In answer to the many mails received almost daily regarding the double base plate for the EQ6 supporting 2 telescopes, go to telekop service


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Acknowledgements: I want to thank Chistophe Demeautis for his remarkable work on the analysis of telescope mounts

I also wish to thank Sp@ceCowboy for his additional analyses,
and for his help on assisting with the interventions on the telescope mount.

Note : the entirety of these operations are applicable by extrapolation to the HEQ5 mounts.
We however did not verify this possibility ourselves.
It's up to the reader to verify the pertinence of these operations on a HEQ5.

I• modification costing 20 euros

Here you can see an ordinary curve of a standard EQ6 mount: it is extremely difficult to extract any periodicity. However this operation is required if you want to analyse the behavior of the mount and when you want to execute the required changes.

We hence need a mathematical method called the (fast) Fourier transform (FFT). See the different FFT curves at the bottom of this page.

Click on the image to enlarge




It is not a small job.
This bull-dozer like mount (1), overwhelmingly powerful but not really precise, displaying a monstruous periodic error... and non-periodic errors (see table below) asks for some minimal anhancements.
Sp@ceCowboy and myself engaged in disassembling the EQ6, at least on the RA axis
(the most important) in order to measure the possible enhancement options.
This is a dirty job, where both precision and (brute) force are combinec (the head of the mount weighs 17kg)
On the lower photo you'll find a description of the exploded view and the tools you absolutely require for the job.
The procedure:


1 Remove the protective cap of the polar finderscope.
2 Remove the RA clutch (cross screwdriver)
3 Unscrew the mini-screws (flat head) from the red clamping washer (flat and small electronic or clockmaker's screwdriver).
4 Unscrew the polar finderscope (with a cloth and a wrench if required).
5 Unscrew the first big black ring (machined part) (photo 3 with the powerful whrench if needed, see exploded view below).
6 Remove the conical bearing.
7 Loosen the 4 screws that support the worm.
8 Keep the mount head vertically.
Remove the boddy from the RA axis by means of vertical traction.
At this point in time, you'd better have some helping hands nearby, you can't afford loosing grip or dropping parts here.
9 Separate the bearing from the wormwheel.
10 For the cleaning: do it like in the army: use a toothbrush.
A liquid or spray chlorine-free grease remover should be used.
The black and compact grease from the worm and wormwheel is difficult to remove; get rid of it entirely as this is essential: this grease has absorbed dust and other small machining debris gathered from the time the mount was built!! For replacement, a Lithium (Li) based and a rather thick Molybdene bisulfide (MoS2) grease is recommended (Belleville grease).
11 For the bearing, axis and other small pleasures of life, a rather fluid Lithium based grease is used.
Reassembling the mount head happens in the opposite way as disassembling the head.
It is recommended you get assisted, expect some assembly problems for the bearings, don't hesitate in lubricating the axes with grease when adding the bearings. Don't use brute force!! Small percussions with little strength may be necessary, but don't apply too much force.
For reassembling the 4 screws supporting the worm, progressively tighten the 4 screws that support the worm (one turn of the Allen wrench on a screw, then the same for the next screw, and so on), in order to distribute the tightening force in an uniform manner.
We'll keep you informed on the performance enhancements of the EQ6 after some tests realised in situ.
After the reassembly, we have observed a 50 to 70% gain in lubrication with respect to the unaltered DEC axis.
We can already see now that, without performing a single test, that the first gain will be a reduction in power consumption (reduced friction), and that additionally the error will be less erratic (as debris and other machining artefacts were removed from the worm and wormwheel).


Click to enlarge the exploded view with the technical details

Click on the image to enlarge



• What is the impact of the cleaning on the EQ6?

Click to see the analysis


II• Modification costing 220 euros

• Changing the gearboxes of the EQ6

+ Update of the EQ6 electronics circuitry


The previous operation having provided a small but tangible reduction in the "periodic" error of the EQ6, we decided to look at other means.

The thorough analysis of the error curve and its FFT transform let us consider the importance of the gearboxes in the poor periodic error of the mount.

The gearboxes are a set of axes and wheels which reduce the rotation speed and at the same time transform this speed reduction in an increase of couple energy (power).

When we inspected the original gearboxes we removed from from the EQ6, it was clear that these gearboxes were a major source of our problems. These gearboxes were a total mixture of metal and plastic wheels and of other parts in materials by now still unidentified.
Their reduction ratio is 1:132

The original gearboxes

On the other side of the Rhine river, the Germans searched for and eventually found gearboxes which could replace the current ones. They ended up with quality gearboxes requiring the minimum of adaptation effort as possible.
It are the 1:100 Conrad gearboxes.

The Conrad gearboxes

The lubricant (grease) which comes on these gearboxes is of excellent quality, hence we don't touch at it.

Those gearboxes were impossible to obtain without accompanying DC motors!
We will now remove the original gearboxes from the original motors, and replace them with the Conrad gearboxes. You'll have to make some adaptations (e.g. drill some holes in the baseplates) as the Conrad DC motors are not compatible with the driver circuit of the EQ6 stepper motors
Keep those DC motors in a safe place: you might want to use them in an electric focuser for example).
Albeit we can see a significant quality boost with our eyes by using the Conrad gearboxes, there's still the problem of the different gear reduction ratio (1:100 with the Conrad gearboxes and 1:132 with the original ones).
This inevitably requires an upgrade of the mount's electronic circuitry.
Again our search led us to Germany where Mr. Aman Rajiva designed a small-sized electronic module.
[photo of the electronics]
The operation cannot be any simpler: unscrew the 4 screws that seal the circuitry to the body of the mount, then unscrew the 4 other screws that hold the circuitry board on the plate, then carefully remove the original EQ6 microcontroller and carefully replace it with the module from Mr. Rajiva.

Electronic update


In order to provide access to the 15-pin connector, the plate that keeps the electronic circuitry must be adapted (make a hole of the appropriate size) [photo of the top view assembly]

The new microcontroller (EEPROM) is more performant than the old one:
It is programmable
By means of some software provided by Mr. Rajuva, you can select the gearbox ratio by connecting the 15-pin connector on the mount with the serial (mouse) port on your computer.
In addition it enables autoguiding, recording the periodic error (hence providing PEC), compensate for backlash, GoTo (additional fee of 10 euros) via many common astronomy software like Cartes du Ciel. It also allows you to program other guiding speeds on your EQ6 handpad.

Additionally, Mr. Rajiva proposes an update of the handpad by replacing its microcontroller with a new one, which took me 16 minutes including unscrewing and screwing of the handpad.

  • Changing the processor: no particular difficulty


    You only need to carefully lift the original microcontroller from its socket and replace it with the new one
    This shows that the upgrade of the handpad was succesful: from now on the LED glows red (instead of green)
    After connecting motors, handpad and PC: we can see that the functionality concurs with the one we expected; we reassembled everything, then a long tweaking session follows where position and backlash of the motors get tweaked.

This operation adds interesting new functionality on the handpad, distributed over several menus, such as:

  • Selection of tracking rate (sidereal, lunar, solar, terrestrial)
  • Selection of guiding speed (x2 or x1.3)
  • Selection of slewing speed (up to 40x)
  • Electric focus (if supported by the telescope)
  • Spiral search of objects
  • PEC recording
  • Enable/disable PEC
  • Etc...

• What is the impact of changing the gearboxes?

Click to see the analysis


analyse FFT

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III • modification costing 70 euros

• The bearings to change on the EQ6

This operation is still pending



Here's the list of the bearings to be changed, knowing that the first 4 are essential as they are directly encountered in the kinetic chain of the drive

  • SKF6008 2RS : 19.73 euros (+ tax) x1

  • 32208 conical (TINKEN) 40x80x23 : 35.81 euros (+ tax) x1

  • SKF608 2RS : 6.01 euros (+ tax) x2 (hour tracking screw)

The bearings on the toothed crown only serve in manual operation; when the axis is locked and the tracking is engaged, then those bearings don't rotate, so there's no need for replacing those.

Thanks to Alexendre (alexandre.lambolez-at-wanadoo.fr (spam countermeasure: replace -at- with @) for this list of bearings :)




retour au menu / back to menu

IV• modification costing 0 euros

• the PEC on the EQ6

being written right now


Also available: Czech translation on the site http://web.telecom.cz/elektro-metal/