This page last modified 2012 December 17

A Simple QuikFinder Dewshield

QF with dew shield



QuikFinders and Dew

The Rigel Systems QuikFinder boasts a "built in dew shield". Although it reduces the rate of dewing, compared to, say, a Telrad, whose screen is completely open, the QuikFinder is not immune to dew.

A solution is to make a simple "flatpack" one out of 2mm foam sheet or similar. I have worked on the assumption that the minimum properly effective length for a dew shield is 4x the diameter of the aperture it is protecting, I have made the effective part 140mm (5½") long. Yes, I know it looks exactly like a DIY prototype: there is a very good reason for that!

Materials

Construction

  1. Download and save the template:

    Template

    Print it out full size from your graphics programme. (Do not do this from the browser: it will probably resize it. If you don't have a graphics programme, get The GIMP; it's free and it works.)

  2. Cut out the pattern.

  3. Place the pattern on the dewshield material, mark around it, and cut out the material. A sharp utility knife or craft knife on a cutting board works best, but you can use scissors.

  4. Cut the Velcro to length according to the pattern. (Cut 70mm of it longitudinally for the 5mm wide strips.)

  5. Stick the hook part to both sides of the QuikFinder:
    QF with velcro

  6. Stick the wide loop parts of the Velcro to the dewshield as shown in the pattern.

  7. Stick the narrow parts of the Velcro to the dewshield as shown in the pattern.

  8. Fix the dewshield to the QuikFinder.

  9. Enjoy a dusk-to-dawn observing with a dew-free QuikFinder


In Use

This dewshield is far longer than many other DIY ones; this makes it exceptionally effective at preventing dew, even on the really dew-soggy nights of southern England. There is no "right length": If it's too long for your liking, just make it shorter. Don't be tempted to make it any wider diameter, though, or it will obstruct, and be obstructed by, the adjustment thumbscrews.

The rearward extension helps with eye-positioning and will also act as a glare shield if there are lights around.

Update: 2012 Dec 17: In some circumstances, I have found that the sticky-back Velcro becomes detached from the dewshield material. You may need to stitch it in place for added security. (I have had no incidences of the Velcro becoming detached from the QuikFinder body.)