Opinion on tracker welcomed..

Hi Ian,

That little telescope looks interesting. The 90mm aperture Maksutov telescope should enable some nice Moon viewing and perhaps imaging. Being able to demount the optical tube and mount a DSLR is also a real plus. It would be beneficial to see some user reviews. But I'll give some comments based on what's apparent from the web-page.

The mount is of the Alt-azimuth type, with one axis vertical. If it performs as described, it will follow an object as the Earth rotates, but the field will rotate around the object being tracked. But for wide field imaging you will get star trails if the exposure is of any length. To enable tracking the sky for photography without trailing, the azimuth axis must be pointed at the celestial pole. The mount description mentions being able to attach it to a photo tripod. So if you have a sturdy tripod, this may enable you to point the axis to the celestial pole. When this is accomplished you have in essence an equatorial mount.

I have a couple of concerns about doing this:

1. Is your tripod of sufficient sturdiness to hold the mount without too much movement and vibration? The mount by itself weighs 3.7 kg, with telescope it's 5.1 kg. I would suspect that a suitable tripod for that load might be expensive.
2. Will the bearing on the azimuth axis (which will now be your polar axis) function as designed while tipped up at the angle needed for polar alignment? In other words if it is a thrust bearing designed for the axis to be vertical, will it still work tipped at an angle?
   
3. What method will you use to ensure that the mount's polar axis is in fact pointed at the celestial pole? One method that I have used to polar-align a barn-door mount is to employ a green laser in an adjustable bracket. This same method may be of use in this instance. For details on this method, see my write-up in DPReview "Articles", "Photo Techniques", "Building and Using a Tracking Mount for Astrophotography".

One thing not mentioned in the telescope web-page is what type of focuser it employs. Does it have a rack-and-pinion, Crayford or just a slip tube (with screw lock) focuser. For lunar imaging through the telescope you need a finely adjustable focuser capable of carrying your camera load. I like the fact that it uses standard 1-1/4-inch eyepieces.

So Ian, these are just a few of my thoughts off the top of my head. I hope these will be of use. I'll try to answer any further questions you might have.

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Best Regards,
Russ