Put a small amount of glue evenly than 10mm. Use sandpaper to smooth the 240.BLT around the inner side of the end with the hole and then roughen the inside of the plug tags, again without drops or strings. to provide a good base for the glue. Remove KLAUS HÜNIG Push the eyepiece into the holder from all dust and loose plastic bits. the tag side and slide it into place by Step 8: pushing it onto the work surface so it is Apply a generous amount of glue onto the flush with the six tags. disk holding the eyepiece and fit it into the The Plumber’s Telescope socket plug so that the hole in the disk sits centrally over the hole in the plug. Again take care that no glue gets onto the surface of Kit for an astronomical refracting telescope with the lens. After the glue has set, push the plug 30x magnification, using 40mm drain pipes into the second push-fit coupling. This from any local DIY store Step 5: finishes the construction of the eyepiece Open the 11mm central hole in Part C holder. (blind) using a sharp knife and then remove the part from the cardboard. D. The final assembly •Achromatic objective lens, Fold the six tags backwards and glue the Step 9: part onto the end of the holder, opposite Remove the rubber seal from the open end of Ø 40mm, f +450mm the eyepiece. the eyepiece holder. Then fit the eyepiece •Colour corrected Plössl eyepiece, holder on the open end of the objective lens Step 6: Ø 15mm, f +15mm Open the 10mm central hole in Part D tube. See if you can focus on a distant object (mounting disk) using a sharp knife and by moving it in or out. If not, you will have •Tripod adapter (without tripod) then remove the part to shorten the objective lens tube by a few •Indestructible HT tubing more millimetres. Since the focal length of from the cardboard. •Shows Moon craters, phases Glue the eyepiece holder the lenses can differ slightly and the adjustment also has to compensate for centrally onto the disk of Venus, Moons of Jupiter, Shopp spectacles, each telescope has to be adjusted ing list for using the tags so that the etc with 30x magnification the D individually. • 1 pi IY stor eyepiece lens is exactly ece of e: Step 10: •Easy to assemble 430m drain pi over the hole. Now the m long, pe, 40m If the eyepiece holder moves too easily, a (B& prefe m diam Plössl eyepiece is ready Q) (for t rably eter, a • 2 pus he te black, bout to be mounted in the few strips of sticky tape can be applied to the h fi lescope e.g. M bla t coupl tube) arley tube to increase its diameter. ck, e.g. M ings, eyepiece holder. (to hol arle 40mm Step 11: d t y WPC4BX , prefe • 1 he obje (B& rably push fi ctive l Q) C. The eyepiece holder Lastly fit the tripod adapter to the tube with W t socke ens and t ickes S t plug, he eye some strong sticky tape. If you want to KU431912 (for 40m t m piece) The eyepiece holder is the piece of (1 1/2” improve the properties of your telescope, you he eye ), e.g. tubing that holds the eyepiece and needs piece) to slide on the objective lens tube for can fit a rolled-up piece of black carton focusing. Unlike on other telescopes, the inside the objective lens tube to reduce light eyepiece holder slides OVER the reflections. objective lens tube. Step 7: Congratulations, you have finished your Astro Didaktik ✵ Drill or file a 10mm hole into the exact Plumber's Telescope! centre of the socket plug. The material is quite soft, so if you don't have a drill, We wish you good luck for your “First Translation: Andreas Schröer you can use a small cross-headed screw Light” (as astronomers call the very first driver to make a hole and then enlarge it use of a new telescope). Astro Didaktik Switzerland with a blade of a pair of scissors. It [email protected] | www.astro-didaktik.ch doesn't matter if the hole is a bit bigger The telescope was invented in 1608 by a What you need for completion: Dutch spectacles maker. He held a concave • 1 piece of drain pipe, 40mm diameter, lens (used for short-sightedness) in front of about 430mm long, preferably black, e.g. his eye and a convex lens (for far- Marley/B&Q (for the telescope tube) sightedness) towards an object. With the • 2 push fit couplings, 40mm, preferably correct distance between the lenses he could black, e.g. Marley/B&Q (to hold the see a magnified picture of the object. Galileo objective lens and the eyepiece) Galilei was the first person to use a telescope • 1 push fit socket plug, 40mm (1 1/2”), e.g. for science in 1609. His telescope design has Wickes SKU431912 (for the eyepiece) the advantage of an upright picture, but also • A small hacksaw to shorten the waste pipe eyepiece. Stand the tube with the cut end work surface. Try fitting the the crucial disadvantage that the field of to the correct length view becomes increasingly smaller with down on the work surface. tube over one of the lenses • Drill and drill bits to drill the 10mm hole of Step 2: and check that it holds the increasing magnification. This is the reason the eyepiece (you can also use a nail or a that today all astronomical refracting Now place the objective lens on top of the lens when you pick it up. If small cross headed screw driver to open the tube with the greater curved side facing not, bend the six sides telescopes are built according to the design hole and then widen it with a pair of of the great mathematician and astronomer upwards. Take care never to touch the slightly inwards. Take the scissors). surface of the lens, only handle it by its lens out again. Put a small Johannes Kepler. In 1611 he described a • Sticky tape for the eyepiece telescope that uses two convex lenses which sides. From the side you can see that the lens amount of all-purpose glue on • Strong sticky tape (gaffer / duct / insulation is made from two single lenses. The thinner all sides of the inside of the allows high magnifications with the field of tape) to fit the telescope to the tripod view staying the same. The picture is upside one of these two has to face upwards. Now end of the tube. Distribute the adapter carefully fit one of the couplings over the glue evenly and avoid any down, but that is of course no disadvantage • Solvent-containing all-purpose glue (not for astronomical observations. This lens and push it firmly down until it holds drops or glue strings. Then water based) the lens tightly in place. This finishes the carefully fit the tube on the “Plumber's Telescope” uses Kepler's • Sharp knife (scalpel or small carpet knife) principle too, but with high quality construction of the objective lens tube. lens again so that the edges stand squarely on • A piece of fine grade sandpaper to smooth the work surface and the lens is glued into achromatic lenses of which Kepler wouldn't the cuts even have dreamt. The colour correcting B. The eyepiece the tube. Do this very carefully so that no properties come from the combination of two The eyepiece is the lens (or combination of glue gets onto the lens surface. After the glue lenses with different refractivity which are Assembly instructions lenses) through which you look with your has set, glue the other lens into the opposite cemented together to form one achromatic Please always read completely through eye. The Plössl eyepiece was invented in end of the tube, following the same lens. Each of the parts on its own would have each step before commencing. 1860 by the Viennese optician Simon Plössl. procedure. Now the two curved sides of the great chromatic errors, in combination It is one of the best eyepieces available lenses face each other inside though these errors cancel out. A. The objective lens tube because it produces a fully colour corrected the tube with a distance of The objective lens (or combination of lenses) and sharp image with a large field of view. It about 1mm. With this your is made from two identical achromatic lenses Plössl eyepiece is finished. It This kit contains: is the one pointing towards the observed object, the one through which the light enters that are mounted in a short tube with their now needs a holder to fit it • 1 achromatic lens, 40mm diameter, 450mm the telescope. It fits just over the end of the rounded sides facing each other. into the telescope. focal length waste pipe and is secured in place with one Step 3: Step 4: • 2 achromatic lenses, 15mm diameter, of the push fit couplings. Remove Part A (eyepiece tube) from the Remove Part B (tube holder) 26.5mm focal length, to build a Plössl Step 1: black piece of cardboard. Don't tear it out, from the cardboard, again eyepiece with 15mm focal length Cut the waste pipe to 430mm ± 2mm using use a sharp knife or scalpel to cut the using a knife to do so. Crease • 4 pre-cut pieces of black cardboard the hack saw. To get a nice straight line at the remaining bits that retain the part in the and fold it to form a • 1 tripod adapter right length, wrap a piece of paper around cardboard. Crease and fold Part A to form a hexagonal tube and connect • 1 assembly instructions the pipe and mark the line to cut with a hexagonal tube, connecting the ends with a the ends with sticky tape. • pencil along the edge of the paper. Cut all piece of sticky tape. Put the two eyepiece Fold the six tags outwards around the line, not just straight through lenses with their flat sides down on a clean from one side. Smooth the edge of the pipe with sandpaper. This end of the objective lens tube will be the end holding the and check that the eye piece fits snugly into the holder.