Astronomy

Mothor Drive for a Telescope



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I have been watching the stars for many a year now, pushing further and further into the cosmos in an attempt to uncover the untouchable beauty of the heavens, more recently I have yearned for a way to record what I see so that I can share my passion with everyone in the entire world! Or at least my close friends and family. That's where the Celestron Dual Axis Drive comes in.

The Dual axis motor can be used for visual observation, that is to say just using your own eyes to gaze at objects through your telescope, it keeps the object in the centre of the field of view without the need for constant adjustment of the slow motion controls on the CG-4 mount. Very convenient but more than that it enables you to focus 100% of your concentration on the object you're viewing which actually improves the amount of details you can pluck out.

Useful for visual observation but integral to astrophotography, that's where this drive goes from being an exciting novelty to a vital necessity. For those who are unfamiliar with the process, here is a simplified guide to the process of photographing the solar system. I use a webcam which I've had to modify then mount it onto my telescope, I take a video clip usually in the area of 2-10 minutes, then using a specialised piece of software that separates the video sequence into individual frames I can "stack" the frames on top of eachother producing one image. Knowing this, it soon becomes obvious as to the importance of a drive that holds an object in the same spot for as long as possible with only the minimalist amount of deviation.

There are alot of drives available out there but there aren't too many for the German Equatorial CG-4 (this simply refers to the type of mount it is). It's important to note that the CG-4 is almost identical to the Skywatcher EQ3-2 and as such any motor drive that works on one will work on the other.

As it turns out the Celestron drive is one of the best available to the CG-4 (and the Skywatcher EQ3-2), it costs around £120 ($180) but for that price you get the Right Ascension Motor as well as the Declination motor (a left to right motor as well as an up and down motor).

If you've performed correct polar alignment (a necessary step in keeping objects centered in the eyepiece) you will probably find you hardly use the declination motor but It's still worth having as you can use it as a cheap backup to the RA drive if that should ever conk out.

The setup of the drive is incredibly easy (believe me I am not a fan of nuts and bolts). If I can do it with no worries even a particularly ignorant chimp could do it. The drive comes with easy to interpret instructions as well as the tools you will need, the whole thing will take a matter of minutes.

It comes with a handheld control which takes four of those big batteries (D-cell) which Celestron rather cheaply do not supply (so make sure you've got some in to avoid disappointment). My advice would be to get your hands on a charger that takes D cell batts otherwise you'll end up spending a fortune on an endless supply of batteries. You should get about 20 hours out of each lot of D cells which would very roughly equate to spending about £7 ($10) every fortnight, whereas a good charger costs only £20 ($30).

There are 4 speed settings that the drive can work at, x1, x2, x4 and x8, the latter speeds are useful in re-centering an object that has started to stray, in effect making your telescope sprint momentarily to catch a speeding target before settling back down to a comfortable jog.

In conclusion if you own a CG-4 or EQ3-2 mount and are thinking of getting into astrophotography this is a great drive to get, it's smooth, reliable and can keep objects centered in your field of view for hours (providing polar alignment has been correctly performed). Even if you aren't into taking photos and just want to observe visually the drive frees your mind by taking care of all the manual work, which not only makes for a more relaxing observation but actually makes it possible to pull fainter details from celestial objects, a definite recommendation.

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