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)
Oct. 19, Observations of 4P, 8P, 29P and 67P. New APASS file for October/November.
Oct. 11, Observations of C/2017 K2, C/2019 F1, C/2019 L3, C/2019 T4, C/2020 F5, C/2020 T2, 4P, 6P, 8P, 15P, 19P, 29P, 67P, 132P and 246P .
Sep. 20, Observations of C/2019 F1, C/2019 L3, C/2020 F5, 4P, 7P, 8P, 19P, 29P, 67P and 284P. New APASS file for September/October.

SQM-L sky brightness measurements at our observing sites. Click here.
Visually observable comets
CometMvTrendChartscovered by APASS file
C/2017 K2 (PANSTARRS)12-13brighteningnoyes
C/2019 F1 (ATLAS-Africano)14-15fadingnoyes
C/2019 L3 (ATLAS)10-11brighteningnoyes
C/2019 T4 (ATLAS)13-14brighteningnoyes
C/2020 F5 (MASTER)15fadingnoyes
C/2020 PV6 (PANSTARRS)14-15fadingnoyes
C/2020 T2 (Palomar)12-13fadingnoyes
C/2021 A1 (ATLAS)11-12brighteningnoyes
4P/Faye11-12near maximumnoyes
6P/d'Arrest11-12near maximumnoyes
29P/Schwassmann-Wachmann 110-11bright outburstnoyes
57P/du Toit-Neujmin-Delporte11-12outburstnoyes
104P/Kowal 215?brighteningnoyes
110P/Hartley 314-15brighteningnoyes
132P/Helin-Roman-Alu 214near maximumnoyes
284P/McNaught14-15near maximumnoyes
NEW! October 19, a new file with comparison stars from APASS in the magnitude 10-15 range is available for the October/November 2021 moonless period.

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.

Click here for older news items.

update 19-10-2021