Modification of 14" telescope - 2

[Chanlunlun]

Dear ATMs,

As a final move towards the modification project we have designed and finished fabricating the controller for the slow motion control of the equatorial platform.

I would like to share my experience with those who is going to deal with motor controlling structure :-

1. Try NOT to use stepping motor as far as you can. Stepping motors are fed on large current, producing much vibration and are difficult to drive.

2. As an alternative a gearheaded d.c. motor should be used. They are cheap and poduces very big torque ( due to the gearhead ). They could be driven by as simple as a single battery and they save a lot of power. A few AA NiMH batteries run the motor for the whole night no problem. The control circuit is simple ( the simplest one : 2 AA batteries and switch )and can easily be fabricated by every one with modest electronic knowledge.

Our motors are d.c motor and driven by a pair of LM317 voltage regualtors. Actaully for those who are seeking the simplest method they can use a few 1.2 V NiMH batteries connected in series and directly coupled to the motors through switches. In this case there will be no speed adjustment by still serve the purpose well.

Now concerning about the 14" telescope modified for planet shooting, we have finished all our preparation.

The only last thing we are waiting for is clear weather.

Best regards
Chan Yuk Lun

[Wah!]

Stepping motors are fed on large current...