To the right is a portion of the carbon fiber secondary mirror assembly for the 24" Dream Astrograph.

The assembly as shown weighs 224 grams. It will hold the 7.75" minor axis cellular secondary mirror, which weighs 2.7 lbs.

The assembly is fabricated with the same method and materials as the rest of the Optical Support Structure: carbon fiber, high temperature epoxy, vacuum bagging and a specific cure (oven) cycle.

This part therefore matches very closely to the CTE of the mirror that it supports.

The yoke (mirror cell) design allows a great deal of air to the back of the cellular mirror. This will help this optic follow ambient temperatures.

A raw stainless steel spider vane can be seen in the background on the top of the photo to the left.

To the right are the cellular 7.75" and 5.75", for the 16" and 24" Dream Astrographs.

To see additional views, click on the rendering to the right.

To the right is the carbon fiber secondary mirror assembly for the 24" Dream Astrograph.

The assembly as shown weighs 812.3 grams (1.8 lbs). It will hold the 7.75" minor axis cellular secondary mirror, which weighs 2.7 lbs. The two carbon fiber subcomponents weigh just under 250 grams each. Together they represent just over 1 pound.

The assembly is fabricated with the same method and materials as the rest of the Optical Support Structure: carbon fiber, high temperature epoxy, vacuum bagging and a specific cure (oven) cycle.

You can see the two controls that project out of the left side of the assembly. These are the free (gross) adjustment of rotation and the micrometer adjustment of rotation, which are indepedant of tip/tilt and axial adjustment. The micrometer allows rotation adjustment as fine as 1/60th of a degree or 1 arc minute.