AZ-3 Servicing (part 1)

Tweaks and tips to get the most out of your Synta AZ-3 mount.

By Antony McEwan

The Synta AZ-3 alt-azimuth mount has been around for a long time. It was originally one of the few alt-az mounts that had slow-motion controls attached, making it a matter of turning a knob to track objects instead of nudging the ‘scope along. They have also been included in beginner’s telescope packages alongside everything from 70mm refractors to 127mm Maksutovs- and they manage them all with ease! The AZ-3 is still available from retailers, and at about £90 new it’s still one of the all-time Astro-kit bargains out there. But… some people (myself included) just can’t resist the ever-alluring pages on eBay, and recently I picked one up there second hand with a telescope stuck on top for, well- let’s just say a very good price and leave it at that!

Now, I’ve owned a couple of these mounts before, and so I knew that there were a few tweaks that could be carried out that would improve my AZ-3 from being a pretty good alt-azimuth mount with some foibles, to a perfectly smooth and reliable one. And the best bit is, this whole job only took two hours to do!

The AZ-3 is made by Synta: a Chinese company famous for producing very good, reasonably priced Astro-kit to a budget. That budget sometimes means that little things like quality control and final checks can get left out. The little quirks that any Synta mount (equatorial or alt-azimuth) is likely to suffer from are shaky tripod fixings, poor lubrication, rough motions and, sometimes, poor fitting of components.

When I first had a play with my new AZ-3 I noticed that the altitude motion was very rough, the azimuth motion rough in some places (with a squelching sound that experience has taught me is associated with Synta ‘lubricant’ – more on that later), and lots of flexing in the tripod legs. I had a job to do, so I set out to do it…

Where To Start?

I decided to do the really easy fixes first, and work my way up from the ground – literally. The first thing I dealt with was the flexing tripod legs. The top of the Tripod is attached to the mount by means of three bolts and the legs also support a three-armed bracing structure that holds an accessory tray, situated about two thirds down the un-extended legs. The arms of this brace attach to the inside of the legs by means of a single bolt each. Looking at this assembly, it is obvious that there is play between the legs and the brace, as there are no spacers or washers to take up the slack, so there is plenty of lateral movement if any sideways pressure is applied.

This can manifest itself when observing in windy conditions, or when the tripod legs are extended. The bolts simply unscrewed, allowing me to place several small washers on either side of the leg attachment and screw the bolts back in place. Result: no sideways motion at the joins.

Heading up the legs I then tackled the problem where the top of the legs attach to the mount head itself by means of a single nut and bolt per leg. Ideally, these bolts should be not too tight when transporting the telescope, so that the legs can be collapsed inwards easily, but should be simple to tighten up firmly when the tripod has to sit firm on the ground. Using a nut and bolt is not best for this, as it means carrying a toolkit whenever you go observing. I replaced the nuts with wing nuts, which are much easier to loosen and tighten. I also replaced the washers that sat against the leg surfaces, as they were very rough and made of plastic. I used smooth aluminium ones instead. Another good result that took a couple of minutes.

The final leg modification I made was to do with the accessory tray. It attaches to the leg brace by means of three wing bolts that screw through the brace and into the underside of the tray. Not quick and not elegant. I stuck a square of ‘hook’ self-adhesive Velcro on each brace leg and a square of the matching ‘eye’ material on the corresponding place on the underside of the tray. Now it takes a second to install and a second to uninstall.

The Mount Head

By the ‘mount head’ I mean the bit on top that holds the telescope, rotates, and raises and lowers the tube. The functional bit, if you like. This attaches to the tripod head by means of a single long bolt that runs from the underside of the mount, through a hole in the centre of the tripod mounting, and is fastened with a nut and two washers underneath. I undid the nut and removed it along with the washers, and carefully lifted the mount off the tripod assembly. At this point you must have space to put lots of little sub-assemblies, nuts, bolts and washers etc, as there are a lot of little bits and pieces that you’ll have to remove, clean, store, and then be able to lay hands on again easily. All of the new washers, nuts and bolts etc that I used are readily available from local hardware stores, and do not cost very much. It’s always worth hanging onto any spares too, as you’re bound to need them one day…

After removing the mount head, I undid the single screw that attaches the azimuth drive rack to the clutch ring section. The clutch ring section then slipped off away from the mount section. It is actually a lot simpler to do this than to read about it- it makes better sense in 3D!

You now notice that all the internal surfaces are coated in what looks like earwax. This is the infamous ‘Syntaglue’ that the manufacturers believe actually ‘lubricates’ their products. It doesn’t. It sticks in globs all over things, is sensitive to temperature changes resulting in things getting even stiffer in cold temperatures, and is just plain awful. If you ever thought to yourself that your Synta mount or focuser etc didn’t need re-lubricating, have a look at the 'before and after' pictures to the left and then consider that this is how it is applied across the whole range! Luckily I have a tin of 25-year-old Castrol Lithium Grease that sees a lot of (astronomical) use from me, so I dug it out. I also dug out WD40, washing up liquid and an old battery operated toothbrush.

The excess Syntaglue had to be removed first, so I just scraped that off with an old cloth. Then I sprayed WD40 onto the surfaces that still had Syntaglue on, and applied some washing up liquid to the toothbrush and let the Duracell Bunnies do the hard work. After a minute or two you can wipe it all off with a cloth and the surfaces will be clean and dry. Then it was time to apply a nice even, thin, coat of Castrol (other brands of lubricating grease are available) using cotton buds or whatever, making sure that it is thin and evenly spread. Having done this to the underside of the clutch ring section and all the underside surfaces where the mount sits against the top of the tripod (and the top surface of the tripod assembly itself) I set them all aside and had a look at the top section of the mount.

Click here to go to page 2.