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Orion SkyScanner 100mm Primary Collimation Help

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#1 7lx200gps

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Posted 27 November 2012 - 12:25 AM

I have a SkyScanner 100 Reflector which is 4" and its a nice little scope but when Orion makes these scopes, they unfortunately glue the primary mirror to the cell, but there are no collimation bolts on the back. Its all just one cell that has the mirror glued in it. You can adjust the secondary, but you need to collimate the primary too. I need to know how to adjust the primary mirror too. Is there some rig I can make that would allow me to adjust the whole cell. Any suggestions would be helpful.

#2 Asbytec

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Posted 27 November 2012 - 12:43 AM

I dunno, you'd have to look at it, see what's there, what can be salvaged or modified, if anything. Maybe you could just remove the mirror and build a custom plywood cell with springs and adjustment screws. It doesn't have to be complicated or robust. Three spots of silicone to hold the primary, paint it black, slip it in, and screw it to the end of the tube using the existing holes.

#3 paul130v

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Posted 27 November 2012 - 05:07 AM

....and this is why I don't have a SkyScanner.....

Anyhow, I think what some folks did with the 76mm f4's was to remove the screws that hold the cell assembly in the bottom of the tube, lengthen the screw holes, and vola! a collimating mechanism - though crude and rough.

Perhaps someone who recalls this will offer a link to the thread and/or some more complete description.

#4 sixela

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Posted 30 November 2012 - 07:48 PM

Actually, you collimate the secondary to eliminate the coma (with a Cheshire at the focal plane) and you live with whatever focal plane tilt you then get.

The scope's got a healthy amount of field curvature anyway, so a bit of tilt will be buried anyway ;-).

Not ideal, but the only thing you can do about it is either hack the thing or buy something larger (a StarBlast or a Skywatcher 130mm Heritage or equivalent).

#5 tnakazon

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Posted 01 February 2013 - 09:08 PM

I have a SkyScanner 100 Reflector which is 4" and its a nice little scope but when Orion makes these scopes, they unfortunately glue the primary mirror to the cell, but there are no collimation bolts on the back. Its all just one cell that has the mirror glued in it. You can adjust the secondary, but you need to collimate the primary too. I need to know how to adjust the primary mirror too. Is there some rig I can make that would allow me to adjust the whole cell. Any suggestions would be helpful.

Just saw this thread, sorry for the late reply.

The primary mirror end fits snug-tight at the end of the tube, so it's more likely the secondary to be misaligned during shipment from factory to warehouse to buyer.

Anyways, here's what I strongly recommend doing:

1) Remove the mirror end of the scope and center spot the primary mirror with black pen/marker and notebook reinforcement ring (I used Gary Seronik's method for center-spotting a primary mirror).

2) Get a collimation cap (I used the one that comes with Orion's Newtonian scopes from Starblast 4.5 and up) and insert into the focuser

3) While looking through the cap and focuser, use an Allen-head screwdriver to adjust the 3 tilt screws on the secondary mirror holder until the black dot is center spotted within the ring of the primary.

Once I followed these 3 steps, the views through my scope improved enormously. The moon and planets are more sharply focused. Stars look more like pinpoints of light, with double stars more cleanly resolved and out-of-focus bright stars showing perfectly concentric rings.

I check the collimation each time before use - it holds collimation pretty well.

I've used the Orion SkyScanner for over 2.5 yrs. and it's still my most widely used scope, despite already owning 5 larger ones! It's easy to transport to darker sky sites and has just enough aperture to see a wealth of deep-sky objects. There are still hundreds more DSO's awaiting my discovery with this scope.

The pic below shows the center-spot ring on the primary and the three tilt screws (holes) for adjusting the secondary mirror.

Attached Files








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