Category Archives: Telescope Maker’s Workshop

Questar Telescope

IMG_5227 smallAt last, after many years of wanting a Questar, I finally own one. Now I know what all the hyperbole was about and am guilty of going over the top myself when describing mine. It is simply the best telescope I own on several levels. Don’t get me wrong; a bigger aperture scope will out perform my little Questar. But, as any Questar owner will tell you, it is impossible to get more performance in any other similar sized scope. Pound for pound, it is the most bang for the buck. And it is astounding to hold a small piece of sheer perfection in your hand.

It seems to me that a Questar demands a fine mount. The scope actually performs well on a nice Bogen Tripod and the Questar folks sell an elegant mount (for a lot of money). But, as an amateur machinist, I wanted to make my own. I wanted a suitable tripod and wedge befitting a Questar, so I modified a wonderful little Celestron CG4 tripod and made a carefully crafted pier and wedge to go on top.

You can see my Questar and its mount at

Tinsley Telescopes

I recently posted a couple of videos about classic Tinsley telescopes.

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The smaller scope in this picture is a Tinsley 3 inch. Video at .  I had to repair the mount as shown in the video but otherwise the scope is all original.

The larger scope in the picture is a Tinsley 4 inch refractor. It is nearly a complete superficial restoration. The basic scope, focuser and objective are all original, as is the wonderful mount. All the paint is new and the finder is a replica I made. Please watch the video at .

Here are some shots of making the replica finder rings on the 4 inch for those interested in machining.

Replica Antique Zeiss Mount

I recenlty purchased a beautiful Zeiss Starmor 60mm spotting scope from about 1918. The scope is in superb condition and works well.


Zeiss Starmor
Zeiss Starmor

The scope did not have any mount and I wanted to display it in my living room so I decided to use my metal working skills to make a replica of the original table-top mount for the scope.

Starmor Mount

So I started by cutting out a piece of 5/8 aluminum plate in the shape of the feet;

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Next, I cut a piece of aluminum tube to make the centerpost, flattened three sides of it in the mill and notched it for 1/4 inch bolts


I drilled and tapped each foot for 1/4 – 20 bolts to attach them to the center-post. Here it is all put together:


I did a lot of filing and shaping of the feet. The idea was to make it look like an antique single-piece casting. The 1/4 -20 bolts do the majority of the support work, but I used some JB Weld high strength epoxy at the joints to make sure nothing could move. I love that stuff! I also used some JB Weld Metal Putty to help fill in some smaller gaps and build up one of the legs where it was not quite symetrical with the others.


Next it was time for some quick work with Bondo automotive metal filler. This stuff sets so fast you barely have time to get it in place. Luckily it files and sands off very easily. Note, the Bondo is not structural in this piece. It is just meant to make the item look more like a casting.


Next came some easy sanding and shaping. It was a piece of cake compared to the raw aluminum in the legs.

I turned a piece of 5/8 Stainless Steel to fit the scope, threaded the other end and turned an aluminum plug. The plug is held in with three small screws through the tube, then the shaft is bolted in. I wanted to make this easy to change should I want a taller mount or maybe want to use the scope on a tripod. I would be easy to adapt the Stainles Steel pinion shaft to most anything.


This is the final product. It looks very appropriate with the scope. It is very nice to have a lathe and mill to make things like this.


Pictures of the original are here: Zeiss Historica (second image down).

Removing the counterweight from a Meade 7 inch Maksutov

Optics from my Meade 7 inch Maksutov

Optics from my Meade 7 inch Maksutov

Recently I began to notice some disturbing loud clunking noises when I moved my Meade 7 inch from one position to another. I was already aware that this scope contained a substantial counterweight inside the tube. The counterweight allows the telescope to balance in fork arms designed for a shorter 8 inch Schmidt Cassegrain telescope. The counterweight was loose inside the tube, bouncing up against the delicate primary mirror! Sooner or later a disaster was inevitable. It had to go. Even if the weight had still been well attached, it would be desirable to remove it. The counterweight causes slowed cooling resulting in problems with the image under less than ideal circumstances. Some ATMs have already removed the weight for that reason alone. See the excellent information from Steve Hollenbach at . His advice and instructions are invaluable!

It was time for major surgery on that telescope. This is not something I recommend for all owners of the Mead 7 Mak. I undertook this with some trepidation and I am a highly experienced Amateur Telescope Maker. You might need to cut your tube or pry the counterweight out of the back of the tube using some sort of crowbar. You could easily drop the mirror inside the tube while in the process of disconnecting the focusing mechanism, damage the mirror while handling it inside the tube, drop the meniscus corrector plate, break the baffling tube, get dirt or metal particles into the grease on the mounting tube or any number of other possible disasters. Consider the risks before you do this yourself!

I could easily have ruined the scope. But, instead, I got lucky. Here is the result:

Mead 7 inch Mak with new balance point

Mead 7 inch Mak with new balance point

Please see my Youtube video at for all the details.

The Result

I had a three scope shootout on 3-5-14. Jupiter was near the zenith and the seeing was very good for Colorado. Here is a picture:

Scope Shootout 3-5-14

Scope Shootout 3-5-14

The “new” Mak is at the far left, then a 6 inch f/15 folded Jaegers achromat, then a Meade 5 inch ED APO at the far right. I was glad to see that the new, lighter mount for the Mak was sufficient for visual observations up to over 200x. The Mak cooled very nicely and what was nifty was that it stayed cool. I have noticed in the past that the scope would look great momentarily but it never really settled down. It was very tempramental and it would shine briefly only to dissapoint a moment later. I hypothesize that this was due to the large thermal inertia of the massive counterweight. Anyway, that behaviour was gone tonight. Hurray! The thermal effects in the Mak have vanished. It still has a relatively large central obstruction, though so putting it up against a couple of smaller refractors is a fair competition.

The optics in these scopes are all nearly perfect. The ED APO is superb. The 6 inch is great but there are a lot of optical surfaces in that scope so it is a little softer. The Mak shows a textbook diffraction pattern inside and outside focus.

So which one is best?

The Mak has a perfect image during the brief moments of perfect air, a few times every several seconds. But, even with the dramatic improvement, it is a bit more susceptible to seeing than the other scopes. The smaller APO is more steady, and the image is nearly as good as its big brother. The six inch is a great big horse compared to these two. The image is lovely but it does not justify the extra effort to set it up. So the little APO wins for nights of poor or mediocre seeing. The Mak wins for nights of good or great seeing. Both of these scopes are simple and easy to use, especially now that the Mak has lost all that weight.

I am very happy with the outcome!


Folded Refractor

Six Inch Folded Refractor

Six Inch Folded Refractor

I have updated my Folded Refractor page as promised earlier. Please check it out if you are interested in strange telescopes. I include the steps I take to align and collimate the scope. Since I last built one about twenty years ago I had to learn this all over again with this more recent scope. I could not find anything useful online about this process so I thought this might, at least, give someone else a place to start. Hope you enjoy!

Amateur Telescope Making Machinist (ATMM)


I used to get frustrated when I read about Amateur Telescope Making (ATM) projects that required machine tools since I did not have access to a machine shop. I still strongly support modest projects designed for the vast majority of telescope enthusiasts who do not have the inclination to buy a metal lathe nor the time to learn how to use it. It is great fun to test the limits of your skills with simple materials. I still enjoy making telescopes and parts from wood. It is a great challenge to make inexpensive telescopes that perform nearly as well as the best commercial products available. John Dobson inspired a lot of us!

Eventually I discovered that I needed metal to experiment with some novel concepts and designs.  As my ATM creations became more sophisticated I had to develop metalworking skills. It is very easy to be drawn away from telescopes. Home Machinists like to make their own tools and create wonderful mechanisms. It is an entire world! Though I have been seduced into a few such projects, I have steered away from all that and always return to my first love – telescopes.

I am working on a page devoted to my six inch folded refractor. I could not have built it without my small home machine shop. I have come to love my lathe and mill as much as my telescopes. My Southbend 10K lathe is one of my most prized possessions. It is an exquisitely beautiful example of perfect design and functionality.

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