After much consideration...
Posted 25 February 2010 - 07:21 PM
I must admit I would have liked the Celestron software, as I'm already familiar with it, but otherwise I am happy with my choice.
Posted 25 February 2010 - 07:25 PM
Posted 25 February 2010 - 08:34 PM
Posted 25 February 2010 - 10:25 PM
I recently rebuilt a CG5 AGT for one of our club members. Celestron carries a lot of their engineering practices from one mount to the other. First off they use DC gear head servo motors. DC motors have brushes that will eventually wear out. The gear head inherently has lots of backlash. Gear heads with straight cut gears are noisy. They use the gear head to get the required torque from a relatively small DC motor. The servo system is a closed loop type that is always trying to move the mount to a specified encoder position. If the mount is unbalanced or encounters an obstruction the closed loop system will keep commanding the motors to match the encoder position required. It does this by increasing the amount of current to the motor. This can lead to armature burn out. The encoder is a 200 step per revolution type which equals 1.8 degrees per tic.
The EQ-6 uses stepper motors. Stepper motors have no brushes and have more torque. The motors are direct drive to the worm gear through 2 spur gears. Stepper motors are very quiet. Stepper motors move by advancing the windings and always see the same amount of current no matter what the load. If a stepper motor is over loaded or encounters and obstruction it will stall. The current remains the same and it will continue to advance the windings and the motor will chatter but there will be no damage. Stepper motors are 200 steps per revolution or 1.8 degrees per step. The synscan uses the motor steps as it's encoder. It takes for granted that it told the motor to step and it did. If the motor stalls it will require a re-alignment.
That is a review of the two systems that I am familiar with. It was meant for comparison of the motor drive systems and how they work. I like the EQ-6 system as it uses stepper motors that will practicably last forever and less electronics are involved in the control of the mount position. Less electronics = more reliability.
I own one of the earliest EQ-6 GTs (the old charcoal grey). It has operated flawlessly for well over 5 years now. When the CGEM came on the scene I seriously considered side stepping to that unit. With all the software offerings for the Atlas and EQ-6 type mounts though I just can't justify leaving such of a robust system behind. Not having to worry about motor burnout or brush wear is a plus for the EQ-6. The reduced complexity of the electronics is another plus for the EQ-6. Direct drive to the worm and no gear head is another plus. After market software another plus and on and on.
This is just my opinion but I find that the EQ-6 in the very long run, will be the most robust system of the two due to it's simplicity and rugged construction.
Posted 27 February 2010 - 11:00 PM
The EQ6 in a no frills mount to be sure. Its heavy and rather blunt, but its proven its reliability. Mine is one from the first shipment to hit Aus (Mid 2002). No Goto option then, just standard dual axis drives. Later I fitted it with a Goto conversion kit. Mine has really been worked hard with no dramas at all. I should say that about 6 months ago I stripped it down, re-greased and adjusted the worm to crown engagements, but hey after nearly 8 years operation I would put that down to an expected and necessary servicing, much in the same way that any piece of machinery will need some grease or oil and adjustments at some times in its life span.
Posted 28 February 2010 - 02:16 PM
Your AT90EDT will work well on the Atlas. I enjoy using mine.
Posted 28 February 2010 - 10:01 PM
I value reliability above all else.
Posted 01 March 2010 - 12:30 AM
The temptation is high to grab a CG-5 since they can be had for around $500. versus almost $1400 for the Atlas.
However, I think I'd rather image with my ST80 on an Atlas,
than an 8" dob on a CG5. I can save up for the 8" dob. ;-)
Posted 01 March 2010 - 06:39 PM
Posted 01 March 2010 - 11:58 PM
Posted 02 March 2010 - 01:02 AM
Posted 02 March 2010 - 08:42 AM
Posted 02 March 2010 - 10:16 AM
And I'm seeing the CGEM for $999. (Ouch... wish I'd have waited.)
Ok, I'll bite... Where did you see that price? Everywhere I look it is at $1399.
Posted 02 March 2010 - 10:27 AM