my recent diary
Mainly, I use
the following materials since the end of October, 2018.
Telescope: D: 45.5cm f: 2037mm
Dobsomian (Newtonian reflector)
Eyepiece: and magnification: Lavendura
63mm, apparent FOV 45 deg. with Paracorr
x37, actual FOV 1.2 deg.
Night Vison: ACT
PVS-14 Photonis 4G INTENS 1800 Auto gate P45 WP
Tuesday, February 27
I comet searched four times this month. I pick up impressive
observation out of them.
Thursday, February 8
Moonless night with air temperature of −2ºC. It was very cold when the
wind blew. The Milky Way rising above the eastern horizon was bright
enough to take it for clouds.
I observed 62P Tsuchinshan 1 prior to the comet hunting session. I
estimated the comet as the magnitude of 9th, the diameter of 5’, the
degree of concentration (DC) = 4, and the tail length of 5’ using a glass
eyepiece, 78x, while the comet looked mag. 11th, dia. 4’, DC = 3, tail
length 2’ using Night Vision (NV). It was reconfirmed that this comet is
exception of my empirical rule that short-periodic comets look brighter
with NV. C/2021 S3 PanSTARRS was observed as follows: mag. 10th, dia. 2’,
DC = 5, tail length 2’ using glass eyepiece, while mag. 9th, dia. 2’, DC =
7, tail length 2’ using NV. Regarding this comet, NV had a better
visibility in comparison with the glass eyepiece.
The southeastern sky at the end of the hunting session. A comet at the
center slightly right is C/2021 S3 PanSTARRS. SkySafari 7 Pro.
Moon rose up to 1º above the southeastern horizon at 6:00 local time.
SkySafari 7 Pro.
I searched the sky using the glass eyepiece with 78x. I started to sweep
the sky from M10, a globular cluster in the constellation of Ophiuchus at
4:44am local time, and ended at 6am when M11, an open cluster in Scutum,
entered the field of view (FOV). When I finished the session, I was
impressed by a beautiful scenery: a thin moon and Venus shinning in the
low southeastern sky.
Monday, February 13
Moonless night with good transparency. The air was warm with the
temperature of 1ºC. I could spot M13 rose as high as 55º above the horizon
with naked eyes in direct vision. Before starting the comet hunting
session, I observed Omega Centauri. The cluster looked bright and powerful
using NV as usual, but tonight it was fine and beautiful using the glass
I began sweeping the sky fromπ Scorpii using the glass eyepiece with 78x.
I identified 18 globular clusters in total including M4, M 80, and
NGC6144, and several open clusters. During the session, C/2021 S3 PanSTRRS
came into the FOV. M9 was seen in the same FOV. Rising to the altitude of
27º, the comet had a fine tail. I estimated it as 9th mag. dia. 6’, and
the tail length of 6’.
Saturday, February 17
Moonless night, air temperature of 0ºC with light breeze. I enjoyed
observing C/2023 A3 Tsuchinshan-ATLAS before starting the comet hunting
session. The comet was well concentrated and easy to observe. The
magnitude was 13th with the diameter of 0.5’, and DC = 3. I am looking
forward to seeing what the appearance will be in the future.
I tried observing the antennae of the Antennae Galaxies using NV, but it
was unsuccessful. It is said that the 60 cm telescope is required to
I began to searching from C/2021 S3 PanSTARRS located near the center of
the Milky Way using the glass eyepiece 97x. The summer showpieces, M8,
M20, M22, M16 and M17 came into the FOV, which are scattered in gorgeous
and countless stars, i.e. Large Sagittarius Star Cloud. The three parts of
the Trifid Nebula, M20, was clearly seen in spite of the low altitude of
only 14º above the horizon.
M23. The image is 1º wide.
The Digitized Sky Survey copyright © 1994
Usually, less impressive star cluster, M23, popped into the FOV with stars
shining powerfully like fireworks today!
As seeing was rather good, I could enjoy clear star image without swelling
regardless of the magnification of 97x. It was a comfortable session.
Monday, January 22
I have comet hunted 5 times this year. I described some impressive
observations among them.
Friday, January 5
I searched under the moonlight; the moon had just passed the last quarter.
I noticed Venus rose above the horizon at 4:37am local time. The altitude
was only 0.4º that meant the observation site has a good visibility to a
very low altitude.
I started comet hunting using Night Vision (NV) 37x from α Librae. The
first deep sky object I identified was NGC5634, a globular cluster in the
constellation of Virgo, and the second was NGC5812, a galaxy in Libera.
When I confirmed the galaxy with a digital map, SkySafari 7 Pro, it
displayed a comet in the same field of view (FOV). The comet turned out to
be C/2023 A3 Tsuchinshan-ATLAS! The comet is expected to become a great
comet in this fall. Even though it was under the moonlight, I thought I
could confirm the comet visually, because I knew Alan Hale, a discoverer
of C/1995 O1 Hale-Bopp, succeeded to observe it visually using a 41 cm
reflector on December 18, 2023, via comets-ml: https://groups.io/g/comets-ml
. I increased the gain of NV and I was sure to see the comet. It was 14th
magnitude with an apparent diameter of 0.2’ that looked like a planetary
nebula. I changed the eyepiece to the glass one, i.e. Ethos 17 mm, and the
image was the same as that of NV. I lasted the searching session hoping
that the comet would become great.
SkySafari 7 Pro displayed that C/2023 A3 Tsuchinshan-ATLS and NGC5812 were
in the same field of view. The circle represents the field of 1.1º.
Thursday, January 11
As always, I enjoyed observing some objects prior to the comet searching
session. I thought I would enjoy because both transparency and seeing were
I could spot C/2021 S3 PanSTARRS that was condensed easily at 4:41am,
although the comet was only 4º above the horizon. I felt it was firmly
discoverable during a hunting session. On the contrary, the comet was
difficult to observe using Ethos 21 mm 97x, as it was diffused, and it was
challenging to spot it during sweeping. The comet looked 11th magnitude
through both eyepieces, but there was significant difference in visibility
between the two.
Omega Centauri, a globular cluster that is the most beautiful in the sky,
rose as high as 6º in altitude. When I observe M13, the most beautiful
globular cluster in the northern hemisphere, I feel use of a glass
eyepiece is better than that of NV. The glass one allows a greater number
of stars visible in the cluster. In contrast, NV is always better for ω
Centauri. This time, ω Centauri looked dynamic with Ethos 21 mm, 97x.
However, using NV the cluster looked brighter and all the stars, which
must have consisted of hundreds, were on and off due to scintillation! I
have ever observed this object many times, but it appeared the most
impressive this time.
I spotted a couple of wonderful double stars during the session. One was β
Scorpii and another wasνScorpii. Those companions looked green and light
blue, respectively, and impressive. One can enjoy double stars only when
glass eyepieces were applied, because NV cannot reveal the color of stars.
Tuesday, January 16
I used NV as it was hazy at low altitude. I began to search from C2021 S3
PanSTARRS located at the constellation of Lupus. Between the comet and the
globular cluster M4 in Scorpius, there is no particular bright deep sky
objects except for NGC5897, a globular cluster in Libra. Contrary, there
are numerous globular clusters beyond M4, i.e. the east at the horizontal
coordinates. I encountered one of those globular clusters named 1636-283
(ESO 452-SC11) for the first time. The visual magnitude in SkySafari 7 Pro
is 12.0. The appearance using NV was a globular cluster without doubt and
I felt the magnitude indicated in SkySafari was appropriate. Nonetheless,
in the photo of DSS the object does not look like a globular cluster, and
there is no description in Guide 9. A scientific paper on the cluster
said, “one of the faintest and least studied stellar clusters of the Milky
Most globular clusters around the region beautifully resolve into stars
using NV. Among them I always feel M19 wonderful. Stars with pinpoint
image appeared tightly packed in spite of the low altitude of only 11º.
ESO 452-SC11. The image is 15’ in width.
The Digitized Sky Survey copyright © 1994
Both the glass eyepiece and NV have their features, and I can enjoy
observing each of them. I must say it is hard to decide which is better on
the potential of the comet discovery.
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