Takahashi PM-1 Mount & BORG T-threaed Helical Focuser (#7839)

This is 1st shot tracked by a new Takahashi PM-1 mount recently Rob Bishop got.

M8 and M2018x60sec
Tak PM1, Tak FS-60w/ red, Fuji XT1

M8 and M20 18x60sec Tak PM1, Tak FS-60w/ red, Fuji XT1 taken by Rob Bishop

This was unguided one minute exposure in 240mm focal length. My experiences so far were unguided 3 minutes in 200mm f.l. (=BORG 55FL F3.6) No problem at all. The result encourages me to try longer focal length.  One day I will use with BORG 71FL F4 or 90FL F4 next time.  Since a polar scope is well aligned by Takahashi, at least I don’t still expect DEC drifting in 3 minutes though. Anyway let’s see.

BTW, my EM-200 has no DEC drift at 360mm focal length in 6 minutes. Probably longer exposure should be still OK. The polar alignment is just done by an original optical scope, without drift alignment or modern electronics method either. So in my opinion as one of users, I really feel Takahashi’s polar scope is under-estimated. Much more actual value than we generally think. Also keep in mind, all of Takahashi polar scopes including these portable mounts are completely protected with a metal cap. I believe this is the extra value generally not specified in specs sheet. As transportable mounts, this is very important to maintain the factory-set accuracy long time.


BORG t-threaded helical focuser has been discontinued several years ago. Since then, it was only available from German Telescope Service. But still same quality and produced by BORG in Japan. And recently new lot should come in stock for TS.

7839If someone are interested, please contact TS. I’m not sure what part number is assigned for this by them though. Its light path is 15 to 25 mm. Really convenient unit.


~ by tedishikawa on August 30, 2016.

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