Texte et images non utilisables sans demande préalable
Astro-Physics 155 f7 StarFire EDF refractor upgrades
The scope has regularly taken advantage of the improvements offered by Astro-Physics.
When I purchased it in 2003, the refractor was equiped with the standard 2.7" focuser.
I first upgraded it with the 2.7" greaseless focuser with Feathertouch Micro 9:1, allowing me extremely accurate focusing with no backlash or wobble for imaging as well as visual observing. It is extremely strong, with a rack and pinion so it won't slip, even when pointing at the zenith with heavy accessories. It features a greaseless drawtube and ball bearings in the pinion block, providing ultra smooth operation. It offers two possible focusing ratios, 1:1 using the normal knobs or 9:1 using the central (or protruding) gold knob on the opposite side of the block. The block is reversible for regular / lefty users.
The original standard 2.7" focuser
The 2.7" Feathertouch Micro focuser
The 2.7" Feathertouch Micro focuser installed on the refractor.
Installation completed! The refractor with the 4" Giant focuser, 4" extension tube and 2.7" adapter.
Although I was extremely satisfied with the 2.7" focuser, I also wanted to have the opportunity to use a large format CCD camera with the last generation of telecompressors correctors. But this required me to upgrade to the 4" Giant focuser (4.3" internal diameter). This kind of focuser has no limits in terms of load capacity or optical performance. And it adds a terrific look to the refractor ;-))
So I decided to go for it also equipped with the Feathertouch Micro 9:1. Now...let's go for the installation...
Information for anxious people: there is no collimation issue to consider...
The 2.7" Feathertouch Micro focuser on the refractor, the 4" Giant focuser before installation.
The two focusers are removed , you can see the baffles through the rear of the optical tube. The 2.7" focuser is still screwed on the adapter that allows coupling on the tube. The 4" Giant focuser directly bolts on the tube.
Comparison of the internal diameters. Note the efficiency of the baffles painting: they are nearly invisible!
Seen from above: on the left the 2.7" focuser with adapter removed. On the far right, the 4" to 2.7" adapter allowing the use of any 2.7" accessory with the 4" Giant focuser.
On the left, before...
...on the right, now...