December 2020
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Chasing Galileo – sketches of the five-six day moon

Six-day old waxing moon

The six-day waxing gibbous moon is visible for many hours in the evening – perfect for lunar observing and sketching. The time of my sketch was closer to the sixth day than the five day old moon. I had a hard time identifying craters using either lunar days! Note how much [...]

Chasing Galileo – sketches of the 3-day moon

three-day old waxing moon

This year, my observing project is to recreate as many of Galileo’s original telescopic observations as I can. I’ll be using my smallest telescope, a 70mm refractor, and making my sketches using a 25mm eyepiece for a magnification of 19x. Each of my lunar sketch pages will each show three [...]

Chasing Galileo – sunspots

Galileo's sunspots

My sunspots

In the summer of 1612, Galileo sketched a series of sunspots which were published in Istoria e Dimostrazioni Intorno Alle Macchie Solari e Loro Accidenti Rome, (History and Demonstrations Concerning Sunspots and their Properties), in 1613. Galileo corresponded with other scientists and artists who also were sketching the [...]

Chasing Galileo: the Trapezium

Galileo’s Trapezium

My Trapezium sketches

Galileo’s observed the Trapezium stars in the sword of Orion on February 4, 1617. He labeled the three stars “c”, “g”, and “i”. These stars are known now as the “D”, “C” and “A” components of Theta 1 Orionis, or 41 Orionis. He did not see the fainter [...]

Chasing Galileo: the Pleiades

Galileo’s Pleaids

My sketch of the Pleiades

Galileo’s sketch of the Pleiades was published in Sidereus Nuncius in 1610.

Galileo identified four levels of stellar magnitude. He represented the six naked eye stars he could see with a large star symbol. These 6 stars were listed in Ptolemy’s Star Catalog. Next come seven stars [...]

Chasing Galileo - sketches of the moon

Folio page 28 manuscript copy of Sidereus Nuncius

sketch of 3-day old waxing moon 2-28-09

sketch of 5-day old waxing moon

sketch of 14-day (full) moon 3/11/09

Galileo’s watercolor drawings were made with brown ink wash on watercolor paper. To me, these are the most beautiful of Galileo’s astronomical renderings. When I look at the [...]

Chasing Galileo: sketches through a small refractor

Galileo telescope replica and my TV Ranger

Galileo's 1609 telescope

There were separate housings at either end for the objective and the eyepiece

When I started thinking about how to integrate International Year of Astronomy into my 2009 What’s Up podcasts I naturally focused on Galileo’s first observations through a telescope 400 years [...]