AST195 ON-LINE PROJECT

SOME EQUIPMENT -- SOLAR FILTER

Do not attempt to observe the sun on your own until you have received training through the Solar Observing Project (Project #H).

VERSION FOR ON-LINE STUDENTS

In this project you will construct a solar filter for your telescope using some cardboard and staples and some high-quality solar filter film, either from Germany called Baader Astro-Solar Film, or from Thousand Oaks Optical (see the section on the class web page on “information on required telescope and solar film”).

You need:

· Your telescope

· Lightweight cardboard (like cereal boxes)

· Small scissors (for cutting small, round holes)

· Good, heavy tape or a stapler

· Solar filter film

· A container (such as a cheap plastic food storage container, or a box with a lid) to safely store the completed filter in. You must have a prominent label on the container that says “TELESCOPE SOLAR FILTER – HANDLE WITH CARE” (why? Because students in the past have had family members trash their solar filters because the family members did not know what the solar filter was and thought it was some cardboard junk).

The basic method of making a filter is to sandwich the film between two rings of cardboard (such as is shown below), which are attached to a sleeve that fits over the end of the telescope. The usual appearance is shown at right. The tough part is attaching the sleeves to the two ring sandwich, without damaging the film. This is usually done by making a strip of cardboard with tabs (such as is shown below). The tabs are attached to the rings.

Click here for a video on how to make a solar filter.

You will need to provide cardboard, scissors, etc. for constructing stuff from cardboard. Light cardboard (such as is used in cereal poxes) is probably the best choice. Heavy corrugated cardboard is probably not a good idea -- too stiff. You also will need your telescope tube for sizing the filter and sleeve.

You will need a container in which to put the filter. The filter is an important piece of safety equipment that will protect your eyes, and it must be properly cared for. The container must be labelled as described above.

Note -- you are not constructing a toy. You are constructing an important piece of astronomical safety equipment. If you do a poor job of constructing your filter, or do a poor job of caring for your filter, you may damage your eyesight when viewing the Sun. Do not attempt to observe the sun on your own until you have received training through the Solar Observing Project (Project #H).

To receive credit for this project you will need to successfully construct a filter and obtain a container/case, and document this through photos.

Create a document that includes the following photos:

· At least five photos showing you at different stages of assembling your solar filter.

· Three “close up” photos of the assembled filter, on the telescope. The photos must be taken from various directions. The filter must have your name on it, and the name must be visible in at least one of the photos.

· A photo of the case, with its label visible.

· A photo showing the filter in the case.

That’s ten photos total. Save the document as a PDF, as usual, and e-mail it to me.

The basic cardboard parts of the filter (see the video):