I've been looking into getting a collimator (Wiki) or autocollimator (Wiki) on eBay, but they seem to be many hundreds of dollars. So I'm thinking of making one out of a telescope. But not just a collimator, but one that includes a reticle (Wiki) scale. This would allow making measurements on optical components. There are a number of old Edmund Scientific white papers on how to make your own collimator with a reticle either from scratch or by using a W.W.II surplus gun sight and how to use it.
This refractor scope (Wiki) was on sale (Orion 9549) for about $100 and it has an 80mm objective lens with a 350mm focal length (hence the short tube), f/number = 350mm/80mm = f/4.4 which is fairly fast.
Looking at the nearby mountain shows a very nice image with the 10mm (35x) eyepiece.
This is one of a family of scopes that all have the same patented Dobsonian type mount.
Orion GoScope 80mm TableTop Refractor (Wiki) Telescope (Item # 10013) 350mm focal length. Eyepieces 10 & 20mm (35x & 17.5x)
The Orion SkyScanner 100mm TableTop Reflector Telescope (Item # 10012) 400mm focal length parabolic reflector (Wiki: Newtonian), Eyepieces 10 & 20mm (40x & 20x)
Orion StarMax 90mm TableTop Maksutov-Cassegrain (Wiki) Telescope (Item # 10022) 1250mm focal length, Eyepieces 10 & 25mm (125x & 50x)
Note the power is the scope focal length divided by the eyepiece focal length.
This is a refractor telescope (i.e. it uses a 80mm diameter lens rather than a mirror).
Included is a 90 deg mirror adapter as well as 10mm and 20mm eyepieces (350mm/10mm = 35x, 350mm/20mm = 17.5x). These are powers that are somewhat higher than binoculars and are high enough that you can not hand hold the scope. But it comes with an elevation/azimuth Dobsonian (Wiki) type stand. The stand has a tripod socket centered on the botom so can be used that way or on a table top.
Apparatus and method for stabilizing an optical tube on a base,Sep 6, 2005, 359/430, 359/409, 359/399 - this is for an adjustable friction coupling between the scope and it's mount. Something that the Dobsonian telescope builderes have been doing for decades, so I don't see why it warrants a patent.
The focusing knob that's adjacent to the eyepiece fitting at the rear turns a threaded rod which moves a cylinder back and forth where the cylinder holds the objective lens.
Full counter clockwise moves the objective back 36.7mm from the most forward position. The position of the objective is not optimized for the largest focus range.
That's to say when the objective is all the way back it's past infinity. It would be better if all the way back was infinity and then there would be more close focus range.
Note the right angle adapter threads onto the back of the scope, it's not a 1-1/4" inch male - female part, so you can not insert an eyepiece into the back of the scope without the 90 deg adapter. Maybe the extra back focus if for a Barlow adapter (Wiki).
See top of page foir Fig 1 & 2.
Fig 3 Stand is also used for the:
9909 StarMax 90 Maksutob-Cassegrain
9541 SkyScanner 100 Reflector, as well as for this
9549 80 GoScope Refractor
Fig 4 The scope can be directly mounted on a
standard 1/4-20 tripod head.
Fig 5 The dovetail on the scope has 3 indents to help balance.
Fig 7 With dovetail pinch screw in the hole near objective
the scope can be positioned plumb with objective down.
Fig 8 With dovetail pinch screw in the hole near eyepiece
the scope can not point straight up.
An improvement would be to move the axle up so that the
scope could be pointed straight up or straight down with
the pinch screw in the center hole.
Looking straight up is important for me.
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