The Alt/Az DM-6 from Discmounts.com
Easy hand tracking at high powers
Switching eyepieces without going through the seesaw shuffle
High quality of construction
Uses Losmandy G11 Dovetail and Plate system
Small footprint when traveling
DiscMounts willingness meet their customers needs
Did I mention the great stability?
DiscMounts.com has come up with a better mousetrap.
Iíve long been a fan of alt-az mounts. Thereís just something
about a simplicity of design that encourages you to take a small scope out
and star hop across the summer milky way, through the virgo cluster, or around
the celestial pole (a location where traditional GEMís have problems).
Where they typically fall down is when it comes to high power viewing. Having
to reacquire the object with a high power eyepiece is never fun, and many of
the alt/az mounts just arenít stable enough to handle high powers well.
When I learned that Tom Peters from DiscMounts
Inc had contacted CloudyNights.com
about submitting the DM-6 for review, I was only too pleased to undertake the
task and put it through its paces with my TV102. Ironically, I had been on
the DiscMounts web page just the day before.
Just in case you arenít familiar with the DM-6, Iíll take a moment
to describe it: From the pictures, it can be a little deceptive Ė itís
a little bigger than it appears. The head is extremely compact and resembles
a black cube with a large disc mounted on the bottom and side. The head is
about 6 inches on a side Ė indeed, the bearings are 6 inch bearings.
Hence the name DM-6 = DiscMount 6. In a slight twist from a typical mount,
the telescope connects to the side of the head using the Losmandy G11 saddle
plate and dove tail system. The DM-6 head itself rests on an extremely solid
ash tripod. Remove the top and back covers of the DM-6 and one can see the
4000 tic encoders that are optionally available, as well as a magnetic strip
that holds the wrench used to adjust the tension on the axis with the tension
nuts themselves being located just under the encoders and easily accessible.
Just from the pictures one can tell that itís compact, elegant, and zen
all at the same time.
The DM-6 head with Sky Commander on top - (Note: the arrangement of the wires
for the computer)
Tom Peters (owner of DiscMounts Inc) makes some interesting claims about the
DiscMount, but the most appealing perhaps is the basic design philosophy of
the mount itself. The DiscMount design is said to allow you to eliminate rebalancing
when moving between heavy and light eyepieces. Because of the friction based
disc assembly used to provide the bearings, locking the axis becomes completely
unnecessary when changing eyepieces and the scope will stay on target. Smooth
motions at high powers are promised, with the ability to go from a Pan 35 or
Nagler 31 to an ortho or Nagler zoom without having to rebalance the telescope.
I contacted DiscMounts directly and made arrangements to have a mount (and
all the accessories) shipped directly to me for this CloudyNights.com evaluation.
The mount shipped in two boxes: one for the head and one for the tripod. Both
survived UPS with nary a scratch on them, and as I unpacked, I could see that
they were both very well designed, and held to extremely high manufacturing
tolerances. The pictures on Discmounts.com Ė as good as they are Ė just
donít do the mount justice. The machining and craftsmanship of the head
shout quality from the first look. The tripod is coated with a clear lacquer
finish that allows the beauty of the ash to show through Ė no stains
or heavy varnishes on this tripod. The classic look speaks to the zen approach
of the simple alt/az head. As you begin to go over the mount with a fine toothed
comb, you find little touches that speak to the quality of the overall design.
the tripod, the leg braces screw into each leg, and have a provision to affix
them to the legs for storage. The top of the tripod is covered with a
rubber and cork mixture, to provide a suitable perch for the mount head,
and the head is itself is beautifully machined and anodized. The plates that
access to the encoders snap into place via a cunning spring arrangement,
and as I previously mentioned, an adjustment wrench for the axis tension is
into place inside the head with a strip of magnetic tape. DiscMounts offers
many other options, including a bracket to mount your finder to the DM-6,
and adapter plates for the Losmandy GM8 and GM11 tripods. No matter what options
you wind up with, the attention to detail is evident throughout. Everything
fits. And fits well.
Surprisingly, the mount and tripod take up very little room when traveling Ė slightly
less in fact than the Gibraltar or Telepod head with the eyepiece caddy mounted
to a comparable tripod. There are no counterweights or counterweight shafts
to worry about, and if you head out to star parties packed to the nines like
I tend to do, this is a definite plus.
Inside the DM-6 - (Note: the head has been offset on purpose in order to see
the rubberized cork on the top of the tripod)
The tripod legs donít extend, but DiscMounts does offer custom lengths Ė something
you may wish to consider depending on your use. For a person of average height
who will be using the mount terrestrially and astronomically, the tripod is
just about the right height. For someone who is a little taller, or whose primary
use is astronomical observing you may wish to opt for the slightly taller tripod Ė simply
to place the eyepiece at a little more convenient height when you strive for
zenith. If you are looking to purchase, Iíd also recommend you inquire
about an eyepiece tray for the mount.
And the big question: How well does it work? Splendidly. I found Tom Peters
performance claims to be completely borne out. This is simply a superb mount.
It does indeed allow you to switch from extremely heavy eyepieces to extremely
light ones without adjusting the tension of either axis. The mount is extremely
rigid, and sharply tapping the side of the telescope / mount resulted in the
scope settling down extremely quickly. Even wind tends to present little obstacle
to an observer. Even focusing at high powers resulted in very little shake.
Ironically, the weakest link in the system showed itself to be the clamshell
ring on the TV102. The DM-6 is a rock. Peters has tested the DM-6 with OTAís
up to 25 lbs in weight, and I can tell you my little 12lb TV102 was of absolutely
Initial use of the system involved frequent axis / friction
adjustments, but since the mount has had a chance to settle in, I havenít
had to touch it. Tom Peters related that he has one that he hasnít changed
the friction on in years. Once the friction is properly adjusted, and the scope
correctly balanced, (and this process is covered in detail in the DM-6 manual)
tracking is extremely easy, even at powers approaching 300x. The only times
I ever wound up rebalancing was when I switched from binoviewing to monocular
viewing, and I suspect that even this would have been unnecessary if I wanted
to tweak the mount a little more, but since I donít usually switch between
modes, I never bothered. I found the ease in which you can go from a heavy
wide angle eyepiece to a lightweight ortho or nagler zoom unparalleled compared
to any alt/az mounts Iíd ever seen. This is a mount that lends itself
to detailed investigation of planets as well as to wide field scanning from
the horizon to the zenith. While switching from low to high power I rarely
lost the target, and on those occasions which I did, it had far more to do
with the initial placement in the field of view than any weakness in the mount.
The Sky Commander mounted on the DM-6
DiscMounts Inc offers to set the mount up with encoders, and will gladly
sell you a Sky Commander if you need one or you may use any compatible DSC
(Sky Tour, JMI, Argo Navis, etc). If you use the included mounting plate, which
puts the DSC right on top of the mount head, the cables are kept to a minimum
and stored out of the way inside the head itself. Itís a nice feature
that effectively eliminates the problem of cord wrap, and yet another example
of a well thought out and implemented design.
As for the orthogonality of the mount and the accuracy of the Sky Commander,
it worked beautifully. Let me give you a specific example: I was lucky enough
to have the mount during the Martian opposition and had a blast using the DM-6
night after night to study mars at extremely high powers. When I got tired
of Mars, I would use the Sky Commander to pan over to Uranus and Neptune while
staying at those extremely high powers. So Ė in short, itís orthogonal.
This is a mount that just gets out of the way and lets you observe.
I took the mount to several star parties with me, and without exception, every
single person who looked at the mount was intrigued by it.
The DM-6 easily carries this TV102 and binoviewer
I wouldnít want you to think everything was all beer and skittles -
there were little things here and there I thought might be improved. Not much
really, certainly nothing major, but I mentioned to Tom that it might be nice
to see an eyepiece tray that drops in on top of the leg supports, and differing
tripod heights would be a nice thing to offer. With the standard tripod I found
myself sitting a little too low for my comfort when viewing near zenith. Ergonomically,
some users might prefer the Sky Commander in a slightly different location,
as I found it a little high to view comfortably when seated. Tom Peters met
the challenge with each suggestion, discussing solutions, additions or redesigns
with aplomb, shipping me new cables when I suggested Iíd like to try
the Sky Commander in a different location, and agreeing that eyepiece trays
and different height tripods were good ideas, and hinting that they would indeed
be available in the near future. Some manufacturers seem wedded to their products
and refuse to admit even the possibility that their may be something that they
can do for enhancement. In my opinion, the best, like Peters, are continually
striving to innovate and improve.
The DiscMount Logo
So are there any drawbacks remaining? Well, yes, but just one. As is true
of anything in this life, if you want excellence you must be prepared to pay
for it. At a cost of $1200 for the head alone or $1550 for the head and tripod
(accessories extra), this mount is no exception. But if you can afford the
price tag, this is a perfect solution for people seeking the simplicity of
an alt/az mount. Balancing form and function, Tom Peters has created a thing
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