Observatory Evolution
Arrival of POD - October 2007
Construction of deck floor inside POD - November 2007 - click for details
Snow bound POD - March 2008 - click for more pictures
Pier Construction - April 2008 - click for details
There's more rocks than dirt in here!
PZT: POD Zenith Truss - May 2008
PZT in this case does not stand for piezo-electric transducer, but for POD
zenith table, the proposed solution to being able to view objects near the zenith
in a SkyShed POD. The "zenith" problem did not bother me for the first 6 months
of ownership since I was content in picking off targets near the celestial equator
and it was winter, with a near record snowfall, so not a great time for observing
anyways. So now the zenith issue has fully settled in. When the POD is open the
interlocking quarter-spheres give an unobstructed view of half the sky minus the
lip overhang (~8") and minus the half diameter of your scope if centered in the
dome. For a large dome compared to the telescope aperture the lost fraction would
be small, for a 7' dome and 11" telescope it restricts viewing to less than +45deg
declination with the mount fully offset (14") towards the south wall. This leaves
less than an inch between the camera and the inner dome surface when a Losmandy
G11 mount is parked in the counterweight down position. One might think that rotating
the dome so the hemisphere cuts N-S would solve the problem, however on a German
equatorial mount the telescope is high on the east of the pier when looking west
and vice versa looking east. Unless the pier is very low the telescope is obstructed
by the dome at altitudes greater than about 45deg. For imaging this is a real problem
since the best seeing and transparency is obtained when the object is high in the
sky near the meridian. For deep sky imaging in marginal climates with only a few
clear nights per month, a clear track +/- 3 hours near the meridian is required.
A CAD generated image of the concept from the manufacturer was implemented by another imager, eager to capture targets north of 45 degrees declination, however in his words: "Once away from the POD, the huge table was so unwieldy that it started to bend and crack, legs bending angle iron and all." The concept needed work. Update January 2009: SkyShed has recently announced significant progress in manufacturing a PZT. A working PZT or do-it-yourself plans with tubular steel supports and wall anchors, QRBs (dome quick release brackets) and other hardware will be available soon. See the manufacturer website and the SkyShed-POD groups.io for details.
PZT Construction details
POD Platform - October 2008 - click for details
Upon making the decision to upgrade to a larger mount I felt I need more headroom
in my POD, and while I was at it I could make a better floor. Above is the end result,
a POD platform with a sunken floor.