Each
month a summary of sunspot activity is written and forms part of a
report sent to the Solar Section of the British Astronomical
Association (BAA)
and to The
Astronomer. Follow
the links below to read a
page summary of
sunspot activity. The McIntosh Sunspot Group Classification is used for
sunspot group descriptions.
January
2020
Activity
increased slightly
through the presence of three groups including two from the new cycle. The first of these was an
Axx sunspot on the
SE quadrant at -35°/358° seen on the 4th (AR 2755). The next observation on
the 9th showed
another new cycle group, AR 2756, close to the NW limb at
20°N/18° of type Bxo
and comprising three sunspots. This
group was not seen on the following day – the disk was blank
as was also the
case on the 11th (when faculae was seen on the SW limb). No sunspots were present
on observations made
on the 18th, 19th and 21st. The
final
observation of the month, on the 28th, show an old cycle group, AR
2757, close
to the equator at 2°N/90° comprising a penumbral
sunspot of area 90 millionths.
Hydrogen Alpha:
The Sun was observed in Hα on four
days. On the 4th
two small prominences
were seen together with a region of plage associated with AR 2755. No features were seen on
the 12th, 18th or 19th.
February
2020
Only
one sunspot was seen during
the month – this was an Axx sunspot AR 2757 on the 1st close
to the western
limb. The other 12 observations spanning the 5th to 29th revealed blank
disks.
Hydrogen Alpha:
The Sun was observed in Hα on three
days. On the 1st
plage was seen
associated with AR 2757 while on the 8th a filament was seen in the
southern
hemisphere and on the 29th a filament was seen in the northern
hemisphere.
March
2020
Two
sunspot groups were seen
during the month. AR
2758 was seen on
the 8th and 9th at 30°S/230° as two small sunspots on
the 8th and a single
sunspot on the 9th (both type Axx).
No
drawings were made on the 7th or 10th.
The second group, AR 2759, was seen near the eastern
limb on the 31st at
26°N/255° as a single Axx sunspot – faculae
were seen following the sunspot. The
other 18 observations made throughout the
month including every day from the 21st to 30th were all blank.
Hydrogen Alpha:
Hα activity remained low although
a number of prominences were seen towards the end of the month (based
on 12
observations). On the 8th, plage was seen associated with AR 2758. For
the six
observations between the 21st and 26th only a small filament
were seen on the 23rd. On
the 29th two
small prominences were seen, one prominence on the 30th but three on
the 31st
together with plage associated with AR 2759.
April
2020
Activity
increased slightly
during the month through the appearance of four groups, one at the
beginning
and three at the end of the month. One of these was from the old cycle.
AR 2759,
first seen in March 31, continued its passage across the solar disk. On the 1st, 2nd, 3rd it
was of type Bxo at 27°N/261°
while it was last seen on the 4th as a single Axx sunspot near the
central
meridian. There were then blank disks until the 25th when AR 2760 was
seen at 8°S/306°
as an Axx sunspot – it had developed in the disk. It was of type Bxo on the
26th, Axx on the
27th and Bxo again on the 30th (no observations were made on the 28th
and
29th). AR 2761 at
17°S/329° of type Bxo
was seen near the central meridian on the 27th only.
On the 30th AR 2762 of type Axx was seen at
22°N/339°
near the western limb.
Hydrogen Alpha:
A
few prominences were seen during the month
based on 26 observations, including on the 1st with three prominences,
a spike prominence
on the 2nd, a small loop prominence on the 5th and small prominence on
the
15th, 16th and 17th. Plage was seen associated with AR 2759 on the 1st,
4th,
6th and 7th and with AR 2760 on the 26th, 27th and 30th. Small filaments were seen
on the 9th, 21st,
23rd and 25th.
May
2020
No
sunspots were observed during
the month from 30 observations (the only missed observation was on the
4th).
Hydrogen Alpha:
There
was some Hα activity during the month but
also some days without any activity (based on 17 observations). Plage
was seen
associated with AR 2760 on the 2nd. A particularly tall thin spike
prominence
was seen on the 10th on the NE limb.
A
striking elevated arch prominence was seen on the NW limb on the 24th
– there
appeared to be a gap between the lower part of the prominence and the
limb.
Smaller spike prominences were seen on the 2nd, 9th, 22nd, 28th and
31st. Small
filaments were seen on the 3rd, 6th and
29th.
June
2020
Three
groups were seen during the
month, two being from the new cycle. On the 1st only an Axx sunspot was
seen
near the north east limb at 33°N/163° (AR 2764). The disk was spotless on the
2nd. On the next
observations on the 5th a Cao
group was seen at 22°S/113° with an area of 140
millionths (AR 2765). The
follower had developed a penumbra by the 6th to become type Dso before
reverting to type Cso on the 7th. It remained of type Cso on the 8th
and 9th
but with the group past the central meridian, it became type Hsx on the
11th
with an area of 90 millionths. It was last seen on the 14th near the
eastern
limb of type Hrx with nearby faculae. No sunspots were seen for the
next 9
observations until the 26th when an Axx sunspot was seen nearing the
western
limb at 10°N/307° (no AR number). A spotless disk was
seen on the next day and
on the 28th and 29th.
Hydrogen Alpha:
There
was an increase in Hα activity during the
month especially associated with AR 2765. On the 1st and 2nd an
extensive
prominence was seen on the NW limb – on both occasions a gap
was seen between
the limb and the prominence. On the 1st further smaller prominences
were seen
further towards the south while on the 2nd plage was seen associated
with AR
2764. On the 6th and 7th two areas of filaments were seen –
one around AR 2765
and the other further towards the south. Plage was seen within the
filaments of
AR 2765 on both dates. On the 13th and 14th plage was seen associated
with AR 2765.
On the 18th a ‘cloud’ prominence was seen on the SW
limb as well as small
filaments in the northern hemisphere. Small filaments were seen on the
22nd and
23rd. Two prominences were seen on the 28th.
July
2020
As
in June, three groups were
seen during the month but all were from the new cycle. On the 1st only
an Axx
sunspot was seen near the south east limb at 23°S/141°
(no AR number). The
disk was spotless until the 21st when an
Hsx sunspot appeared on the south east limb, AR 2767, at
19°S/198°. On the 23rd
with the sunspot further onto the disk it had an area of 100 millionths
while
on the 26th a following sunspot appeared to make the group type Cao.
Thereafter
it became type Hax of a similar size and it was last seen on the 31st
approaching the western limb. On
the
29th an Axx sunspot was seen near the eastern limb at
25°N/112°, AR 2768. It
remained of this type on the next two days and there was an extensive
following
area of faculae.
Hydrogen Alpha:
Two small prominences were seen
on opposite limbs on the 1st and another small prominence was seen on
the
15th. A pillar
prominence was seen on
the SW limb on the 20th while another tall prominence was seen on the
SW limb
on the 29th. Filaments
were seen in the
northern hemisphere 6th, 7th, 11th and 12th and again on the 31st. Plage was associated with
AR 2767 on the
31st.
August
2020
AR
2767 at 18°S/198° seen during
the July continues its progression towards the western limb on the 1st
and 2nd,
still of type Hsx. On
the 1st only an
Axx sunspot was seen just past the central meridian and near the
equator at 3°N/143°
(no AR number). No
sunspots were seen on
the 3rd. On the
4th, a Cso group
appeared near the eastern limb at 23°N/24° –
this being AR 2770. The
following pore was present intermittently
as the group progressed across the disk. It obtained an area of 80
millionths
on the 8th when it was type Hax. On the 10th the penumbra has
disappeared to
leave two pores that were once the main sunspots umbra. Only one of
these was
present on the following two days and the group had disappeared by the
13th when
it would have still been on the limb.
On
the 13th the only group seen
was AR 2771 of type Bxo at 18°S/297° in the south-east
quadrant. Another blank
disk was seen on the next observation on the 17th. Another Bxo group
appeared
on the disk on the 18th – this being AR 2772 at 19/295 in the
north-west
quadrant. It was
seen on the next
observation on the 20th but not on the 21st.
There were then blank disks for the remainder of the
month.
Hydrogen Alpha:
Plage
was seen associated with AR 2770 for
observations on the 4th, 6th, 7th, 9th-11th.
Of particular interest was a B.6 flare seen within
AR 2770 on the 11th
from 17:00 – 17:20 UT. The maximum of the flare was at 16:59
UT and indeed the
flare was at its brightest at the start of the observing period and was
not
different in appearance to other plage within the group at the end of
the
observing period. Small
prominences and
filaments were seen on a few of the 15 observing days.
September
2020
From
24 observations made during
the month only one showed any sunspots.
This was on the 28th when a pair of nearby sunspots
of type Axx were
seen at 20°S/91° (no AR number).
Hydrogen Alpha:
Activity during the month
remained low. Small filaments were seen on some of the 16 observations
– for
example three were seen on the 2nd in the NW quadrant.
Small prominences were seen on most days
including the same prominence on the SE limb on the 20th, 21st and 22nd. Also on the 20th several
prominences were
seen on the NW limb. On the 24th, plage was seen near the eastern limb
associated with AR 2773 – this was also seen on the 28th and
29th. A smaller
region of plage was seen in the S hemisphere on the 28th and 29th.
October
2020
There
was a substantial increase
in activity during the latter half of the month through the appearance
of the
most complex group so far in cycle 25. Five new cycle groups were seen,
all
being the southern hemisphere.
The
first four observations of
the month on the 1st, 5th to 7th all showed blank disks. On 9th two groups were
seen either side of
the central meridian: AR 2774 at 23°S/309° of type Axx
and AR 2775 at 23°S/273°
of type Bxo. The
first of these groups
was not seen on the 10th while AR 2775 was still of the same type
before
becoming type Cro on the 11th when several sunspots were seen within
the
group. AR 2775 was
not seen on the 14th
– another blank disk observation although faculae was seen on
the east,
north-west and south-west limbs.
On
the 17th a Cao group was in
the south-east quadrant at 12°S/161°. On the 19th the
group, AR 2776, was near
the central meridian and a small number of followers were seen. These had disappeared by
the following day to
give an Hsx sunspot and AR 2776 remained of this type as it progressed
towards
the western limb – it had an area of 140 millionths on the
23rd and it was last
seen on the 25th. Also on the 25th a Bxo group appeared near the
central
meridian at 19°S/86°. By the following day, this group
– AR 2778 – developed
into a Dso group with several small penumbral sunspots throughout the
group. It
had an area of 140 millionths. Further development took place by the
19th when
substantial leading and following penumbral sunspots were seen and the
group
became type Dac with an area of 370 millionths. Only a single Hax
sunspot was
seen on the 31st when this group was close to the western limb. Also on
the
31st another group was seen to the north of AR 2778; this was AR 2779
of type
Bxo at 12°S/75°.
A
revised and more accurate
method is now being used to calculate sunspot areas. As described in
paper https://doi.org/10.1093/mnras/staa2007,
a pixel mask approach is now being used from scanned disk drawings
rather than
using a square grid overlay on the paper version of the drawings. The areas will now
generally be larger previously
measured and than those derived by NOAA (as also described in the
paper) and
more consistent with other professional sunspot area databases.
Hydrogen Alpha:
Prominences were seen on all 7
observations made during the month – the most spectacular
being a series of
nearby spike prominences on the 22nd near the E limb. A broken filament
was
seen in the NW on the 25th and 26th. Plage was seen in the NE quadrant
on the
1st (not associated with any group) and on the 25th around the Bxo
group AR
2778.
November
2020
December
2020
Page
created on 11 November 2020.
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