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APM-100mm binocular telescope “More horse power for the aperture hungry eyes”

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APM-100mm binocular telescope “More horse power for the aperture hungry eyes.”

By Steve Brian

Figure 1.

Good evening to all you binocular aficionados. I have been a long time fan of astronomy but not active sense moving my family to New Hampshire from Florida 12 years ago. This was a real shame because the night skies are wonderful here in NH.

Why the change? I recently purchased a new Canon Power Shot SX20IS point and shoot camera with 13MPs and zoom. I turned the camera to the sky and snapped a few photos of the Moon and Jupiter. You know, the photos came out pretty darn good and I have been hooked ever sense.

Why binoculars? Will with age comes wisdom… I have owned a variety of telescopes and binoculars in my life but 20 year ago I bought the optics to build a 13” DOB which I have started several time but never seemed able to complete this project for one reason or another, but the main problem was the thought of dragging around 80 or 100 plus pounds of gear in and out of the cold and snow. And then there is the one eyed squinty thing which to me gets old real fast. So I grabbed and old pair of Bushnell 10x50 out of my closet dusted them off and turned them loose on the night sky and wow! For days after I was beating my self up for not doing this year’s ago.

Sense turning the binoculars to the sky I have spent a lot of time over these pass few months reading all CNs binocular reviews and educational information on these forums and some of those articles I read twice… what a great website! Reading one forum I quickly learned how to clean and repair my old binoculars which improved my viewing in short order, but the eyes get sophisticated pretty fast and the search began for more horse power to search the night sky. Bigger Bino’s!

Now many amateur astronomers where claiming 10x50 are a good staring point and I suppose so, if that’s all you have to work with, sure! But the truth is these smaller binoculars are just the appetizer before the big meal, and that’s just what happened. I purchase a pair of Celestrons 15x70 and although this was a step in the right direction, I was still hungry for more!

Utilizing the internet I began the search for perfect binoculars but there was no such thing to be found! Well I lied, because with enough money, you can buy something petty darn close… But what I was looking for was, a light weight, large aperture binoculars with variable magnification and something in the $1000 range and can be used for both planetary and DSO. My search began for the Holy Grail of binos “The Binocular Telescope”.

Now as you travel down this path a couple of things happen… 1. Your eye sight improves! Well not really, but through binoculars you see the sky in a whole new light literally. 2. You realize that size does matter! If you heard differently he or she was lying to you! 3. You learn a whole new language reserved for only a few enthusiasts. 4. Addiction to binocular astronomy is going to be expensive for all those who travel down this path.

The APMs! More horse power.

Over the months reading review after review and forum after forum on CN as well many other sites on the web I came to the conclusion that the APM might be the right choice for a couple reasons. 1. They look great! Sorry but this is important! 2. They met my budgetary requirements, kinda. 3. Portability for my “grab and go” travel needs. 4. Favorable review from a bold few who dared to take the leap. So I made my decision on the APMs and paid the price for admission $1200 including shipping and I jumped into the pool and within a week my APM-100s arrived ahead of schedule. So let’s start the show!

APM-100s fit, finish, mechanics and optics…

If appearances are important to you, then the APM will not disappoint. The finish is high quality glossy black finish with a faint blue metallic flake which seems to resist finger print as well. The over all fit of the components are tight, with no chips cracks or misalignments of any kind.

The mechanical design of these giants are solid, made from a three piece cast aluminum assembly which is beautiful but not with out flaws. The main body of this binocular is made from a single cast aluminum core which includes the two main tubes and center cross support. I like this design because it prevents the tubes from ever becoming misaligned as well as making them very resistant to dents and dings in the field. The down side to this design is weight, and because it’s a casted part, the possibilities of imperfections in the surface of the tubes and the other cast components may exist as well. The pair that I purchase did have such a flaw.

At first glance inside the tubes I found a small depression in the bottom of the left tube resulting from the molten aluminum not flowing to all areas of the casting. This flaw does not affect the optical quality or strength of the design, but under the magnification of the giant 100mm lens, this small imperfection looks cavernous and with the black paint/ flocking applied to the inside of the tubes to reduce reflection, the defect looks even more pronounced. But I quickly got over this once these big binos were under the stars!

The helical focusers operate smoothly allowing you to quickly bring the image into sharp focus and remain there without the need for readjustment for any reason. The hinge for adjusting the IPD or 'inter pupillary distance' was stiff but solid, perfect for the guys that don’t like to share!

Figure 2.

My only real complaint about the focusers were, when switching out the eye pieces sometimes you have a tendency to lock down the eye pieces before they reached their hard stops. This makes it impossible to reach focus or sometime causing misalignment in the optics making you think you might have a collimation issue specifically at high power. This typically happens while viewing at or near zenith and can give you heart burn till you figure out what’s wrong. My suggestion for all those who choose these binos is to learn how to operate the focusers and locking ring in the day light, this will avoid frustration in the night time viewing.

One additional point I would like to make regarding the mounting of the APMs to a tripod. The location of the ¼ screw is right at the CG and balanced perfectly on my heavy duty tripod which makes mounting quick and easy for all those who can curl the 16 lbs BTs on to the pod.

The optics: Once again gawking down the barrels of the APMs to view the 100mm ED glass lenses in various light conditions revealed a flawless even coating of multi-color glass with hints of green and purple hues with minimal amount of reflections viewed. Closer inspection of all the optics revealed no dust, dirt, fingerprints, navel lint or flaws of any kind on or in the glass. Very nice!

APM ships these binos with two sets of 1.25” eye pieces with this configuration, an 8mm and 20mm which are also multi-coat optics which claim to have 70deg FOV for the 20mm and 58degs for the 8mm eyepiece. I found these eyepieces worked well with the binos and complements the binoculars abilities.

Note: The eye pieces I received are different from the magnifications shown on the APM website, 23x and 41x and the eye pieces I received are 20mm producing 25x and the 8mm = 63x. I’m pleased I received this configuration with my order because I believe it made for a more well round viewing experience.


Manufacturer:  APM
Model:  100 mm doublet
Magnification:  Variable
Objective Diameter:  100 mm
Prism:  BAK4 Prisms
Optical Design:  Doublet ED (Semi-APO)
Coating:  Fully Multicoated
Focal length:  500 mm
Dimensions:  510 x 230 x 133 mm (20" x 9" x 5.3")
Weight:  7200g (15.9lbs)

The APM-100s first light

Day light:

I tested the APM-100s during the day light on targets some 5 miles away. These targets are radio towers which have good vertical and horizontal lines to test the focus, flatness, color and CA using the 8 and 20mm lens supplied with the binoculars. During the test, focus was sharp, color was good, images were flat and no CA that I could detect at ether magnification. And most importantly, these binoculars’ are collimated! At 5 miles the radio towers revealed detail not see in my Celestrons 15x70 and both vertical and horizontal line are sharp to about the last 10-15% of the FOV. So far so good!

The Night sky:

The night sky viewing in and around the Manchester NH area is only fair do to moderate amounts of light pollution which limits viewing of DSO objects with a visual magnitude of 5 or 6 with other binoculars. But with the APMs this jumped to 8 or 9.

My first stop was M45 the Pleiades. The 20mm or 25x eye piece offered with this binocular is too much power for M45, although the whole open cluster is seen, it does not have that wow factor like you get with less magnification. A 15x to 20x would be my preference for this DSO. But even at the 25x you see the faint white gaseous ghosts surrounding the brightest of blue jewels. Not bad!

Next stop, the constellation Orion… M42 the Orion nebula at 25x show faint blue green colors with some detail and depth to this majestic giant. Closer observation revealed 3 stars shown in the Trapezium Cluster. I switch to higher magnification 63x and could resolve 4 of the star in the Trapezium with clean separation. At the higher power dark lanes start to become visible at the cost of some color and depth but still very nice. By the way, my next purchase will be a pair NB filter.

Swinging a little farther east I located M78 with a magnitude of 8 which showed faint ghostly blue green nebula. This to me was a good test too how good these binoculars really are. My reasoning for this assessment is that I have never seen M78 with binoculars from my home in New Hampshire till now. I can’t wait to go to a dark site and see what these BTs can really offer.

The Double cluster NGC 884 and 869 was a real treat, revealing a nice tight as well bright field of pin point stars. I quickly panned over to Andromeda and its companion which filled the entire field of view. Sky glow washes out much of the detail but a bright central core could be seen. The same night I even detected Comet Hartley 2 with its faint blue hue.

Jupiter puts on an awesome show and at the higher power you can view 4 to 5 bands with 4 moons in the same field. At this point the APMs do show some CA on bright objects perhaps most noticeable on Planets and very bright stars which exhibit some flaring.

After detecting the CA, I quickly ran down to the basement and made a pair of 20% aperture stop from black craft hobby foam to reduce the aperture to 80mm which easily controlled and almost eliminated the CA completely. If I was the manufacture of these binoculars I would ship every unit with a lens cap that had a removable 80mm center for viewing planetary objects. I also believe that these giant binos are capable of reaching much higher magnifications in the 125 to 150x range and not suffer any ill effects.


These Binoculars are beautiful… The three piece cast assembly is heavy for its size, but I did quickly over looked this because in my book this does have a built to last quality about it… and will most likely look great for years to come. The optics are quite good and produce very sharp images and have a well round capability for the grab and go armature astronomer who is off to the backyard or traveling cross country to a star party. All in all these are keepers, and I would recommend the APMs for individual’s looking for a quality, portable binocular telescope at just over the $1000 price point.

Clear Skies!

  • Bill Lee, JMB and Legeres like this


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