REVIEW: Synta EQ6 Driven Equatorial Mount


EQ6 head and tripod without counterweights, beside standard milk crate with extension tube on top.
The EQ6 mount is presently the largest made by Synta, and is sold under other names such as Atlas. I bought mine in 2003 just before they were available with the GO-TO option. I'm not sure what the load capacity of this mount is, but it is definitely much more solid than an EQ5 or CG5 mount. My 10" Newtonian or 6" refractor weigh 40 lbs. at the most when loaded with accessories and can be balanced and maneuvered with ease on this mount.

There were GO-TO mounts available when I bought my EQ6 mount, but at the time I was just getting back into astronomy and settled for my 6" refractor on the EQ6. A GO-TO mount would have added at least $1,000 to the price if not more, and I had no objection to having to search for objects as long as the mount could track them once I located them.

All of this stability and load capacity comes at a price, and I'm not just referring to the money. The 2" steel legged tripod, mount head with clutches and built-in motors, battery pack and controler, plus the 2 counterweights needed for my refractors weighs about 90 lbs. (without the telescope), and if I want to put my 10" Newtonian on it I need another 5 Kg. counterweight due to the increased tube diameter and weight distribution. I can transport and set up this telescope by myself, but at times it's not something I really look forward to. The heaviest single component is the mount head which weighs around 40 lbs. and must be lifted onto the tripod, then the telescope goes on top of the head. It's not a complicated task but does require some strength and co-ordination. It's a good idea to have a little help when you use a mount like this in the field, not only for set-up but to carry it as well.

The mount head accepts a standard Synta/Celestron style dovetail which is held in place by tightening 2 large thumbscrews. Once the telescope tube and counterweights are positioned to balance the telescope on each axis, you move it around by hand to aim it(very easy when it is balanced) and tighten down the clutch levers for each axis to lock the telescope in position. There is also a built in polar alignment scope in the mount head which is used to aim the mount itself so the tracking motor works correctly. The more accurately the mount is aimed, the longer things will stay centered in the telescope's field of view when the motor is turned on.

The hand control box houses all control switches and adjustments. For fine adjustment of the aim there are 4 buttons (2 for each axis). There is a 3 way speed control to adjust how fast the telescope moves when you press one of the 4 buttons (note*- there are no manual fine aim adjustments on this mount, so if the batteries die or a motor goes it would be almost useless). There is also a switch to select for operation in the northern or southern hemisphere. In the northern hemisphere the stars appear to "rise" in the east and "set" in the west. In the southern hemisphere however, they move from west to east across the sky.


EQ6 head and tripod with counterweights,extension tube, battery pack and hand control installed.

Optional 10" Extension Tube
The optional 10" height extension tube is a nice accessory for this mount, and fits in between the tripod and the mount head. When using a refractor or SCT on the EQ6, it becomes necessary to raise the mount height to put the focusser in a more convenient viewing position. Not only is it quicker and easier to install the extension tube than it is to adjust the height of each leg individually, but it gives more clearance between the telescope and the tripod. I have never had a problem with my scope running out of room and hitting the legs of the tripod, but it is possible depending on what type of telescope and accessories you put on the mount.


LEFT: EQ6 mount head with counterweight shaft retracted set for 44° latitude.
RIGHT: EQ6 10"extension tube with custom made shaft, and original mounting shaft.
There is one aspect of the extension tube which could be improved, and that is the way it installs on the mount. The screw that comes with the EQ6 to attach the mount head to the tripod screws through the tripod into the bottom of the extension tube. Using the supplied parts (see sketch below), to install the tube to the head you must remove the screws (B) mounting the top plate (A) to the main body of the tube in order to thread the handknob (D) to the bottom of the mount head. The roller bearing (E) is supposed to keep the handknob tight while still letting it turn in order to facilitate polar alignment. I discovered 2 problems with this set-up:

a)- I found it difficult to tighten the knob just right without having it too tight and being unable to rotate the mount, or too loose and having the mount wobble.

b)- I use both my large refractor AND my Newtonian reflector on the EQ6 mount. The extension tube places the Newtonian too high to look through the eyepiece when aimed high, even with the tripod legs all the way down. Unless I want to start bringing a ladder with me, I have to remove the extension tube when using the Newtonian on the mount. It is a long task (not to mention a pain in the ass) to disassemble both the mount and the extension tube every time I want to switch.

Extension Tube Modification
I came up with a solution so simple, I'm surprized that it isn't a part of the package when you buy the extension tube. Why use one screw to mount the tripod to the extension tube and another screw (inaccessable without disassembly) to mount the extension tube to the head? Couldn't you just use one long screw that holds all 3 together since they are all on the same centerline? I purchased 2' long threaded rod with the same thread as the supplied screws (I forget the size). With a little planning I calculated the length of the replacement rod, and how much thread I needed on the end of it to screw it into the mount head. I placed a stopper on the threaded rod to bottom out when it is screwed into the tripod, and lathed off all of the thread in between it and the section needed to screw into the mount head. I was going to remove the threads in the 2 plates inside the extension tube so I could just slide the rod through them without having to turn the threaded section on the end through each one, but I haven't bothered yet. I also thought I would have to insert a locator pin between the tripod base and the bottom of the extension tube to keep it from rotating independently on the tripod during polar alignment, but surprisingly that doesn't seem to be a problem. Now it's a simple matter to remove the extension tube when switching telescopes, and I don't need a tool to do it.


LEFT: Diagram showing installation procedure for extension tube with stock parts.
RIGHT: Diagram showing installation procedure using custom made shaft.
If you own a large telescope but don't intend to do any imaging, then this could be the ideal mount for you. The only minor negative comment I can make about it other than it's hefty weight (but that's the price you pay for such a solid mount) is that aim shifts slightly when you tighten the clutch for the RA axis (a glitch not exclusive to this mount).It is available with a GO-TO option now, but I am not sure if it comes with automatic periodic error correction or not. I do know that the newer versions of this mount are white instead of black. I locate objects visually (wihout using the setting circles) and have never used the setting circles on this mount, so I don't have much to say about them. I guess I should line them up the next time I get the scope out and see how accurate they are.