About this product
Takahashi FSQ-85EDXP f/5.3 Quadruplet Petzval Apochromat Refractor
Updated version includes EDP Flattener (TKA37582) and Extension no.50 (TKA23250).
Noticing the rising popularity of short refractors and improvements in the performance of CCD and DSLR cameras, Takahashi introduced the FSQ-85ED. A more compact version of their FSQ-106ED intended for deep-sky and wide field photographers.
The FSQ-85ED is based on the same ED glass Petzval quadruplet design as the larger FSQ-106ED but offers a 450mm focal length and 5.6° imaging field, which is ideal for astrophotography.
It is equipped with an oversized rack-and-pinion focuser and independent camera angle adapter.
An optional focal reducer is also available that transform reduces the focal length to 328mm / f3.9 and provides a wide 7° field of view. When using the focal reducer the imaging field is 40mm.
Weighing only 4kg without accessories, you will not need a heavy mount so the FSQ-85EDX can be used as part of an impressive portable imaging setup.
The package version includes Tube Holder, 6x30 Finderscope and Bracket.
Quadruplet Petzval Design
The FSQ-85EDX's modified Petzval quadruplet design has a built-in flattener inside the optical tube, a large 44mm imaging circle and a field of 5.6° so it is not necessary to add a reducer/flattener. However, an optional 0.73x focal reducer is available that changes the focal ratio from 450mm (F/5.3) into 328mm (F/3.9).
The Takahashi EDP Flattener for FS-Q85ED corrects the mild field curvature and edge of field astigmatism visible when using larger format ultra small pixel sensors with the original telescope. It results in improved field flatness when using a full frame digital camera or CCD/CMOS Camera.
The focal length of the system is increased to 455mm (F5.4).
When used with the EDP flattener, the FSQ85ED delivers sharpness comparable to that provided by the larger FSQ-106ED over a 44mm imaging circle.
Rack & Pinion Focuser
The FSQ-85ED is equipped with an oversized rack-and-pinion focuser, like the FSQ-106ED, though the camera angle adjuster has been moved to a more traditional position. Accessories are screwed onto the focuser tube. Focus is achieved via two focus wheels with a 1/7 microfocuser.
Although designed primarily for astrophotography various accessories are available, including some intended for visual astronomy. Please see the system-charts below for an idea of what can be achieved. The telescope's 220mm back focus provides a number of options when fitting accessories.
As on the FSQ-106ED, the built-in field flattener provides an almost homogeneous flat field of 44mm diameter. At prime focus, at the edge of field (22mm from the optical axis) stars remain pinpoints, including on pixels of 7µ width.
The optional 0.73x Reducer-QE (optically-matched to the telescope) widens the field of view even further while preserving the high optical performance.
Telescope Field of View Simulator
- Tube length (min/max) w/ standard accessories: 553mm-645mm (retracted dew shield/extended dew shield)
- Tube diameter: 95mm
- Rack-and-pinion tube diameter: 80mm
- Tube weight: 4 kg
What's in the box
OTA Only Includes:
OTA Package Includes:
- FSQ-85EDX OTA
- TKA00551 6x30 Finder
- TKA00562 Finder bracket
- TKA21420S Tube holder with off-set plate
|Spec. ||FSQ-85ED |
|Optical design ||Modified Petzval quadruplet apochromat |
|Aperture ||85mm |
|Focal length ||450mm |
|Focal ratio ||F/D 5,3 |
|Resolution ||1,5" |
|Limiting magnitude ||11,6 |
|Light grasp ||178x |
|Image circle ||44mm |
|Photo field ||5,6° |
|Back focus ||197,5mm |
|With Reducer-QE 0.73x |
|Focal length ||328mm |
|Focal ratio ||F/D 3,86 |
|Image circle ||40mm |
|Photo field ||7° |
|Metal back ||72,2mm |
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