Comets are big. While the nucleus is quite small, we do not see the nucleus even with the enormous power of a 10 meter telescope. It is hidden in the coma and quite dark, the average nucleus is a shade of dark gray equivalent to charcoal.
The coma and tail are very extended, much larger than the field of view of the telescope, thus the entire frame is inside the coma. The photo of Hartley 2 Greg and I took was no exception.. The image is notable for its complete lack of any interesting structure. There are no jets, shells or other inner coma detail visible. The tail is simply a general brightening to the southwest (lower right in this image).
Small telescopes, in the hands of amateurs, are going to produce the prettiest images of comets. With fields of view measured in degrees, not arcminutes, the comet is going to be seen in all its glory.
I am waiting for the Moon to leave the evening sky before shooting the comet again. In the meantime I am processing more of the material obtained earlier in the month. In this case a photo of Comet 103P/Hartley 2 taken October 6th with Keck 2 and DEIMOS. The image marks the first time I have attempted to take and process an image with a 10m telescope. Just a wee bit larger than the 76mm refractor I usually use to take astrophotos!
The image is notable for its complete lack of any interesting structure. There are no jets, shells or other inner coma detail visible. The tail is simply a general brightening to the southwest (lower right in this image).
The comet is moving very quickly across the sky, even more so with the high magnification lent by a large telescope. Even short exposures turn the stars into long streaks. In this case multicolor streaks as the camera cycles through the filters needed for a color image.