Astronomical Diary
MOON PHASES
newmoon fq fm
lq
New Moon First Quarter Full Moon Last Quarter
Sep 7
8:52 AM
Sep 14
4:39 AM
Sep 21
7:55 AM
Sep 29
9:57 AM
SPACE WEATHER
Current Condition
SOLAR WIND

Speed: 337.2 km/sec
Density: 15.4 protons/cm3
More Data: ACE, DSCOVR
Updated: Aug 31 at 1350 UT
***Sunspot AR2860 has a 'beta-gamma' magnetic field
that harbors energy for strong M-class solar flares.

Credit: Solar Dynamics Observatory(SDO)/
Helioseismic and Magnetic Imager (HMI).
X-ray Solar Flares
6-hr max: B3 1323 UT Aug31
24-hr: C3 2134 UT Aug30
Updated: Aug 31 at 1400 UT


Sun: 31 Aug 2021
DSun
Time (PST) of rise and set of some planets at 10-day interval
DATE MERCURY VENUS MARS JUPITER SATURN
Rise Set Rise Set Rise Set Rise Set Rise Set
Sep 08 7:31 AM 7:22 PM 8:34 AM 8:16 PM 6:27 PM 6:36 AM 4:48 PM *4:25 AM 3:45 PM *3:11 AM
Sep 18 7:32 AM 7:12 PM 8:43 AM 8:15 PM 6:14 PM 6:17 AM 4:06 PM *3:41 AM 3:05 PM *2:30 AM
Sep 28 7:09 AM 6:43 PM 8:53 AM 8:15 PM 6:01 PM 5:59 AM 3:23 PM *2:59 AM 2:24 PM *1:49 AM

* = following day
Astronomical Events September 2021

Equinox

The September equinox is when the sun will be exactly above Earth’s equator, moving from north to south. This happens either on September 22, 23, or 24 every year.

On an equinox, day and night are of approximately equal duration all over the planet. They are not exactly equal, however, due to the angular size of the sun and atmospheric refraction.

This year, Autumnal equinox will occur on September 23 at 3:21 AM. Hence, thereafter, Philippine nights will be longer as the Sun moves below the celestial equator towards the southern hemisphere.

Figures 2 and 2a represent the position of the Earth and Sun during Solstices and Equinoxes.

Fig2
Figure 2
Fig2a
Figure 2a
Stars and Constellations

Stargazing during the month will give fine display after sunset and before sunrise of celestial bodies such as stars and constellations. The famous Summer Triangle of the stars Vega, Deneb and Altair of the constellations Lyra, Aquila and Cygnus respectively, is well placed above the eastern horizon, as shown in Figures 1 & 1a. This month, the rich band of constellations and stars along the Milky Way from the constellations Cygnus, the Swan, in the north to Sagittarius and Scorpius in the south, begin to give way to fainter constellations, many of them with watery associations such as the constellations of Capricornus, the Sea-Goat, Aquarius, the Water Bearer and Pisces the Fish. The famous asterism Teapot in the sky of the constellation Sagittarius can be observed at about 40 to 45 degrees above the south-southeastern horizon as also shown in the Figures.

Figure1
Figure 1
Figure1a
Figure 1a
Planets Whereabout

On September 1 at 1:00 AM, Uranus, Neptune, Jupiter and Saturn, will be observed in the early morning sky. Uranus will be located in the eastern horizon which abode among the stars of the constellation Aries, the Ram, while Neptune will be found in the southwestern horizon among the stars of the constellation Aquarius, the Water-Bearer. Both of these planets require observing equipment like binoculars, telescopes, and star maps. Jupiter and Saturn can be seen at about 49 and 33 degrees above the southwestern sky lying among the background stars of the constellation Capricornus, the Sea-Goat. They will be glowing at magnitudes -2.86 and +0.36, respectively. These planets will remain visible in the early morning sky throughout the month.

At 6:40 PM, Venus, and Mercury can be spotted at about 23 and 10 degrees above the western horizon, shining brilliantly at magnitudes -4.28 and 0.02, respectively. Both planets will lie among the background stars of the constellation Virgo, the Virgin. The planets will remain visible in the sky after sunset during the month of September.

Mars will be difficult to observe due to its proximity to the horizon and the Sun during the month.

Fig3
Figure 3


SEPTEMBER 2021
DATE
EVENT
TIME (PST)
11 Moon at perigee (nearest distance to Earth = 368,463km) 10:00 AM
14 Mercury greatest elongation East (27˚) 12:00 NN
14 Neptune opposition 5:00 PM
23 Equinox 3:21 AM
25 Uranus 2° N of Moon 12:00 AM
27 Moon at apogee (farthest distance to Earth = 406,228 km) 6:00 AM
27 Mercury stationary 12:00 NN



ERRATA FOR THE ALMANAC FOR GEODETIC ENGINEERS 2020

Regarding the publication on page 2 of the ALMANAC FOR GEODETIC ENGINEERS 2020, which contains the data for the EPHEMERIS OF THE SUN, it was verified that the February 29, 2020 date is missing but the data for the particular date is the data printed as March 1, 2020. The data printed from April 3 to December 31 are all correct.

Kindly refer to the image/link below for the data errata on the Ephemeris of the Sun 2020.
Errata2020
Errata of AGE 2020, page 2
(Errata of AGE 2020 pdf file)