| review: Modified TAL-2M with Tech2000 Dob Driver ATM stepper in RA and DEC ( appr. € 1200,- ) |
This TAL mount is equipped with 2 steppers in RA and DEC.
They are controlled with the DobDriver in equatorial mode.
The mount now is perfect for high power views of the planets and the moon.
Just press the 4 direction buttons in comfortable sitting position to hold the planet in the center of the view.
The Dob Driver controller has an input for CCD autoguiding.
Because the worm and wheel drive has a periodic error of appr. 30 arc secs even this sophisticated technique can not be used for astrophotography with the 1200mm focal length of the TAL OTA.
But the mount can now be used to reliable piggy-backed astrophotography with telephoto lenses up to 135mm.
And there are a lot of objects in the sky for this kind of pictures!
The DEC Motor with home grown mount.
It is connected to the DEC axis with a belt and wheels supplied by Tech2000.
The control box.
The stepper nicely replaces the original DC motor.
Conclusion
The TAL 2M is now a very good visiual telecope.
The additional possibility to make piggy-backed astrophotography is another plus.
The Dob Driver ATM is a very fine option!
As you can see it is *not only* for Dobsonians :)
Comment: I found the info on the TAL-2 mods especially interesting as I just put a stepper motot on mine as well plus a dc motor with cog belt drive for dec control.
I made a stepper motor controller that has proven to be very stable and my periodic errors are about what you state once every 8 minutes.
However I have had pretty decent results with up to 350mm lenses but manual guiding, not auto(don\'t have one!!)
I am also going to adapt a Sky Commander DSC to the unit strictly for increased pointing accuracy.
I use the mount to hold an 8\" f/6 newt ota that weighs about 20 lbs and it wotks very well for me.
Walt Hamler
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