Build Your Own Telescope For The Ultimate Experience
Would you like a quality but inexpensive, quick setup, fast cool down, and
sharp imaging telescope? If so, you might find it hard to put all of that
together in one package. Fast cool down means either quite small, or a
refractor. But a quality refractor is not generally that inexpensive.
You could try a DIY refractor project to get that super telescope.
Above you see a quality 60mm refractor telescope of the classical
design. It is about 40 inches long, yet very light to handle. It is shown
mounted on my trusty Pipe Fitting Mount.
What is the classic design?
The classical refractor telescope used for astronomy has a long focus 2
element objective (front lens) made of Crown and Flint
glass. The long focal length is used in conjunction with the achromatic (2
element) lens to reduce the chromatic dispersion caused by refractor optics. By
making the focal long enough, color dispersion is reduced to a
negligible level, making the instrument perfect for lunar, planetary, and
general astronomical observing.
A handy chart for determining adequate focal ratios for different
telescopes to achieve low chromatic aberration is the Chromatic
Aberration chart. Use this as a guide to determine what size and length
refractor you want to construct (or purchase). Try to keep the focal ratio
divided by the telescope diameter in inches to the Sidgwick criteria or better.
That means keep the focal ratio divided by the diameter in inches to 3 or
Color dispersion, or chromatic distortion, refers to the characteristic
spreading of light colors caused by prisms and lenses. If you view the bright
limb of the moon with a poor lens or a short focus refractor, likely you'll see not the bright curve of the moon's limb with a black background, but rather
a bright limb that is bleeding a thin ring of colors, yellow, red, and blue. The dominance of colors is determined by the particular focus setting of the
This is caused by the color spreading characteristic of the objective
lens (or lenses). Since the colors are spread slightly by the objective,
all colors do not come to focus at the same point. So at any particular
focus setting, a narrow band of colors is properly focused, and the colors
further away in the spectrum are slightly out of focus, leading to the
halo of colors visible whenever viewing a bright target, like the limb of
the moon. It has the effect of softening the details of the image, in that
always some colors are out of focus as others are in focus.
Long ago telescope makers learned that making a telescope objective out of
two lenses back to back, each out of a different type of glass, decreased this
unwanted color dispersion. Crown and Flint glass has been and is still a common
choice of glass types, though newer types of glass with less color spreading
characteristics are now used on shorter focus telescopes. These newer
refractors are called ED telescopes, for extra-low dispersion. Using two
lenses together allows telescope makers to bring some of the color spread under
better control, greatly reducing the problem. The classical crown and flint
lenses work good in larger focal ratios, and the new ED refractors can work at
focal ratios perhaps half of what classic refractors require.
So a long focus refractor, even using the older and less expensive Crown and
Flint glasses, produces images with virtually no noticeable color dispersion.
The result, no halo of colors around bright objects, and sharper images. The
classic refractor telescope of moderate diameter has been a refractor with an
f/15 focal ratio or longer. That means that the focal length of the telescope
is 15 times the diameter of the telescope.
The bigger the diameter of a telescope objective, the bigger the focal ratio
must be to achieve good color correction. Referencing the Chromatic Aberration
chart you can see that a classic design 60mm of f/7 or greater meets the
Sidgwick (3 ratio) standard of color dispersion. A very common focal length for
60mm telescopes is 700mm, which gives a focal ratio per telescope diameter
value of nearly 5. For both 60mm and 70mm telescopes, a ratio of f/12 or
better will deliver nearly chromatic-error free images, meeting even the
Conrady (5 ratio) standard.
The telescope you see above is a 60mm diameter instrument of 1000mm focal
length, having a focal ratio of f/16.7, and a chromatic aberration ratio of
6.9. Plenty long to have the depth of field necessary to eliminate color
dispersion. It's hard to find such long focus telescopes in today's market. The
closest complete telescope I've found comparable to the one shown here is the
21062 AstroMaster 70 EQ Refractor Telescope, which is a 900mm focal length 70mm telescope. It
would be a good choice if you'd rather buy than build, and the Celestron is
70mm, providing greater light gathering power at a similar focal length.
The 60mm telescope I constructed from parts is mounted on my DIY Pipe Tripod. The homemade
pipe tripod is inexpensive and easy to make, and in my case is used to hold any
one of several different instruments, including three other refractors and my
Meade ETX90. You can save some time and still end up with a super setup by just
building your telescope and purchasing the Celestron
Heavy-Duty Altazimuth Tripod. It's an easy to use altazimuth mount that's likely
superior to what comes with most 60mm telescopes, and saves you the hassle of
building a mount like mine.
But as you might guess, I not only love astronomy and telescopes, I also
like to tinker. I'm kind of a low level amateur ATM (Amateur Telescope Maker).
If you love the astronomy and telescope part, but not so much the tinker part,
something like a ready made refractor on a computerized mount (at a reasonable
price) might be your cup of tea, like the Celestron
SkyProdigy 70 28x165 Telescope. This choice, looking at the Chromatic Aberration
chart, gives a focal ratio to diameter value of 3.63, which is respectable.
The computerized mount may be handy for you. Such mounts require you
to align on 2 or 3 stars (depending upon alignment option), then you can just
enter values into a hand controller and the telescope will move to the target.
They don't always land right on target, but a very small amount of slewing with
the controller push buttons usually brings the target into view.
Gather The Parts
But if you are interesting in making your own custom telescope, you need the
right parts. Given that I use my trusty pipe-fitting mount as my tripod, all I
needed were the parts for the telescope. The above image shows basically all
that there is to a refractor telescope.
It shows the eyepiece end of the tube, the focuser, the finder scope, and
the telescope objective. That's about it. And if you get compatible parts,
about all you have to do is drill a few holes and screw the parts together.
I purchased all of the parts for this telescope except the focuser from a
store on the Cloudy Nights Forum. At last check, the Cloudy Nights store
didn't seem available anymore, so you'll likely have to find a good objective
I got the focuser from Meridian Telescopes, another source that seems to
have dried up. The entire telescope project cost me only about $120.
The heart of the telescope is the object lens, which is a Japanese one of fine
quality made by the Carton company. Other sites to check out for inexpensive
telescope project parts are the SurpluShed, and eBay-Store
By compatible parts, I mean that in the example given, the telescope tube
was already the proper length, was threaded to accept the objective cell, and
already had a baffle in the tube to limit stray light. The objective lens was
already mounted in the cell. The focuser already properly fit the inside
diameter of the tube. I only had to drill holes to accommodate the focuser and
the finder scope.
If you must collect parts from different sources, then you'll need to be
sure of a few measurements. Be sure the lens cell fits the tube you purchase.
Be sure the focuser and finder mount fit the telescope tube size. Also,
carefully measure the focal length of the of the objective and be sure to cut
the telescope tube at a length that properly brings the image to focus within
the focuser travel range.
If you must cut a tube, it's important to cut it as square as possible.
Wrap a 2 inch or wider strip of paper around a tube where you want to cut,
making sure the ends of the paper overlap perfectly. With this strip of paper
taped into place with a bit of masking tape, use the edge of paper as a guide
to draw a line around the telescope. This will ensure that the traced line is
in fact square with the length of the tube. Then carefully cut along the line.
Cut just through the line, and rotate to an adjacent portion of the line to
continue cutting. A bit of finish up filing should leave you with a near
perfect, square cut.
Also, if your telescope tube has no baffles already in it, you'll need to
add a couple of those. This FAQ on Refractor
Baffles can help answer your questions on positioning baffles.
Add Just A Bit Of Improvising
The only part I could not readily find for my simple project was a
lens hood. Above you see my solution to that problem.
I was able to find an empty plastic soap bottle that was just bigger than
the diameter of my telescope. I cut off the neck end, and cut a hole in the
bottom to just accommodate the threads on the objective cell.
I then sprayed the inside and outside of the bottle with flat black
paint and screwed it onto the front of my telescope. It has made a fine
lens hood, cost nothing, and took little effort.
If You Can't Find Good 60mm Telescope Parts
What do you get for all of this work? Mainly you get a solid telescope
with good optics that will last for years. Many off the shelf modern telescopes
have a lot of plastic parts, like plastic focusers, and/or plastic lens cells.
Some even have plastic lenses. By purchasing quality parts, you can approach
the off the shelf cheap telescopes and end up with a solid performer with all
Another option, maybe an even better one, is to find a vintage Japanese 60mm
telescope on EBay, such as the 60mm Monolux that
I obtained from an on line acquaintance. Then you can used some of the
information on this page and on the Monolux page as a starting point and
improve your used purchase to make a super performer. How I did the
improvements is described on the Monolux reference above.
As to new telescopes, I've heard good reviews for the long focus 60mm
telescopes from Celestron, like the Celestron
21043 60mm Equatorial PowerSeeker Telescope. They tend to be sold as kids telescopes, but an
experienced observer that I know has one of the long focus Celestron 60mm
telescopes, and gives it a thumbs up. The main problem with them is they'll
likely have inadequate mounts (tripods). There are on line sites that give
suggestions on how to improve the tripods, but you may find the pipe tripod
that I use a good alternative. It is way better than the mounts
delivered with most 60mm telescopes.
Another option is to go just a bit larger and consider the Vixen
2602 A70Lf Telescope, which is available at Amazon for less that
$200, about what you might have to pay for an EBay 60mm quality telescope.
And the Vixen is a nice f/12.9 70mm telescope of 900mm focal length. I have one
which I've reviewed at the Vixen 70mm Review site. A
bit shorter than my classic 60mm DIY instrument, which is 1000mm, but a bit
bigger in diameter. That extra 10mm in diameter increases resolution and
light gathering power in a noticeable way.
At the low price of the Vixen, it does not come with a tripod, but does
come with a dove tail to fit a standard Vixen mount. A same sized Vixen
telescope complete with mount is the
Vixen Vixen Space Eye 70 Refractor Telescope, 70, which comes in at less than $400. Makes
the old $50 pipe mount a bit more attractive, no?
A Simple Method Of Attaching The Telescope
The above view shows the business end of my DIY telescope, with lens
hood in place. Notice the simple attachment method used to affix the telescope
to the pipe-fitting mount. The telescope sits on two plywood blocks with v
cuts, and the blocks are glued to a piece of plywood attached to a floor
The street L shown has polished and lubricated threads and
makes the azimuth and elevation bearings for the simple tripod.
Above is shown another view of the telescope mounting block, or cradle if
you prefer. Here you can easily see the plywood piece that attaches to the
floor flange of the mounting head, and the v-blocks glued to the ends of the
piece of plywood.
In this image, you can also see the simple method of attaching the
telescope to the v-block unit. A hose clamp has a 1/4 inch hole drilled
into it. A screw goes through the clamp and protrudes through the plywood.
The clamp goes around the telescope. A wing nut on the end of the 1/4 inch
screw draws the telescope tightly into the v-blocks.
By testing balance with the star diagonal and eyepiece in place, I can find
the perfect balance point and then tighten the hose clamp in place. In this
way, unscrewing a single wing nut lets me remove this telescope and mount a
different one, each having a hose clamp at its respective balance point.
Tighten the wing nut, and I'm instantly ready to go with a different
Here's a drawing of the modified hose clamp. It simply has a hole drilled
through the clamp, opposite the screw mechanism. The drilled hole is 1/4
inch in diameter, enough to accommodate a 1/4 inch screw that's long enough
to extend through the wooden telescope cradle. I always put a strip of felt
or some soft cloth around the telescope with the clamp fitting over the
felt. This protects the telescope finish from the clamp.
Pointing The Telescope
As you can see in the above illustration, the telescope is complete with a
6x30 finder, helpful for finding objects. But to further aid in the finding of
faint fuzzies (yes, you can see many such objects with a 60mm telescope), the
mount has Altazimuth setting circles. Most computer planetarium programs will
optionally list out the azimuth and elevation of any given object.
To use the circles, I must level the tripod. By that I mean the when
pointing both North/South and East/West, the telescope should be level when at
elevation zero. I place a small level on the telescope to make this adjustment,
placing shims under the telescope legs to get the level readings.
Then I point the telescope at Polaris, at which point I set the azimuth ring
to read zero. At that point my telescope is aligned, and my Xephem planetarium
program can be used to tell me the current azimuth and elevation of any desired
The display above is the night sky display from the Xephem program, available in both free and
commercial forms. This display is from the free version.
In this example, I left-clicked on an object of interest in the displayed
star chart (re-sized smaller for this example). This caused current positional
information for the object to be displayed in the upper-right corner, including
the object's azimuth and elevation (altitude). I've expanded that portion of
the display in the blowup. By using the Az and Alt numbers, I can
point my telescope to an object using Altazimuth setting circles. Other
computer planetarium programs, such as Stellarium and Kstars can also display
azimuth and elevation coordinate numbers.
The Ultimate Pointing Aid
I think a much better aid to help in pointing my telescope is to use the web
Star Pointer utility. It's available for you too, freely and conveniently. Just
grab your smart phone, laptop, or Chromebook, and go to the Star Pointer web
page. There you can select objects from either the Messier, Caldwell, or
Herschel 400 target lists, and get updated pointing coordinates to all targets
in the selected list. You can choose altazimuth or equatorial coordinates, and
the equatorial coordinates (which provide an alignment procedure) will present
adjusted RA coordinates throughout the night in order to account for
earth's rotation since alignment.
The image above is an abbreviated view of what the Star Pointer web page
displays. The utility can use a device's auto-location services (GPS) if
available, or if not, allow you to enter your location. The
utility needs this to compute the proper coordinates of each target for your
particular viewing position.
If you allow it to do so, the Starpointer utility saves your location in a
cookie so it will be available automatically on your next visit. That's
assuming that you observe from the same location next time. So with Star
Pointer, you don't need charts, just a smart phone and your telescope (with
setting circles). It's all I use now -- try it.
But Is All The Effort Worth It For A 60mm Telescope
I'd have to say -- absolutely. I'm in my retirement years now -- that's
right -- I'm a Stargeezer, as this
humorous t-shirt design suggests. And after years of lugging bigger telescopes
around the yard, I have to say that the incredible simplicity of using a
quality 60mm to 70mm refractor on a solid mount has given me hours of
For quick proof of what such ans instrument can do, check out my 60mm Astrophotos for
some surprising images of the moon and Jupiter, all taken through the telescope
shown on this web page. Of course, not everyone agrees that so small a
telescope is sufficient, so let me justify my enthusiasm.
Certainly there are those (I was one) who recommend something like a 6 inch
Dobsonian telescope as a first telescope. The reasoning is that a 6 inch
aperture is enough to see a wealth of targets quite well, yet a 6 inch
Newtonian is not an expensive telescope. Newtonian telescopes have long been considered
the most bang for the buck, telescope-wise. And over the years I've
certainly owned my share of Newtonian telescopes, with two 6 inch ones in my
In fact, I started out in astronomy some 50+ years ago with Newtonian
telescopes. Like most youngsters at that time, I'd read that one needs at
least a 3 inch refractor or 6 inch reflector to do serious work, and
I could get a 6 inch reflector for about the money of a 3 inch refractor. So
in those days, I never tried a refractor of quality -- of any size.
But as I've grown older, I've found that convenience is moving up in
priority as an observing criteria. If my telescope isn't convenient, it
doesn't get used much. And it's been said many times that a big telescope that
is rarely used isn't as good as a smaller one that does get used. So, I've
started working with a couple of nice 60mm refractors to see if I'd been
missing anything, the one described on this page and my
Monolux that was
brought back from near death.
What I've been able to see with these effortless to use, ready to go at a
moments notice telescopes has really surprised and pleased me. With the two
instruments I've observed countless craters on the Moon, Jupiter, Saturn, Mars,
quite a few open clusters, and a few globular clusters and nebula. The
instruments both can perform well up to about 150x, and the Carton shown on
this page can be pushed up to 180x to 200x on bright targets while still
yielding good images in adequate seeing.
On my Telescope
magnifications of different sized telescopes, and minimum star magnitudes
observable with different sized telescopes. On my Simulated Views page you
can compare simulated views of Jupiter through different sized telescopes.
While you'll certainly find that bigger telescopes (under good conditions) can
see more, hopefully you'll also notice that what can be seen with a quality
60mm refractor is nothing to sneeze at. Especially given the cost, simplicity
and convenience of the venerable 60mm.
Photos Through My 60mm Telescope
The following photographs were all taken through the 60mm telescope
described on this page. Most were taken just by holding my digital camera
to the eyepiece. Some were taken with a Celestron NexImage web cam.
As just an example of the power of a small refractor, this picture of the
Apennines Mountains region of the moon, taken with a hand-held digital camera
through the telescope described on this web page. This isn't the best
one can do through a 60mm, but it isn't bad given the simple way the
image was taken. It shows the kind of detail one can see through a 60mm
telescope, and I can testify to the fact that the actual view through the
telescope was sharper.
Here's another lunar image taken through the Carton telescope described
on this web page. This is a view of the Plato region, with the Straight
Range also visible.
And if you happen to think that a 60mm telescope is only good for panoramic
views of the moon, think again. You can get very good close up views of the
moon as well, as the above image of the crater Eratosthenes reveals. It too was
taken through the telescope shown on this web page, but using a Celestron NexImage
astro-camera. Notice the 3 central peaks of the crater. Look for them next time
you view the region, near the crater Copernicus.
When Mars was at an apparent size of only about 12 arc-seconds, it still
gave up a few details to this 60mm wonder. I've also been able to watch Io's
shadow move across Jupiter with both of my 60mm telescopes. Admittedly, I am
generally unable to catch the Great Red Spot, but I can discern the NEB and
split the SEB, as well as see some dark regions in the NEB. In 2010, Jupiter
presented a seldom but occasionally seen phenomenon when the SEB virtually
disappeared. I managed to capture that view with the Carton 60mm on my 60mm Astrophotography
web page. For this image I didn't use a handheld camera, but the Celestron
NexImage web cam astro-camera.
At the time of this writing, Saturn's rings are viewed nearly edge-on, so
I've not been able to try seeing the Cassini division, so hopefully I have
a treat still in store.
As to stars, refractors of this size give the nicest views of double stars
that I've seen. Yes, on nights of very good seeing my bigger reflectors can
separate closer doubles, but even then the reflectors' don't give the crisp,
satisfying images that the refractors do.
Open clusters are easy and enjoyable to see with a 60mm, and unlike my
f/5 Newtonian, stars are crisp and pinpoint right to the edge of the field
of view. Globular clusters are easily visible in my 60mm telescopes, but
most can't be resolved beyond a fuzzy image.
I was surprised to see how well some nebula can be observed with 60mm
telescopes. I was able to find the Ring nebula (M 57) even when a quarter
moon was out. And on dark nights I can make out the faint Crab nebula.
Those views have whetted my appetite for more star and nebula targets.
Simplicity And Convenience
So why not just use a bigger telescope instead of trying to squeeze
performance out of a lowly 60mm?
For me it's similar to the reason I liked the QRP low-powered equipment when
I was into ham radio. Then, it was easy to sit at a microphone in Denver with a
several-hundred watt unit and chat with a fellow in Florida, but seemed more
satisfying to have done it with a telegraph key and a mere 500 milliwatts of
power. My skill at using the low power rig added to the challenge, and the
That's what I'm experiencing now in astronomy, with 60mm and 70mm
refractors. Sure I can find and see targets easier with my 6 inch reflectors.
But they are more of a hassle to set up, and must cool down for at least 45
minutes before they can deliver good views. My f/5 Newtonian on its equatorial
mount is often sitting at an odd angle for observing, so I have to loosen bolts
and rotate the telescope in its cradle to find a more comfortable position.
But my 60mm refractors (whichever one I'm using) sit mounted on my simple
but sturdy Altazimuth pipe tripod ready to go to work. They provide quality
images with just minutes of cooling. With the simple Altazimuth mount, the
finder and telescope eyepiece are always in comfortable positions as I move
from target to target. Putting up the equipment is a snap -- just put the tripod
back in the shed and cover the lenses. Done.
For casual observing, nothing could be simpler or more convenient.
One final thought.
A small telescope in dark skies can often trump a bigger telescope in
light polluted skies. It's easy to see from one to two more magnitudes of
stars in dark skies versus one's backyard. At a two magnitude difference
in darkness of skies, a 60mm in dark skies can see as well as a 6 inch
in light-polluted skies. At a one magnitude difference in sky quality,
a 60mm in dark skies can see as well as about a 90mm in light-polluted
Add to that the plethora of techniques for pushing your observing limit. For
example, be sure your eyes are dark adapted. Use the appropriate magnification
for the target. Be sure your lenses are clean, and position the telescope
behind anything that can block off a troublesome light source. Practice using
averted vision, you'll be amazed at the targets you can see with that
I've found I can pick up a magnitude just by using my left eye rather
than my right. How? Easy, I had cataract surgery on my left eye, and it
no longer has decades of aged dimming to filter the view.
As one fellow that also belongs to an astronomy e-club that I frequent put
it, you can put your money into a bigger telescope, or use a quality 60mm or
70mm refractor and put you money into gas to get to a darker site.
In any event, if you haven't bought a telescope yet and aren't sure if you
want to learn about aligning and cleaning mirrors, consider starting with a
good 60mm to 70mm telescope. Or, if you want to challenge your skills, try DSO
hunting with a good 60mm or 70mm. Your sense of satisfaction at finding objects
with such modest equipment will surprise you.
If you observe with a 60mm or any other size telescope, consider filling out
the Amateur Astronomer
Survey. Then compare your use of telescopes and other equipment with that
of other amateur astronomers.