Last updated: August 12, 2018

This page will list all the comets that I am currently observing, in west-to-east order from low in the western evening sky to low in the eastern morning sky. It will provide brief information about a comet's location, motion, and current brightness at the time of the update, as well as, when appropriate, notes about potential future activity. The page will also list any asteroidal objects I am following that might potentially be comets, and for the benefit of comet observers in the southern hemisphere it will also list those comets (and other objects) that are bright enough for observation but that are not accessible from the northern hemisphere. Comets (and other objects) that are expected to be 9th magnitude or brighter (and that are also easily accessible for observation) at the time of the given update will be highlighted in red print. Orbital elements and ephemerides for the comets and other objects listed here can be obtained via the Minor Planet Center's Ephemeris service or via JPL Horizons. I expect to update this page on approximately a weekly basis.


Comet NEOWISE C/2018 N1 (no. 648)

My tally's most recent addition appeared as a large, vague, diffuse 10th-magnitude object when I last saw it a few nights ago, however it is now rapidly receding from both the sun and the earth, and I expect it to fade fairly quickly during the coming few weeks, likely beyond visual detectability by the end of this month. It is presently located in eastern Libra one degree southwest of the star Theta Librae; it is traveling towards the northwest, currently at 75 arcminutes per day but slowing down to 15 arcminutes per day by month's end; it passes almost directly over Gamma Librae on August 16 and at the end of August will be located a little over one degree southwest of Beta Librae.

Comet ATLAS C/2017 M4 (no. 644)

Now almost two months past opposition, this distant comet is currently located in western Hercules three degrees southwest of the star Zeta Herculis and is traveling towards the south-southwest at approximately half a degree per day. It has appeared as a small, condensed object of 14th magnitude ever since I first picked it up in early June, and I expect little, if any, change in brightness over the next few weeks.

Comet 48P/Johnson (no. 646)

I have not had an opportunity to observe this comet for some time, although I hope to do so soon; meanwhile, reports from other observers indicate that its present brightness is around 13th magnitude, perhaps slightly brighter, which is about what I would expect. It is currently passing through perihelion, and is located a little over four degrees north of the star Epsilon Piscis Austrini; it is traveling towards the southwest at slightly under 15 arcminutes per day and crosses into northeastern Piscis Austrinus on August 18. Since the comet is nearest Earth (1.014 AU) on August 21 and is at opposition about a week later, it is probably close to its peak brightness, and I don't expect much change over the next few weeks.

Comet 29P/Schwassmann-Wachmann 1 (no. 498)

This distant comet underwent a small outburst at the end of July, and I was able to observe it a few mornings ago as a vague and diffuse object of 14th magnitude. It is presently located in western Pisces two degrees southwest of the star Gamma Piscium (in the "circlet" of that constellation) and is traveling slightly southward of due west at just over five arcminutes per day as it approaches opposition in early September. I expect the current outburst to fade and diffuse out over the next couple of weeks, but as is always possible with this comet, new -- and potentially stronger -- outbursts can occur at any time.

Comet P/Scheila P/(596) (no. 624)

I have not had a chance to observe this object in some time, but in the absence of any reports to the contrary -- and I don't expect any -- I presume that it is behaving in accordance with ephemeris predictions. It is currently located in south-central Cetus some two degrees south of the stars Phi-3 and Phi-4 Ceti and, having just passed through its stationary point a few days ago, is traveling slowly towards the southwest at five arcminutes per day. It should presently be around 14th magnitude and should brighten by about a half-magnitude by the time it goes through opposition near the end of September.

Comet 21P/Giacobini-Zinner (no. 642)

This comet has developed nicely over the past few weeks, being visible in binoculars as a relatively condensed object of magnitude 8 1/2 and telescopically exhibiting a broad dust tail several arcminutes long when I last observed it a few nights ago. It is currently located in central Cassiopeia 2 1/2 degrees north of the star Epsilon Cassiopeiae (the easternmost star of the "W") and, having passed its farthest north point (declination +66 1/2 degrees) a few days ago, is now traveling towards the east-southeast (gradually turning more and more towards the south), presently at a little over one degree per day but increasing to somewhat over 1 1/2 degrees per day by the latter part of this month; it crosses into western Camelopardalis on August 16 and spends most of the rest of the month traversing through the southern reaches of that constellation. I expect the comet to continue brightening, to at least 8th magnitude and possibly close to 7th magnitude, by the latter part of August, and I also expect continued development of the tail.



Comet PANSTARRS C/2016 M1 (no. 629)

This intrinsically bright but relatively distant comet just passed through perihelion a couple of days ago. It is currently located in northern Circinus four degrees northeast of the star Alpha Centauri and is traveling (through rich Milky Way star fields) towards the west-southwest at approximately 15 arcminutes per day, crossing into southeastern Centaurus on August 20. Reports I've read from observers in the southern hemisphere indicate that the comet's brightness is still around 9th magnitude, but since it is now receding from both the sun and the earth I suspect that it may begin fading soon.

Comet 364P/PANSTARRS P/2018 A2 (no. 643)

According to reports from observers in the southern hemisphere, this comet apparently became as bright as 11th or 12th magnitude around the time it was close to Earth last month, although it has apparently faded by about a magnitude since that time. It is currently located in southeastern Fornax 1 1/2 degrees west-northwest of the star Chi-1 Fornacis (and two degrees north-northwest of the bright galaxy NGC 1316 ("Fornax A")) and, being right at its farthest south point, is now traveling just northward of due west at 75 arcminutes per day; it passes 2 1/2 degrees south of the star Beta Fornacis on August 17 and less than 20 arcminutes south of the Fornax Dwarf Galaxy one day later. The comet is now becoming accessible again from my latitude and I am cautiously optimistic about picking it up again soon; it should continue fading but should still be around 13th magnitude for at least another couple of weeks.

Comet ATLAS C/2017 T3 [not observed]

I discuss this comet on my "notable upcoming comets" page. It became accessible to observers in the southern hemisphere in late June, albeit at a fairly small elongation, and in fact it has remained at a small elongation throughout its period of visibility; this reaches a maximum of just under 43 degrees in one week before decreasing to 36 degrees by the end of this month. The comet is currently located in eastern Pyxis two degrees north of the star Lambda Pyxidis and is traveling towards the east-southeast at a little over 1 1/2 degrees per day; it is presently crossing into northwestern Antlia and passes 15 arcminutes south of the star Theta Antliae on August 14 before crossing into western Hydra on the 23rd. Reports from observers in the southern hemisphere have indicated a brightness between magnitudes 9 1/2 and 10 ever since it became visible and it still is apparently close to that; however since it is now receding from the sun (perihelion being on July 19, at 0.83 AU) and also from the earth (minimum distance 1.35 AU, on August 1) it should begin fading within the not-too-distant future.


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