Mercury Sightings - Details for 2021

Mercury has six elongations in 2021. The initial sighting by Joe Stieber for each of these is tabulated below:

Sequence

Initial Sighting Date (2021)

Observing Location

Greatest Elongation (2021)

1

January 7, 5:13 pm EST, #64 Swede Run, Moorestown, NJ

January 23, eastern (evening)

2

February 21, 5:56 am EST, #65 Swede Run, Moorestown, NJ

March 6, western (morning)

3

April 23, 7:49 pm EDT, #66 Swede Run, Moorestown, NJ

May 17, eastern (evening)

4

June 30, 4:36 am EDT, #67 Laurel Run Park, Delran, NJ

July 4, western (morning)

5

August 24, 8:05 pm EDT, #68 Swede Run, Moorestown, NJ

September 14, eastern (evening)

6

October 16, 6:20 am EDT, #69 Swede Run, Moorestown, NJ October 25, western (morning)

 

Elongation #6

The first sighting of the sixth elongation for 2021 (the 69th elongation in a row overall) was on October 16, 2021 from Swede Run in Moorestown, NJ. The weather was cool and dry (mid-sixties F and no dew on the car), but there were some thin clouds overhead and some streaky clouds along the eastern horizon. Mercury was initially sighted at 6:20 am in moderate twilight with 15x56 binoculars by scanning near the treetops at the approximate azimuth established by dropping down from Leo's hindquarters. When first sighted, it was at 2.0 altitude, 96 azimuth and 12.7 from the sun (the ecliptic was at a favorable 73 tilt to the horizon, so with an ecliptic latitude of +0.3, most of the solar elongation was vertical). At the time, Mercury was  magnitude +1.5, 8.9" diameter and 14% illuminated. At 6:25 am, I started looking with an 88 mm apo spotting scope up to 60x, but it was mostly a seething blob due to the poor seeing at the low altitude. I followed it with the 15x56s and the 88 mm scope until 6:45 am (6.6 altitude), by which time in the scope it looked vaguely elongated with a tilt from the approximate 10 to 4 o'clock position, but not at all the crescent I had hoped too see. It was not seen with unaided eyes.

The second sighting of the sixth elongation for 2021 was on October 18, 2021 from Swede Run in Moorestown, NJ. The weather was cool and dry (mid-fifties F) and there were clouds moving in, but the band above the eastern horizon was clear. I was on the way home from Wharton State Forest, where I had been clouded out for the Zodiacal Light, but since it was on the way, I decided to stop at Swede Run for a quick look. I pulled in, got out the 15x56 binoculars, and knowing about where to look from the Oct 16 sighting, I quickly spotted Mercury at 6:12 am EDT. I was also able to see Porrima (Gamma Vir) 1.9 from Mercury at the 9:30 o'clock position. Mercury looked like it was "boiling" from poor seeing, so I didn't get out the 88 mm spotting scope. When sighted, Mercury was at 2.5 altitude, 96 azimuth and 15.1 from the sun, magnitude +0.8, 8.4" diameter and 23% illuminated. It was not seen with unaided eyes. This stop was less than 5 minutes long.

 

Elongation #5

The first sighting of the fifth elongation for 2021 (the 68th elongation in a row overall) was on August 24, 2021 from Swede Run in Moorestown, NJ. Although it was warm, 82F, and humid, the sky was generally clear, but it somewhat murky, along the western horizon after sunset at 7:43 pm EDT. Venus, which was well above the murky band at 16.9 altitude, was spotted with 15x56 binoculars at 7:42 pm, then seen immediately with unaided eyes. Mercury was initially sighted at 8:05 pm in moderate twilight with 15x56 binoculars (stabilized on a monopod) by looking towards the approximate altitude and azimuth given by SkySafari, using the compass on my Apple watch for azimuth and the 4.5 binocular field of view to gauge the altitude, 4.9 when first sighted. I followed it with the 15x56s until 8:10 pm in the 15x56s to insure it wasn't an aircraft and never saw it with unaided eyes. At the time it was first sighted, Mercury was magnitude -0.2, 5.5" apparent diameter, 81% illuminated, 20.2 solar elongation and 0.22N ecliptic latitude.

The second sighting of the fifth elongation for 2021 was on September 2, 2021, from WAS's Barnegat Road Observing Site in Woodland Township, NJ. The sky was exceptionally clear after tropical storm Ida passed through the previous night, so along with a few other WAS members, I headed out there for an observing session, with no real intention of spotting Mercury. However, on arrival shortly after sunset (7:27 pm EDT), I noticed how bright Jupiter was low in the east; it was obvious despite the relatively bright twilight. Venus was also blazing in the west, so I got out my handheld 15x56 binoculars and after a very brief search below-right of Venus, I spotted Mercury at 7:47 pm. At the time, Mercury was at 5.9 altitude, magnitude 0.0, 6.0" apparent diameter, 72% illuminated, 24.5 solar elongation and 1.0S ecliptic latitude (the ecliptic was only at a 27 angle to the horizon). I followed it above the tree line with the binoculars for about 5 minutes to be certain it wasn't an aircraft. It wasn't seen with unaided eyes. Saturn was much dimmer than Jupiter, but is was still visible with unaided eyes during early twilight. Later, in full darkness, Uranus (greenish-blue) and Neptune (bluish) were observed through my 16-inch Dob. Rounding out Solar System object types with the 16-inch, I also saw Comet C/2017 K2 (PANSTARRS) in Hercules and minor planet, or asteroid, (2) Pallas in Pisces.

The third sighting of the fifth elongation for 2021 was on September 7, 2021, from Swede Run in Moorestown, NJ. Mercury wasn't the prime target this time, instead it was a nominal 22 hr old waxing crescent moon. I arrived at 7:15 pm EDT and located Venus in my 15x56 binoculars at 7:20 pm; sunset was at 7:21 pm and I saw it with unaided eyes at 7:23 pm. After some diligent searching, I spotted the very slender (1.6% illuminated), waxing Crescent Moon at 7:41 pm with the 15x56s when it was 22:49 hr:min old, not a personal record (which is 20:01 h:m old from 2011, or 19:08 h:m before new in 2016). Regardless, it's a sublimely beautiful sight. After spotting the moon, I looked for Mercury and found it with the 15x56s at 7:45 pm when it was 5.0 altitude, magnitude +0.1, 6.4" apparent diameter and 66% illuminated. It was at 26 solar elongation, but because of the shallow angle of the ecliptic from the horizon in the west after sunset, plus Mercury's 1.8S ecliptic latitude, much of the elongation is sideways rather than vertical where it could contribute to greater altitude. Next, Jupiter and Saturn were readily visible to the southeast with unaided eyes during twilight. Jupiter's four Galilean satellites were visible with the 15x56s steadied on a monopod (while leaning against a utility pole). Finally, I spotted Neptune and Uranus with the 15x56s from a friend's backyard in Merchantville, NJ, later that night.

The fourth sighting of the fifth elongation for 2021 was on September 10, 2021, from the Barnegat Rd Observing Site in Woodland Township, NJ. I spotted Mercury with 15x56 binoculars at 7:42 pm EDT through murky clouds along the western horizon. At the time, it was 4.4 altitude, magnitude +0.1, 6.6" apparent diameter and 62% illuminated. Solar elongation was 26.7, but because of the shallow angle of the ecliptic from the horizon in the west after sunset, plus Mercury's 2.2S ecliptic latitude, much of the elongation is sideways rather than vertical where it could contribute to greater altitude.

 

Elongation #4

The first sighting of the fourth elongation for 2021 (the 67th elongation in a row overall) was on June 30, 2021 from Laurel Run Park in Delran, NJ, the same site where the solar eclipse was observed on June 10, 2021. Although it was warm, 78F, it was a bit less humid than previous days when Mercury was not seen and the sky was generally clear with some murky, streaky clouds along the northeastern horizon in advance of sunrise at 5:35 am EDT. Mercury (magnitude +1.0) was initially sighted at 4:36 am in moderate twilight with 15x56 binoculars (stabilized on a monopod) by looking about 8 below-left of Aldebaran (magnitude +0.9), which was initially sighted with the 15x56s shortly after arrival at 4:30 am, and later seen with unaided eyes. When first sighted, Mercury was at 1.8 altitude, 8.9" apparent diameter, 26% illuminated. I followed it with the 15x56s until 4:48 am, but never saw it with unaided eyes.

The second sighting of the fourth elongation for 2021 was on July 5, 2021, one day after its greatest western elongation, from Laurel Run Park in Delran, NJ. Most of the sky was quite clear, but it was humid with dew forming on the car and tripod, and there was ground fog with thick murky haze along the eastern horizon in advance of sunrise at 5:37 am EDT (astronomical twilight began at 3:36 am). Mercury was initially sighted at 4:35 am in moderate twilight with handheld 8x42 binoculars by looking about 12 below-left of Aldebaran. When first sighted, Mercury was at magnitude +0.4, 2.9 altitude, 7.9" apparent diameter and 38% illuminated. I followed it with the 8x42s until I lost it at 4:55 am, but never saw it with unaided eyes. The snapshot below was taken at 4:37 am with a Canon EOS RP camera and a Canon 200 mm, f/2.8L lens on a fixed tripod. Exposed 1/13 second at f/2.8, ISO 12,800. Mouseover for a label.

 

Elongation #3

The first sighting of the third elongation for 2021 (the 66th elongation in a row overall) was on April 23, 2021 from Swede Run in Moorestown, NJ, under a clear sky without pesky clouds along the western horizon around sunset at 7:47 pm EDT. Mercury (magnitude -1.8) was initially sighted at 7:49 pm in moderately bright twilight with 15x56 binoculars (stabilized on a monopod) by looking about 2 below-right of bright Venus (magnitude -3.9), which was initially sighted at 7:45 pm in the 15x56s. When first sighted, Mercury was at 4.5 altitude, 5.2" apparent diameter, 97% illuminated. It was last seen when reached the treetops about 7:58 pm. Despite its bright magnitude, Mercury was not seen with unaided eyes, and even in the binoculars, there was minimal contrast with the fairly bright salmon-orange twilight sky. I think I glimpsed Venus before it reached the treetops at 8:05 pm.

The second sighting of the third elongation for 2021 was on April 26, 2021 from Carranza Field in Wharton State Forest, NJ, under a very clear sky without pesky clouds along the western horizon around sunset at 7:47 pm EDT. Mercury (magnitude -1.5) was initially sighted at 7:45 pm, a few minutes before sunset at 7:48 pm, in bright twilight with 15x56 binoculars (stabilized on a monopod) by looking about 1.6 above-right of bright Venus (magnitude -3.9), which was initially sighted at 7:38 pm in the 15x56s. When first sighted, Mercury was at 8.7 altitude, 5.3" apparent diameter, 93% illuminated. It was last seen when it reached the treetops at 8:15 pm, about 3.3 altitude. Neither planet was seen with unaided eyes.


Venus and Mercury from Carranza Field, 1.6 separation

 

The third sighting of the third elongation for 2021 was on May 1, 2021, from Swede Run in Moorestown, NJ, under a clear sky with only a few wispy clouds along the western horizon around sunset at 7:53 pm EDT. Mercury (magnitude -1.1) was initially sighted at 8:08 pm with handheld 8x56 binoculars by looking about 5 above bright Venus (magnitude -3.9), which was initially sighted at 8 pm with the 8x42s, then immediately seen with unaided eyes. Mercury wasn't seen with unaided eyes until 8:33 pm, after Venus dipped below the treeline, so both planets were seen with unaided eyes fairly easily, but not at the same time. When first sighted, Mercury was at 10.7 altitude, 5.8" apparent diameter, 81% illuminated.

The fourth through seventh sightings of the third elongation for 2021 were on May 8, 2021, from Camp Ockanickon in Medford, NJ, and May 10, 12 & 13, 2021, from Swede Run in Moorestown, NJ. In each case, Mercury was seen relatively easily with unaided eyes after initially finding it with binoculars. On May 13, the 2.3 day old crescent moon was just 3 to the left of Mercury, so I hoped to get a snapshot of them. Alas, there was a cloud mass above the horizon in that direction which largely obscured the view. At 9:35 pm, I noticed a glow in the clouds (about 4 altitude), aimed my 8x42 binoculars at it and saw the slim crescent emerge through the clouds, along with Mercury at the 4 o'clock position. I then looked with unaided eyes and saw them. Mercury was visible for half a minute or less, some portion of the lunar crescent for a few minutes. In the 8x42s, some earthshine was noted; I didn't even set up the camera.

The eighth through eleventh sightings of the third elongation for 2021 were on May 15, 2021, from Swede Run in Moorestown, NJ, and May 14, 18 & 19, 2021, from Collins Lane Park in Maple Shade, NJ, easily with binoculars, difficult with unaided eyes. Of particular note, Mercury was also seen through my 88 mm apo spotting scope on May 18 & 19. On May 18, I did not have the 1.6x extender in place, so I was limited to 60x maximum. Seeing wasn't ideal at the nominal 12 altitude around 8:50 pm, but the magnitude +0.7, 32% illuminated, 8.4" diameter disc looked mostly like a thick, seething oval oriented roughly from 2 to 8 o'clock. On May 19, it was also about 12 altitude at 8:50 pm, and now magnitude +0.8, 30% illuminated and 8.6" diameter. This time, I had the 1.6x extender installed so I could observe at 96x. Again, the seeing wasn't ideal at he low altitude and consequentially, the image was somewhat woozy, but in steadier moments, I was able to unambiguously see a thick crescent shape, again oriented in the nominal 2 to 8 o'clock position.

The twelfth sighting of the third elongation for 2021 was on May 20, 2021, from Collins Lane Park in Maple Shade, NJ. Mercury was initially located with 8x42 binoculars at 8:39 pm EDT when it was at 14 altitude, 7.1 above bright Venus at the 11 o'clock position. At the time, it was magnitude +0.9, 28% illuminated and 8.9" diameter. It was then observed with an 88 mm apo spotting scope at 96x and the thick crescent was unambiguously seen for the next ten minutes (although seeing did degrade a bit as it's altitude declined). Mercury was also seen with difficulty using unaided eyes. The sky was generally quite clear with a few thin clouds towards the sunset horizon. There was also a bright moon (a day past first quarter) high in the sky.

The thirteenth sighting of the third elongation for 2021 was on May 25, 2021, from Collins Lane Park in Maple Shade, NJ. Mercury was initially located and sighted at 8:53 pm EDT with the 88 mm spotting scope when it was at 9.2 altitude, 3.4 above bright Venus at the 10:30 o'clock position. At the time, it was magnitude +1.7, 18% illuminated and 10.0" diameter. It was then observed at 96x and the thinning crescent was unambiguously seen for the next ten minutes (although seeing did degrade a bit as it's altitude declined). Mercury was never seen with unaided eyes, and I never got binoculars out. The sky was generally quite clear with a couple of thin clouds towards the sunset horizon. There was a bright full moon rising in the southeast.

The fourteenth sighting of the third elongation for 2021 was on May 27, 2021, from Collins Lane Park in Maple Shade, NJ. Mercury was initially located and sighted at 8:50 pm EDT with the 88 mm spotting scope 40x when it was at 8.8 altitude, 1.3 above bright Venus at the 10:30 o'clock position. At the time, it was magnitude +2.0,14% illuminated and 10.4" diameter. It was then observed at 96x, but the thinning crescent was not well resolved. Seeing was poor initially and worsened as the altitude declined. Mostly, the crescent looked like a wriggling and/or woozy oval with the axis running in the 7:30 to 1:30 o'clock direction. Occasionally, in moments of better (but not good) seeing, the oval became banana shaped. Mercury was never seen with unaided eyes, and I never looked with binoculars. The sky was generally quite clear with a few streaky clouds towards the sunset horizon. I was able to see the magnitude 5.4 star 121 Tauri, 8 arc minutes above Mercury, in the spotting scope at 40 to 60x, from 8:59 pm until the last look at 9:15 pm.

The final attempt of the third elongation for 2021 was on May 31, 2021, from Collins Lane Park in Maple Shade, NJ, under a clear sky with a few streaky clouds above the horizon in the northwest. Venus was initially sighted at 8:42 pm EDT, then searching until 9:05 pm with 15x56 binoculars and the 88 mm spotting scope at 25x in an area below Venus (nominally 3.8 below at the 5:30 o'clock position) yielded no sign of Mercury in the brightish twilight (until the tree line interfered). At the time, Mercury was magnitude +2.8, 11" diameter and 8% illuminated.

 

Elongation #2

The first sighting of the second elongation for 2021 (the 65th elongation in a row overall) was on February 21, 2021 from Swede Run in Moorestown, NJ, under a clear sky without any pesky clouds along the eastern horizon before sunrise. Mercury was initially sighted at 5:56 am in moderately bright twilight with 15x56 binoculars (astronomical twilight began at 5:14 am EDT and sunrise would be at 6:44 am), then it was confirmed by spotting Saturn about 4 to the right of Mercury with the 15x56s. At the time, Mercury was at 3.4 altitude, 9.0" apparent diameter, 29% illuminated and magnitude +0.8 (nearby Saturn was magnitude +0.7). Using 60x in the 88 m apo spotting scope at 6:05 am, Mercury was just a wriggling blob that suffered significant atmospheric chromatic aberration, but was seemingly elongated from the upper left to the lower right. By 6:19 am, the atmospheric chromatic aberration was minimal and Mercury was vaguely a crescent with the cusps pointing to the upper right. The ansae of Saturn's rings were visible in the 88 mm scope at 60x. At 6:15 am, magnitude -2.0 Jupiter was spotted with the 15x56s behind the distant, leaf-bare tree tops at 2.5 altitude. None of the three planets was seen with unaided eyes.

The second sighting of the second elongation for 2021 was on February 25, 2021 from Swede Run in Moorestown, NJ, under a clear sky with a band of horizontal clouds just above the eastern horizon (in the direction of the objects of interest). Mercury was initially sighted with 8x42 binoculars at 5:55 am EST, then Saturn 4.3 to its right, with the 8x42s. Then, using unaided eyes, Mercury was spotted at 5:56 am and Saturn at 5:57 am, both with some difficulty in moderately bright twilight (since astronomical twilight started at 5:09 am and sunrise would be at 6:39 am). In the 8x42s, Mercury was star-like while Saturn looked like an elongated disc. Jupiter wasn't seen until 6:07 am, with the 8x42s and followed immediately with unaided eyes, after it rose out of the cloud band. It was definitely a disc in the 8x42s, and all three planets fit in the 9.1 field of the 8x42s. Easternmost Jupiter was 4.2 from Mercury and 7.7 from Saturn. At 6 am, Jupiter was magnitude -2.0. Mercury was +0.5 and Saturn was +0.7. When first sighted, Mercury was 4.7 altitude while Saturn was 5.2 altitude, well above the cloud band. Jupiter was 3.4 altitude when first sighted. Finally, Mercury was 8.4" apparent diameter and 39% illuminated.

The third sighting of the second elongation for 2021 was on March 3, 2021 from Swede Run in Moorestown, NJ, under a clear sky without any clouds along the eastern horizon. Mercury was initially sighted with 8x42 binoculars at 5:40 am EST, after first picking up brighter Jupiter, a little more than a degree below-left of Mercury. I then shifted the binocular view 7 to the right and up a little to find Saturn. Once found in the 8x42s, I was able to spot them with unaided eyes, and I was still able to see them through the windshield in brightening twilight at 5:55 am when I pulled out of my parking space. Astronomical twilight started at 5:00 am and sunrise would be at 6:30 am. In the meantime, I walked away from the car to get a better viewing angle and was able to see Denebola with unaided eyes towards the west. From there, I was able to spot the asteroid, (4) Vesta, with the 8x42s. When first sighted, Mercury was at 3.2 altitude, magnitude +0.2, 7.5" apparent diameter and 52% illuminated.

The fourth sighting of the second elongation for 2021 was on March 4, 2021 from Swede Run in Moorestown, NJ, under a clear sky with distinct haze along the eastern horizon. Mercury and Jupiter were initially sighted with 15x56 binoculars at 5:44 am EST, just 40 arc minutes apart. I then shifted the binocular view about 8 up and to the right to find Saturn. Once found in the binoculars, I was able to spot the three planets with unaided eyes, but with difficulty due to the haze. Astronomical twilight started at 4:59 am and sunrise would be at 6:29 am. I was also able to see Denebola with unaided eyes towards the west, and from there, I was able to spot the asteroid, (4) Vesta, with the 15x56s. When first sighted, Mercury was at 4.0 altitude, magnitude +0.2, 7.4" apparent diameter and 53% illuminated.

The fifth sighting of the second elongation for 2021 was on March 5, 2021 from Swede Run in Moorestown, NJ, under a clear sky. Mercury and Jupiter were initially sighted 8x42 binoculars at 5:44 am EST, just 21 arc minutes apart after their conjunction at 2 am. I then shifted the binocular view about 8 up and to the right to find Saturn. Once found in the binoculars, I was able to spot the three planets with unaided eyes, but with some difficulty due brightening twilight. Astronomical twilight started at 4:57 am and sunrise would be at 6:27 am. Just before that, I was able to spot the asteroid, (4) Vesta, with the 8x42s. When first sighted, Mercury was at 1.5 altitude, magnitude +0.2, 7.2" apparent diameter and 55% illuminated.


Jupiter and Mercury on March 5, 2021, at 5:39 am EST


The sixth sighting of the second elongation for 2021
was on March 20, 2021 from Swede Run in Moorestown, NJ, under a clear sky. I didn't plan any more observations this elongation, but was prompted to do so by Sky & Telescope's weekly planet roundup issued March 19, 2021, that said "Mercury had sunk out of sight into the glow of sunrise." I checked SkyTools and spotting Mercury seemed quite plausible on the morning of March 20 (see this page). As soon as I arrived at 6:32 am EDT (about an hour after the Vernal Equinox), I spotted Jupiter with unaided eyes in a somewhat bright blue twilight sky. Then i got out my 15x56 binoculars, and gliding up and to the right of Jupiter, I found Saturn. Both were identifiable in the 15x56s, Jupiter a definite disc and Saturn a smaller, but elongated shape due to the rings. Then moving below -left of Jupiter with the binoculars, I found Mercury at 6:35 am in brightish orange-white twilight just above the distant tree tops. Mercury was star-like and required some effort to pick out. Neither Mercury nor Saturn were seen with unaided eyes. Astronomical twilight started at 5:32 am and sunrise would be at 7:03 am. When first sighted, Mercury was at 3.0 altitude, magnitude -0.1, 5.9" apparent diameter and 74% illuminated.

 

Elongation #1

The first sighting of the first elongation for 2021 (the 64th elongation in a row overall) was on January 7, 2021 from Swede Run in Moorestown, NJ, under a clear sky (with just a few wispy clouds along the western horizon). Using bright Jupiter as a starting point, Mercury was initially sighted at 5:13 pm EST in moderately bright twilight with 8x42 binoculars (sunset was at 4:51 pm). At the time, Mercury was magnitude -0.9 and 3.9 altitude (about 5 from Jupiter at the 5:30 o'clock position).

Jupiter was was initially spotted at 5:12 pm with the 8x42s, then seen immediately with unaided eyes. Saturn was spotted with the 8x42s at 5:14 pm, about 2 from Jupiter at the 5 o'clock position. Subsequently, all three of these planets, Mercury, Jupiter and Saturn, were seen simultaneously in the 9 field of the 8x42s, but neither Mercury or Saturn could be seen with unaided eyes. Around 5:25 pm, I remembered to look up at Mars, which by then, was easy to see with unaided eyes in a darkening sky. Using Mars as guide as twilight deepened further, I found Uranus in the 8x42s about 5:35 pm, then a few minutes later using Fomalhaut as a starting point, I found Neptune with the 8x42s (so six planets in half an hour). At the other end of the night of January 7/8, I was  back at Swede Run before sunrise (7:22 am) and spotted Venus with unaided eyes at 6:25 am. When I arrived back at home before 7 am, I could see Venus with unaided eyes in the gap between houses across the street. So, all seven major planets (plus earth of course) were seen overnight.

In the interim, I stepped out front and spotted the minor planet, or asteroid, (4) Vesta with the 8x42s at 1:30 am on January 8 (then confirmed with my 16x70s). Vesta has brightened to magnitude 7.5 (a tad brighter than Neptune at magnitude 7.9) and will reach magnitude 6.0 (per the USNO's MICA software, 6.2 per SkyTools) at opposition on March 4, 2020.

The second sighting of the first elongation for 2021 was on January 10, 2021 from Swede Run in Moorestown, NJ, under a clear sky. Jupiter, Mercury and Saturn formed a compact triangle about 2 on each side. Mercury was at the lower-left vertex as shown the snapshot below, taken at 5:37 pm with a Canon EOS RP digital camera and a 200 mm lens on a fixed tripod. It was cropped to 64% from the original linear dimensions for a field 6.6 wide x 4.4 high. All three planets were seen with 8x42 binoculars; magnitude -2.0 Jupiter was visible with unaided eyes, magnitude -0.9 Mercury was glimpsed with unaided eyes and magnitude +0.6 Saturn was never seen with unaided eyes.


Jupiter, Mercury and Saturn on January 10, 2021, at 5:37 pm EST


The third sighting of the first elongation for 2021
was on January 12, 2021 from Swede Run in Moorestown, NJ, under a clear sky, but with distinct murkiness along the western horizon up to about 10 altitude. Mercury was now higher than Jupiter, and both were first spotted with 8x42 binoculars (in the same field) at 5:13 pm EST. I continued to observe until 5:30 pm, and neither was seen with unaided eyes, and nearby Saturn (lowest of the three) was not seen with unaided eyes or the 8x42s. All three of these planets remained at the same magnitude they were on January 7, 2021.

The fourth sighting of the first elongation for 2021 was on January 13, 2021 from Swede Run in Moorestown, NJ, under a clear sky, but with some murkiness along the western horizon. The evening's main objective was to spot a very young moon (17 hr old at 5 pm EST), which would have been difficult enough with clear skies, but with the murky horizon, virtually impossible. The extremely thin crescent (0.6% illuminated) was not seen using 15x56 binoculars on a monopod. However, with the 15x56s, Jupiter, 5 above the moon at 7 altitude, was spotted at 5:07 pm EST, while Mercury, about 3 from Jupiter at the 10 o'clock position, was spotted at 5:08 pm; both were followed until about 5:30 pm. Jupiter and Mercury were still at magnitude -2.0 and -0.9 respectively. Saturn, about 2 from Jupiter at the 5 o'clock position and magnitude +0.6 was not seen in the 15x56s, and none of the three planets was seen with unaided eyes. We are reaching the end of Saturn and Jupiter's visibility for this apparition; they will reach solar conjunction on January 23 and 28 (EST) respectively.

The fifth sighting of the first elongation for 2021 was on January 19, 2021 from the baseball field complex in Maple Shade, NJ, under a clear sky, which was also generally clear along the western horizon. Mercury was initially sighted at 5:27 pm EST (sunset at 5:04 pm) with 8x42 binoculars when it was at 10.5 altitude and magnitude -0.8. It was then seen with difficulty using unaided eyes at 5:29 pm. By 5:40 pm, it was no longer difficult to see with unaided eyes and at 5:45 pm, it was almost obvious in the deepening twilight. Saturn and Jupiter, 9 to 11 below Mercury, were never seen, even with binoculars they're getting too close to the sun now as they approach conjunction.

While there, I also looked for several other planets. Magnitude +0.2 Mars, about 18 east the nearly first-quarter Moon, was easy with unaided eyes at 5:31 pm. Magnitude +5.8 Uranus was picked up with the 8x42s at 5:48 pm, just 1.7 to the southeast of Mars (so they were easily in the same binocular field, even with the 15x56s). Mars and Uranus will be at conjunction in geocentric right ascension on January 21 at 19 hr EST, but their appulse (closest apparent approach) will be on January 20 at 13 hr, 1.6 apart. In any case, finding Uranus with binoculars is pretty easy now using Mars as a guide. Finally, I spotted a faint pinprick of magnitude +7.9 Neptune at 5:59 pm with the 15x56s. I had a rough idea of where it was about 1.5 east of Phi Aquarii, somewhere between a pair of sixth magnitude stars that formed an isosceles triangle with Phi Aqr. I noticed the pinprick using averted vision, then checked that location against a SkySafari chart and it matched.

 

________________

 

The current streak is now 69 elongations in a row in my eleventh calendar year of Mercury elongation sightings (beginning in January 2011). There are six or seven elongations per year. The years 2011, 2015 and 2018 each had seven (7) elongations, while 2012, 2013, 2014, 2016, 2017, 2019, 2020 each had six (6). 2021 will have six (6). Click here for sightings in 2020. The purpose of this ongoing effort is not to set some sort of record, especially since I have no idea what sort of record might exist, but to demonstrate that locating and seeing Mercury is not nearly as difficult as many suppose. It just takes some planning and a little effort, although circumstances make some elongations easy and some difficult.

 

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Last Update: Monday, October 18, 2021 at 02:35 PM Eastern Time