Image 1: The Green Comet, observed at Lac Teeples on February 12, 2023.
This winter there was a lot of buzz about a green comet. At first I thought it must be visible to the naked eye, but it certainly was not visible to me. I tried to observe it with binoculars and may or may not have been successful… hard to tell. Wikipedia says that on a moonless dark night it would have been just visible with the naked eye. With the big scope, however, it was easily found - a bright green comet with two tails (if you look closely).
One tail is the trail of debris melted off the dirty snowball that is a comet as it follows its curved path in space. I believe this is a four-o’clock. The other tail is directly in the direction opposite of the sun, known as the ion or gas tail. This is material being blown back by solar radiation pressure. I believe this tail is at five o’clock. The tails extend millions of kilometers and this icy snowball has a diameter of roughly one kilometer.
Normally images of faint astronomical objects involve stacking of many subframe images. This object was bright enough that nothing of the sort was needed. I manipulated the image that was forming on the screen and saved it. Basically this is a screen capture of a few seconds or minutes of imaging data. The comet does not move significantly relative to the stars during this time period so no streaky stars or comets appear.
This image was captured at lac Teeples on the evening of February 12, 2023. The telescope was a RASA-11 with a colour ZWO ASI-6200MC Pro camera.
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