Tumbleweed Observatory's

Astronomy Hints



Drawings of the Mars 2003 Opposition

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Observing Notes For The Mars 2003 Opposition

This page presents Mars drawings made during the 2003 opposition. Mars was observed with a 6" f/10 Dobsonian designed especially for planetary observing by Steve Dodson. Also included is one composite of a Mars sketch and photograph showing their correlation. The photograph is a 48 stacked image taken with a Quickcam Express Webcam through an ETX 90.

Mars has always been my favorite object. I still remember on night over 30 years ago when conditions were just right, and my old 6" f/12 was giving the best views ever. I stayed up pretty late that night, much to the consternation of my folks. I was always most intrigued by the stories of Percival Lowell and the construction of the Lowell observatory in Flagstaff, Arizona. I was there a few years ago, and wanted most of all to see the famous 24 inch refractor. I went there, but the place was jammed. Oh well, maybe next time.

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The above images were drawn on the indicated dates, and reveal the rotational period difference between Earth and Mars, as indicate by the moving position of Syrtis Major

Drawing Technique

I'm not highly experienced at sketching at the eyepiece, but I've made a few moon crater and planet sketches over the years. I enjoy sketching Mars the best, and it's probably because I enjoy looking at Mars the best.

I agree with many other sketchers that drawing what you see through your telescope makes you a more critical observer. Soon you begin to see details that escaped you before you began sketching.

For these Mars sketches, I used just a drawing tablet, a number 2 pencil, and a smudge stick. Before I went out, I used a 2 inch diameter bottle cap to draw a circle to represent the planet. I made the sketches of Mars within the circle. On occasion I also used a red filter which helps enhance contrast.

I started by observing first for major features, and then outlined lightly these features. When these were all outlined, I shaded them in. Then I began the critical examination phase to seek out any details I could discern.

My greatest obstacle was my glasses. I don't use them when looking though the telescope, but must use them to draw. It made the procedure certainly more cumbersome than in my youth.

Since the 2003 opposition, I've added a muffin fan behind the main objective. I've found that the muffin fan, removed from an out of service computer, is vibrationless and pushes quite a bit of air.

I've only began to test the arrangement, but it appears that best use is to leave the fan on while observing. When the fan is on, it disrupts the layer of turbulent air that boils over the mirror surface, and leads to significantly improved views. I look forward to using the scope with this enhancement this (2007) opposition.

The Planetary Dob

The telescope pictured above is the specially designed planetary scope used for observing the Mars 2003 opposition. The telescope is a 6" f/10 Newtonian on a Dobsonian mount. The instrument was designed as a kit by Stargazer Steve Dodson.

The scope mount is a low-profile design, made possible by adding counterweights to the uniquely designed mirror mount.

The telescope uses an oversized tube to keep air currents away from the Field of View.

The secondary is small due to the long focal length, and mounted on a single element, curved vane. This eliminates spikes normally caused by a conventional secondary mount.

You can contact Steve about purchase of one of his telescopes at Steve Dodson.

The composite above shows a drawing made using the 6" on September 10, and a CCD image taken through an ETX 90 on September 12". The CCD image is a stack of 48 single images. The composite indicates both the remarkable capability of the ETX 90 for such photography, and the accuracy of the drawing.

This composite is based on the same ETX 90 photo, but with some Martian feature labels for reference.

Other Targets: Comet 17P/Holmes

I primarily use the instrument described on this page for lunar and planetary observing. As described, the telescope has features especially designed for that purpose.

That is not to suggest the telescope has no other use. It is a good instrument for a wide range of observing. It just isn't optimal for wide field viewing.

As an illustration, I used the telescope to view comet 17P/Holmes in 2007, a couple of weeks after it appeared to explode. At left is a drawing of how 17P/Holmes looked on October 29, 2007.

Check out the Holmes Comet page for more observations and sketches.