Home >> Science & Nature >> Astronomy

How to Flock a Dobsonian

Light pollution washes out more of the night sky with each passing day. New malls, homes, billboards and streetlights hide the stars and planets from view. Astronomers find light pollution especially frustrating. Fortunately, there is an easy way for astronomers to counteract some of light pollution's negative effects without driving to the countryside every time they want to stargaze. If you want to reduce light pollution's effect on your Dobsonian telescope, consider flocking the inside of the tube. Flocking material adheres flat against the telescope's inner wall and eliminates light reflections from sources outside of the telescope.

Things You'll Need

Screwdriver
Measuring tape
Self-adhering flocking mats
Razor knife or scissors

Instructions

- 1
  Remove the thumbscrews holding the secondary mirror. There will be three or four screw heads on the outside of the upper end of the telescope tube.. Maintain a firm grip on the spider vane, the metal structure inside the tube that holds the secondary mirror, to prevent it falling as you remove the screws. Slide the spider vane, with the secondary mirror still attached, out of the top of the telescope tube once all screws have been removed.
- 2
  Remove the screws holding the primary mirror in the bottom of the tube. You may want someone to help hold the mirror since primary mirrors are heavy and expensive. Carefully slide the mirror from the bottom of the tube. Measure the mirror's height, you do not want to flock where the mirror fits into the tube. Store the primary and secondary mirror with the spider vane in a safe place away from your work area.
- 3
  Cut the flocking material into manageable strips. The width of the strips depends on telescope size and personal choice. Cut with scissors or a razor knife.
- 4
  Peel back 1 inch of paper from one side of the flocking material to expose the adhesive. Place the flocking inside the telescope tube and press down the exposed adhesive. Once the adhesive sticks to the telescope, pull the rest of the paper off the flocking, smoothing the flocking with your hand as you remove backing paper.
- 5
  Continue adding sections of flocking material until the inner tube is covered. Leave only the space for the primary mirror, eyepiece (cut flocking to fit around the hole), and spider vane screw holes free of flocking. Measure and cut small pieces to finish any small gaps that remain. A small amount of overlap is expected and acceptable.
- 6
  Replace the primary and secondary mirrors after flocking the telescope. There will be noticeably less stray light reflecting in the telescope tube.

Astronomy