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May 1, 1999, 2:50 - 3:35 UT, seeing 6 - 7 (0 worst, 10 best), transparency 3.5. Central Meridian 130.43 degrees.

Astro-Physics 7.1" f/9 EDT refractor on homemade Dobsonian-style mount. Magnification 203x-289x with Baader binoviewer.

Noted a large limb cloud on the preceding edge. Chryse was located on preceding edge as well and to the south of the limb cloud. There appeared to be a light colored band that extended across the equator from Chryse on the preceding limb to the following limb. It was faint yet noticeable, and was more pronounced with a light blue filter, which suggested it was an atmospheric phenomena. It reminded me of an equatorial belt on Jupiter or Saturn, but much fainter.

I had not seen this feature before, and after completing the drawing went back inside and checked the various Mars maps that I had, as well as books on Mars. I could only find one drawing that showed a similar feature, known as equatorial cloud bands (ECBs), but it had been made with a 30" telescope at 560x magnification, and it was noted that this feature is exceedingly rare. So I thought that perhaps my observation was incorrect, and did not report it.

However, around a year and a half later I attended a star party where a well-known planetary astrophotographer was showing images of Mars he had taken with a 10" aperture telescope during the 1999 opposition. One of them showed what appeared to be the ECBs that I saw visually. After his talk ended I asked him if he could see the ECBs through his telescope and he indicated that he had, and that he felt that I should be able to see it in my 7.1". So I then reported my observation and submitted my sketch to the Mars ALPO section.