Welcome to Astrosite Groningen. On these pages you mainly find information, and a presentation of results, on a number of astronomical subjects that we find most interesting. Our main interests are comets and variable stars; therefore, emphasis will be on the various aspects of observing these objects (charts, observations, photographs). But we also plan to cover other topics, albeit only as an aside, such as eclipses, and atmospheric phenomena like aurora and noctilucent clouds, mainly by presenting a selection of our photographic results. We hope you enjoy this site. We always welcome comments, and suggestions for improvement. And feel free to contribute: observations, images, whatever you want to share... |
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Recent updates (over the last month) Nov. 14, Observations of C/2022 E2, C/2022 N2, C/2023 A3, C/2024 B1 and 487P. New charts for C/2023 A3. New APASS file for November/December. Nov. 7, Observations of C/2022 E2, C/2022 N2, C/2023 A3, C/2024 B1, 29P, 333P and 487P. New chart for C/2023 A3. Oct. 31, Observations of C/2022 E2, C/2023 A3, C/2024 B1 and C/2024 G3. Oct. 26, Observations of C/2023 A3. New chart for C/2023 A3. Oct. 25, Observations of C/2022 E2, C/2023 A3 and 13P. Oct. 17, New APASS file for October/November. Observations and images of C/2023 A3.
SQM-L sky brightness measurements at our observing sites. Click here.
NEW! November 14, a new file with comparison stars from APASS in the magnitude 10-15 range is available for the November/December moonless period.
Visually observable comets Comet Mv Trend Charts covered by APASS file C/2022 E2 (ATLAS) 12-13 near maximum no yes C/2022 N2 (PANSTARRS) 14-15 near maximum no yes C/2023 A3 (Tsuchinshan-ATLAS) 8-9 fading yes no C/2023 C2 (ATLAS) 14 fading no no C/2024 B1 (Lemmon) 13-14 fading no yes C/2024 G3 (ATLAS) 11 brightening, small elongation no no P/2024 M1 (ATLAS) 14-15 brightening no yes 29P/Schwassmann-Wachmann 1 12 fading from outburst no yes 37P/Forbes 14 fading no no 333P/LINEAR 12-13 brightening no yes 487P/Siding Spring 15 near maximum no no
Bright comet C/2023 A3 (Tsuchinshan-ATLAS) in the evening sky
This comet, after being briefly visible in de morning sky for southern observers as a 2nd magnitude comet with a long dust tail, has now become an evening object
best placed for northern hemisphere observers, with visibility improving every day now that the elongation is increasing again. But over the coming days the situation will improve further. After October 20 the comet can be observed in a dark sky near the end of evening twilight without lunar interference. Although the comet now is moving away from both the Earth and the Sun and gradually fading it is expected that it will still show a long dust tail, which under the best conditions may still be some 20 to 30 degrees long. By the time the Moon is starting to interfere again during the second week of November the show will be virtually over. Nevertheless observers with proper equipment will be able to follow this comet until the end of the year. By that time it probably will have faded to magnitude 10 or so and gradually disappear in evening twilight. On October 14 the Earth was predicted to pass the orbital plane of the comet, and the geometry was perfect for observation of an anti-tail.
Fortunately that day brought clear skies for us, albeit with considerable lunar interference.
The image at upper right was taken close to my observing site near Westerwijtwerd by Iris Veronique Mulder with a Canon EOS R10.
It is a 8s exposure at ISO400 with a 40mm f/5 lens taken at 18:07UT and is a good representation of the naked eye view. The close-up image at lower right was taken at the Aekingerzand near Wateren by Rik ter Horst at 18:05UT. It is a 3s exposure at ISO1600 using a Sony A7III camera equiped with a Canon 100mm f/2 lens, and is a good representation of the view in (larger) binoculars. Note the very faint anti-tail pointing at lower right opposite the main dust tail. A larger version of this image can be viewed by clicking here. [RJB17102024] |
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This comet, discovered a year ago as the first one of 2021 is passing perihelion today. Over the last couple of weeks it has developed into a very fine object in the evening sky, in particular for observers in the southern hemisphere. It is very active, producing modest brightness outburst every 4 days or so since the middle of december, and showing a spectacular tail in wide field images, unusual for a comet that never became brighter than about magnitude 3-4 in a dark sky. A good example is the image above which was taken less than 24 hours from perihelion by Michael Mattiazzo from SWAN Hill, NSW. Currently the comet is about magnitude 5 visually. It is expected to fade gradually over the coming weeks moving away from both the Earth and the Sun. [03-01-2022]
This comet, discovered on March 27 by the NEOWISE satellite as a magnitude 17 object, brightened to 7th magnitude for southern hemisphere observers before disappearing in evening twilight en route to perihelion on July 3 at slightly under 0.30 AU from the Sun. In the meantime it had become evident that this was an 'old' object, and there was good hope that northern hemisphere observers would see a naked eye comet near about magnitude 3 deep in morning twilight shortly after perihelion. So it was a pleasant surprise that C/2020 F3 actually emerged as a first magnitude object sporting a bright dust tail that rapidly grew longer and longer over the last week as the comet could be seen higher above the horizon in a darker sky. The (binned) image to the right was obtained on the early morning of July 12 by Martin Mobberley from Cockfield, Suffolk, UK and is a fair representation
of what visual observers were able to see around the same time. Over the coming weeks comet NEOWISE, now placed in the evening sky, will fade fairly rapidly after its closest approach to the Earth - the minimum distance was 0.692 AU around 23.0 July - moving south and becoming better placed for more southerly observers. |
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