Borg 55FL f/3.6 Astrograph Set A

Borg 55FL f/3.6 Astrograph Set A

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  (1 Review)
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About this product

Model:  borg_55fl_f3.6_set
Part Number:  6258

Japanese made Borg 55FL f/3.6 astrograph features a premium quality Flourite objective from Canon.

Includes a Borg Helical focuser for precise dependable focusing. 

Modular Borg design allows you to reconfigure the scope for visual observing or to disassemble it for ultra portability.

Can be used visually by adding a 2" eyepiece holder available separately (7508 or 7509).

Specification

  • Aperture: 55mm
  • Focal length: 200mm
  • F-ratio: 3.6
  • Lens configuration: 6 elements in 5 groups
  • Coating: Fully multi-coated
  • Physical length: 200mm
  • Tube diameter: 60mm
  • Weight: 0.6kg
  • Filter: 58mm (front hood) & 52mm (7000)
  • Parts included: 2555, 7761, 7604, 7880 & 7000
  • Notes: Camera rotator (7352) is sold separately

55mm Flourite Objective

  • Focal length: 250mm (fluorite)
  • F-ratio f/4.5
  • Length: 95mm
  • Weight: 205g
  • Interface (rear): M57/P0.75
  • Interface (front): 58mm filter thread in front of hood

Precision helical focuser

  • Length: 27 to 44mm light path
  • Weight: 98g
  • OD: 73mm
  • ID: 49mm

0.8x Reducer

  • Four-element reducer
  • Back focus distance: 60mm
  • Objective side interface: M57 P0.75 male
  • Camera side interface: M57 P0.75 female

System Diagram

Items in the red box are optional and available separately.

Telescope Field of View Simulator

What's in the box

  • 2555 - 55FL Flourite Objective
  • 7761 - M57 Helical Focuser DXII
  • 7604 - M57/60 L 60mm Extension
  • 7880 - 0.8x Quadruplet Reducer
  • 7000 - SLR Camera Mount Adapter

Customer reviews

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Firstlight
Friday, 9 August 2019  | 

Received this as an open box product from FLO a few days ago and have finally had some clear skies to try it out.
Thanks to FLO as always for great service.
This is a fantastic small scope and works exactly as expected.
I have it attached to a SX EFW and SX Truis Pro 694 Mono with no issues
The instructions (come in Chinese but English on the FLO web site) don't really cover astronomy cameras but it is relatively easy to set up
If you are thinking of this type of set up the back focus from the 7000 adaptor to sensor is 50mm and is very sensitive. ie more than +/- 3mm from this figure and you cannot achieve focus with the supplied helical focuser.
There is also a sweet spot which I found to be that the indicator on the focuser needs to be between 7.5 and 8.5 when focused. Go outside of this and there is a lot of coma; so the unit does require a fair amount of tweaking before use.

As you can imagine with this camera many stars are under sampled. As I work in mostly narrow band this is not an issue, the frequency shift is still within the range of my standard Baader set,
There is also an added bonus that you can screw a filter into the the 7880-3 adaptor - I leave a light pollution filter in there as standard
This big advantage for imagers in the UK is speed - full, high quality image of NGC7000 and surrounding areas in just 20 minutes (5x2min Ha, 1x5min each Oiii and Sii. Using a clear filter the outline of NGC7000 shows easily in just 10 seconds
Dark nebulas show up just as quickly

I don't believe this is a good scope for amateurs as you do need lots of experience of getting back focus just right
If I could change one thing - get rid of the helical focuser and replace with a rack and pinion type
Clear Skies

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