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(Above) C/2023 A3 from China Sept 28th by Kai Yuan
Bright comet C/2023 A3 T-A reached perihelion on Sept 27th at a peak magnitude of +2.8. The comet has been well observed from the southern hemisphere where observers and photographers have been getting superb views of the promising visitor. With darker skies at those latitudes the comet has been standing out well for observation despite its low solar elongation. At the current time, Sept 30th, experienced comet observers are now saying the comet is mag +2.5 and easily visible with the naked eye, I've also just seen a very credible observation describing a 10 degree naked eye dust tail (20 full moon diameters), the consensus is the comet is already as good as or better than NEOWISE from 2020 while others describe it as the best comet they have seen since Lovejoy in 2011.
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C/2023 A3 from Gerald Rhemann Sept 30th from Namibia with ion tail
The comet is getting so distinct there have even been images captured using mobile phone cameras. Advanced imagers like Gerald Rhemann (above) are capturing breathtaking detail on CCD images with a broadening dust tail and now a long blue ion/plasma tail which is exhibiting kinks and knots due to interactions with the solar wind. The comet is becoming very impressive and the stage is now set for a promising show post-perihelion in mid October.
T-A is now visible from all latitudes however for the far N (UK/Ireland/Europe) it remains extremely low on the horizon and has barely been observed due to cloud or other inhibiting factors, however all that is about to change. The comet will get lost again in solar glare soon, then moves N, if forward scattering happens as forecast the comet could attain negative magnitudes and be visible in daylight beside the sun. By Oct 12th-19th the comet will emerge into the evening sky after sunset then climb into the bright twilight arch when it could be a significant object with a bright dust rich anti-tail. If the comet brightens as expected (remember comets are like cats) then we could have our best comet since Hale-Bopp in 1997. I will be doing regular updates as this event unfolds and I look forward to seeing it soon within the next two weeks.
Bright Sungrazing Comet!
As if all this wasn't exciting enough a new bright comet has been discovered which could put on a show during late Oct or early Nov. This comet is a sungrazer, perhaps a member of the Kreutz family which get extremely close to the sun during perihelion. If it can survive this encounter it might become a 'great comet' with a prominent search light beam tail above the horizon. We don't know yet which hemisphere is favoured and the orbit needs further refined, however the prospects are interesting. Could we have two significant comets within the same month?, two naked eye comets? two daylight comets?, we are living in a very exciting time.
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(Above) C/2023 A3 by Gerald Rhemann from Namibia
Comet C/2023 A3 Tsuchinshan-ATLAS (T-A) is here!. This is perhaps the most anticipated cometary visitor to visit our skies since it was discovered back on January 2023 and it's journey into the inner solar system has been fraught with suspense, anticipation, and excitement. This comet has the potential to be on par with comet NEOWISE from 2020 (it already is) and might even be the brightest comet in the northern hemisphere since Hale-Bopp in 1997. However its journey has been an emotional roller coaster ride with great uncertainty.
During Summer the comet's rate of brightening stalled leading some experts to think the comet would be a celestial damp squib, however others confidently announced the comet was breaking apart and would cease to exist in the near future and hence be a non event. None of these predictions came true so here's the latest. T-A has now emerged from solar conjunction during September and the good news is the comet is very healthy, bright, still intact, and looks stunning. Visual observers have been reporting the comet at mag +3 using binoculars with a tail 1.5 degrees in length, images show a bright dust tail at least 6 degrees in length with a developing anti-tail. Expert comet observes have also detected the comet with the naked eye as a fuzzy star with a short tail.
The comet is currently extremely low in the pre-dawn sky as I write this on Sept 26th, it can be found a few degrees above the E-SE horizon between Hydra and Sextans below Leo. Perihelion takes place on Sept 27th when the comet will peak at mag +2, then comet can be found close by to the right of the slender crescent moon before sunrise on Oct 1st. Then the comet dives back into solar glare for a few days and will be unobservable.
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(Above) Phase Angle and Forward Scattering from Sky & Telescope
Then the real show begins, as T-A passes close to the sun its phase angle with our star will cause a dramatic forward scattering affect greatly enhancing the comet's brightness due to sunlight back scattering light through the comet's dust tail and coma, and this comet is extremely dusty. With a phase angle of more than 170 degrees (greater than McNaught in 2007) the comet could brightened to negative magnitudes, forecast predications suggest a peak brighter than mag -4, or in other words as bright as planet Venus.
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(Above) The Oct 9th-10th period will present the greatest brightness surge.
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(Above) A daylight comet?
Between Oct 7th and 10th the comet may be seen in broad daylight close to our sun at high noon if your sky is clear and transparent. I expect many observations from trained observers who detect T-A through telescopes and binoculars (and cameras) around this time, actual naked eye sightings can't be ruled out. Then the comet moves above the sun and may be sighted after sunset from the northern hemisphere. During this time the comet gets closer to the Earth and begins to climb into the bright evening twilight when it may still be of negative magnitude.
Then the greatly anticipated evening apparition begins, even though the comet will be gradually fading as it moves away from the sun it will be climbing into darker twilight and better seen. If predictions come true we could be seeing a record breaking anti-tail spike pointing towards the sun for many degrees in length followed by a stubby classic dust tail. As the comet fades after mid Oct the dust tail and ion tails will lengthen so this could be the most photogenic stage for imagers, especially after Oct 19th then the full moon moves away from the evening sky.
What exactly we will see is anyone's guess, but for a short interval we could see our brightest comet in decades, will it reach 'great' status?, only time will tell. I will update again during October regarding the daytime potential with another update for the October evening spectacle. I wish you all clear skies for in my opinion could be one of the most exciting astronomical events in recent times.
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On September 13th 2024 a good CME hit generated a G3 class geomagnetic storm during daylight hours, but would it wait until darkness many hours into the future? with a Bz of -22 and KP7 things were looking good so several friends and I met near Beaghmore within the Sperrins. The aurora faded to a faint glow upon arrival and stayed that way for much of the night, we stuck it out for hours in the frost anyway. Then at 01.00 a glorious outburst happened with auroral rays reaching 60 degrees high with naked eye red and orange colours which we captured over the famous fairy tree in the area, what a photogenic treat this was. One page report with 9 images. - REPORT.
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September 4th 2024, dark moonless skies and Milky Way season lured was out on our first big night shoot since Summer. Paul Martin and I decided to meet up and do a return trip to Fanad Head in Co. Donegal, this would be our third night shoot in this area. We made it just in time for sunset and drone filming, then captured derelict fishing boats with twilight stars then made our way to Fanad. It was here where we witnessed a stunning Milky Way in truly dark skies with galactic dust clouds like mist among the stars combined with an explore around the old WWII observation posts. A faint aurora and green airglow also appeared for a great night under the stars. One page report with 17 images. - REPORT.
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August 11th 2024 brought a much welcomed thunderstorm outbreak when an elevated plume engaged with an active cold front producing hours of night time lightning. A rare event from Ireland which brought the entire Summer thunder drought to an end. I spent the entire night with Colleen Webb on Benbradagh and the back roads of the west watching hours of distant lightning, beautiful orange c-gs, glimpses of a planet conjunction, Perseid fireballs, a surprise aurora, the loudest thunder in a long time and a beautiful G2 aurora the following night. Despite much frustration and not getting the photo opps I wanted seeing all these phenomena at the same time was a very special experience. One page report with 14 images. - REPORT.
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On August 8th 2024 I headed out on a ship chasing adventure to catch an exceptional vessel called the MPI Adventure, a famous off-shore supply vessel and wind turbine installation ship. She was anchored on Drains Bay near Larne so I did the two hour drive and arrived on location during the late evening before sunset where I filmed her with my drone. This ship uses six 60m tall legs to jack herself up out of the water to undertake her operations with greater stability at off-shore wind farms making her an exceptional vessel. My last aerial flight took place in twilight with the MPI lit up with lights when she made for a spectacular scene on the tranquil bay. One page report with 12 images and 2 video clips. - REPORT.
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Solar maximum is a time when NLCs are expected to wane in activity with the prospects of a good display being a rare event. On June 25th/26th 2024 I walked outside to check the sky and was shocked to see a vast type 5 NLC display covering the NW to NE sky sectors and directly overhead. In a panic I drove to Lough Fea where I spent the night observing what I can only describe as an epic display which rivaled the best I had ever seen back in 2009. The NLCs exhibited insane structure in the form of large whirls, knots and herringbone waves all moving in real time while casting shadows on the ground and bathing my dog and I in eerie blue light. This was a spectacular experience and to make things more interesting scientists reckon the 2022 Hunga Tonga undersea volcano seeded the Mesosphere with water droplets causing this NLC storm. One page report with 23 images and 1 video clip. - REPORT.
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May 10th 2024 - Mega sunspot group unfurling six CMEs and a violent impact at 800km/sec with a Bz of -50, the result was the most severe geomagnetic storm since 2003 and we had perfect clear skies. I was located in a field at Beaghmore in Co. Tyrone beside the famous fairy tree alongside a television film crew. As twilight deepened a truly spectacular aurora manifested covering the entire sky 360 degrees. Pink, green, blue, crimson and purple rays and streamers astonished us while overhead a remarkable corona dominated the sky. This corona took on the forms of birds and even a giant Angel, the display washed most of the stars from the sky and even appeared on the southern horizon. I observed it all night long and obtained my finest astro time lapse of my life. This was easily within my top five aurora experiences ever and a night never to be forgotten! One page report with 34 images and 1 video clip. - REPORT.
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Astronomy is not the only subject I'm interested in, check out my N. Ireland Storm Chasing section and view the chase reports and images which detail not only storms but other phenomena such as a moonbows, noctilucent clouds, aurora displays and exciting nature related photo shoots.
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Martin McKenna
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