My William Optics
FLT-110 f/6.5 Triplet SD APO refractor
My WO FLT-110 f/6.5 APO refractor with its aluminum case
In July 2003, to complete my setup, I decided to order, for the first time, an APO refractor. With the large chip of my SBIG ST-10XME CCD camera, my Meade f/3.3 focal reducer on my Meade 12" OTA was out of order, with a lot of coma and vignetting. My project was too, to take some beautiful widefield CCD pictures. An APO refractor with a reasonable diameter and with a short focal length was necessary.
We can find several type of APO refractors on the market : Takahashi, Astro-physics, TMB, Televue, TEC............etc. But for these brands, the prices are very high.
I found and chose William Optics with their famous FLT-110 refractor. I found the price very nice for a 4.3" triplet APO, delivered with its aluminum case and 2 mounting rings. For $2,995, It is the best price for a triplet of this diameter (4.3") and this focal length (f/6.5-715mm). The optics are made by the famous TEC company in Colorado. It is the same optics, by their quality, found in the famous TEC-140 APO refractor :
The FLT-110 has a lot of beautiful components. The 4" focuser is very smooth and we can rotate it at 360°, very nice to rotate the CCD camera to find a good guide star. A solid aluminum lock is there for the focuser. The FLT-110 dewshield is very long, very good too to avoid the bad lights in the OTA. I use a Kendrick dew heater to complete the system.
About the Optics, they are outstanding !!!! Very sharp stars. The optics, in & out, are multi-coated on the 2 faces with 7 layers. The first CCD image I have taken with this refractor was beautiful. I've never seen that with all the CCD shots I took since 5 years.
If you use this refractor with a ST-10 chip or larger, you will be out of the flat-field. The William Optics 4" FLT-110 field flattener is necessary to have the best results in the edges with perfect round stars. My first pictures have been taken without this accessory but they are beautiful with a few elongated stars in the edges. We can see that in my gallery. Now, I use the FLT-110 Field Flattener. The results are outstanding.
My WO 4" FLT-110 Field Flattener
My special 4" FLT-110 Field Flattener Adapter. William Optics made me it to adapt my ST-10XME/CFW-8A combo
My FLT-110 is installed on the Losmandy DUP (Dovetail Universal Plate). The weight of the WO FLT-110 OTA (without the DUP) is 14.3 lbs (6.47 Kg).
With the FLT-110, I use the Celestron Star Pointer as viewfinder. I found this accessory, with the short focal length, was Great to put every stars on the ST-10XME CCD chip without problem. I recommand it (~$39), not necessary to purchase an expensive viewfinder for that.
I recommand this APO refractor for its optics of high quality and its Great 4" focuser. The FLT-110 package is a beautiful package with a beautiful price for the CCD imaging.
My WO FLT-110 Triplet SD APO
on my Losmandy HGM TITAN Gemini GOTO mount
