Choosing A Telescope
Telescope Aperture Considerations
Introduction to Planetary Sketching
Refractor Dobsonian Style Mounts
The Bonds: Pioneers of American Astronomy
Saturn's Encke Minima and Encke Division
Nature and Travel Photography
Recommended Astronomy Books
Comet Ikeya Zhang, April 21st, 2002
Original drawing made using white pencil on black paper:
Same drawing on a white background:
Comet Ikeya Zhang, April 21, 2002, 7:25-8:25 UT, seeing 5-6, transparency 5.1 with a few clouds.
Astro-Physics 5.1" f/8.35 EDF refractor on homemade Dobsonian-style mount. Magnification 115x, field of view approximately 0.7 degrees. North is to the upper left in this drawing.
The coma appeared very large and blue-green in color, with the blue color more pronounced than the last time I observed the comet on April 11th. The coma surrounded a relatively bright parabolic hood and star-like pseudo-nucleus. The gas and dust tail were both visible behind the coma, the more prominent gas tail on the left, while the fainter dust tail on the right.
The gas tail curved up and away from the coma on both sides, but was not as pronounced along the left edge as noted during the April 11th observation. However it did appear to have a couple of kinks along the left side. The gas tail had a multi-threaded appearance to it that extended from the coma to the left side, middle, and right side of the tail. Tail length was between 3 - 3.5 degrees.
The dust tail appeared as fine strands of light off to the right of the coma. There was a dark gap or opening between the dust tail and gas tail.