness. This shouldn't be a huge issue, but since Spectrum will inexpensively recoat the original secondary for me anyways, I may as well try it with the original first and see how the views look. The 1.30" mirror is a bit small for my 8" newt, but perhaps after I do some measuring (and possibly investing in a low-profile focuser) it will be a good fit without losing much of the light cone. We shall see!  

 

I have flat black paint to use for the inner portion of the tube- in fact I've disassembled the mirror cell, sanded, and painted it. The fasteners and springs still look good, so I don't think they'll need to be replaced. 

 

20211102_115714.jpg

20211103_103205.jpg

 

While waiting for the primary to come back (30 day rough estimate) I intend to strip the tube and fill some holes- it seems like maybe a 14" losmandy dovetail may have been bolted on at some point, and up closer to the camera/paper stalk holder there are 4 more holes drilled that would accommodate something about the size of a telrad. I plan to hit up Lowes soon for some Krylon. I think an off-white will look nice on the exterior of the tube, and I have plenty of the flat black Rustoleum remaining to re-blacken the interior. I also have "chalkboard paint", which seems to be even flatter, though less dark, that I might experiment with. 

 

Also starting up the search for some replacement hardware (nylon-tipped fasteners for the finder, new bolts for the counterweights - they're all bent in some way or another) and something to use for resting the primary on the mirror cell. The original pad was very degraded and oily, the side supports and under the mirror clamps used a kind of felt that has likewise become brittle and dusty with age. If you have any suggestions regarding what I should use to replace them, I'd welcome them! 

 

20211103_103918.jpg


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#23 Senex Bibax

Senex Bibax

    Viking 1

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  • Posts: 856
  • Joined: 01 Feb 2019
  • Loc: Ottawa, ON

Posted 03 November 2021 - 11:17 AM

I submit that the photos of the mirror show it to have very degraded coating. It would be best to send it off for a new coating. I have had excellent service from Spectrum Coatings in Florida. We recently restored a Cave telescope for a local school and Spectrum did a fantastic job. They even put a center triangle on it to make aligning the optics easier.

 

If you shop around you should be able to find another secondary on the stalk. They show up on Evil Bay and here every so often. However, you can fit a new diagonal to the stalk. You need to remember to account for the space between the front reflective surface of the mirror and the mounting point on the stalk. Edmund used old prisms with a good flat side to make those secondary mirrors. You will need to measure the distance between the contact point with the flat on the stalk and the reflective surface of the prism and then make a spacer to account for it. Also, subtract the thickness of the new secondary before mounting it. Of course, you could go to the trouble of using a new spider secondary support but, then you would need to measure and drill holes in the tube for the mounting hardware. That can be a bit tricky if you've not done it in the past.

 

Many ATMs and such like to use Rustoleum products. We prefer Krylon for it's consistency in color and quality. Also, we haven't had as many splatters from their products. Then again, nothing beats a good old compressor and spray gun! LOL

 

Definitely use a self etching primer. They come in several colors. Many times, we used to use two colors. One as the initial coat and then a different color AFTER wet sanding. Once the second color was sprayed we would then again wet sand down to the first coat. If any of the second color remained we knew that we had a small low spot that needed to be filled and sanded smooth to match the rest of the surface. We repeated that as many times as required until there were no low spots, or high spot, left. That's what makes a show car class of finish when compared to just spray bombing the tube. LOL It all depends upon just how nice of a finish you want. (Grin)

 

One nice thing about using automotive grade materials is that the enamels are harder and can be covered with several layers of clear top coat which helps to reduce scratches in the color coat. Most hardware store spray bombs do not allow clear coats and if they do, the clear coats don't turn out very well. That's just something to consider in case you really want to go to town on this thing. LOL

 

By the way, a lot of people like to paint the mirror cell flat black. It helps to control random glare and stray light which can get into the optical path. It was an extra step that few manufacturers took, Edmund included. At the time, I don't think that we were as knowledgeable about stray light and it's effects as we are now.

 

FWIW

 

Q

I had good luck using Rustoleum white appliance enamel spray paint. It dries hard and durable, but it does take longer to dry than regular spray paint. And I second the use of self-etching primer first.


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#24 YourNotSirius

YourNotSirius

    Ranger 4

  • -----
  • Posts: 360
  • Joined: 01 Feb 2015
  • Loc: Somewhere in New Hampshire

Posted 10 November 2021 - 11:05 PM

The downside to Rustoleum Appliance paint is that it reacts to UV light and will fade and crack over time. It even states on the can that it is for inside use only. For the money, having a porcelain type of coating done would be best. However, using a GOOD automotive grade primer, color coat and clear top coat is the next best thing.

 

The one thing about Edmund was their frugality. I'm convinced that they must have been located near a hardware store because everything they ever used is still sold in those places today! That includes the thumb screws and everything else! LOL

 

For felt, just hit up a hobby shop. They carry thin felt in sheets that are normally about $1 each. You can trim what you need from the sheet with a paper cutter board or just a straight edge and an X-Acto knife. To attach felt to anything we use automotive body side molding adhesive that we purchase at local stores such as Auto Zone. I believe it is made by 3M or DuPont. We spray some onto both surfaces then let it tack up. Once we place the two surfaces in contact it takes little time for it to bond well. However, we try to let it sit for 24 hours before use. It cleans up very nicely with automotive prep solvent or CRC Brake Parts Cleaner. Get the red and white can. The stuff in the green and white can is trash and doesn't work very well. NAPA sells it for $3.50 per can. I know that for a fact because I just bought a case of it on Friday. Yeah. It works on car stuff, too. LOL

 

Let me know if you need anything else and keep up the good work.

 

Q


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#25 eric_zeiner

eric_zeiner

    Phoenix's Dad

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  • Joined: 09 Dec 2006
  • Loc: Perry, GA USA

Posted 11 November 2021 - 12:46 PM

I'm headed out to Lowe's today for some project supplies, and while I'm at it I thought I might pick up some supplies for the Space Conqueror. I'm going to be looking for some new galvanized bolts for attaching the tube to the saddle (current ones are bent and I can't remove them from the tube, so I'll be snipping them off later) as well as some new nylon-tipped thumb screws for the finder. I'll be looking for something to allow some degraded zinc-coated parts to soak in and remove the white rust, as well as some zinc spray paint to cold-re-galvanize some parts, especially the mirror cell. 

 

While I'm there I might pick up some primer/paint for the tube- if anyone has any suggestions based on what's worked well for them regarding these products, please let me know! 

On all of my ATM builds and restorations, I use Rust-Oleum Appliance Epoxy.  It goes on nicely and it gives a tough durable coat.  Is doesn't take that long to dry and I have never had it run.


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