My William Optics
Megrez 80 f/6 Triplet Fluorite APO refractor
My WO Megrez f/6 Triplet APO refractor package with its accessories
In January 2004, to complete my setup, I decided to order a third APO refractor. After a summer of images with my William Optics FLT-110 refractor, I dreamt of a new APO with a shorter focal length. The large chip of my SBIG ST-10XME CCD camera can give a superb large wide field of view on the Great nebulas with a short focal length.
We can find several types of small APO refractors on the market with a focal length of 480, 500 or 600mm : Takahashi with the Sky90 or the FS-60, TMB with a 80mm f/6 Triplet APO, Televue with the NP101, and ORION with their small ORION 80ED. My choice was for a Triplet APO with a focal length between 400mm & 500mm, no more. TMB and Televue are Great but a bit expensive to me. The ORION ED refractor is not a Triplet and the mechanical parts have a lot of plastics, not great to support a ST-10XME with its CFW-8A filter wheel.
So, I chose William Optics again with their New Megrez 80 Triplet APO. Again, I found the price very nice for a 3.18" (80mm) Triplet APO, delivered with its soft backpack. For $1,595 It is again the best price for a triplet of this diameter (3.18") and this focal length (f/6-480mm). About the optics, the design comes from TMB Optical USA and is made in Russia by LOMO Optical. The optics, in & out, are multi-coated on the 2 faces with 7 layers.
The Megrez APO has a lot of beautiful components. The Crayford focuser is very very smooth and as my WO FLT-110 APO, we can rotate it at 360°, very nice to rotate the CCD camera to find a good guide star without to change the focusing. An aluminum screw ( 1 ) is there to lock the system. Another aluminum screw ( 2 ) with a small part of Teflon at the top, is located under the focuser to release the focusing knobs and to lock the main tube of the focuser. The Megrez dewshield is enough long and very good. I use a Kendrick dew heater to complete the system. You will find no plastic parts, except the small cap to close the rear of the OTA, on this APO. The OTA is solid as a rock, very beautiful design !!!
With the SBIG ST-10XME / CFW-8A combo , It is very important to use a Field Flattener to avoid the field curvature. I decided to use the Tele Vue TRF-2008 0.8x Focal Reducer/Field Flattener. Tele Vue specified a correct distance of 55mm (an error of +/-2mm is good) between the CCD chip and the FR lens. For that, I purchased a Baader 15mm. Now, I took only one image for a test but the results seems really Great.
Check the mounting below :
Mounting of the Tele Vue 0.8x FR/FF with the ST-10XM/CFW-8A
My Megrez is installed on the Losmandy DUP (Dovetail Universal Plate) and with the William Optics Megrez mounting rings. The weight of the WO Megrez OTA (without the DUP) is 6.12 lbs (2.8 Kg).
With the Megrez, I use the Celestron Star Pointer as viewfinder. It is the same used with my FLT-110 APO. It is not necessary to purchase an expensive viewfinder for this type of refractor with this short focal length.
My WO Megrez 80 Triplet Fluorite APO
on my Losmandy HGM TITAN Gemini GOTO mount :
