Electrical modifications and construction of electrical accessories can
be dangerous. Do not attempt such activities unless you are qualified
to do them
safely, without injury to yourself or your property. Anyone
not qualified for these activities should secure the help of a
licensed electrician. It is always recommended to consult with the
appropriate manufacturer prior to modification of any equipment, as
this may void warranties and/or alter the
Philips SPC900NC Web Cam Adapter
Low cost astrophotography with a web cam requires some sort of adapter
to attach the web cam to the telescope. Typical methods are to tape a
35 mm film can or eyepiece barrel to the webcam or purchasing a
commercial adapter (typically $20-$50). I constructed a
homemade adapter for the Philips
SPC900NC by reusing the lens focus assembly. The entire adapter was
scrap tubing and materials, making it essentially free. The following
instructions are for a 0.965 inch. adapter, however the same procedure
could easily be applied to constructing a 1.25 inch. adapter.
The first step in using a web cam for astrophotography is to remove the
lens; the web cam lens is not needed because the telescope
will function in place of the web cam lens. Photos of this
procedure and a commercial webcam adapter can be found at First Look at
the Philips SPC900NC Webcam.
The basic idea is to remove the lens from the plastic lens housing and
reuse the empty plastic
lens housing as an adaptor. Note that this
procedure will destroy the glass lens and the camera can no longer be
a webcam! I used a hammer and a small screwdriver to remove the lens.
This process will most likely chip and break the small glass lens, so
be sure to wear appropriate eye protection. If you plan on also using
the SPC900NC in the future as a webcam, then you need to keep
plastic lens housing with the glass lens intact and instead purchase a
commercial SPC900NC adaptor (about $25 on eBay).
The below photo shows the SPC900NC webcam lens housing after
removal of the glass lens.
I located several scraps of tube and an unused 0.965 inch.
eyepiece barrel (below photo).
The adapter needs to mate the eyepiece barrel (left) to the plastic
lens housing (right). I did this by finding several tubes
be inserted inside of each other until eventually the metal eyepiece
barrel could be slid over the plastic lens housing. Most parts were
wrapped with electrical tape to give snug fits and also provide
electrical insulation. The final assembly is shown below:
The small threaded section (top) screws into the webcamera and the
metal barrel fits a 0.965 inch. draw tube. The
black tape electrically insulates the adaptor and
also gives a snug fit inside the webcam lens hole. The below top and
bottom photos show the webcam with 0.965 inch. and 1.25 inch.