Hours were spent with a grinding stone trying to get all the edges to about 1/8" wide. I regret not requesting the factory do this job. To ensure that the mirror or tool edges won't chip during grinding, the edges of the mirror and tool must be beveled. Getting Started - Beveling the Mirror and Tool More importantly, figuring and testing the mirror's surface to a good parabola becomes easier with longer focal ratios. Why such a long focal length? Well, I mainly enjoy looking at the planets and so a long focal length and small secondary mirror are desirable. To eliminate the need for rough grinding and save time, I had the mirror kit supplier rough grind the mirror to focal ratio of about F/8 (they also ground the back of the mirror nice and flat). I could have gone with a thinner blank or one made of plate glass to save even more money, but I read that working with such blanks can be a challenge (a thin mirror can end up being astigmatic if you are not careful during grinding, while parabolizing and testing a plate glass mirror can be difficult) and I wanted to avoid such risks even if they were minimal. By making a mirror of this size I would save hundreds of dollars compared to buying one already made. In 1999, a 14.5 inch diameter pyrex mirror blank (2.3 inches thick) was purchased as part of a kit that included a plate glass tool, numerous grits, burgundy pitch, and cerium oxide (CEO) polishing compound. So, in 1998 I decided to make a new "planetary" telescope that would be larger in size and with better quality optics. The highest power I could use before the images got really "soft" was about 130X. With such a poor wave rating, it could not resolve fine lunar or planetary details. The telescope was completed in 1983 and it worked okay for general viewing, but a spherical mirror of this size and focal length has a ~1/3 wavefront rating at best. I did not have the time or equipment to figure/test the mirror to a parabola. I ground and polished the F/8 mirror, and it came out better, but I left the mirror surface spherical. In 1982, I completed another 8 inch telescope mirror. Yet, it showed me things in the sky I had never seen before with my own eyes. The telescope itself was not any better looking. It was an 8 inch, F/10, spherical mirror and was awful looking! It had about a dozen scratches on it, two bad chips on its edge (I didn't bevel the edge enough) and a hazy unpolished zone around the mirror, starting about one inch from the edge. In 1978, I finished my first homemade telescope mirror. I've also added a short description of a homemade refracting telescope lens I made years ago, making an optical flat, and a section on my astrophotos. HOMEMADE SUN SPOTTER TELESCOPE PLUSAt the bottom of this page there are photos showing the telescope under construction, plus links to ATM sites and weather webpages to better help you determine the seeing conditions. These sources of information provided many of the techniques I used to make the telescope. HOMEMADE SUN SPOTTER TELESCOPE HOW TOI read several telescope and mirror making books and visited many amateur telescope making or "ATM" websites to learn how to build a 14.5 inch homemade telescope of this size. Since it is calculated that at 4:46 pm the sun will begin to disappear, it will reach 52 percent coverage at 5:57 pm and then, after a few minutes, the sun will completely disappear.This web page provides an overview of my large homemade telescope making project. If you are looking for the best place to enjoy this particular phenomenon, the alternative that will provide the most attractive panorama is ushuaia. On the other hand, to the north of these countries and to the south of Bolivia, Uruguay and Paraguay, it will cover between 5 and 40 percent, according to different geographical locations. In southern Chile and Argentina, the Moon will block 55 percent of the Sun. Meaning, the Sun will not be completely covered.Įclipses can be total, if the sunlight is completely obscured by the Moon or annular and partial, if only part of the Sun is obscured. The eclipse to be seen tomorrow, April 30, is partial. What will the April 30 solar eclipse look like? On the other hand, those responsible for the Osiris Astronomical Group provide as a guide the Authorized lenses should have low magnification lenses because they produce less heat and thus protect the instrument.Īlso, when telescopes or binoculars are used there is no appropriate filter for this type of event the recommendation is to ensure that sunlight passes through the lens of the device and is projected onto a smooth surface.ĪngIf in doubt, it is advisable to consult a trusted ophthalmologist. A solar eclipse will be seen on the April 30 Photo Shutterstock
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