Comet McNaught & Mercury

Date: 14 January 2007 U.T.

Time: 20:10 U.T.

Binoculars: 25x100 (tripod-mounted)

Seeing: Fair

NELM: Daytime

Temperature: +14 F (-10 C)

The above sketch shows the full 2.3 degree field of view of the large binoculars. Comet McNaught is to the lower left. Mercury is the small 'star' to the upper right. North is roughly up; and west is roughly to the right.

The sky appeared clear at the time of the observation; but ice crystals were suspected in the upper atmosphere. A segment from a large, white halo was visible to the left of the Sun immediately following the observation.

The comet was relatively easy to see; but Mercury, due to its faintness, was much more difficult for the eye to perceive.

I had tried earlier to spot Mercury with hand-held 8x42 and 20x80 binoculars; but those efforts proved unsuccessful. Even with the tripod-mounted 25x100 binoculars, and even knowing where to look for our solar system's innermost planet, it took a few minutes to 'spot' Mercury.

Unrelated Note: Using 8x42 binoculars I managed to watch Comet McNaught set yesterday evening. In a mostly cloudy sky I had a thin strip of partial clearing just above my horizon in just the right location. The clearing was only one-fourth to one-eighth of a degree wide! The setting comet looked much like the sketch I had made earlier, in the daytime, with an 80mm refractor -- only not quite as good!

Comet McNaught - Saturday Morning

Date: 13 January 2007 U.T.
Time: 16:05 - 18:45 U.T. (9:05am - 11:45am)
Telescope: 80mm f/5 refractor
Magnification: 24x
Binoculars: 20x80
Seeing: Fair
NELM: Daytime - Very Good Transparency
Temperature: 0 F to 13 F (-18 C to -11 C)


Over the above mentioned time interval I made intermittent daytime observations of Comet McNaught. Weather predictions called for clouds today. Indeed, there were scattered clouds in my sky, but much of the sky remained crystal clear! The top sketch above was made at 16:30 U.T. with the refractor. The lower sketch is based on observations made with 20x80 binoculars from 16:45 - 18:45 U.T.

Even immediately after making the refractor-based sketch, the binoculars revealed substantially more of the comet's tail. From then on I used only the binoculars. The refractor showed a smaller, almost stellar pseudo-nucleus.

Near the end of the time interval I found the comet to be "easily" visible to the unaided eye. It was definitely more easily seen with the unaided eye today than it was yesterday. Either my sky improved, the comet brightened, or both. In my opinion the more important factor was a brightening of the comet.

At the end of the session I was able to compare the comet with Venus, both in the 20x80 binoculars. Both objects were at a similar altitude in my sky. Overall, I had no doubt that the comet was brighter than Venus; but Venus seemed to be more intense. That is, per square arcsecond Venus seemed to be more brilliant; but the comet (even its pseudo-nucleus alone) was 'putting out' more light.

Post Script: 21:00 U.T. I just took another (daytime) look at Comet McNaught. It's fantastic with the 20x80 binoculars! This time the tail was 'obvious' even to the unaided eye! This comet is putting on a fantastic show!!

Unaided-Eye Daytime Comet!!

Date: 12 January 2007 U.T.
Time: 20:54 U.T. (1:54pm local time)
Sky Transparency: Very Good
Temperature: +9 F (-13 C)

Earlier today I posted my first daytime binocular observation of a comet -- complete with sketch. Well, I've now managed to see Comet McNaught in the daytime with the unaided-eye!

I went out (TAKING ALL NECESSARY PRECAUTIONS) and spotted Comet McNaught once more with 20x80 binoculars. This time my single goal was to try to detect the comet with the unaided-eye. Knowing exactly where to look (after the binocular observation) was critical to my success. Of course, the nearby Sun was COMPLETELY blocked from view during the observation.

Twice I suspected that I might have glimpsed the comet with the unaided-eye; but finally I was able to maintain the comet in my vision long enough to remove any remaining doubt! The comet's tiny, bright, pseudo-nucleus could be held more or less indefinitely in my unaided vision. Even a hint of tail was suspected!

I hereby declare Comet NcNaught to be a Daytime Comet to the unaided-eye!

Daytime Binocular Comet!

Date: 12 January 2007 U.T.
Time: 18:50 U.T. (11:50am local)
Binoculars: 20x80 and 8x42
Seeing: Good
NELM: Daytime! in highly transparent sky
Temperature: +5 F (-15 C)


WARNING!! CAUTION!! NEVER look at or toward the Sun with a telescope or binoculars. If the Sun crosses your field of view eye damage or blindness is VERY likely to occur.

As a practicing amateur astronomer since the late 1960s, I've read much on the subject; and I've accumulated a fair amount of experience. Precautions were taken in today's observation that made it physically impossible for me to catch even an accidental glimpse of the Sun while searching for Comet McNaught in the daytime sky.

With the above caution and qualifications in mind, I searched for Comet McNaught in the daytime sky with the aid of 8x42 binoculars. Initially this search was unsuccessful. I switched to 20x80 binoculars. Unlike my 8x42s, my 20x80s have individually focussing eyepieces. This means that the 20x80s were alreadly 'locked' into focus for objects at infinity (Comet McNaught in the evening sky was the last object I had focused on).

I was surprised not only at the brightness of Comet McNaught as seen in the daytime with the 20x80 binoculars, but also at the amount of detail that was visible. The inner portion of the comet's tail was easily visible in the 20x80s! The comet was a very pure white in color. It looked somewhat like a white feather against the deeper blue sky.

The above sketch shows the comet as I saw it with the 20x80s near 12:00 noon. I estimate that I was seeing approximately 15 arcminutes (maybe more) of the comet's tail -- in broad daylight! The observation was made at 18:50 U.T.

After spotting Comet McNaught with the 20x80s I was eventually able to see it with the 8x42s as well. The tail was also visible in the smaller binoculars.

I tried to spot Comet McNaught with the unaided-eye, but was not successful. I judged the comet as "easy" to see with the 20x80s. It wasn't difficult to see with the 8x42s; but it was difficult for the eye to initially acquire.

A Successful Comet Expedition

Date: 11 January 2007 U.T.
Time: 00:21 U.T.
Binoculars: 20x80
Seeing: Good
NELM: Twilight
Temperature: about +35F (+02C)

A growing concern brewed today. Comet McNaught was getting closer to the Sun and growing brighter every day. Would I get a chance to see it again? The weather forecast called for clouds tonight. The prospect for tomorrow looked even worse (no clear skies anywhere nearby). In a matter of days the comet will be too far south to be seen from my location.

Making use of the "Clear Sky Clocks", I checked projected satellite images for cloud cover and transparency in and around my area. Eventually I decided to travel to a semi-promising location in the region around the Montana - Wyoming - South Dakota border.

I quickly tossed into my Jeep a clipboard, one sheet of paper, a pencil, a pen and a flashlight along with 8x42 and 20x80 binoculars. I was soon on the road.

As I approached my targeted area, it began to look like the clouds would increase if I kept driving. So, about 1/2 hour before sunset I stopped about 30 miles short of my original goal. I was on a field-access trail facing west into the Sun.

I was beneath a gigantic V-shaped clearing with its apex near the Sun. Clouds were present to my left and right. A few low, scattered clouds were directly in front of me. Venus was spotted with the 8x42 binoculars, followed by the unaided-eye, prior to sunset. The comet was spotted at 23:37 U.T. (10 January U.T.) with the small binoculars shortly after sunset, higher in the sky than I had ever seen it before. A quick sketch was made at 23:47 U.T. with the aid of hand-held, 20x80 binoculars. I rested both elbows on the Jeep's fender to steady the view.

Some scattered clouds were just below the comet. I hopped into the Jeep and back-tracked about 8 miles to a location from which the comet could be better seen. During the drive I occasionally glanced out the driver's side window at the easily visible, naked-eye comet. I made another quick sketch at 00:04 U.T. (11 January U.T.) Then hopped back into the Jeep and back-tracked a few more miles. Finally, at 00:16 U.T. I stopped for my final observation. A careful sketch was made at this time. It was completed just before a major, low-lying cloud swallowed the comet permanently from view.

My observing locations were on either side of the tiny town of Hammond, Montana on Highway 212. The town of Hammond consisted of only one or two buildings -- or that was all I noticed in my preoccupied state of mind.

The above sketch is based on the final (00:16 U.T.) rough, 20x80 binocular sketch. Based on the 3.0 degree binocular field of view, I estimated the comet's tail to be 1.4 degrees in length. A rough estimate of the comet's brightness placed it at magnitude -2.7 (brighter than Jupiter, but not quite as bright as Venus. The above sketch is oriented correctly in relation to the binocular view.

Comet McNaught's pseudo-nucleus appeared to be non-stellar, disk-shaped, and very bright. It and the inner-most region of the tail took on a very slightly yellow-orange color by the time the final sketch was made. Earlier, with the comet higher in the sky, the only color seen was white -- of various intensities.

The faintest, outermost region of tail was 'imagined' to have a slight reddish color. I say 'imagined' because I'm not convinced that I was really seeing any color there.

The Road Home: On the way home I saw flashing red lights in front of me. As I got closer I saw that those lights were on a tow-truck just off the right side of the highway. Parked perpendicular to the highway, beside the tow-truck, was an 18-wheeler. Nearby was an individual holding a "SLOW" sign.

A little further along the road, down a hill, on the left side of the highway I saw several more vehicles with flashing red and blue lights. Another individual was holding up another "SLOW" sign. I spotted several additional tow-trucks off the left shoulder of the road. Then I saw another 18-wheeler. This one was off the left side of the highway, parallel to the highway, lying on its side. It was facing west, the same direction I was driving.

The highway was clear and dry. I found myself wondering if the driver had gotten distracted by the comet. On the other hand, there were quite a few deer in the area . . .

Anyway, I eventually made it home to completely overcast skies. It started snowing within an hour. My 'Comet Expedition' was a success! I'll feel a little better now if I don't get another chance to see this small, but bright comet.

Comet Update

Date: 09 January 2007
Time: 14:11 - 14:16 U.T.
Telescope: 80mm f/5 refractor
Magnification: 24x
Seeing: Bad
NELM: Bright Twilight & Clouds
Temperature: +22 F (-6 C)

My morning sky was partly cloudy with enough clear area to provide some hope of seeing Comet McNaught. The comet was spotted in the small refractor at 14:11 U.T. just as it cleared my local horizon. The eastern sky was already quite bright. Clouds were in the immediate area around the comet. During the five minute observation the comet vanished at least twice behind clouds.

This was my poorest view of Comet McNaught so far. The seeing was bad. Clouds were present in my line of sight; and the sky was so bright that not much tail was visible. I took a few notes; but no sketch was made. The persistent clouds and brightening sky seemed reason enough to cut this session short.

Last night, under a 99.9% (at least!) cloud covered sky I used 8x42 binoculars to look through a solitary, narrow break in the clouds for the comet. Venus made a brief appearance; but nothing else was seen.

From here on, Comet NcNaught drops rapidly lower in my morning sky. This means that on each successive morning the comet will be in a brighter sky, making it increasingly difficult to see. My best chance of seeing the comet in the next few days will be in the evening sky -- weather permitting.

Comet McNaught

Date: 07 January 2007 U.T.
Time: 14:05 U.T.
Telescope: 80mm f/5 refractor
Magnification: 41x
Seeing: Poor
NELM: Bright Twilight
Temperature: +20 F (-7 C)


The above sketch is mirror-reversed. West is toward the upper right. South is toward the upper left. The observation was made in the morning before sunrise. This sketch is more accurate than that accompanying my previous comet observation.

The comet was initally spotted in 8x42 binoculars just as it cleared the trees along my east-southeastern horizon. It was very easily visible to the unaided eye at that time.

After completing the sketch I lowered the magnification to 16x and kept an eye on the comet as the sky brightened. In time, the sky became too bright to make out the comet's tail. Even later, the comet's central condensation appeared to shrink due to the increase in sky brightness and/or improved seeing conditions.

I was able to maintain sight of the comet until the last time I shifted the scope (to keep the comet in view). At that point my observing eye was unable to pick the comet out of the bright telescopic field of view. This was two minutes before sunrise!

Comet McNaught should be visible in the early evening sky as well. As a matter of fact, it will probably now be easier to catch in the evening sky than in the morning sky. I would have tried yesterday evening; but my sky was cloudy and the ground was accumulating a small amount of snow.

Theophilus - Lunar Observation

Date: 07 January 2007

Time: Centered around 12:00 U.T.

Telescope: 80mm f/5 refractor

Magnification: 65x

Seeing: Fair-Good

NELM: 5.1 or better

Temperature: +20 F (-7 C)

The above sketch shows Theophilus (the large formation) and the nearby crater, Madler. West is toward the upper right. South is toward the lower right in this mirror-reversed view. Some of the surrounding details were very hastily rendered, resulting in a more inaccurate sketch. I really need to start using my larger refractor, on it's sturdier (tracking) mount while I sketch comfortably seated. The at-the-telescope sketch that the above was based on was made while standing. The telescope was on a homemade alt-az mount that was set up on a porch -- not the best of situations! Nevertheless, I wanted to continue with a bit of lunar observing and sketching.

Comet McNaught (C/2006 P1)

Date: 05 January 2007 U.T.
Time: 14:00 U.T.
Binoculars: 20x80 (hand-held)
Seeing: Fair
NELM: Bright Twilight
Temperature: +15F (-9C)


Under a partly cloudy sky bathed in bright, morning twilight I searched for and found Comet McNaught while scanning the clear eastern sky with 8x42 binoculars. I described the comet's location to Ann; and she also was able to find and observe the comet using the small pair of binoculars.

The above sketch, correctly oriented in relation to the horizon, comes close to matching the view as seen with 20x80 binoculars. North (toward Polaris) is to the upper left. The maximum length of visible tail was estimated (roughly) to be ten minutes of arc (about 1/3 the apparent diameter of a full moon). The comet's head was bright, somewhat 'fuzzy', and non-stellar in appearance. If it could be observed from a dark sky, this comet would be very easily visible to the unaided-eye; but unfortunately Comet NcNaught is currently too near the Sun.

In the next few days the comet will be moving closer to the Sun, making it increasingly difficult to observe from Earth. A low, clear, transparent eastern horizon are necessary in order to see Comet NcNaught. A telescope or a pair of binoculars might also be needed.

Bailly -- a Lunar Observation

Date: 02 January 2007 U.T.
Time: 4:30 - 5:00 U.T.
Telescope: 80mm f/5 refractor
Magnification: 65x
Seeing: Good
NELM: 4.5
Temperature: +15F (-9C)



The above sketch is 'mirror reversed' -- the way things look when a simple, mirror diagonal is used with an astronomical refractor. East is roughly up. North is roughly to the right. The moon was a little more than one day away from being in its full phase.

At 65x the entire moon was visible in the refractor's FOV. Yet, the sketch shows a very small fraction of the moon's visible surface. The largest feature in the sketch is the walled-plain "Bailly." Bailly is the largest walled-plain on the Earth-facing side of the Moon. Its position on the Moon is: 66.8 degrees South latitude, 69.4 West longitude. The three large craters shown above Bailly are, from left to right, Kircher, Bettinus, and Zucchius. Those craters are each roughly 70km (44 miles) in diameter.

The sketch was fairly quickly executed and is the first lunar sketch I've made in quite a long time. A quick comparison of the above sketch with the actual 'at the telescope' sketch reveals that Bailly appeared more foreshortened with a narrower floor and walls than depicted in the sketch above. Perhaps I'll use the original for a somewhat more accurate sketch at some later date . . .

As I worked on this observation I found myself wishing I had set up a larger, higher quality telescope. Nevertheless, the sketch gives some idea of what can be seen on the moon with a small, relatively inexpensive telescope.

The telescope was set up on a porch. My fully shielded porch light (which is almost always turned off) was turned on to provide brighter (than that provided by moonlight alone) illumination on my clipboard.