Eyes to the skies

I have a range of telescopes for different purposes and occasions. My latest addition is the ultra fast RASA8 F2. When you have the need for speed, the RASA8 delivers in spades. Imaging times when using the sensitive ASI294Mc Pro colour camera attached are astonishing and I amĀ  able to capture enough data of celestial objects in under 30 minutes (from dark sky sites). The RASA8 is perfect for nebula and large galaxies. My portable “grab and go” telescope with a similar field of view is the William Optics GT71 f5.9 refractor. For planetary nebular and galaxies, I turn to the William Optics GTF102 f6.9 refractor.


  • Manufacturer: Celestron
  • Telescope type: Rowe Akerman Schmidt Astrograph
  • Focal ratio: f2
  • Focal length: 400mm
  • Aperture:201mm
  • Weight: 8Kg
The RASA8 on my fouth floor balcony looking north through the light pollution
RASA8 captures M42 - only 15 minutes of total capture time.

William Optics GTF102

  • Manufacturer: William Optics
  • Telescope type: Refractor
  • Focal ratio: f6.9
  • Focal length: 703mm
  • Aperture:102mm
  • Weight: 5.0Kg
  • Resolving Power: 1.13 arc”
  • Limiting Magnitude: 13.9

The William Optics GTF 102 is a 5 element APO telescope designed for both visual and photographic use. It features a 5-element objective using high-quality FPL-53 glass and combined with other extra-low dispersion glass provides an exceptionally flat field, perfect for imaging. Unfortunately William Optics has ceased production of these outstanding 5 element APO’s.

I have imaged with this telescope using a variety of cameras including the Olympus OMD EM5, SBIG ST-10XME and ASI294MC Pro.

The William Optics GTf102mm f6.9 astrograph on an Ioptron IEQ30 mount
HA acquisition of NGC 6188 with William Optics GTF102 - Queensland Astrofest 2014

William Optics GT71

  • Manufacturer: William Optics
  • Telescope type: Refractor
  • Focal ratio: f5.9 (f4.72 with field flattener 6A2 * 0.8)
  • Focal length: 420mm ( 336mm with field flattener 6A2 * 0.8)
  • Aperture:71mm
  • Weight: 2.2 Kg
  • Resolving Power: 1.62 arc”
  • Limiting Magnitude: 11.1

The William Optics Gran Turismo (GT) uses apochromatic triplet objectives with an FPL-53 element to achieve a higher degree of color correction. When using the WO GT71 with cameras including micro 4/3, APS-C, or full-frame sensors, a field flattener or focal reducer is required to ensure sharp images across the entire field.


The William Optics GT71 with ASI183MM Pro - balcony astrophotography
The Veil Nebular - Captured with William Optics GT71, ASI294MC Pro on A Sky Watcher Star Adventurer mount