For Sale:
ASTRO-TECH 2" Dielectric Diagonal
Quartz
Part Number AT2DQ
This diagonal has been extensively used, but is still in pristine condition.
It has provided exemplary views when used on my previously owned CPC1100. Since I have sold the SCT I have no further need for this very nice diagonal.
(Note: it does not have SCT thread, but can be used with any 2" visual back.
The documentation states that it is designed primarily for use with a refractor).
RRP: US$199.95
Asking only A$99 (pick up NSW Central Coast)
(For postage registered and insured, please add $12)
Product Info:- 1/10th wave quartz substrate for high contrast/sharp details
- A supplied interferogram provides proof of mirror surface accuracy
- Long-life 99% reflectivity dielectric first surface mirror coatings
- Heavy machined metal body for precise collimation and long life
- 2” barrel has internal antireflection threading and fits any 2” refractor focuser
- 2” compression ring eyepiece holder won’t scratch eyepiece barrels
- 1.25” eyepiece holder has non-marring compression ring
- Weight: 17 oz.
While designed primarily for refractors, the diagonal can also be used with a Schmidt-Cassegrain or Maksutov-Cassegrain telescope with a 2" eyepiece adaptor.
The diagonal’s stable 10mm thick quartz mirror substrate has better thermal expansion and contraction characteristics than a conventional glass mirror. There’s no need to worry about the focus changing as the diagonal cools down to ambient temperatures.
The interior of the body is lined with light absorbing materials, in addition to being anodized an antireflective matte black. The 2” focuser-side barrel is also anodized antireflective matte black, and is internally antireflection threaded for even higher contrast. The barrel is threaded to accept standard 2” filters.
The 2” eyepiece holder uses a non-marring soft brass compression ring to secure eyepieces and the standard equipment 1.25” eyepiece adapter. The knurled and chromed thumbscrew that operates the compression ring is a full 1/2” in diameter, twice that of many competitive diagonals. This provides a sure grip in cold weather when wearing gloves or mittens. A slanted groove cut into the outside of the focuser-side 2” barrel catches the scope’s focuser drawtube thumbscrew to act as a safety stop. This keeps the diagonal from falling should the scope’s thumbscrew loosen slightly from cold or use.
The supplied 1.25” eyepiece adapter also uses a compression ring to hold eyepieces in place. The scope-side barrel of the 1.25” adapter is likewise grooved to keep it from accidentally slipping out of the 2” diagonal.
