EQ8-Rh Pro

[jambouk]

There is still very little discussion about this mount on here or elsewhere. £6000 seems like a big jump from £3700 for the standard EQ8-R Pro (without the encoders). And it all seems a lot of money when there isn't even an internal spring mechanism to sort out the backlash on the RA.

The 50kg payload capacity though and the familiarity with the Skywatcher handset is all very appealing. £2300 extra for the Rh encoders though seems too steep given the potential gains.

James

[SamAndrew]

I think it's up the manufacturer or retailer to quantify the benefit. Ask FLO if they'll let you test one

[Sp@ce_d]

Are you going to use it for imaging? I've had my EQ8 Pro in the Obsy since 2014.. never use the freedom find encoders.. ok not comparable to the Renishaw. The point is, if imaging with it then once the balance is sorted for the offset motors & encoders are disabled, then it guides fine. The new ones have re positioned motors so I'd hope they're easier to balance. Personally if I were looking to change it & I was looking at the load capacity & a 6 grand budget... for Obsy based.. I'd be looking at the Mesu. I can't see what the extra 2 plus grand would do for me. Probably why there's been very little discussion!

[jambouk]

Thanks both. Yes, the £2000 extra seems steep when in reality one would still need to guide anyway.

James

[jambouk]

There is a review of the EQ8-R in October’s S&T. No mention of the backlash others have complained about, and the tests of tracking were undertaken with 200mm focal length optics which doesn’t seem particularly challenging, though they managed to get good 120 second unguided subs with this. 

[tonyowens_uk]

The EQ8-R is functionally identical to the older EQ8 Pro. The improvements (through-the-mount cabling, improved microstepping quality, better static balance, better clutch design) are useful but not groundbreaking. The more fundamental upgrade, antibacklash gearing, was not implemented. The -Rh variant with an RA encoder apparently does a good job of reducing RA worm periodic error.

On the other hand, autoguiding, especially with an off-axis guider (where possible) on the original EQ8-Pro can match the  -Rh's guiding quality, provided the OEM clutches are modified, antibacklash gear modifications are installed, and Green Swamp Server is used to control the mount. This latter replaces EQMOD and brings better motor microsteppign performance and sutoguiding correction quality.

High resolution axis encoders are not an answer to any problem in mounts of this class, by themselves. Sophisticated pointing model capability is needed in addition. That is not offered currently either by Skywatcher or EQMOD or GSS. And even when it appears, for most purposes it will offer no practical advantage over refined autoguiding and platesolving.

 

Tony Owens