The HEQ5 Arrives
I ordered the mount from O'Neil Photo and Optical mainly due to the fact that Joe O'Neil is a member of the RASC centre I belong to. I felt guilty in that I had discussed mounts (and other things) with him in the past and never bought anything so it was time to make amends.
Less than a week after placing my order (yep... a week, not a month, 3 months or a year... a week) I received an email from Joe informing me that the mount had arrived. Naturally, I dropped everything and headed for his place of business. The mount arrived in two boxes; one holding the head, hand control, battery pack etc. and the other holding the tripod legs and counterweights. Hauling them out to the car I had my first misgivings about 'portability'. The head weighs over 10kg by itself. Oh well... in for a penny, in for a pound (pun intended).
The HEQ5 comes from SkyWatcher with the following included:
- Equatorial head
- Polar alignment scope (installed)
- Hand controller
- Battery box
- Short dovetail rail
- Tripod
- Two 11lb counterweights
- A wrench to tighten the tripod legs
- A spreader bar cum eyepiece holder (both 2" and 1.25")
Notice that there was NO instruction manual. Joe pointed out that to 'save money' SkyWatcher had the instructions in PDF format on the web. Great for me, but what if someone doesn't have internet?
A word on the battery pack. It's a great idea but very impractical. It holds 8 D cell batteries and the HEQ5 can, I'm told, suck them dry in no time. So the first thing I did was to cannibalize it's power connector and modified a cable to power the scope from my heater controller/power box connected to the cigarette lighter of my car or my 12v regulated power supply for use on mains..
Description
The HEQ5 is a massive mount. The castings are big and other than the cover for the top of the motor/electronics area everything is steel. Both axes ride in a pair of self-centering ball bearings; no nylon bushings. There is no slop or play in either axis but I did notice that the axes are fairly stiff. This could be a function of the 'roofing tar' that Synta calls lubricant or it could just be that it's still tight. I vote lubricant and Dave Rubenhagen agrees with me.
The first night I had it out the temperature hovered close to 0C and there was no problem with the function of the unit, but I think the Synta goop is going to have to come out sometime before next winter and be replaced by white Lithium grease. Just a note... one of our variable star observers has an EQ-4 with the original 'tar' still in place and says that he has no problems in the winter here in southwestern Ontario. We'll see.
Synta seems to have forgotten one small item when they designed the HEQ5; there is NO level on the tripod or equatorial head. While it's not a great hardship to throw a bulls-eye or combination level in my 'kit' they should have built one in. Preferably on the equatorial head.
The 'fit and finish' aren't quite up to Losmandy standards but then it uses castings instead of Losmandy's 100% machining and therefore costs 1/2 the price of a Losmandy GM-8. The parts do fit where they are supposed to fit and there are no ugly gaps or mis-alignments. The mount looks good and the locking levers are placed well and easy to operate.
Unlike the motors on many mounts which sort of 'hang' out i space to be bashed about the motors for the HEQ5 along with their transmissions and the motor control electronics are all internal. They ride in a large 'box' at the top of the RA shaft and are well protected from bumps, bangs and weather. This is a nicely thought out design.
The polar alignment scope's eyepiece is also protected from abuse. A fairly heavy plastic 'cup' threads on at the bottom of the RA shaft over eyepiece end of the polar scope. A nice touch which makes it a little harder to whack the polar scope out of alignment hauling the mount around.
The equatorial mount fits snugly into the top of the tripod and once there is quite stable before being tightened down. I've seen some mounts where you have to hang onto the head for dear life while getting the screw(s) tightened so as not to lose things. All that needs to be watched for is that the azimuth adjustment screws be backed out a bit to make room for the pin in the top of the tripod head.
Adjustments in altitude/azimuth are fairly standard with the altitude being handled by two large stainless steel screws with a 'flipping' handle on the end (a la Vixen) and two hand screws with plastic knobs that push against a 'pin' that's part of the casting of the tripod head. I would much rather have seen the pin be a seperate threaded piece that can be reversed much like the pin in the Celestron CG-5 but at 42N latitude it's not an issue. Both motions are smooth are predictable but to adjust the azimuth one has to remember to take some of the tension out of the centre bar that holds the mount to the tripod so as not to bend the azimuth screws.
The tripod is a fairly simple unit that comes with 1.5" legs (which caused me some trepidation) and a functional spreader bar cum eyepiece holder. It is, as Synta states, stable but I would have much rather have seen them ship the EQ6 tripod with it's 2" legs with the unit. In use, I've noticed no tendency to wobble but I have added a lower leg brace to the tripod which does stiffen things up. The tripod legs extend but only about six inches so the adjustability isn't as great as in some other tripods. With a 1" lower leg if they had made the legs extend any longer they would have added some instability. In use with the C-8 I've not noticed any 'lack' of needed height with the legs as they are. At the end of the tripod legs are rubber(ish) feet that appear to act like anti-vibration pads. If this is indeed their function they work. All-in-all the tripod is basic but functional.
Note the home-made leg brace
The hand controller is straight forward with two sliding switches, one LED and four push buttons on the face, and two sliding switches on the right side. The switches on the face control (left switch) selectability for north and south hemishpere operation and 'Off'. The other switch (right switch) controls the slewing speed; 2x, 8x and 16x. The switches on the side of the unit allow you to reverse the operation of the RA and Dec push buttons. There is one huge, glaring (pun intended) problem with the hand-control unit. The LED glows green when the unit is powered and is BRIGHT. This has to be fixed somehow. There are three LEDs that illuminate in the same place. The afforementioned green one (power on) which changes to orange when you push a button to slew. I haven't figured out what the red LED does yet. The hand controller connects to the telescope using a coiled cable and a telephone-style RJ45 plug.
The clutches on both axes are fairly positive (though it's still possible to move the axis against them) and are well placed and easy to use with gloves on. A similar clutch secures the counterweight shaft which retracts into the Dec axis.
The counterweight shaft, as mentioned above, retracts and is fairly heavy with an 18mm diameter. When locked it doesn't appear to have any play in it. At the bottom of the shaft is a large gnurled 'safety' nut to keep the weights from sliding off if you're not paying attention to them. The weights (2 are provided) are large, rough castings which fit the shaft nicely. The locking screws in each are also large and have a nylon tip so as not to mar the shaft. This means that they CAN be moved along the shaft if not tightened down sufficiently.
At the business end of the head the dovetail clamp is large and secure. There is only one angled bearing surface with the pressure on the rail being applied by two large screws with plastic knobs. A sliding angled section might have been better as the screws do mar the dovetail rail. They hold the scope very securely.
The setting circles are large, easy to read and are useable in both the north and south hemispheres. Unlike the EQ6 the HEQ5's RA circle is in the 'proper' place at the bottom of the RA shaft next to the polar scope. The Dec circle is at the lower end of the Dec shaft. Both circles have locking screws and appear to be lubricated with the same 'tar' that Synta uses on the rest of the mount.
The polar alignment scope is aligned with the RA axis, but the reticule needs to be centred. Unlike the Losmandy offerings it isn't centred from the factory but this is a fairly simple process and setup/use of the polar scope is discussed in a few seperate pages starting with with aligning the scope.
Design and Construction
Body
The main body of the mount is comprised of three large castings and two smaller ones. These are:
- The base
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This is the part that sits in the tripod head and has the lower half of the altitude hinge.
- The polar casting
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The lower part of this casting is the upper half of the altitude hinge. The upper part carries
the polar shaft.
- The declination casting
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This carries the delination shaft, the electronics and them motors and worms for both axes.
- Worm carriers
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Two cast parts that carry the worm gears. One for each axis
Shafts
Both of the shafts (RA and Declination) in the HEQ5 are laid out identically with the only differences between the two shafts being that the declination shaft is pierced for the polar alignment scope and is machined internally to carry the counterweight shaft. Both shafts are comprised of the shaft, one sealed bearing and one tapered roller-bearing to carry the weight and centre the shaft and two sealed bearings that carry the brass worm gear. This is a very good design. It allows for simplicity in the gear train along with keeping all the electronics and both motors in a single casting. Unlike most German equatorials, the worm gear is not tied to the shaft; it is allowed to rotate freely at all times. When a locking lever is engaged, it locks the worm gear to the external casting. The worm on the RA axis, turned by the motors then rotates around the worm gear; on the dec axis the worm is stationary and the gear and casting turn.
Locks
The locks for both axes are very simple. They consist of a very coarse threaded brass screw with a square head. The lever fits over the head and is fixed by a single screw. The brass screw bears on a brass 'button' which presses against the worm gear locking it to the casting. Once all trace of the factory lubricant has been removed both axes lock positively. With the goop still on the worm gears they still lock the axis but can be shifted fairly easily.
Worms and gears
The two worms are carried in castings and both are stainless steel. Both are supported at each end by a pre-loaded bearing. On one end of the worm is the brass spur-gear which drives the worm and on the other end is a 1/2 moon attachment which could be used for a slow-motion device of some form. The worm gears are of brass and are large cylinders with the teeth cut on one end and being carried on it's shaft by two sealed bearings. There are 135 teeth on each worm gear. Adjustment of worm/gear meshing is very simple. Slightly loosen the three chrome cap-screws (just barely loosen) and adjust two set screws 180 degrees opposed in the worm carrier until you feel no 'slack'. The worms are driven through a pair of brass spur-gears with 1.333:1 reduction giving a final reduction rate of 180:1.
Motors
The stepper motors are 7.5 degree/step units driven in 1/2 step mode for tracking and guiding and full-step mode for slewing and centreing. The final drive in sidereal mode equates to a .56 arcsecond per step resolution. The RA motor has two seperate sets of poles and can is driven in a low-voltage 'power-saving' mode for tracking/guiding and at full voltage during slewing and centreing. Attached to the motors are 132:1 reduction transmissions.
Electronics
The electronics are carried on a single circuit board that is attached to the inside of the declination/motor casting with two screws. There are three connectors on the top of the circuit board for 12v power from the connector panel and one connector for each motor. The declination motor is a 4-wire connection while the RA motor is a 6-wire connection. There is no connection provided for polar-scope illumination.
Setting circles
The setting circles are engraved aluminum with the marks and numerals blackened. Each can be locked to it's casting to limit it travelling as the axis turns. The locking design is not very good and I don't think that the circles will be of much help to anyone as they both appear to shift when locked.
Power and controller connections
The power plug and hand controller connection are carried by a plastic unit that attaches to the declination casting at the front. This is held in place with two screws and the wiring passes back into the declination casting through a gap under the unit.
Covers
There are two removable covers on the mount; both are plastic. One covers the motors and drive gears for the two worms; the other is the curved top cover that protects the electronics. Neither appear to be very strong and aluminium would have been better.
The design is about flawless, the execution is not. As mentioned previously the machining of the interior of the castings could be better and the lubricant that Synta uses should be banned. On the plus side set-screws are used everywhere to keep things locked in place which is a good point. The biggest 'flaw' I have found in it's function other than the setting circles is that I can't ever seem to find the axis locking levers. But that may be my problem. For the money it's a whole lot of mount.
On to part 3 - HEQ5 in the field
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