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 [...]]]>

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 sketches on the page. My first sketch is an “outline” of major features. The second sketch shows more detail, and the third is the final sketch. When I’ve matched all of Galileo’s lunar sketches, I’ll make a comparison montage.

The three-day waxing gibbous moon is high enough above the western horizon and far enough away from the setting sun to be easily visible. Earthshine illuminates the unlit features, and sun shines on the narrow crescent. Mare Crisium (the Sea of Crisis) is the oval dark geological feature visible on the lower right edge of the three-day-old crescent moon.

The crater Picard can be seen within the smooth surface of Mare Crisium. Along the terminator are some distinctive craters and other features, visible even at 19x. Following the terminator from right to left in my sketch, are dark Mare Fecunditatis and the large oval craters Langrenus, Vendelinus, and Petavius, all partially lit by the sunrise on their walls.

Petavius, the third of the 4 evenly spaced, and similarly sized craters shows some of the prominent crater floor structure of central peak and rimae – which I sketched as a dark angluar line. Funerius, fourth and last of the big craters on the terminator tonight, are near the two smaller craters, Snellius and Stevenius. In my sketch, I just show the crater floors flooded with shadow.

Earthshine reveals Mare Imbrium and Mare Serenitatis, Nubium and Humorum. And I was able to see the crater Aristarchus (the white feature top middle of the earthshine) and Plinius and Linne — the small white features in the lower middle of earthshine.

Use the link below to Hitchhikers Guide to the Moon to identify other features.

Hitchhikers Guide to the Moon

Sketch of Petavius

Sketch of Langrenus, Vandelinus, Petavius, and Furnerius a few days after full moon February 3, 2007, a 16 day-old waning moon.

My photo of the 3-day moon

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 [...]]]>

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 lunar terminator through my own telescopes, and hunt for interesting features to sketch, I sometime daydream, and try to imagine what Galileo thought as he surveyed these surprising lunar features. I feel a tingle every time I see the sunrise or the sunset illuminate a lunar crater floor, or escape through a crumbling wall to create a fleeting sun ray.

I’ve been sketching the moon for about 20 years, but I’ve always focused on a small segment of the lunar terminator as my sketching target. I’d never tried to sketch the entire moon in one sitting before. Sketching the entire lunar disk is a daunting project. So I decided to make my sketches very small – three sketches to a page. I like to show my “rough sketch” first. It is sort of a outline of the major features. Then I create a finer sketch, filling in the details. Often, I make a third “final final” sketch, too.

I used a 5″ x 8″ inch bound sketch book instead of my usual 3.5 x 5 inch 400 Series Strathmore spiral bound sketch pad. I always use my slender set of 12 mix and match Pitt pure graphite, Castell fine, and Wasserlack bold Faber-Castell graphite art set pencils. I like to keep the sketching process simple and uncluttered and the supplies compact. No table, no lights shining off my forehead, no messy products that would get on my Zeiss eyepieces or my fingers. Armed with these supplies, all I have to do is wait for the moon to become visible on a night of above-average seeing.

Here is a partial collection of “cropped” lunar sketch pages made at the eyepiece of my 70mm Televue f/7.8 Ranger refractor. I haven’t completed my “Galileo-like” lunar sketches yet because I prefer to wait for those nights of exceptional seeing to sketch at the eyepiece, and I am in no hurry to finish this project. These crops don’t show the “rough” sketch, and are rotated to match Galileo’s brown ink wash paintings. There is one full sketch linked at the bottom of this article, and I’ll dedicate one future blog to each of the lunar sketches.

I used one of the finest planetary eyepieces to complement my telescope — a 25mm Zeiss Abbe Orthoscopic. This gave me a 19x view of the lunar surface, similar to what you would see through a pair of binoculars, but also similar to the magnification (but not the same field of view) of Galileo’s telescope, which was 21x. Twentieth century Extra-Low Dispersion (“ED”) glass in the Televue Ranger and the exceptional quality of the Zeiss Abbe orthoscopic eyepieces plus a wider field of view give me quite an advantage, but that’s the telescope and eyepieces I have at my disposal. Lucky me!

An example of my uncropped 3-to-a-page lunar sketches through a 70mm refractor