Sky & Telescope - December 2023 - 63

Speaking of collimating, how about installing a couple of
Center pivot bolt
thin plastic washers under the collimation screws on your
secondary-mirror holder so it's easier to rotate it without
loosening the center bolt? That lets you twist, rather than tilt,
the mirror for side-to-side collimation, which is less likely
to lead to vignetting. Cutting washers from a milk jug works
great for this.
Back to the subject of knobs, consider installing a handhold
on the front of your Dobsonian so you can nudge it
along with the knob rather than with your hand on the lip of
the scope and your fingers in the light path. Cabinet knobs
and doorknobs work well for this, or you can go whole hog
and make a form-fitting hand grip. This is a modification
that seems trivial, but it makes using the scope so much more
comfortable you'll wonder how you ever observed without it.
Another how-did-I-ever-do-without-it modification is
a laser finder. Mount a green laser pointer so it's parallel
to the optical axis of the telescope, and you'll never have
to bend sideways or crouch down to look through a finder
again. Just push the laser button and aim the beam at your
target. My back used to hurt after a night of contorting to
see through my optical finder, but a laser finder solved that
completely. But be sure to check to see if there are any laws
in your area regulating the use of green lasers before committing
to this mod.
That leads directly to the next mod: Install dovetail
brackets on each of your scopes so you can use the same
laser finder on all of them. You can leave your other finders
in place if you want. Optical finders still come in handy for
star-hopping when you get near your target, or when your
observing group includes any astrophotographers who won't
appreciate your laser's beam intruding into their images.
Flocking, Fans, and Other Mods
Focusers often have shiny metal knobs, which can reflect
Base of rocker box
Teflon
Shim washers
Ground board
Teflon
AZIMUTH IMPROVEMENT Washers stacked between the rocker box
and ground board can help to reduce friction in the azimuth axis.
unwanted light into your eyes when you lean in for a look.
Other metal screws and various other parts might do the
same. A black Sharpie is your friend here. Darken those
screws, knobs, etc. so they don't disturb your view through
the eyepiece. If your scope has a white tube, paint the top half
black. You'll be surprised at how much difference that makes,
especially if you observe with both eyes open (as many of us
do to prevent squinting).
Even the flat black inner surface of a telescope tube can
reflect light. Flocking the inside of the tube can improve
contrast considerably. (Flocked paper is an adhesive-backed,
velvety fabric with millions of tiny, black, light-absorbing
fibers sticking out of it.) I didn't realize how much difference
flocking makes until I was observing with Lauren Wingert
(S&T: Aug. 2023, p. 74), who had flocked the inside of her
10-inch Dob. I had my open-truss trackball of equal aperture,
but the view through Lauren's scope was vastly more contrasty
than in mine. I flocked the inside of my secondary cage
and added a shroud, and the next time we observed together
my view matched hers.
Speaking of shrouds: Yes. They're well worth the effort.
They cut down on stray light and also help prevent dew from
settling on your primary and secondary mirrors.
GRIPPING CONVENIENCE A hand knob helps you move the telescope
smoothly. Yes, that's a doorknob. They're made for hands.
LASER-GUIDED A green laser pointer makes a dandy finder. See my
column on making the mount in the March 2022 issue, page 72.
sk yand tele scope .o r g * DECEMBER 2023 63
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Sky & Telescope - December 2023

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