Question
Maybe I’m missing something, but if the telescope (or cooker) is mounted on an axis parallel to the equator, it seems like all the tracker has to do is turn the telescope (or cooker) at (360/24) = 15 degs per hour in the opposite direction to the way the earth is rotating?
Anwser
The trouble is that, except at the poles, the axis is not vertical. If your cooker is attached to a sloping axle which rotates, the cooker will be slowly tipped over until the food falls out. Generally, it’s a better idea to keep the cooker stationary, relative to the earth, and arrange some sort of reflector that moves so as to keep reflecting sunlight onto the cooker from the correct direction. A heliostat, in other words.
Associated Sun Telescope Question: In order to avoid misunderstandings: If you are using a telescope, the film MUST be placed in front of the telescope. NOT between eye and eyepiece. Usage as “window” or solar goggles is only for observation with the bare eye. BTW: Don’t miss to cover your finder when observing the sun by telescope. An uncovered finder may focus the sun on your head!
- Anwser: An uncovered finder can be a useful way of finding the Sun, which can be an extremely “elusive” object to actually get into the telescope’s field of view! My normal method of finding the Sun is to use the scope’s shadow to get it approximately in the field (by moving the scope until the shadow of the tube is minimized), and then to place my hand a few inches behind the finder’s eyepiece and move the scope until I see an image of the Sun on my hand. I can then centre the image in the finder’s field, which will place it into the scope’s field of view. Having done that, I obviously cap the finder. Regard,
Associated Sun Telescope Question:Okay, I’m going to come out really idiotic-looking here, but I figure anything I learn now will prevent patrons of mine from doing damage to themselves later, especially with the annular eclipse coming in May. We have all seen the Mylar balloons, and have all heard of Mylar filters for telescopes. Is the Mylar used in the balloons as thick as the filters, or are they completely different animals. I want to keep someone from cutting one of these deflated balloons and using it for a filter to view the sun.
- Anwser: Nothing idiotic about it! A little learning is a dangerous thing, and nothing is so boneheaded that someone won’t try it. The Mylar could be the very same stuff in both applications, but the COATING is what does the work, not the Mylar. Tell them, for God’s sake don’t use a cut-up balloon! The balloon might appear nearly opaque to visible light but will almost certainly pass dangerous amounts of UV or infrared. Ask them whether the risk of permanent eye damage or blindness is worth saving a few dollars.
Associated Sun Telescope Question: No matter where the sun is in the sky, and no matter whether it’s in eclipse or not (same question, basically — both situations reduce the amount of solar radiation reaching the telescope, but not enough), IT IS *N*O*T* SAFE TO PUT YOUR EYE TO THE EYEPIECE WHEN THE TELESCOPE IS POINTED AT THE SUN.
- Anwser: You definitely want to be extremely cautious when risking your eyesight, but I have viewed a sunset with binoculars. When I was on the Gulf side of Florida, I was watching a boat on the horizon which went near the setting sun. I noticed as I was getting nearer the sun, that the sun’s rays were so attenuated that it was comfortable to look at in the binoculars. At this point, the sun had already started to dip below the horizon, which was the sea. It was cool because you could see the silouette of the waves on the horizon against the sun (I calculated that the waves were three or four miles away). However, at other locations, the sunset will likely occur higher in the sky (over trees, hills, or buildings) and therefore be attenuated less, so USE CAUTION! By the way, the company I work for makes some equipment for measuring electrical stuff. Accessories for one of the products includes a fixture for measuring very small capacitors, and it has an attached magnifying glass to help position them. There is a warning in the manual not to view the sun through the magnifying glass. How stupid do they think people are? Do they also need a warning telling someone not to drop the equipment on his foot?
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