An observing report in the November 1983 issue of the magazine *Sterne und Weltraum*: Helmut Spaude with his 45 cm telescope at Sudelfeld in the Bavarian Alps! This report was read with great excitement! Helmut transported a German-equatorially mounted 45 cm telescope up to Sudelfeld in the mountains using a compact Opel Kadett City.

In the 1980s, Coulter Optical Company advertised large mirror optics in the American magazine *Sky & Telescope*—at the attractive price of 600 US dollars for a 17.5-inch mirror set! This was the manufacturer that had produced the telescope mirror for Helmut Spaude. It fueled an ever-growing desire for a large reflecting telescope.

Around that time, I also read reports about John Dobson. John was very popular in the USA and demonstrated how ATMers (amateur telescope makers) could build large, uncomplicated reflecting telescopes themselves at low cost.

Many large amateur-built telescopes were regularly featured in the magazine *Sky & Telescope* during the 1980s under the "Gleanings for ATM" column.

Along with Walter Scott Houston’s "Deep Sky Wonders" column, these were reasons to eagerly await the next issue of *Sky & Telescope*.

My favorite was a report by Ron Ravneberg:   

"A 17,5" Dobsonian Telescope doing it right."

This followed a night of observing in March 1987 using the 24 inch Newtonian in the dome and a 17.5 inch Newtonian set up outside the Johann Kern Observatory in Wertheim. I swept across the spring sky and into the Virgo Cluster of galaxies with the 17.5 inch telescope—an experience that definitively infected me with "aperture fever."

The following day, Stefan Thiele ordered a 17.5-inch mirror set for me from the Coulter Optical Company in the USA.

A delivery time of one year was quoted, starting from the receipt of a 50% deposit. My beautiful 75mm Unitron telescope had to be sacrificed to cover the 50% deposit due upon ordering

At the same time, work began on the construction of a 17.5 inch Dobsonian telescope, and a search was undertaken for suitable materials and standard parts for telescope building.

Telescope components made of birch plywood—such as the primary mirror box, the upper cage, and the rocker box—slowly took shape in the workshop.

The contours were patiently cut from wooden panels using a jigsaw and custom-made jigs.

A former colleague from my master craftsman training helped me with the height-adjustment mounts. Two rings were machined from 250 mm diameter aluminum round stock on a large lathe. Afterwards, the machine was practically buried under a pile of chips.

Together with Teflon bearing pads, the aluminum rings served as friction bearings for moving the telescope in altitude.

Three Teflon pads were mounted on the top of the base plate, and an "Ebonystar" sheet was glued to the underside of the rocker box. This formed the azimuth bearing. The movement was guided around a central axis.

The telescope could be moved smoothly in all directions, without any initial jolt.

Even without practice, the telescope can easily track celestial bodies at high magnification.

Auch ohne Übung kann das Teleskop mit hoher Vergrößerung problemlos den Gestirnen nachgeführt werden.

Alongside the optics, the heart of the telescope is the primary mirror cell, made of aluminum and featuring 18 gimbal-mounted support points.

Triangles were cut by hand from 8 mm thick Duralumin using a hacksaw. Rocker arms were sawn from solid 10 mm brass rods. My friend Reiner machined the bearing blocks for the rocker arms on his "Hommel" milling machine.

Spring 1989: The finish on the completed telescope tube has long since dried. Two years have passed since the order was placed, yet there is still no sign of the optics being delivered. Once again, my inquiries were met with the reply: "We will deliver soon."

3-year delivery time for a 17.5 Inch mirror set.

In the spring of 1990, finally some good news! I was allowed to select my set of mirrors from three available options at Stefan Thiele’s place.

I was lucky in my choice and picked out a good specimen. This was confirmed later during observation. The finished telescope impressed with superb images.

Planets were imaged sharply and with high contrast. Many structures and subtle color gradations were visible in Jupiter's cloud bands, and the Great Red Spot appeared in a delicate salmon-red hue.

Dark surface features are visible on the orange-red globe of Mars, along with a snow-white polar cap. Syrtis Major and Sinus Meridiani are easily identifiable.

With 17.5 inch aperture, the spiral arms of the galaxy M51—including the bridge to its companion—are clearly visible, while the globular cluster M13 is resolved almost to its core at 200x magnification.. 

Numerous deep-sky objects reveal their true form. The gaseous nebulae in the summer Milky Way are magnificent objects when viewed through a large Dobsonian telescope.

Galactic and planetary nebulae can be seen with visible structure and, in some cases, color.

Strolling along the filaments of the Cirrus Nebula in Cygnus and tracing the entire complex is an impressive experience. With the use of a narrowband filter, many details become clearly visible.

The first large Dobsonian at the ITT Star Party

In the autumn of 1990, the telescope was presented to visitors at the 6th ITT on the Wollner Nöck in Carinthia. Upon seeing it during the day, some had doubts and prematurely judged that a 17.5 inch telescope with an alt-azimuth mount would not work well in practice. However, once darkness fell, numerous fellow observers had to wait patiently in line behind the eyepiece.

Critics also joined in, delighting in the details of deep-sky objects—such as the dust structures in the galaxy NGC 253 in the constellation Sculptor. Stefan Thiele was very impressed by the performance of my telescope and asked if I would build Dobson telescopes for him. The following year, production began on a small batch of the first "Dobsonian made in Germany."

The story of the Skylight 16 can be read in one of the subsequent reports.