How to Install and Aim a Rotating Gobo Projector

What to check on the first visit

A rotating gobo projector install is mostly survey work. Walk the site at the hour the projection will run, because the ambient light, the position of vehicles, and even the position of a display stand all change what works. Take a photo, measure the throw, and mark the cable route before ordering anything.

1. Nearest power and whether it is switched
2. Surface material, colour and ambient light at the working hour
3. Fixing substrate and bracket load
4. How the unit will be reached for cleaning

Mounting height and bracket choice

Choose the bracket before the fixture. A rotating gobo projector needs to hold its aim through thermal cycles and, outdoors, through wind loading; a lightweight bracket that drifts a degree will put the image off-target within a month. Use a bracket rated above the fixture weight, and if the install is exposed, check the fixings are stainless.

• Bracket rated above the fixture weight
• Stainless fixings for exposed positions
• Beam as close to perpendicular as the site allows
• Position reachable without powered access

The order of adjustments

Adjust in this order: position, zoom, focus, then rotation. Moving the bracket after you have focused wastes the whole sequence, so get the geometry settled first. On a rotating gobo projector, set the zoom to frame the image on the target surface, then focus at the centre of the image and check the corners — if the corners are softer than the centre, the beam is off-axis.

• Set the bracket position first
• Zoom to frame the image on the surface
• Focus at the centre, then check all four corners
• Lock the focus if the unit allows it

Power, cable routing and switching

Route the cable as if somebody will try to unplug it, because somebody will. Use a switched, protected supply, keep the run out of reach where possible, and make sure the connection point is accessible for service without dismantling the rotating gobo projector. If the install is outdoors, the cable entry — not the housing — is the most likely place for water to get in.

1. Fixed, switched, protected supply
2. Cable gland rated for the environment, fitted with a drip loop
3. Run out of reach and out of the cleaning route
4. Connection point accessible without dismantling the unit

Commissioning checks

Before you leave site, run the unit for an hour and check the housing temperature. Thermal problems on a rotating gobo projector rarely show up in the first ten minutes, and a unit that cuts out at 90 minutes will be a callback you could have caught on install day.

• Image sharpness at the centre and all four corners
• Contrast against the surface at the working hour
• Full duty cycle run without thermal cut-out
• Housing temperature after an hour at full output

Handover notes worth leaving behind

The handover note should include the artwork file reference and the supplier's reorder code. Custom gobos are the one part of a rotating gobo projector install that cannot be improvised on site, and re-cutting from the original file is far cheaper than redrawing it.

1. Installed throw distance and image size
2. Gobo size and reference code
3. Lens settings
4. Reorder contact and lead time