More info on the EQ7.

[mill (Martin)]

This site http://www.robtics.nl has some more info about the coming EQ7.

Dual Encoder Design
With the patented dual encoder design, you may move the scope to any position manually or electronically without deactivating the tracking mode first. After moving to a new object, the telescope will automatically begin to track the new object accurately. No re-setup is required in one observing session.

Motors
It utilizes 0.9 degree per step bipolar stepper motors to get high resolution. It uses stepper motors without reduction gear to drive worm shaft directly so to remove the periodic error caused by reduction gear.

Computer Operation
Couple the solidly-built mount with the included SynScan computer controller to utilize many of the same functions and features as Sky-Watcher's most advanced SynScan mounts. It also could be controlled by SynScan Tour.

PEC
Permanent programmable periodic error correction (PEC) - corrects for periodic tracking errors inherent in all worm drives.

Convenient Alignment
It could go back to initial position of the telescope automatically, which is convenient for alignment.

Superior Stability
The EQ7 mount is supported by an improved Super HD Tripod. The tripod is made from the finest rolled carbon steel and can be raised to a height of 1347mm. The tripod uses a dual leg support for maximum rigidity with an upper leg brace to provide an outward preload and a lower leg brace providing inward tension.

45kg Payload Capacity!

[Astroman (Andrew Wall)]

Still waiting on a Price, seen those specs before on another website, which I cannot find now (typical)...

[mill (Martin)]

The suspense is killing me Andrew
I am in the market for a G11 but if the EQ7 is cheaper i will buy it just to test it.

[h0ughy (David)]

be very interesting to see the price point andd quality of this mount?

[mick pinner]

it will be way more expensive than a G11.

[mill (Martin)]

Soooo Do you have any inside info then Mick?????????

[h0ughy (David)]

Originally Posted by mick pinner

it will be way more expensive than a G11.

g11 payload is 27kg, the eq7 supposed to have 45kg and the titan is in this class, which is well above the g11 price. will be very interesting

[Bassnut (Fred)]

Originally Posted by mill

Motors
It utilizes 0.9 degree per step bipolar stepper motors to get high resolution. It uses stepper motors without reduction gear

Somethings very wrong there . 0.9 deg steps with no gear reduction would be hopelessly unuseable . Bad translation perhaps?.

[mill (Martin)]

Originally Posted by Bassnut

Somethings very wrong there . 0.9 deg steps with no gear reduction would be hopelessly unuseable . Bad translation perhaps?.

Yeh i thought the EQ7 would come out with servo motors ??

[Bassnut (Fred)]

No, not that (although thats a good point) can you imagine with 0.9 deg steps imaging an object 30 arc secs in diameter? (0.5 deg). Nah, anything over the FL of a wide angle DSLR lens would be a blurry mess. Its a joke, or Im missing something, or the translation is wrong.

[adman (Adam)]

The stepper would turn the worm 0.9 degrees per step - not the axis it is driving....

[Steffen]

I suppose there would still be the worm, that'll cut those 0.9 degrees into very fine slices.
</speculation>

Cheers
Steffen.

EDIT tips hat to Adam

[Bassnut (Fred)]

Originally Posted by adman

The stepper would turn the worm 0.9 degrees per step - not the axis it is driving....

So whats the worm reduction?, not impressed at all so far.

[Steffen]

If the worm is single pitch then the reduction ratio is the number of teeth of the gear.

Cheers
Steffen.

[ericwbenson (Eric)]

So let's be generous and call it a 300 tooth main gear. 0.9 deg / 300 = 0.003 deg, which sounds small but.... multiply by 3600 arc sec / deg and you get 10.8 arc per step, yikes! Completely unusable by a factor of 100! Something must be wrong in the translation.
BTW 0.9deg steppers are hardly hi-resolution or anything to write home about, that's only a standard stepper motor being operated in half step mode, the same garden variety is used in the robofocuser for example. The other issue they will have with steppers is a very poor torque vs velocity curve. This is why for example the digital drive that came with the original G11 could only go about x32-x64 sidereal, and still had vibrations problems from the stepper jolts while tracking...

EB

[tlgerdes (Trevor)]

Originally Posted by Bassnut

Somethings very wrong there . 0.9 deg steps with no gear reduction would be hopelessly unuseable . Bad translation perhaps?.

That's Chinglish for you.

[Barrykgerdes]

Reading through that Promo list. It doesn't really give much info when analysed.

Dual Encoder Design
Does this mean two encoders on each axis as well as a step counter for the stepper motor, or is it a servo system just using a stepper and encoder for motive power and an encoder on the RA/Dec axes?

Motors
A .9dg per step is quite standard and will need at least a 60 x 60 x 3 (10800) reduction to get a reasonable resolution of .3 arc seconds per step (common for cheap servo systems). Then to get a reasonable slew rate the motors will need to accept at least 10000 steps/sec

Computer Operation
I think this is just referring to the inbuilt controller. I would assume that it could interface with a PC/laptop as well

PEC
Permanently stored PEC is available on most drives these days and considered a must by most but is easily overcome by guiding.

Convenient Alignment
A standard “park” position available on just about all controllers these days

Superior Stability
Ah this is what is needed for a big payload and is the real selling point

45kg Payload Capacity!
Great should satisfactorily carry a 14” OTA

I think we will need to wait for its release to find out what it will really do.

Barry

[garymck (Gary)]

Hi,
the step size is not a problem.

If the individual step size is 9 arc sec, then all that would be needed is to microstep the motor. lets say 64 microsteps (there are already drive systems out there that do this) and suddenly we have a .14 arc sec step size. Easily a high enough resolution to provide smooth tracking. Cant remember the actual figure, but EQ6's are significantly higher in their step size (and use microstepping as well) and no-one complains about seeing jumps in the eyepiece.....

cheers
Gary

[Barrykgerdes]

Originally Posted by garymck

Hi,
the step size is not a problem.

If the individual step size is 9 arc sec, then all that would be needed is to microstep the motor. lets say 64 microsteps (there are already drive systems out there that do this) and suddenly we have a .14 arc sec step size. Easily a high enough resolution to provide smooth tracking. Cant remember the actual figure, but EQ6's are significantly higher in their step size (and use microstepping as well) and no-one complains about seeing jumps in the eyepiece.....

cheers
Gary

I think the step size is quoted as .9deg (54 arc minutes not 9 arc secs).
In any case I would expect the drive to be similar to the NEQ6-pro and using micro stepping with a 300 tooth worm wheel it could use direct coupling to the worm to give sub arc second steps and smooth operation. However this information is not given directly in the promo.


Barry

[garymck (Gary)]

"It utilizes 0.9 degree per step bipolar stepper motors to get high resolution"

This is different to saying the motor moves the scope .9 degrees per step.

The .9 degrees must be the step size of the motor. This is a standard 400 step per rev stepper.

360 degrees = 1296000 seconds

1296000 seconds / 360 teeth / 400 steps per rev = 9 arc secs per rev of motor.

Microstep this by 64 and we get .14 arc sec per step...

Could even use less and Microstep by 16 = .6 arc secs per step - have use Bartels drive at this level with no problems...

Gary