28 November 2007: Comet Holmes, Mars
Over the last few weeks either circumstances or weather conspired to keep me from tracking Holmes, but tonight I had a chance and the sky was clear with only a few high clouds scattered about. Around 7:30 I scanned the area around Perseus with my binoculars. The comet was no longer visible to the naked eye (at least not around here) and even with binoculars it was hard to find—it had grown much larger but also much dimmer than it was before. It appeared as a large (greater than a full moon’s-width) but dim, gray, fuzzy smudge just to the east of Mirfak.
With the comet as dim as it was, I decided to use the 10 in. Dob. I let the tube cool outside for a few minutes while I bundled up (the temperature was just below freezing). After setting it up on the sidewalk in front of my house I scanned the sky around Perseus for the comet. It took a few minutes to find it; oddly enough, it seemed easier to see through the binocs than through the scope. I suppose the extra magnification spread it around enough so that it appeared very indistinct even using the 35 mm eyepiece. It had a very low surface brightness and it appeared as a wispy gray ghost that occupied nearly the entire field of view.
For comparison, I also located M31; it was nearly straight up so I had to crane my neck to use the spotter. I could now see that Comet Holmes had a lower surface brightness than M31.
Before calling it a night, I noticed that Mars was rising; it had been growing noticeably brighter lately so I took a quick look. I could make out a distinct orange disk, but not much surface detail was visible. I’ll have to give it another look sometime when it is higher in the sky.