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Old 06-10-2008, 10:45 PM
Wavytone
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Wavytone is offline
 
Join Date: Jul 2008
Location: Killara, Sydney
Posts: 4,147
I have the Orion version and it is crap...

... Having just returned from a 10 day break in nice dark skies down south at Bright, in Victoria.

Mine is the Orion SkyView AltAz mount from Bintel, it appears identical to some others around and I guess the manufacturer is just rebranding them to suit. There are issues with it, however. I have been using it with an Orion 102ED f/7 refractor (all up 5 kg with tube rings, diagonal and 2" eyepiece) on one side and an Orion 180mm Black Diamond Maksutov (about 10kg) on the other side. Each of these weighs much more than what you suggest, and yes it will easily carry your scope and provide a convenient, rigid mount.

IMHO a 102mm refractor is about the upper limit on what is suitable on these mounts, and they are only useful at magnifications up to about 70X. Beyond that you will find the stiction in the bearings make it difficult to aim accurately. Smooth tracking is impossible, you can only accomplish small step-movements. 70 is the minimum power I have in the Maksutov and at 140X the mount is not particularly useable due to stiction in azimuth.

Conversely in altitude my mount is so free I have to be very careful to balance the scopes and when changing eyepieces, a few grams imbalance on the Mak or refractor will cause it to slew uncontrollably in altitude; in cold weather the altitude clamp will barely hold the torque arising from my Vixen NLVW30 mm eyepiece.

In addition, Orion have some quality issues to sort out, and I suspect the same is true for the others if these come from the same factory and you must look closely at these before buying.

(a) The mount uses three tiny 4-40 grubscrews to secure the dovetail base on the altitude axis, and another three to secure the altitude axis assembly to the vertical (azimuth) shaft. The parts are entirely made of aluminium and are hollow, with a mere 3mm wall thickness so there is not much meat to hold the grub screws and on my mount they are already ripping out sideways. On arrival, these grub screws were all loose on my mount and if I had attached a scope without checking these first a disaster would have followed fairly quickly.

Despite the external appearance my Maksutov is way over the weight this thing can safely support and I'm already considering another mount.

(b) inside the axes the clamps are some sort of nylon gripping anodised aluminium. There is no visible image shift when you lock/unlock the clamps, so there are half-way well designed, except for an almost total lack of friction until they are screwed up so tight they bind. After 8 nights use in cold weather (0-5 degrees C) the clamps have degenerated to all-or-nothing, and "all" is barely able to support a heavy eyepiece in the altitude axis. In warmer weather the grip might be better but I'm not hopeful.

(c) the vertical (azimuth) axis consists of several parts. What looks externally like a decent solid vertical base in fact isn't, its actually 4 aluminium parts screwed inside each other and the stiffness of the mount is limited by the smallest part which uses a (roughly) 25 mm diameter x 1mm pitch thread. When my mount arrived this was not only loose, but had stripped, and I have had to resort to applying Loctight to secure this.

(d) Mine slews with a lot of stiction in azimuth. It's a ***** to use, pure and simple.

(e) the best part of the mount is the tripod. It's a keeper - solid, stiff, light and quick to assemble, with a wide stance that is not prone to toppling even when i have the Maksutov alone on top. However $500 is a lot to pay for a tripod, assuming you will ultimately throw away the head and replace it.

In conclusion, if you are a casual observer only not pushing the limits, and can afford to take a gamble on this mount, it might turn out OK for you, but if you're a seasoned observer looking for a really decent altaz mount, stay away.

In my case I am about to replace mine with a DM-4 or possibly a DM-6 from www.discmounts.com in coming months.

Last edited by Wavytone; 06-10-2008 at 10:56 PM.
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