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Equilibrating a Mewlon

Started by RobertHowe, 08/30/2021 03:41PM
Posted 08/30/2021 03:41PM | Edited 08/31/2021 03:54AM Opening Post
Hello Tak fanatics,

A couple months ago I sold my TEC 180 apo, which had come to present me with insurmountable physical challenges, using a portion of the proceeds to buy a new Mewlon 210.  It is kept in a roll-off observatory and is piggy-backed on an AP130 f/8.35 refractor.  Although the ergonomic issues have now been resolved, I'm very disappointed by the Mewlon,  I've observed with it 8 times and only once has it behaved well.  Images are unclear, they don't snap to focus.  I can get higher clear magnification with the much smaller aperture of the AP.  The clever gentleman at Texas Nautical tells me there are tube currents to be waited out.  This would invalidate my usual modus operandi of going out on a whim, observing for 30-40 minutes and then going to bed.

Has anyone a strategy for eliminating these currents?  Is there a fan I can plug into the diagonal for 10 or 12 minutes before observing?  At present, if I expect to observe I will slew the mount so that the rears of the scopes are upright, take the front cap off the downward-pointing Mewlon, then take the rear plug out of the diagonal, in the hope that hot air will rise into the night and ambient air will replace it.  I let it sit like this for four hours before observing on the one night that it behaved well. 

A means to accelerate this process would help.  Is there a fan mounted to fit in the diagonal?
Indeed, a means of adding a fan that allows me to observe simultaneously would be even better.

Many thanks

Robert Howe
Wilbraham MA

Attached Image:

RobertHowe's attachment for post 182174

Robert Howe
Wilbraham MA


TeleVue 85 f/7 // Astro-Physics Traveler 105 f/6 // Astro-Physics 130 f/8.35 // Tak Mewlon 210 //
Coronado 60 DS
"Scopes, Brains and Wisdom--but no Beauty"