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Play in Mak Meniscus

Started by jameswilliamjohnson, 07/11/2012 12:55PM
Posted 07/11/2012 12:55PM Opening Post
Some time back when checking out my Intes 6" Mak-Cass, I heard a slight rattling from the corrector plate when I moved the scope up/down. I was looking at Jupiter at the time and the image was very good. I just now retrieved it from storage with a view to selling it. I have only used the scope a few times in the 10 years I've owned it an never noticed it before. Should there be any play? Is it a tough job to tighten it up? Anyone have any instructions or point me to some?

Jim J

"Much of the social history of the Western world, over the past three decades, has been a history of replacing what worked with what sounded good." - Thomas Sowell
Posted 07/11/2012 03:20PM #1
Jim, I recommend that you take off the meniscus cell before doing anything further and check the condition of the retaining clips. I've had two Intes meniscuses damaged in transit. One was an MK67 that I shipped; the other an MK66 I received. Both were caused by defective retainer clips. The MK67 had a 5mm-wide tab which projected slightly over the meniscus to a depth of about 2 mm. The glass slid away from under the other two tabs and broke the mirror and meniscus. The MK66's retaining slips are screw washers that have been filed flat on one side so the meniscus can fit into the cell; the round side projected about 1.5 mm over the meniscus surface to hold it in place. One of the screws had loosened and the washer rotated till its flat side uncovered the area over the glass. The glass slipped away and the meniscus floated freely in the tube (picture 1; pic 2 in next post). In both cases the OTAs were very well packed in bubble-wrap and foam, inside their factory soft-bags inside firm cardboard boxes. I think Intes did a poor job in their meniscus retention design. I have a Santel Mak whose meniscus is retained by a full-circle ring; there's no chance a severe ride in a box will jar it loose. I was able to salvage the MK66 despite the horrible chip and it does surprisingly well for low-power gazing. Later I had to carry it in my airline baggage to a new home and took the precaution of rolling a round ball out of bubble wrap, large enough to fill the tube and to bottom against both baffle tubes without actually touching any glass. Had a clip come loose as before, the ball would have held the meniscus in place.

Attached Image:

atelierbks's attachment for post 144747

Stargazing since 1954
Six refractors 80mm to 150mm
Four reflectors 150mm to 310mm
Posted 07/11/2012 03:26PM #2
With as much attention as the various Intes marques lavish on optics, you'd think they could come up with a better meniscus retainer than this.

Attached Image:

atelierbks's attachment for post 144748

Stargazing since 1954
Six refractors 80mm to 150mm
Four reflectors 150mm to 310mm