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Building width, length, wall height, and mount pivot position — height above floor, and N/S and E/W offset from the building's center. All in centimetres.
For anything other than a simple rectangle — angled corners, an extension, an irregular footprint — turn on "Use a custom wall shape" to describe the building as up to 6 walls, each with its own angle from North and distance from center.
Pick which wall the roof rolls off past and how far. Three roof shapes:
A scaled floor plan of the building sits above the Telescopes card. Click anywhere inside the building outline to place a telescope pier at that position. Drag to reposition. Each enabled telescope appears as a colour-coded dot with a faint dashed swing-radius circle. The NS/EW number fields in the Telescopes card stay in sync — move a pier and the numbers update, or type in a number and the dot moves. Use the floor plan for initial placement and the number fields for fine-tuning.
Each telescope is on its own independent mount. Telescope 1 uses the mount type and optics from the Optical Axis card, but its own position (NS/EW from building centre, in cm) and mount height defined in the Telescopes card. Enable Telescopes 2–4 for additional mounts — each gets its own position, mount height, mount type (GEM/Alt-Az), GEM axis length or Dec horizontal offset, tube length (mm), and aperture (mm).
Use the Pointing telescope dropdown in Step 4 to choose which mount drives the live pointing preview, obstruction check, and sky coverage sweep.
Each telescope's swing radius is checked independently at its own mount position against the nearest wall, floor, and ceiling — since each is on a separate mount, their clearance envelopes don't share a pivot. A separate check catches telescopes hitting each other: two mounts collide when the distance between their pivots is less than the sum of their swing radii plus the minimum walkway gap you specify.
The 3D view shows a wireframe sphere per telescope at its actual swing radius. The selected telescope's OTA tube tracks the live pointing direction; other scopes point straight up in a neutral pose.
Same concept as the dome tool. The plot is stretched to your building's actual width/length ratio. Includes an Export as Horizon File (.hrz) button.
Same Hour Angle/Dec or Alt/Az controls, jog pad, and pier-side handling as the dome tool. The 3D view shows the actual building shape, the parked roof, cardinal directions, the celestial equator, and wireframe swing-radius spheres per telescope (red if any fails to clear).