MK67 Focus Question

I have heard that the MK67 with factory-supplied Crayford focuser cannot come to focus when using 1.25" eyepieces and adapters in a 2" diagonal. Thus, you would need both 2" and 1.25" diagonals to use both types of eyepieces. Have you found this to be the case? Would switching to a JMI focuser help? Is this even possible?

Thanks!
Dave

Ad copy for Orion's Argonaut Maksutov-Cassegrain was as follows: <>

This copy always confused me. It implied that 1.25-inch eyepieces -- as you've noted/heard -- would not reach focus in a 2-inch diagonal. It also implies that 2-inch eyepieces, as well, would not reach focus, as the 2-inch diagonal/eyepiece combo would not allow enough inward focus.

However, a review of the Argonaut in "Sky & Telescope" (April '99 issue) noted that a 2-inch diagonal was actually *required* for 1.25-inch eyepieces. The S&T article -- *not* the Orion ad copy -- better fits my own experience with the Intes MK67 (Intes branded; not the Argonaut). Orion's recommendation for 1.25-inch eyepieces simply would not work in my MK67.

As per my understanding of the Intes MK67's focal plane position relative to the rear of the scope tube, I included a 50mm extension tube (2-inch diameter) with my MK67 order back in 2000. When coupled with a 1.25-inch diagonal, the extension allows all my 1.25-inch eyepieces to reach focus. *Without* the extension, a 2-inch diagonal is needed.

In other words: all Intes-branded MK67s of the past few years were/are designed with 2-inch diagonals in mind. As for Orion's old ad copy -- I'm just not sure how accurate it was. Perhaps early Argonauts were spec'd a little differently (focal plane further "forward," nearer the focuser) than latter versions.

Nutshell:
-If I were ordering a new Intes MK67 today, and I needed it to reach focus with a 1.25-inch diagonal, I would *expect* it to require an extension tube to do so.
-If I needed the MK67 to reach focus with a 2-inch diagonal, I would *expect* it to do, right out of the box.
-If I had any doubts or worries as to my expectations, I'd check with the dealer.

I hope this helps.
Best wishes.
-Dan

Dave,

I have a newer MK-67 Deluxe (Delivered November, 2002), and use a 2" TeleVue Everbright diagonal. My eyepieces (Parks Super Gold 10mm, 15mm, 20mm, 35mm - the same as Orion Ultrascopics) all achieve focus with & without the TeleVue 2.5x Powermate. The focuser is almost all the way racked in with the 35mm, but it does focus.

Greg

One more story. My MK67 was new in 2000, and I use a Lumicon 2" diagonal. My UO MK70 40mm, Widescan III 30mm, 24.5mm SWA, 19mm Panoptic, 13.8 SWA, 12.5mm & 9mm UO orthos, 11mm TV plossl, 9mm nagler T1, 7mm Nagler T1 all come to focus. There is not enough inward travel for my 6 & 7mm UO Orthos to reach focus.

I have the Orion version, purchased about two years ago, and my 1.25 EPs will NOT come to focus in a 2" diagonal. Needs more in-focus.