Bob's Knobs


The good folks on the newsgroups raved about Bob's Knobs, which replace the Philips- or Allen-head collimation screws on a wide variety of scopes with finger-adjustable screws. And after a week of trying to get the name out of my head, I had to just go ahead and order a set.

Image: Bob's Knobs installed
In trying to get better performance from my Nexstar 8i, I had found a few interesting sites about collimation. I had assumed that a new scope from the factory would be in perfect alignment, naively overlooking the UPS trip from factory to retailer, not to mention my own tender mercies getting the scope 40 miles to my house, unboxing and assembling it. After being a bit disappointed with the clarity of my Saturn and Jupiter views, I decided that a careful collimation would fix all my probs, so soon did I order these Knobs of Bob's.

Installation was a snap, and with the help of one or two excellent tutorials on collimation, I was back in business after an hour or so of viewing. It would have been even quicker, except that the seeing wasn't as good as I could have used, and also I finally figured out what all those wavy lines were when I defocussed the scope on a bright star: tube currents! Still, I got the scope in pretty darn good collimation, and Saturn did indeed look sharper.

The great thing about Bob's Knobs is that I can adjust the scope while I'm looking through it, and immediately see how much effect my adjustments are having. Plus, I can put my hand in front of the scope, casting a shadow through the optical path, and see which knob needs to be adjusted. I still want a night of great seeing to dial the scope it the last little bit. I can easily see making a quick collimation check part of my nightly or weekly routine.

Very, very nice. And cheap. Highly recommended.


Posted: Sun - March 14, 2004 at 12:32 AM             |

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