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Posted by Chris on August 11, 2002 21:42:03 UTC

Taking photos with a Dob is impractical, not to mention almost impossible. Almost all dobs are unable to track an object (a function of both its Alt-Az mount AND the expense of hooking up motors to such a mount), meaning that all exposures would have to be a maximum of just a small fraction of a minute. In addition, dobs are made to be easily pointed, meaning that they will move easily when you push them. As a result, many dobs can't even support the weight of a camera, except a CCD - and if you have enough for a CCD, then you've got enough money for an 8" or 11" SCT, which is 100x better for a dob for astrophotography.

The Dob will supply spectacular deep sky views (albeit with less contrast and detail than a SCT, refractor or one of the new compound Newts popping up)...Using a dob is basically a comprimise between aperature, portablility, usability, and image quality. Since they have the ability to get much larger, they suck in a lot of light, but lack definition and contrast on close objects. They are also a snap to assemble and break down, but you won't be able to track objects, you'll have to give it a nudge every few minutes as the image travels.

If you are willing to deal with the cons of a Dob to gain the pros, it will serve you with plenty of great views.

Also keep in mind that grinding a mirror is tough work, and it needs to be precise or you risk not being able to focus images. Don't be discouraged, though. It's great fun, and the rewards are endless when you succeed...But do yourself a favor and buy an extra mirror blank, breaking one or grinding it too thin can ruin your weekend while you wait for another one to come in.

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