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... Reinder J. Bouma Edwin van Dijk

Minor planet 9706 on August 17, 2002 in NEAT images.

Recent updates (over the last month)
Jan. 16, Observations of C/2017 K2, C/2019 L3, C/2021 A1 and 67P. New APASS file for January/February. New charts for 19P.
Jan.  6, Observations of C/2019 L3, C/2019 T4, C/2021 A1, 4P, 6P, 19P, 29P, 67P and 104P.
Jan.  3, Observations of C/2019 L3, C/2019 T4, C/2021 A1, 19P, 67P and 104P. Image of C/2021 A1 near perihelion.
Dec. 31, Observations of C/2019 L3, C/2021 A1, 4P, 6P, 19P, 29P, 67P and 104P.
Dec. 27, Observations of C/2019 L3, C/2021 A1, 4P, 6P, 19P, 67P and 104P.
Dec. 24, Observations of C/2019 L3, C/2021 A1, 4P and 67P. New chart for C/2021 A1.
Dec. 19, Observations of C/2021 A1. New APASS file for December/January. Charts for 19P.


SQM-L sky brightness measurements at our observing sites. Click here.


Visually observable comets
Comet
Mv
Trend
Charts
covered by APASS file
C/2017 K2 (PANSTARRS)
12
brightening
no
yes
C/2019 L3 (ATLAS)
9-10
near maximum
no
yes
C/2019 T4 (ATLAS)
13
brightening
no
yes
C/2020 J1 (SONEAR)
14-15
near maximum
no
yes
C/2020 V2 (ZTF)
14-15
brightening
no
yes
C/2020 Y2 (ATLAS)
14-15
brightening
no
no
C/2021 A1 (Leonard)
6-7
fading
yes
no
A/2021 F1 
14-15?
brightening
no
yes
C/2021 O3 (PANSTARRS)
14-15?
brightening
no
yes
4P/Faye
12
fading
no
yes
6P/d'Arrest
11-12
fading
no
yes
9P/Tempel 1
12
brightening
no
yes
19P/Borrelly
9
near maximum
yes
no
22P/Kopff
11-12
brightening
no
yes
29P/Schwassmann-Wachmann 1
-
regular outbursts
no
yes
67P/Churyumov-Gerasimenko
10
fading
no
yes
104P/Kowal 2
10
near maximum
no
yes
110P/Hartley 3
14-15
near maximum
no
yes
116P/Wild 4
14
brightening
no
yes
117P/Helin-Roman-Alu 1
14-15
brightening
no
yes

NEW! January 16, an updated file with comparison stars from APASS in the magnitude 10-15 range is available for the January/February
        moonless period.


Comet C/2021 A1 (Leonard) at perihelion

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]


Bright comet C/2020 F3 (NEOWISE)!

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.

A full version of this image including observing details can be viewed by clicking here.
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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