Mirror Alignment of the FACT telescope

Our FACT telescope has a multi mirror reflector of 30 single hexagonal mirror facets. To feed our G-APD camera with high resolution images, the reflector's mirrors have to be aligned. The mirror alignment is about the mirror's position and it's orientation.

Mirror Position

The mirror position is fixed in directions perpendicular to the telescope's optical axis by the honeycomb grid of the mirror facets. The crucial position left is the distance of the mirror's centre to the centre of the camera window. The distance between the mirror centre and the camera window centre is determined using a LASER distance meter. As decided on our General Meeting 2014 in Dortmund, we will set this distances to obtain a hybrid reflector. A hybrid reflector is partly a Davies Cotton design and partly a Parabola design. This was chosen to improve temporal resolution.

Status of Hardware for position determination

Item	design	order	machining	note
Optical table	100%	100%	75%	weight reduction
45DEG mirror	100%	-	100%	plane,front coated mirror
45DEG mirror mount	25%	-	0%	plane,front coated mirror
Protection shield	0%	0%	0%	to protect the G-APD window
LASER DM (distance meter)	-	100%	-	Bosch PLR 50, 2x (one spare)
LASER DM camera	-	100%	-	Sony CCD analog for remote readout
LASER DM monitor and transmission	-	100%	-	Sony CCD analog for remote readout
LASER DM mount	50%	100%	25%	motorized mount for radio remote control
altitude actuator	100%	100%	100%	6V DC motor 1000:1
rotation actuator	100%	100%	100%	6V DC motor 1000:1
Radio remote control 2Ch.	-	100%	-	40Mhz analog FM 2Ch. RC transmitter to remote control the LASER DM
Battery pack 12V	-	100%	-	6V AA GP recyko cells
Battery charger	-	0%	-	charger for AA batteries
small stickers ~2cm	-	0%	0%	A sticker for each mirror's centre

Mirror Orientation