Optical Configuration; Gobos - Martin MAC 2000 Profile II User Manual

O
PTICAL CONFIGURATION

Gobos

Specifications
All gobo slots including the seven color/gobo wheel positions accept round theatrical size-E glass gobos. Aluminum
gobos are suitable for short-term use only. For best results, custom gobos should meet the following criteria.
Outside diameter: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37.5 +0/-0.3 mm (1 15/32 +0/-0.01 in.)
Maximum image diameter: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 mm (1 3/16 in.)
Material: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . High temperature Borofloat or better glass
Coating: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Dichroic or enhanced aluminum
The color/gobo wheel accepts 1.1 mm thick gobos and color filters. Thinner gobos must be secured with a drop or two
of glue. Use a high-temperature silicone adhesive such as Dow Corning's 732 Multi-Purpose Sealant.
The rotating-gobo wheel positions hold gobos up to 3 mm thick with the gobo retention spring. Gobos thicker than 3
mm must be glued in the holder.
Orientation
Coated gobos are inserted with the coating against the rim of the holder (away from the spring). Textured gobos are
inserted with the smooth side against the spring. This provides the best results when combining rotating gobos.
When an object is held up to the coated side
there is no space between the object and its
reflection. The back edge of the gobo cannot
be seen when looking through the coated
side.
Image projection size
To calculate the size of a projected image using a gobo of a given size, the formula is
To calculate the gobo image size required to achieve a projected image size, the formula is
The focal length of the MAC 2000 Profile II ranges from 64 - 171 mm (2.5 - 6.7 in) because of the zoom.
Coated side
Figure 13: Finding the coated side
projected image size
gobo image size

Optical configuration

Uncoated side
When an object is held up to the uncoated
side there is a space between the object and
its reflection. The back edge of the gobo can
be seen when looking through the uncoated
side.
×
gobo image size projected distance
----------------------------------------------------------------------------------------
=
focal length
×
projected size focal length
------------------------------------------------------------------- -
=
projected distance
17