Astro-Physics 175 EDF Triplet Refractor

The Astro-Physics 175 EDF triplet air-spaced refractor sitting atop the 1200 GTO mount.
The 1200 mount handles this large refractor quite well.

 

Here's the hefty 86 pound shipment containing the 175 refractor. The mounting rings,field flattener and telecompressor shipped in a separate box.
Note the 12" ruler atop the box for scale.

 

Removing the carrying case from the shipping box and opening it, this photo shows the optical tube wrapped in plastic. There are two wide nylon straps around the tube
to facilitate lifting the telescope out of the carrying case.

 

The telescope is shown here on its carrying case with the 8" mounting rings (80RING2) and 16" long dovetail plate (SBD16) attached.
The dewshield and focuser are both retracted in this image.

 

The 175 f/8.3 Field Flattener

This dedicated field flattener allows use of the AP 175 EDF refractor with
large format chips such as found in the SBIG STL-11000M CCD camera to obtain
diffraction-limited results to the very edge of the field of view.

For a larger image of the field flattener click here or on the above image

  

The 175 f/6.1 Telecompressor

This 3 element high index glass telecompressor/flattener reduces the native f/8
focal ratio of the 175 EDF refractor down to f/6.1 (1064 mm focal length) while
providing diffraction-limited, pinpoint stars at the edge of the chip on the large
SBIG STL-11000M CCD camera.

For a larger image of the telecompressor click here or on the above image

 

Here is a photo of the 175 and 160 field flatteners and telecompressors side-by-side for comparison.
Wow, now there are some "chunks" of glass!

 
 

 

The 175 and 160 Starfire EDF's piggybacked for a size comparison. To truly get an appreciation for the size difference you've got to see them in real life.

For a larger image click here or on the above image

 

  

 

Another way to compare the two telescopes is by the size of the carrying cases.
160 EDF on top; 175 EDF on bottom.
 

 

Objective end of the 175 showing the machined baffles progressing down the optical tube. These baffles are not glued in like on most other telescopes, they are instead
machined into the tube by hogging out a solid 8" round billet of aluminum stock!

 

 

Focuser end of the 175 showing the full baffling leading up the optical tube.
Like the front end baffling, these baffles are coated flat black to minimize
reflections and scattered light. The attention to detail in the construction of
this telescope is amazing.

 

The 4" greaseless Astro-Physics focuser with dual-speed FeatherTouch 9:1 Micro mechanism. A new addition to the focuser end are the three "captain wheel" standoffs
for addition leverage when using the rotating focuser collar.
This photo shows the Robo-Focus bracket and motor attached to the non-Micro mechanism side of the focuser.
The bracket is attached to the bottom of the FeatherTouch focuser by means of two socket head cap screws
threaded into existing holes in the focuser body.

 

Looking down on the focuser reveals the drawtube millimeter scale, which helps to provide position repeatability. At first blush this may not seem a useful feature but in actual
practice it is quite handy. When imaging the Sun in H-alpha and switching between an ERF/Daystar filter arrangement or Herschel Wedge for high resolution white light
imaging with various Televue Powermates, the drawtube position can vary by a large amount in order to achieve focus. Having these setting identified and recorded, the
millimeter scale really helps to dial in rough focus when making equipment changes "on the fly" without having to spend precious time hunting for focus.

 

Shown here are the Astro-Physics 8" mounting rings (Part No. 80RING2) and 16" long dovetail plate (Part No. SBD16). The dovetail plate is very adaptable and drilled for a wide
variety of mounting rings supplied by other manufacturers, including Parallax, Takahashi, TeleVue, AstroTech, Stellarvue, TMB, and ASA.

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The underside of the Astro-Physics 16" long dovetail plate showing the four (4) countersunk bolts supplied to attach it to the mounting rings.

That's all Folks!