Build Your Own Telescope For The Ultimate Experience
At left you see a quality 60mm refractor telescope of the classical
design.
What is the classic design?
The classical refractor telescope used for astronomy has a long focus 2
element objective made of Crown and Flint
glass. The long focal length is used to reduce the chromatic dispersion caused
by refractor optics. By making the focal ratio f/15 or longer, color dispersion
is reduced to a negligible level, making the instrument perfect for lunar,
planetary, and double-star observing.
The telescope you see here is a 60mm diameter instrument of 1000mm
focal length, having a focal ratio of f/16.7. Plenty long to have the
depth of field necessary to eliminate color dispersion.
This telescope is mounted on my Pipe Tripod. The pipe tripod is inexpensive and easy to make, and
in my case is used to hold several different instruments, including two
other refractors and my Meade ETX90.
If you want to shop for your telescope parts, use this custom
search engine:
Custom Search
Gather The Parts
Given that I use my trusty pipe-fitting mount as my tripod, all I needed
were the parts for the telescope. This 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 from The MASILMW Store on Cloudy Nights Forum, except for the focuser. I got that from
Meridian Telescopes. 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 the eBay-Store Telescope Warehouse.
By compatible parts, I mean that in the example given, the telescope
tube was already the proper length, and was threaded to accept the objective
cell. 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. At left 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.
A Simple Method Of Attaching The Telescope
This is a view of the business end of the telescope, with
lens hood in place. You can see from this view that the telescope is mounted
on my sturdy pipe-fitting mount.
Notice the simple attachment method used to affix the telescope to the
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 flange.
The street L shown has polished and lubricated threads and
makes the azimuth and elevation bearings for the simple tripod.
Here's another view of the telescope mounting block, or harness 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 snuggly 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, it also with a hose clamp at its balance point. Tighten the
wing nut, and I'm instantly ready to go with a different telescope.
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.
Pointing The Telescope
As you can see, 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
target.
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 (resized 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.
I've also written a program for my HP128 calculator that
holds the Messier, Caldwell, and Herschel 400 catalogs, and converts the Right
Ascension and Declination of selected targets to azimuth and elevation
angles. While the calculator program offers only a text output, it does give
the convenience of needing on site only a calculator instead of a laptop
computer.
But Is All The Effort Worth It For A 60mm Telescope
I'd have to say -- absolutely. For quick proof, 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. Newtonians 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
current arsenal.
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
Tutorial page you can use javascript calculators to compare the useful
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 this image of the crater Copernicus reveals. It too was taken
through the telescope shown on this web page. And I must report that while this
isn't a bad photo for this size telescope, the actual view through the
instrument reveals more details than this photo has captured.
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 astrocamera pictured at right.
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 ghostly 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
ultimate enjoyment.
That's what I'm experiencing now in astronomy, with 60mm 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
skies.
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
technique.
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 telescope. Or, if you want to challenge your skills, try DSO hunting
with a good 60mm. 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.