Friday, March 30, 2012

Edmund Scientifics AstroScan

AstroScan has a really impressive engineering design. See the good in depth review here. This is how I'm rigging mine to the task.
Stock eyepieces are really good and also parfocal (28mm and 15mm). Their barrel size is interesting. It is a bit larger than a regular EP of 1"1/4. I suspect it is metric, because my Russian eyepieces from TAL reflector fit the AstroScan focuser almost perfectly (this way I can use the 3x TAL Barlow lens with the AstroScan).

F=445mm,
so the zoom line I can use will be:
16 30 48 90

On the image above

g) I have outfitted each eyepiece with the rubber eye guard, which makes focusing more comfortable by providing a soft grip, as well as covering the open side of the eye from strain light.

c) The scope shoulder belt. It can be also adjusted to help protect the scope from falling off the base (h) when it is mounted on the high tripod (i).

a) The button of the green laser pointer. I can keep the pointer on simply by turning it around so the scope side will depress the button. Or I can depress the button momentarily while correcting the pointing direction. This is an ultimate solution for the missing dioptric sight and much more comfortable as well. Mounting is possible with the unbelievable simplicity because of the precise design and craftsmanship of the focuser bulge. It creates a perfectly straight corner for the cylindrical laser pen's body, so I can see the end of the laser beam exactly at the center of the 15mm EP.

b) The green laser pointer held in place by two rope rings (I call it "harness"), which allows for quick laser pointer installation and rotation.

d) and e) The OTA "harness" is a single piece of 550 paracord, making 2 loops fixed with the figure eight knots around the OTA in two places as pictured.

e) The open ends of the rope are in the figure eight knot too, providing necessary tension for loops. Much better than any rubber bands and also serving as a carrying loop and a single finger pointing handle.

I call this design Spherical Dob. Perhaps the inventor must let us know his name. It is truly ingenious. It is much more comfortable compared to the classic Dobsonian design because you can place the eyepiece in almost any position as you feel comfortable and you can "move the sky" in the field of view in any direction in a single smooth motion.

I'm enjoying this little telescope between large dob sessions and always taking it on my camping trips with kids. To add to its amazement, I'm sometimes using the 9mm WO UWA 101 EP with it. Views are just spectacular! I have 3D printed a replacement fixed focuser draw tube for it and invented the special "ball-holding" technique to amend its unbalancing weight while working from the picknick table.

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