Astroblog

View of the Northern Sky as seen from Adelaide at astronomical twilight(90 minutes before Sunrise) on August 11 showing the location of comet 220P McNaught (red cross). Similar views will be seen elsewhere in Australia 90 minutes before sunrise.  The location of the asteroid Ceres and Mars are also shown as Ceres is within a binocular field of Mars. Click to embiggen	Binocular view of Cetus as seen from Adelaide at astronomical twilight (90 minutes before Sunrise) on August 11 showing the location of comet 220P McNaught (red cross). The location of the Guide Stars μ Ceti and Menkat (λ Ceti) are shown for comparison with the black and while charts. Similar views will be seen elsewhere in Australia 90 minutes before sunrise. Click to embiggen

Comet 220P McNaught should have been a barely visible telescopic object but it has undergone two large outbursts, soaring from magnitude 18 to now roughly magnitude 7, a nearly 7000 fold increase in brightness. Of course, while this is "bright" in astronomical terms, you will still need binoculars or a small telescope to see it. 

It will only stay binocular bright for a short time, so you should look in  the next few days .The bad news is that it is only visible in the morning. The good news is that it is quite high just before Astronomical twilight, and the moon is trending to New, so it should be easy to pick up in binoculars. 

The other good news is that there are good guide stars, μ Ceti and λ Ceti (Menkar), just below the bright star α Ceti (also called confusingly Menkar) in the loop of Cetus, See the charts below.

As a bonus, the asteroid Ceres is close to Mars. although at magnitude 9 it will be more of a tough catch.

Black and white view of the Northern Sky as seen from Adelaide at astronomical twilight(90 minutes before Sunrise) on August 11 showing the location and track of comet 220P McNaught. Similar views will be seen elsewhere in Australia 90 minutes before sunrise. The circle shows the field of View of 10x50 binoculars. The tracks of Asteroid Ceres and Mars are also shown as Ceres is within a binocular field of Mars

Black and white Binocular view of Cetus as seen from Adelaide at astronomical twilight (90 minutes before Sunrise) on August 11 showing the location and track of comet 220P McNaught. Similar views will be seen elsewhere in Australia 90 minutes before sunrise. The circle shows the field of View of 10x50 binoculars.

Downloadable printable B&W maps are at the links for the Spotters Map and the Binocular Map. 

Labels: binocular, comet

To be read in conjunction with the "Tangent" section of the astrophiz podcast #235
https://soundcloud.com/astrophiz/astrophiz-235-june-2026-sky-guide

 There is a video going around on that wretched hive of villainy and scum called twitter labelled “Comets are not what we’ve been told”.  It shows some very nice time lapses of bright comets with the caption ‘Watch how it moves in lockstep with the stars” …. And that’s it. That’s the argument. 

Now, many people think because bright comets with the luminous tails look “swooshy” they must move perceptibly, like meteors. So perhaps the the lack of perceptible movement meant the comets were something else due to their naive expectations .... hence the earth is flat for .. reasons.  But comets are exactly what we have been told (and the earth is not flat).

In a single night, when viewed from afar, most comets will not seem to move against the background stars, especially as the time window before they set is short. But through a telescope (or telescopic lens) you can see them move a bit. For C/2024 G3 and C/2025 R3 I had a roughly 20 minute window for imaging, so I wasn’t going to see much motion, but for C/20025 R3 I could compare my images with those by other astrophotographers in the Southern Hemisphere, and see for example, images taken a few hours previous in New Zealand showed the comet had move compared to my images.

And night after night they are against different stars as the follow their orbit. Comet C/2025 R3 was particularly lovely, not bright but drifting past the sword of Orion’s belt each night was memorable.  

Comet C/2025R3 and Orion on the 10th May. Can't really see the tail against the light pollution. My image, long exposure (left) vs stellarium.	Comet C/2025R3 and Orion on the 10th May as simulated in stellarium.. Compare with my image, long exposure on the right.

Comet C/2025R3 and Orion on the 11th May. Sort of got a stubby tail against the light pollution. My image, long exposure (left) vs stellarium.	Comet C/2025R3 and Orion on the 11th May as simulated in stellarium.. Compare with my image, long exposure on the right.

Comet C/2025 R3, at the time it was crossing Orion’s belt, was moving around 1 degree every 24 hours, slow compared to the moon, which moves ~13.2 degrees every 24 hours, but not too different from the movement Venus, which moves on Average ~1.2 degrees per day and fleet Mercury which moves on average ~1.3833 degrees per day (0.5 degrees is roughly the diameter of the moon, which moves approximately one lunar diameter per hour). Mars moves ~ 0.5242 degrees per day and Jupiter, Saturn and the rest much less. This is why Jupiter and Saturn seem to stay in roughly the same place night after night. This is complicated by retrograde motion, where earth overtakes the planets in their orbits. 

Mercury and Venus have a narrow window before they set to see them move in a single night. On the 20th and 21st you have about a 2 hour window to see Venus move against the background stars of the Beehive cluster, you do need a flat level horizon for this. (of course, day to day they move quite a bit with close approaches to other planets and stars over a matter of days).  

Western sky on the evening of Saturday, June 20 as seen from Adelaide at 18:11 ACST (60 minutes after sunset, click to embiggen).  Venus is at its closest to the Beehive Cluster (M44).	Binocular view Venus and the Beehive at 18:11 ACST	Binocular view Venus and the Beehive at 19:41 ACST. Venus has slightly, but perceptibly moved against the stars of the Beehive.

We tend not to notice the relatively rapid movement on the Moon during the night, not may people are out looking at the sky for hours on end. Only when the moon is close to a very bright star do we sometime take notice. 

On the 23rd you can follow the waxing Moon as it comes closer to the bright star Spica, in binoculars you will be able to see it come close to the star 49 Virginis over the span of a few hours. Of course on the 28th, in the early Morning you can watch the moon occult (or graze) Antares. 

The Moon at the evening of Tuesday, June 21 as seen from Adelaide at 18:12 ACST (60 minutes after sunset, click to embiggen). The Moon is close to the bright star Spica	The Moon as seen through binoculars  at 18:12 ACST (60 minutes after sunset, click to embiggen). The Moon is near the star 49 Virginis	The Moon as seen through binoculars  at 22:00 ACST. The Moon is now beside the star 49 Virginis and visibly closer to Spica.

Labels: Astrophiz, comet, Moon.

 

Comet C/2025 R3 captured from Caufield Australia by Con Stoitsis ©, May 4th. 
 

Comet C/2025 R3 (PANSTARRS) has been recovered in the Southern Hemisphere and Australasia by multiple observers. Magnitude seems to be in the order of 5 or so. Although this makes it theoretically dark sky visible to the unaided eye, most observers will find binoculars or a small telescope best.

The comet is now climbing into darker skies and will be visible when the sky is full dark. I have been able to detect it in 10x50 binocular at nautical twilight, so it should remain visible when it gets fully dark for several days, especially as the  moon wanes.

Of course this cloud permitting. Which it hasn't been.

While there has been outstanding images of the comet (see here and here) they are all long exposures, though binoculars it will look like a small fuzzy ball with a stubby tail

I finally got Comet C/2025 R3 after days of rain and cloud. It was still cloudy, but there were gaps that let me catch it in binoculars. Its the fuzzy dot roughly in the centre above the line of three stars. My long exposure got photobombed by clouds so I'm not presenting it. Under difficult conditions with twilight and drifting clouds interfering I estimated maybe magnitude 5.5? 

Comet C/2025 R3, 4May, 2026 at 18:39 ACST as captured with my Samsung S24, 5x zoom, ISO 3200 and 2 seconds exposure from Largs Bay. The small unprepossessing fuzzy blob roughly in the centre is the comet, compare with the stellarium chart. t the right. Click to embigen	Stellarium chart of the comets position on 4May, 2026 at 18:39 ACST. Nestled between 48 and 57 Eridanus.

A printable B&W spotters chart and viewing guides are at my comet PANSTARRS page  

https://astroblogger.blogspot.com/2026/04/c2025-r3-panstars-how-to-see-it-from.html 

 

 

 

 

 

 

Labels: binocular, C/2025 R3, comet

Western sky on Thursday, April 30  as seen from Adelaide at 18:30 ACST (60 minutes after sunset, click to embiggen). Comet C/2025 R3 may be visible in the twilight. Similar views will be seen from the rest of Australia at roughly the equivalent local time  (60 minutes after sunset)	Path of Comet C/2025 R3 over the month. Similar views will be seen from the rest of Australia at roughly the equivalent local time  (60 minutes after sunset).	Approximate binocular view of Comet C/2025 R3 until May 4th. Similar views will be seen from the rest of Australia at roughly the equivalent local time  (60 minutes after sunset).

Labels: binocular, C/2025 R3, comet

Comet C/2026 A1 (MAPS) before heading into the oculting disk of the LASCO C3 imager	Comet C/2026 A1 (MAPS) debris plume exiting the oculting disk of the LASCO C3 imager
Comet C/2026 A1 (MAPS) before heading into the oculting disk of the LASCO C2 imager	Comet C/2026 A1 (MAPS) debris plume exiting the oculting disk of the LASCO C2 imager
Comet C/2026 A1 (MAPS) before heading into the oculting disk of the CCOR-1  imager	Comet C/2026 A1 (MAPS) debris plume exiting the oculting disk of the CCOR-1 imager

Comet C/2012 S1 (ISON) ISON on the 28/11/2013 before and after its encounter with the Sun.  

Comet C/2026 A1 (MAPS) did not survive perihelion, looking a lot like comet C/2012 S1 (ISON) as the debris cloud exited the occulting disks of SOHO Lasco C3, C3 and CCOR-1. 

The debris plume is a lot more rarefied than the more condensed ISON plume. But like ISOn we are unlikely to see a  C/2011 W3 (Lovejoy) style headless tail. 

 

 

 

 

 

 

 

GIF animation of C/2026 A1 (MAPS) heading into and debris exiting the C3 occulting disk	GIF animation of C/2026 A1 (MAPS) heading into and debris the C2 occulting disk

Labels: C/2026 A1, comet, Kreutz, sun grazer

UPDATE: The comet did not survive: https://astroblogger.blogspot.com/2026/04/upate-comet-c2026-a1-maps-did-not.html

Comet C/2026 A1 (MAPS) in the STEREO H1 imager on 30 March. It's the faint streak at the bottom far right.	Comet C/2026 A1 (MAPS) in the SOHO LASCO C3 instrument on the 3rd of April. the "T" shaped head is an imaging artifact.

 C/2026 A1 (MAPS) is a Kreutz family comet, one of a group of related comets that pass close to the sun. Everyone was very excited that it might become an extremely bright ("great") comet. However, it’s brightness increase stalled (everyone gasped) then started up again (everyone cheered), with what looked to be an eruption plume. As the comet neared the sun all eyes turned to solar monitoring satellites to follow its progress (and possible demise).

C/2026 A1 as seen in the GOES-19 CCOR1 instrument.

The comet has passed intact through the STEREO H1 imager (see above) and was in the field of view of the PUNCH (Polarimeter to Unify the Corona and Heliosphere) satellite, It had a magnitude of 6.5 and a tail extending more than 3 degrees. It has now passed into the field of view of SOHO and the CCOR1 chronograph. 

 In both these imagers the comet continues to survive and brighten. It is now around magnitude 2-1, bright but a bit dimmer than the sungrazers C/2012 S1 (ISON) and C/2011 W3 (Lovejoy). and not dissimilar to C/2012 E2 (SWAN). SWAN disintegrated before it reached the sun, ISON disintegrated on its pass by the sun, Lovejoy survived solar passage then broke up shortly after.

Currently the two most likely outcomes are that the comet disintegrates before it reaches the sun (like comet SWAN) or it breaks up after perihelion and forms a “headless” comet like C/2011 (W3) Lovejoy. In the latter case we may see a bright tail stretching up from the horizon as twilight fades. 

However, astronomer Pedro Rincon reports that MAPS is exhibiting "extremely high cohesion" and is "shedding thin layers from its volatile surface." This suggests there may be a possibility that the comet will survive perihelion. Fingers crossed it will survive after perihelion on the 4th.

If it does survive there is the possibility the comet head will be around -3 to -4 magnitude, (about as bright as Venus), but it will fade rapidly and may be difficult to distinguish against the twilight by the time it is above the horizon in Australia. 

Western sky on the evening of Tuesday, April 7 as seen from Adelaide at 18:28 ACST (30 minutes after sunset, click to embiggen). If it hasn't disintegrated,  Comet C/2026 A1 may be visible low in the twilight. 

C/2026 A1 perihelion is 4 April, the soonest we can see the comet head is probably the 6th or 7th depending on how bright it turns out to be. If there is a decent tail we should see it as the twilight fades, possibly as early at the 5th.

Look to the west, bright Venus will be your guide, the comet should be to the west and a bit below. As the twilight fades the comet and its tail may become more visible. As the days progress the comet gets higher, but it will also be dimming rapidly. 

Spotters chart for C/2026 A1 (MAPS) looking west from Adelaide at civil twilight (30 minutes after sunset) from the 7th. The circle is the field of view of 10x50 binoculars. Click to embiggen. Elsewhere in Australia will see a similar view at the equivalent local time (30 minutes after sunset).  

Click this link for a printable black and white spotters chart. 

We may see the tail in the late twilight, we may be in a C/2011 (W3) Lovejoy situation, where a bright, long headless tail was seen for a couple of days, or a C/2024 G3 Atlas situation, where a modest length but faint tail was visible in the late twilight for nearly a week, depending on how dusty the tail is.  Either would be good.

C/2024 G3 atlas seen on 24 January 2025 from Sandy Point Victoria in the late twilight. ƒ/2.4 15s exposure 7.9 mm ISO3200

 

Labels: C/2026 A1, comet, Kreutz, sun grazer

North-western sky on Tuesday, October 21 as seen from Adelaide at 21:05 ACDST (90 minutes after sunset, click to embiggen). Comet C/2025 R2 (Swan) is between the handle of the teapot of Sagittarius and the bright star Altair. The inset is the approximate binocular view of the comet at the time.	North-western sky on Sunday, October 26 as seen from Adelaide at 21:11 ACDST (90 minutes after sunset, click to embiggen). Comet C/2025 is close to the moderately bright star epsilon Aquarii not far from the obvious pair of alpha and beta Capricorni. The inset is the approximate binocular view of the comet at the time.	North-western sky on Wednesday, October 22 as seen from Adelaide at 21:05 ACST (90 minutes after sunset, click to embiggen). The track of the comet every three nights is shown the comet starts at aroun magnitude 6 and will slowly fade, and the waxing Moon will make it harder to see.

Comet C/2025 R2 (Swan) is is now at its brightest, around magnitude 6 (binoculars only), but it is well placed near some reasonably bright guide stars so it will be easy to find. It is currently a fuzzy disk in 10x50 binoculars. Although it is ~ magnitude 6, and theoretically visible to the unaided eye, it is still best in binoculars or a telescope. It has climbed high enough into dark skis to make spotting relatively easy.  

 The comet is now setting after midnight, so you have plenty of time to observe. at the beginning of the week the comet is between the handle of the teapot of Sagittarius and the obvious bright star Altair. Sart hopping along the line of brightish stars from the handle of the teapot towards the obvious bright star Altair should bring to the the comet. By the 24th it is just under the obvious part of stars alpha and beta Capricorni and within a binocular field of  alpha Capricorni. By the 26th it is within a binocular field of the moderately bright star epsilon Aquarii. On the 29th and 30th it is within a binocular field of the moderately bright star beta Aquarii. The on 2 November it s almost on to of the brightish star alpha Aquarii (see the printable charts below).

more information can be found at  https://www.aerith.net/comet/catalog/2025R2/2025R2.html see also https://www.minorplanetcenter.net/iau/MPEph/MPEph.html for an ephemeris (type C/2025 R2 in the ephemeris box).

Black and White printable chart of the western sky starting Tuesday, October 21 as seen from Adelaide at 21:05 ACDST (90 minutes after sunset, click to embiggen and print). The track of the comet over successive nights is shown (the comet starts around magnitude 6 and will fade over the month but still will be binocular visible).	Black and White printable chart suitable for binoculars of the comet for October 21 to October 24. (90 minutes after sunset, click to embiggen and print). Use in conjunction with the spotters chart.	Black and White printable chart suitable for binoculars of the comet for October 24 to October 30. (90 minutes after sunset, click to embiggen and print). Use in conjunction with the spotter chart.

Labels: binocular, C/2025 R2, comet

North-western sky on Tuesday, September 17 as seen from Adelaide at 19:35 ACST (90 minutes after sunset, click to embiggen). Comet C/2025 R2 (Swan) is just above Mars. The inset is the approximate binocular view of the comet at the time.	North-western sky on Saturday, September 20 as seen from Adelaide at 19:35 ACST (90 minutes after sunset, click to embiggen). Comet C/2025 R2 (Swan) is just above Mars. The inset is the approximate binocular view of the comet at the time.	North-western sky on Tuesday, September 17 as seen from Adelaide at 19:35 ACST (90 minutes after sunset, click to embiggen). The track of the comet over successive nights is shown (ignore the magnitudes, the comet is around magnitude 7).

Comet C/2025 R2 (Swan) is (very) recently discovered comet that is around magnitude 7 (binoculars only), but it is well placed near some very bright guide stars so it will be easy to find (especially Mars and Spica this week). it is currently a dim dot in 10x50 binoculars. It will brighten a bit as it climbs higher into the darker skies, but will not really reach visual magnitude. 

 For this week it is relatively low above the horizon, and sets an hour after astronomical twilight, so you have a narrow window to observe. https://www.aerith.net/comet/catalog/2025R2/2025R2.html see also https://www.minorplanetcenter.net/mpec/K25/K25RA2.html for an ephemeris. 

Black and White printable chart of the western sky starting Tuesday, September 17 as seen from Adelaide at 19:35 ACST (90 minutes after sunset, click to embiggen and print). The track of the comet over successive nights is shown (ignore the magnitudes, the comet is around magnitude 7).	Black and White printable chart suitable for binoculars of the comet for September 17 to September 23. (90 minutes after sunset, click to embiggen and print). Use in conjunction with the spotters chart.	Black and White printable chart suitable for binoculars of the comet for September 23 to September 30.(90 minutes after sunset, click to embiggen and print). Use in conjunction with the spotter chart.

Labels: binocular, C/2025 R2, comet