APM 100ED SEMI APO REVIEW

By Haseeb Modi

Having owned three different types of scope systems, I always wondered about a Bino-scope or rather the views through one. Bino-scopes are no different from Binoculars except of course they are much larger in aperture, have the provision of Helical focusers to change eyepieces of different magnifications.  This makes an APM doublet a very high powered, magnifying instrument with wide field refractor like views.  In fact an APM can be termed as two doublets combined to form a single three dimensional image. 

The images of course are not really three dimensional but gives you an added depth, making objects appear almost 3D like and High definition for added effect.

These instruments do not come cheap. In fact they are expensive and only those fortunate enough to own them know the value of their money well spent.  I am fortunate in the sense I have a friend who owns probably enough scopes, mounts, eyepieces and accessories to open a mini telescope store.  He is the passionate astronomer and a kind one at that.  His favourite possession was the APM 100ED, at least till he offered me to take it at differed payment.  He of course is still passionate about binocular telescopes and in fact bought a new one, i.e., a Vixen BT-81S.

Back to the APM 100, here are the official specs:- 

SPECIFICATIONS:

Manufacturer: APM 
Model: 100 mm ED binocular
Magnification: 25x
Magnification: 50x
Objective Diameter: 100 mm 
Prism: BAK4 Prisms 
Optical Design: 2-element ED-semi apo
Coatings: FMC
Focal length: 500mm 
Exit Pupil diameter: at 25x: 4 mm
Exit Pupil diameter: at 50x: 2 mm
Field of view: at 25x: 2.9°
Field of view: at 50x: 1.47°
Dimensions: 510 x 230 x 133 mm 
Weight: 7200 gr.

The binocular is well crafted and the tubing seems perfectly smooth and aerodynamic in appearance, almost like two mini turbo jets.   Painted black with flecks of metallic dust.  The images may not do justice to both its looks and volume but this APM is huge for those who may not yet have experienced large telescopes or binoculars. The optics consists of 2-element ED with each fully multi- coated resides within the strong tubing.  According to APM,  each and every piece that comes out of the factory is checked, tested and then shipped, I would expect collimation to hold for the lifetime of the user. 

Now with such types of binocular scopes, Mounts plays a pivotal ( pardon the pun ) part. The Mount needs to be sturdy and the Tripod holding the Mount sturdier. The minimum payload for a mount head should be on par with 8 kgs or more with the Tripod’s payload being in excess of 12 kgs. You will then have a Mount capable of not only holding the APM 100ED but also reducing dampening times caused by sudden movements or vibrations or strong wind. 

The APM 100ED Semi-Apo comes shipped in an aluminium case with foam fitted inside with the APM nestled nicely in it. There are a couple of inserts for eyepieces which come as part of the package, i.e., 20mm and 10mm APM eyepieces.  These eyepieces are quite nice and adequate for sessions with your binocular scope. The 45 degree diagonal is a personal choice but serves for easier viewing while seated.  I am used to 90 degree diagonals so hopefully I get used to this as well.

The  Helical focusers are simple and work flawlessly. The eyepiece gets inserted and there is a knurled ring to lock them in place. You then turn the focuser in the same direction both ways to achieve focus.

Now having an APM 100 sitting next to you with clear skies above with three quarter Moon, Jupiter, Orion, Pleiades and a thousand other celestial objects in the night skies beckoning, it is all too easy to get carried away and go for a quick round. I tried this handheld and soon gave up, I knew it wasn’t possible but still.  A thought struck me. Why not utilize the focus rails on my Manfrotto 055XPROB? It just might work. It did albeit for a very short time.

After ensuring all the locks were tightened and the quick release plate firm, I took the APM for a second quick round. Feeling my excitement, my family joined me.

With the APM 100 pointed roughly 30 deg East towards the Moon and with the 20mm eyepiece, the Moon was incredibly detailed and seemed to ‘hang’ in space. I changed eyepieces to 10mm and this was even more detailed with the Moon well within the Field of view. The craters, riles all sprung up with a bit more clarity. Moreover, the moonlight was not hurting the eyes. My wife, daughter and son all took their turn and were equally astonished.

Next was Jupiter. The mighty planet was small but detailed with four of its moons shining away.  However in my case the view seemed to be that of two Jupiter’s but in the case of my family, they all felt nothing of the sort. I know there could be collimation issues at high magnifications ( in terms of binoculars, 50x is pretty high ) on brighter objects and perhaps this may have been the case with my eyes.  Anyway, I swung the mount towards NGC 869, the Double cluster and the beauty of both clusters within the field of view and like diamonds hanging in space will not be lost on you. I doubt if any one single telescope would afford such a view.  I then became a bit too overconfident and swung the mount towards the Zenith to view Pleiades.  This is where both the Tripod and Mount started to show their limitations and the jerky movements did not warrant I push them any further. However, I did manage with the help of my son and daughter to hold the APM 100 in place for a few jerky seconds and the Pleiades almost made me jump.  Globs of star light sprang up making me all the more eager to hold the APM without shaking. The view of seven sisters were in focus, of that I am sure but what surprised me was the nebulosity that was seen surrounding these stars. The whole scene was simply unreal and one has to see it to believe it. Far after we packed up and went to sleep, the blobs of star light were still bouncing in my eyes.

Now all that I need is a good solid Mount head and a Tripod.

Haseeb Modi.