I am currently looking at the Stellarvue Nighthawk II 80mm F/6 Dual speed focuser or the William Optics ZS 80mm Single speed focuser Package A with a 2" Dielectric and VR1 filter. I wish to ask if you had the choice which would you take? I need some help deciding. Thanks in advance.
Nighthawk II or ZS 80
Started by buzzman, 10/23/2006 12:32AM
Posted 10/23/2006 12:32AM
| Edited 10/23/2006 12:33AM
Opening Post
Posted 10/23/2006 04:18AM
#1
My Nighthawk II with single speed Crayford can't support a TEC EP turret at zenith with 5 EP's installed due to the excessive weight. Even with the focusing lock engaged. It also does not support binoviewers well. Don't know if a dual speed focuser would do a better job. My JMI dual speed focuser handles heavy binoviewers just fine. The Nighthawk II single speed Crayford is only suitable for single EP's....and I don't mean a 31mm Nagler or 41mm Pan.
My next refractor will have a large Feathertouch focuser of over 2", or I probably will not get a refractor at all. My Russian Mak with 2" visual back will support anything you want to hang on it, as it focuses internally. Small refractors are very limited in what the focuser will support from my limited experience. I have no problem with terrestrial observing with my NH II as the focuser doesn't have to vertically support weight.
Tightening the single speed Crayford focuser too much in order to prevent slipping can damage the roller bearings. None of the Chinese Crayfords will do the heavy work that a Feathertouch focuser takes in stride, or what a dual speed JMI is capable of handling. A 2" diagonal and hefty 2" EP's may tend to slip in a single speed Chinese Crayford when pointed to the zenith. My minimum focuser from now on will be a dual speed JMI.
My next refractor will have a large Feathertouch focuser of over 2", or I probably will not get a refractor at all. My Russian Mak with 2" visual back will support anything you want to hang on it, as it focuses internally. Small refractors are very limited in what the focuser will support from my limited experience. I have no problem with terrestrial observing with my NH II as the focuser doesn't have to vertically support weight.
Tightening the single speed Crayford focuser too much in order to prevent slipping can damage the roller bearings. None of the Chinese Crayfords will do the heavy work that a Feathertouch focuser takes in stride, or what a dual speed JMI is capable of handling. A 2" diagonal and hefty 2" EP's may tend to slip in a single speed Chinese Crayford when pointed to the zenith. My minimum focuser from now on will be a dual speed JMI.
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