You can easily make your own. A piece of tough 5/8-inch (16-mm) foam rubber — the kind sold in sporting-goods stores to go under sleeping bags — makes a dew shield that's cheap, durable, and very lightweight.
I haven't done collmation yet but I'm starting to learn about it. There are both short & long Cheshire collimators. It's looking like the long ones are also meant to be used with refractor telescopes also.
Last Edit: Nov 1, 2016 6:35:40 GMT -6 by pickinduck