Notes from an Amateur Telescope Maker’s Journal, Part 2

First of all, I’d like to say thank you for all the feedback on the first entry from the Amateur Telescope Maker’s Journal and say “Hello! Kia ora! Namaste! Greetings and Salutations!” to all the amateur, professional and armchair astronomers who wrote from the USA, Guatemala, New Zealand, Finland, India and elsewhere. What a kick it’s been to hear from everyone, and I like to think that astronomy and watching the stars is a shared language between people from around the world.

If I have succeeded in whetting your appetite for such things and you are still interested in, or even thinking about trying to build your own telescope, you might want to read on.

Two tips to remember: “Any job worth doing is worth doing right!” No excuses! and “The longest journey begins with the first step!” Here we go!

My first step was collecting as many fasteners as I could gather. I like to repair and build things and have found that fasteners always come in handy for this or that project. Eventually the fasteners I collected became crucial in the building of my telescope! If you do decide to, or are thinking about building your own telescope, you might do some serious fastener scavenging first, or if you can afford it, go out and buy a complete set of precision stainless steel nuts and bolts. I can’t over emphasize how important this step is. Believe me, you will need them.

My favorite scavenger hunt was the result of looking in a trash bin (dumpster diving anyone?) next to a computer test equipment manufacturing company where I worked the 1980’s. During inventory the ‘powers that be’, found it actually cheaper to throw away – if you can believe it — the used and/or unsorted fasteners left over from one project or another. This was cheaper than re-sorting and re-stocking I was asked by one of the techs, if I’d be interested in collecting some of them. Of course I was! Some of those ‘slightly used’ fasteners still live in mayonnaise, peanut butter and pickle jars in my garage!

A word about scavenging, in fact, a caution: Remember to be extremely careful when handling old electronic components. For example: TV or stereo capacitors when not fully discharged present a serious shock hazard! Also, collecting components from any leaky or cracked open transformers or other components should be suspect and left alone. Got contamination? Burnt components or signs of burning are also a not good prospect. Leave it alone! Old machinery and tools found at swap meets, garage sales and recycle centers are the best resource.

Many of us amateur astronomers are on a very limited budget. We have to do the best we can to find, adapt or modify that which allows us to follow our astronomy bliss. I am not above scavenging and getting my hands dirty to do the deed!

The main mirror in a Newtonian telescope is obviously the most important single component? That is to say, aside from the eyepieces, the secondary and main mirror mount! I’ve always wanted a larger scope and was hugely excited when I heard about a 12 ½-inch mirror for sale through a friend. Buying that mirror made the rest of my project possible and the other pieces fall into place. Here, I’d like to applaud the synchronicity and blind luck!

Originally I opted to build the easiest and quickest to build mount for this telescope. That would be a ‘Dobson’ style or alt-azimuth style turntable mount. A 14 inch diameter ‘sono’ tube (a concrete pier mold) came with the mirror I bought. I experimented with this tube for a while as part of the OTA (Optical Train Assembly) but found it too heavy and clumsy to handle easily. So instead, I decided to build some sort of N/S E/W polar aligned mount. A yoke mount? A German Equatorial? or a fork mount? I had to think on that for awhile.

After buying the mirror, I found myself at a ‘point of no return’. Now was the time to consider the final design and move forward! At first, I was tempted to build a simple Dobson style mount. (John Dobson is a hero of mine!) The heavy duty ‘sono tube’ concrete pier form was originally intended as the main body of the scope. Man-O-Man, was that thing ever heavy! And kind of ugly too. The more I thought about it the more I realized it would be too heavy and probably too hard to transport. That’s when I decided to try something a little bit lighter… and maybe a little different.

I received several requests for more construction details which follow, after this progress report…

I painted the counter balance arm and counter weights with acrylic paint(s). For transporting the telescope the OTA is removed and the lead weights and steel counter balance bar removed. Handling uncoated lead or galvanized steel pipe regularly is known to be a source of heavy metal contamination. Use precautionary measures including gloves and or masks when handling or working these materials!

The most recent addition to my home-built telescope is the bright orange tennis ball at the end of the counter balance bar. I traced the end of the pipe onto the tennis ball with a pencil, then cut out the circle with an exacto knife. (CAREFULLY!) After trimming, it fit snugly in place. Next up: I will find a small battery powered red LED and mount it on the end of the tennis ball. The batteries will ‘live’ inside the removable ball. I made the plywood box to hold counter balance weights, tools, supplies and battery(s). It is also a handy ‘step up’ to the eyepiece, for shorter viewers. The top of the box I covered with a new car floor mat I found lying on the side of the road… Is that road kill?

Now, how about some more construction details:

The plant saucer I used to cover the main mirror housing has a dual function.

The circularly embossed rings in the top help align the focuser and secondary!

Now, let’s talk about some inexpensive eyepieces. Have you ever made your own? Why not?

I collected optical components from old cameras, dark room projectors, binoculars and video cameras I found along the way. Some of the optics had quite reasonable focal lengths and diameters, which made them easier to modify and turn into useful eyepieces! Inexpensive and readily available materials can be used with quite satisfactory results… that is if you aren’t a perfectionist.

Above, I show how I used old 35 mm film canisters to make eyepieces. Use an Exacto knife to cut out the bottom of plastic film containers. These containers come in several colors. I prefer the black one’s but transparent work well too! The canisters have a 1 1/4 inch outside diameter and will fit into the 1 1/4 inch eyepiece holder later.

In these views I am shown attaching a modified film canister to a ‘recycled’ 24mm video camera lens.

I wrapped the end of the film canister with black tape to make up for the difference in diameters. The modified canister then fit snugly into the end of the lens body. This handmade eyepiece has a VERY wide field yet performs fairly well! There is no color shift in the crisp, wide angle view… Yes! I like!

I did the same thing with one of the eyepieces from the Chinese binoculars I had. The 20 mm eyepiece has great eye relief! In this case, the modified film canister is super glued into place. Note: BE VERY CAREFUL when applying super glue near any optical surface! The fumes released during curing can severely damage any lens! Not that this has ever happened to me…. no……

Construction details: Continued

The leveling screws use drilled out faucet handles. I found that needed to rub some graphite onto the threads to stop them from squeaking loudly. The lag bolts pass thru clear holes in the 2 X 4’s. There are threaded inserts installed on the bottoms of the four hole locations. The faucet handles are locked in place with cap screws and nuts. The wheel axle is a solid steel rod, 3/8 inches diameter and has holes drilled thru either end for cotter pins, washers and keepers. The gap between the wheel and the modified aluminum router table is maintained with a cut piece of clear, thick walled nylon tubing.

The main mirror adjustment or collimating screws are accessed through these holes in the base of the main mirror mount.

Eventually, I will mount a cooling fan here.

Here’s how I made the secondary spider legs…

I used 2 inch long 1/4-20 bolts and cut off the heads. Then I cut a slot 1/2 way down the bolt shafts with a hand held hacksaw. I cut thin stainless steel packing straps to fit – rounded the ends – then drilled a thru hole for #00 lock nuts and screws to fasten the assembly. On the far side, there’s a SS washer and thumbscrew.

The secondary mirror housing mount was made from a 1 inch long section of 1 inch square stainless steel tubing. The stainless steel packing straps were then inserted and bent 45 degrees to fit.

How’s that for details? Of course, some ideas are not mine. I copied good ideas from elsewhere, created my own and am passing them forward to you. Does that work for you? I hope you’ve found some of this stuff useful or at least interesting? Please write and let me know? I’d appreciate it and promise to reply. I’m just a ‘lonely’ astronomer and would love to hear from you!

By the way… got any old telescope parts laying around? I’m always looking for more!

Notes from an Amateur Telescope Maker’s Journal, Part 1

A home-made equatorial wedge used with an off-the-shelf telescope, just one of the ways you can improve your telescope experiences. Credit: Dale Jacobs

Editor’s note: Interested in DIY telescopes? Amateur astronomer Dale Jacobs will be sharing his experiences in using everyday items to build or enhance telescopes.

I am an amateur astronomer and have been since the late 1970’s. I’ll be sharing some of my adventures in building and modifying telescopes for my personal use. Hopefully I can help instill the ‘bug’ in those of you who have been thinking of building your own scope but have yet to do it, or help others avoid some of my pitfalls. I’ll also be sharing my successes, which has inspired me to continue and enhance my stargazing endeavors. As you’ll see, it doesn’t always require expensive equipment, and I’ll show you how to be creative in using some things that you may have right in your kitchen cupboard or garage.

But first: how did I get started in this great hobby? Back in the 70’s I lived in a beachside studio apartment in overly crowded southern California. One chilly mid-November night (on my birthday!) I decided to go for a walk on the mostly deserted beach in front of my apartment complex to meditate and take in whatever stars I could see through the bright city lights. When I got down to the water and looked up, I was surprised to see a swarm of meteors overhead! Wow! Unknown to me at the time, this was the annual Leonid Meteor shower. I felt blessed and lucky to see those Leonids, which fell in near ‘storm’ proportions that year. I was truly amazed and watched for hours. Soon after, I began reading Sky and Telescope and Astronomy magazines to find out more about what I’d seen and then I signed up for an astronomy class at the local junior college.

One of my upstairs neighbors in the apartment building I lived in, heard about my new fascination and offered to lend me an unused and quite dusty 80mm ‘dime store’ refractor. The telescope was mounted on a poorly built alt-azimuth style tripod and came with three overpowered and very small eyepieces. Only one of them was any good and even so the eye relief was just terrible. No matter, I was young and had good eyes back then. So I took that telescope out every chance I could get and was amazed to see Jupiter’s bands and its brighter moons, Saturn’s rings with Titan, and the great Orion Nebula! The Moon soon became a constant companion as my fascination grew.

In 1984 after breaking up with my fiancée, I decided I needed a change of pace to keep from going crazy. So I quit my aerospace job and moved to Northern California. My new ‘digs’ were on a 1,000 acre cattle ranch half way up Sonoma Mountain. The ranch was only a few miles from the town of Petaluma, yet still had that ‘country’ feel – for a ‘city boy.’ The skies were usually pretty good there, especially when the fog rolled in and covered the lights of the S.F. Bay Area. At times, the brilliant stars above literally ‘took my breath away.’ We didn’t have skies like that down in Southern California! At least not within 100 miles of the greater metropolitan area…

I opted to buy a Meade model 2040, 4-inch Schmidt Cassegrain, fork mounted telescope for about $800 rather than the T.V. I was tempted to buy. This telescope turned out to be a MUCH better ‘deal’ and has been a great night time companion over the years! Since I wasn’t dating or even interested in the opposite sex for a quite awhile, it suited and served me well. A small scope is easy to set up and transport, which is key for casual observing. I even put it on the back of my motorcycle one time and drove up to Lake Tahoe with it! (Minus the tripod – it has screw-in legs for setting up on any suitable flat surface – such as a picnic table.)

The top image is of that telescope mounted on an equatorial wedge I made for my latitude. The wedge is constructed of a hard wood core, marine grade plywood. It is very stable! The cost for this endeavor was about $10, which included the wood, glue and fasteners. It was well worth the price, and I’m still using it! The tripod is an old surveyor’s backsight that my brother, a land surveyor, found one day working way back ‘in the woods’, up on a mountaintop. It had obviously been forgotten and had been there for who knows how many years. It was probably made in the 1940’s. It sure soaked up/took a lot rejuvenating oil and rubbing to make it useful again, but I like reusing old tools.

Building this equatorial wedge was a great confidence builder and inspired me to continue my star gazing. A 4-inch scope may be considered ‘small’, but a scope this size is a GREAT beginner’s scope and is a handy adjunct for any serious star gazer. Not shown in this image is the tar paper/roofing felt tube I rubber band around the end of the scope for dew protection. Yeah… this is ‘my baby’. It has served me quite well throughout the years! I saw Comet Austin, Comet Halley, Comet Hyakutaki, and Comet Hale Bopp with this scope, along with 41 other comets! I may have been taunted by other astronomers at star parties for having such a ‘small’ scope… but I’ll tell you what… smaller scopes can sometimes ‘see’ through upper atmospheric disturbance cells and are actually better than larger scopes at doing so. I have seen where they will sometimes outperform 8-, 10- or 12-inch scopes! Many times at ‘star parties’ I was the one to found that obscure comet… long before the larger scopes did.

One thing I discovered is that while adequate for casual viewing, this scope doesn’t do all that well with faint galaxies. As a result, I’ve always dreamed of having a larger ‘light bucket’ for those clear nights, when the seeing excels. Then one day, a scientist friend of mine, who was leaving the area to work at the new Virgin Galactic space port in New Mexico, offered to sell me a 12 1/2 inch mirror he’d ground and polished back in the 1970’s. He’d never completed the project due in no small part to the arrival of babies and pressing career responsibilities. Along with the 12 1/2″ mirror he also sold me several components he’d collected to build his ‘dream’ scope, but never did. What you see below is what I ended up doing with some of those components and my own additions.

Here ‘she’ is, warts and all…. my new baby!

Dale’s 12 1/2 inch lightbucket…. or light pot. Image: Dale Jacobs.

The base of the mount I made from a modified aluminum router table. Attached to that is a Doug Fir 2X4 leveling and support base. The leveling screws I made from 8-inch long lag bolts with their rounded heads pointing downwards. The handles of the leveling screws I made from drilled out garden faucet handles. They are captured by stainless steel cap nuts and threaded inserts. The wheels on this side of the base I purchased at a local hardware store, the axle too. The two front wheels on the side opposite, are from a baby carriage! The equatorial wedge I cut from a piece of 1 inch thick plywood. The cast aluminum equatorial mount was made from an old Navy gun alignment bore sight. The R.A. axis is mounted where the spotting or alignment scope once lived. The clamps that held that bore scope now hold the R.A. shaft bearings in place.

Here’s what I did with the old refractor/bore sight.

I mounted it on a German Equatorial from an old Tasco 4 inch reflector a friend gave me. The aluminum pie pan makes the shadow for the projected solar image. To connect the imager to the eyepiece I used black PVC tubing with straightened clothes hanger metal spokes in drilled through holes. The spokes are held in place with a stainless steel tube clamp. Rubber bands behind the white projection plate hold it firmly in place. I use this scope to observe Sun spots. Not only can I see the spots but also sometimes can see the whitish faculae which frequently accompany and surround them!

I finally got the balancing just right for the 12 1/2″ scope. That was tricky! This mount allows me to move the whole assembly with a finger light touch. I made brakes to stop motion A/R in either axis from hard wood cutouts.

Here’s a view of the secondary mirror housing:

The aluminum struts I purchased at a scrap and hardware store. I made the finder scope from a pair of ‘funky’ plastic Chinese binoculars that never focused properly anyway. The finder’s body and mount are constructed from white PVC tubing and held in place with nylon screws. The base of the finder mount was made from a broken finder scope that I modified to fit with a Dremel tool. The eyepiece focuser can be moved left/right, up/down on any of the four paired dowels by loosening the attached nylon screws. Next up, I will make a ‘clocking mechanism’ so I can easily turn the secondary 90-180 or 270 degrees.

I can add other focusers, cameras or instruments on any of the 4X ‘dowel flat’ pairs. I made the secondary mirror from a precision optical flat another scientist friend gave me back in 1984 when I worked at a semiconductor equipment manufacturing company. Ever cut glass before? Triple trick! Those flats were coated with aluminum during a vacuum/deposition chamber test. The secondary housing I cut from an old fishing rod transport tube. Later, I plan to purchase a 1/10 wave or better secondary and new mirror mount. The spider legs are modified stainless steel packing straps. Both the secondary housing and main mirror housing were made from 34 qt. alum. cook pots! What’s cooking Daddy-O or Momma Mia?!

Here’s a view of the mirror cover I made from a ‘spare’ plant pot saucer. (Don’t tell the wife!) I sewed the ‘grip handles’ into the nylon mounting straps to aid in tightening the straps. Part of the two wooden brake assemblies are also shown in this view:

In this view you can see the ‘yet to be coated’ primary mirror and the ‘at that time’ mostly unpainted secondary mirror housing:

I’ll have the mirror tested and coated soon and plan on using a web cam or DSLR for imaging after I install some sort of clock drive mechanism. I hope to eventually participate in the Universe Today’s weekly online Virtual Star Parties with this ‘puppy’ (as David Letterman would say) when completed. I hope so anyway… only time will tell!

In the next episode… I hope to ‘show off’ some images! There’s that ‘only time will tell’ thing again!

Have any questions or comments for Dale about his amateur DIY astronomy? Leave comments below, or you can send him an email

All images are courtesy Dale Jacobs