Thermalert ET Series Operator's Manual
2-7
2.2.5 Right Angle Mirror
The Right Angle Mirror is used to get a perpendicular view of a target when space is
limited or when you need to avoid excessive radiation to the sensor. It must be
installed after the bracket or after the Air Purge Collar, if used, and screwed in fully.
In dusty or contaminated environments, connect air to the mirror’s nipple to keep the
first surface mirror clean. If used in conjunction with the Air Purge Collar, both the
Right Angle Mirror and the Air Purge Collar must be air purged.
Figure 2-9: Right Angle Mirror
IMPORTANT
When using the Right Angle Mirror, adjust emissivity settings downward by 5%
(e.g., for an object with an emissivity of 0.95, use 0.90; for an object with 0.80 use
0.76; for 0.65 use 0.62. This corrects for infrared energy losses due to the mirror.
2.2.6 Sighting Viewer Tool
The Sighting Viewer Tool accessory is used to aid in the alignment of the sensor. It is
often used when the object is small and far from the sensor as well as in situations
when obtaining a direct in-line sighting is difficult. It can be used both with and
without the Air Purge Collar but not with the Right Angle Mirror. For best results,
first secure the sensor to the bracket using the mounting nut or Air Purge Collar and
then screw on the Sighting Viewer Tool fully. Next, position and secure the bracket,
being sure to remove the Sighting Viewer Tool when alignment is complete.
Figure 2-10: Sighting Viewer Tool