Quote:
Originally Posted by mental4astro
When building a scope, mass production or custom, there comes a point where producing a scope costs exactly the same, be it a 4" or 10". In the end, to cut costs it becomes a function of components & care in assembly. At f/8, primary mirror is likely to be spherical as these are cheaper to fabricate. As you've noticed, the 6" has a simple single speed focuser. It also may only have rubber I-rings instead of springs in the primary mirror cell - you'll never be able to properly collimate the scope if this is the case. You NEED to check this out before you make a purchase. At this year's IIS Astro Camp one participant's brand new 6" dob had O-rings, not springs. We also couldn't get the secondary mirror 100% collimated as the spider was placed too high above the focuser. We fixed up their scope as best we could, and the image quality improved markedly - but not to what it should be.
You get what you pay for.
Mark, I didn't think of coating quality also being a factor. Thanks for that  |
Thanks for your input Alex, it was very informative as I wasn't aware of the lack of springs. How though would I go about checking for springs? Is it just a case of looking at the back of the mirror cell? I can check them that way on my current dob.
Other things I've noted by looking at the information on the sales sites is that the Skywatcher/Saxon/Synta models offer 2"/1.25" focuser and tension control handles for the Alt....whereas the GSO model doesn't seem to offer any of this.