AstroSystems DEW GUARD

Dew Guard 1, Dew Guard 2, Dew Guard 3

Dew Guard shown installed on back

 of Secondary Mirror

Optional installation kit

AstroSystems amazing Dew Guard secondary mirror heating system automatically senses the air temperature and the mirror temperature, then maintains the secondary at a preset (adjustable) temperature above the ambient air temperature.  Gently warms the secondary at 2-4 watts when on full.  The DG-1 has 4, The DG-2 has 6 and the DG-3 has 8 evenly spaced contact points for optimal thermal distribution.  Uses any external 9-15 volt dc supply or you can run on a 9v battery mounted at the holder, eliminating the need for wires across the spider.  Note: 9V rechargeable NiCd or NiMH batteries will not work, they are only 7.2-8.4V with the NiCd having low capacity.  Rechargeable Lithium cells are 9V and will function properly.  No more heat ropes!  Three sizes to choose from.

Note: If your secondary is glued to a center post, the Dew Guard cannot be used. If your secondary is exposed and not inside a shroud the Dewguard will not be effective in controlling dew.


Dew Guard Installation Kit

The Dew Guard installation kit contains all the hardware to wire the Dew Guard across the spider and connect to the remote switched battery box.  Click the link below for complete installation instructions.

Kit includes:

1 Wire-24" (28 gauge) and 9V plug    2 Heat Shrink Tubing
1 9V Battery Case w/ switch   2 Wire Mount Screws- #8 x 1/2"
2 Wire Mounts (adhesive backed)   1 Aluminum Tape- 12"
1 Velcro- 2"   2 Wire Ties



DG-1  Secondary minor axis  1.5" - 2.4" $42.00 ShipWeight 1/2 lb.
  DG-2    Secondary minor axis  2.5" - 3.5" $47.00 ShipWeight 1/2 lb.
  DG-3   Secondary minor axis  4.0" - 7" $52.00 ShipWeight 1/2 lb.
Installation Kit Hardware to install a remote switched 9v battery $21.00 ShipWeight 1/2 lb.


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Click here for operating, dimensional and installation notes.

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