Originally posted by k5astro: These trackers were originally designed to support a 200-300mm (max) prime lens. Great well designed products. Then for some reason they come out with the counterweight system so you could overload it with a bigger lens or a telescope! To me the use of the counterweight smacks of department store telescope marketing. A guide port is also supplied if you want to further overload your poor little tracker with a guide scope because you overloaded it with a big lens and a counterweight. I'm not saying thats what you've done - I'm just ranting - but a 500mm lens is way too big and even 300mm is pushing it for 1 min exposure. Better check the specs and keep your overall weight well within that number. Personally I wouldn't put more than a 200mm. Trackers are not telescope mounts. Even a telescope mount has a lot of issues to get good solid round stars. (Polar alignment is key!)
I don't know if you're using a counterweight or not, but while I'm on the subject, my guess is that they are really intended for using something like a Redcat (which has a 250mm fl) or telephoto lens where the camera is mounted to the lens rather than the other way around. Also, you can get rid of the ball joint otherwise necessary. One still has to stay within the weight load.
Again, sorry if it sounds like I'm not picking on you. I'm not. Its just that your problem has reminded me of some issues on the subject that I wanted to express. Thanks.
Absolutely agree. Hence, looking at a CEM60 for my next tracking mount. I doubt the trackers would support a decent 300mm prime lens very well, even. The counterweight on the Skyguider weighs 3 lbs in itself, plus at least 1 lb for the shaft and axis, leaving a 7 lb payload capacity. A good rule of thumb seems to be 1/2 the payload for good astro - ergo, leaving 3.5 lbs max for the other end of the shaft. My Pentax weighs roughly 2 lbs, leaving roughly 1.5 lbs for the lens. My Tamron 60-300 weighs about 2 lbs. An FA 200 weighs 1.7 lbs.
As you say, mounting a camera directly to the front of the Skyguider makes it easier in terms of weight, although that then obscures the alignment scope and seemingly limits rotation.
