Collateral Software
A blog by fschuindt

Kugelblitz telescope

The Kugelblitz is a handmade Newtonian reflector telescope. This project started on November 19th, 2019 when I decided to assemble my own Newtonian. 10 months after I can say the project is ready for clear skies.

I’m publishing this page to serve as a documentation/specification for this instrument.

Specs.

  • Tube dimensions: 260x1455mm
  • Primary mirror diameter: 210mm (≈ 8.27”)
  • Focal length: 1390mm
  • Focal ratio: f/6.62
  • Distance from the secondary to the focal plane: 275mm
  • Visual secondary mirror dimensions: 60x80mm
  • AP secondary mirror dimensions: 70x98mm
  • OTA weight: 7.9kg
  • Dobsonian mount weight: 9.15kg

Staff & Off-the-shelf

  • Optic engineering, executive and assembly: Fernando Schuindt
  • Assembly date: Oct, 2020
  • First light date: Oct 17th, 2020
  • Assembly location: Aracaju - SE; Brazil
  • Primary mirror artisan: Sebastião Santhiago Filho
  • Primary mirror crafting date: Dec, 2019
  • Primary mirror crafting location: São Paulo - SP; Brazil
  • Visual secondary mirror artisan: Roberto Fornaciari (Pending)
  • Visual secondary mirror crafting date: Pending
  • Visual secondary mirror crafting location: São Paulo - SP; Brazil (Pending)
  • OTA artisan: Douglas Lucyrio (Telescópios Matão)
  • OTA crafting date: Sep, 2020
  • OTA crafting location: Matão - SP; Brazil
  • Dobsonian mount artisan: Douglas Lucyrio (Telescópios Matão)
  • Dobsonian mount crafting date: Sep, 2020
  • Dobsonian mount crafting location: Matão - SP; Brazil
  • Focuser manufacturer: Orion
  • AP secondary mirror manufacturer: GSO

Optical Project

Visual Setup

AP Setup

Diagonal off-axis illumination

Off-axis illumination

Results:
Smallest possible diagonal = 32.62 (mm)
Smallest user defined diagonal = 60 (mm)
Diagonal size maximizing illumination integrated across the field = 60 (mm)
Diagonal size for most even illumination across the field = 70 (mm)
illumination integrated across the field:  60: 90.8%; 70: 88.9%;

Central obstructions are 60: 28.6%; 70: 33.3%;
RMS wave deformations due to central obstruction are 60: 1/16; 70: 1/14;

Diagonal offset on fully illuminated field (towards primary mirror and away from focuser) = 1.84 (mm)
Diagonal offset (along diagonal face) = 2.61 (mm)
Diagonal offset on focal point (towards primary mirror and away from focuser) = 1.92 (mm)
Diagonal offset above focal point (towards primary mirror and away from focuser) (76.2 (mm) above) = 3.08 (mm)
Diagonal offset field edge (towards primary mirror and away from focuser) = 1.41 (mm)

Off-axis mask results:
maximum off-axis diameter = 76.84 (mm)
highest magnification = 76x
Dawes' Limit = 1.5 arc seconds
limiting magnitude = 13.2

Pictures

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Special thanks to Catarina Dantas and the following Cloudy Nights members:

B 26354, SarverSkyGuy, Garyth64, JoeInMN, brebisson, GDAstrola, photomagica, Jon Isaacs, kathyastro, KLWalsh, dogbiscuit and Star Shooter.