The school year is starting back up, and my wife and I will again be running an after-school astronomy and space science club: the Endeavour Space Academy. This year, I’m going to concentrate on different bodies in the solar system, and the science of how astronomy is done. Students will also be required to log some observing sessions. During the first few minutes, I take the students through my latest “In the Sky” post for current events, and what to look for in the sky.
Saturn, Jupiter and the Moon grace the southern sky all week, making this a great time to do early evening sidewalk astronomy!
Saturn, Jupiter and the Moon in the south-southwestern sky at 10:00 PM from Sep. 3-8, 2019. Credit: Stellarium / Bob Trembley.Before sunrise the constellation Orion can be seen in the southeastern sky.
Orion in the southeastern predawn sky this week. Credit: Stellarium / Bob Trembley.Ursa Major appears in the north-northwestern sky at 10:00 PM this week
The “Big Dipper” asterism of Ursa Major with a red line showing how to star-hop to Polaris “the North Star” in the north-northwestern sky at 10:00 PM this week. Credit: Stellarium / Bob Trembley.
M 20 – The Trifid Nebula
Trifid Nebula (Messier 20). Image: Subaru Telescope (NAOJ), Hubble Space Telescope, Martin Pugh; Processing: Robert Gendler.“Messier 20 (M20), also known as the Trifid Nebula, is a famous star-forming region located in the constellation Sagittarius.
The nebula’s designation in the New General Catalogue is NGC 6514. The name Trifid refers to its three-lobed appearance. Messier 20 consists of several different objects: an emission nebula, a reflection nebula, a dark nebula and an open star cluster.The dark nebula, catalogued as Barnard 85, consists of dust clouds that absorb and block light from the bright objects behind them. It is responsible for the apparent gaps in the larger emission nebula that give M20 its trifurcated look.
The other two types of nebulae – emission and reflection – make M20 glow in different colours in images.
Emission nebulae are energised by the ultraviolet light of nearby stars and usually appear red in photographs. These nebulae are clouds of extremely hot hydrogen gas and usually regions where new stars are being formed. The light of the stars illuminates the surrounding clouds, ionizing photons in large portions of the clouds.
Reflection nebulae, which typically appear blue in images, consist mostly of clouds of interstellar dust. They are also usually star-forming regions, but unlike emission nebulae, which emit spectral line radiation from ionized hydrogen, reflection nebulae do not emit any light of their own, but simply reflect the light of nearby stars.
Messier 20 is a popular target for amateur astronomers as it is quite bright, even when seen through a small telescope. It has an apparent magnitude of 6.3 and lies at an approximate distance of 5,200 light years, or 1,600 parsecs, from Earth. M20 has a linear diameter of over 40 light years and is only 300,000 years old. – messier-objects.com
As a child of the 1960’s, I remember the first time I learned about the Trifid Nebula – it was after having seen the movie “The Day Of The Triffids;” I am unable to think about M 20 without thinking about the monster movie… Oh to see a meteor shower like the one in the beginning of that movie! Although meteors don’t typically come from all different directions like in the movie tho…
https://youtu.be/QXOikSqJ83k
The Moon is a waxing crescent, visible toward the southwest in early evening.
The first-quarter Moon occurs on Friday September 6th, it will be visible high in the southern sky in early evening.
After September 6th, the Moon will be a waxing gibbous, visible to the southeast in early evening, and up for most of the night.
The Moon from Sep. 3-9, 2019. Visualizations by Ernie Wright / NASA’s Scientific Visualization Studio.Moon News
The Sun has a very small spot – Spaceweather.com says that “AR2748 has a magnetic polarity that identifies it as a member of old Solar Cycle 24. It poses no threat for strong solar flares.”
https://www.facebook.com/photo.php?fbid=10217705493782856
The north pole coronal hole continues to be enormous, while it appears that the hole at the south pole has diminished greatly. Several smaller coronal holes pepper the Sun’s face.
Some excellent prominences for photographs over the last couple days. The location of sunspot AR2748 can be seen as the bright area just above the equator.
The solar wind speed is 625.3 km/sec (↑), with a density of 0.6 protons/cm3 (↓) at 1300 UT.
Animated LASCO C2 Coronograph showing the solar corona above the Sun’s limb (the white circle). Credit: NASA/JPL-CaltechYou can create your own time-lapse movies of the Sun here: AIA/HMI Browse Data.
You can browse all the SDO images of the Sun from 2010 to the present here: Browse SDO archive.
Sun News
Upcoming Earth-asteroid encounters::
| Asteroid |
Date(UT)
|
Miss Distance
|
Velocity (km/s)
|
Diameter (m)
|
| 2019 QA5 |
2019-Sep-02
|
5.7 LD
|
13.5
|
21
|
| 2019 QX1 |
2019-Sep-02
|
18.9 LD
|
16.8
|
30
|
| 2019 OF2 |
2019-Sep-03
|
18.3 LD
|
10.7
|
53
|
| 2018 DE1 |
2019-Sep-03
|
12.7 LD
|
6.6
|
28
|
| 2019 QX3 |
2019-Sep-04
|
11.2 LD
|
17.8
|
32
|
| 2019 QE1 |
2019-Sep-05
|
13.2 LD
|
6.6
|
34
|
| 2019 GT3 |
2019-Sep-06
|
19.5 LD
|
13.6
|
218
|
| 2019 QZ |
2019-Sep-08
|
15.7 LD
|
4.3
|
21
|
| 2019 QZ3 |
2019-Sep-09
|
9.7 LD
|
7.5
|
40
|
| 2019 QY4 |
2019-Sep-10
|
2.5 LD
|
7.8
|
9
|
| 2010 RM82 |
2019-Sep-13
|
18.2 LD
|
14.6
|
23
|
| 2013 CV83 |
2019-Sep-13
|
16.1 LD
|
13.1
|
62
|
| 504800 |
2019-Sep-14
|
13.9 LD
|
14.4
|
155
|
| 467317 |
2019-Sep-14
|
13.9 LD
|
6.4
|
389
|
| 2019 JF1 |
2019-Sep-16
|
11.2 LD
|
4.3
|
62
|
| 2018 FU1 |
2019-Sep-16
|
18.4 LD
|
4.7
|
16
|
| 2017 SL16 |
2019-Sep-21
|
7.9 LD
|
6.5
|
25
|
| 2017 SM21 |
2019-Sep-21
|
11.5 LD
|
9.6
|
20
|
| 2019 QZ1 |
2019-Sep-22
|
12.5 LD
|
8.2
|
77
|
| 523934 |
2019-Sep-24
|
10.9 LD
|
22.3
|
257
|
| 2019 QY3 |
2019-Sep-26
|
13.9 LD
|
8.4
|
41
|
| 2017 KP27 |
2019-Sep-26
|
6.2 LD
|
4.8
|
25
|
| 2006 QV89 |
2019-Sep-27
|
18.1 LD
|
4.1
|
31
|
| 2018 FK5 |
2019-Oct-01
|
13.3 LD
|
10.5
|
8
|
| 2018 LG4 |
2019-Oct-02
|
13.8 LD
|
8.1
|
12
|
| 2017 TJ4 |
2019-Oct-05
|
13.5 LD
|
8.9
|
32
|
| 162082 |
2019-Oct-25
|
16.2 LD
|
11.2
|
589
|
| 2017 TG5 |
2019-Oct-25
|
14.4 LD
|
11.9
|
34
|
Notes: LD means “Lunar Distance.” 1 LD = 384,401 km, the distance between Earth and the Moon. Red highlighted entries are asteroids that either pass very close, or very large with high relative velocities to the Earth. Table from SpaceWeather.com
Near-Earth objects (NEOs) discovered this month: 0, this year: 1941 (+654), all time: 20777 (+63)
Potentially hazardous asteroids: 1983 (last updated May 8, 2019)
Minor Planets discovered: 796,802 (+116)
On Aug. 26, 2019, the NASA All Sky Fireball Network reported 35 fireballs.
(34 sporadics, 1 alpha Aurigid)
In this diagram of the inner solar system, all of the fireball orbits intersect at a single point–Earth. The orbits are color-coded by velocity, from slow (red) to fast (blue). From: Spaceweather.comFireball News
Position of the planets and a couple bodies in the inner solar system – I highlighted the Parker Solar Probe, which has passed perihelion #3 on September 1st.
Position of the planets and a couple spacecraft in the inner solar system, Sep. 3, 2019. Credit: NASA Eyes on the Solar System / Bob Trembley.Position of the planets and a couple bodies in the middle solar system:
Position of the planets in the middle solar system, Sep. 3, 2019. Credit: NASA Eyes on the Solar System / Bob Trembley.Position of the planets and a couple bodies in the outer solar system – I highlighted dwarf planet Eris:
Position of the planets in the outer solar system, Sep. 3, 2019. Credit: NASA Eyes on the Solar System / Bob Trembley.This pic is a hypothetical view of the dwarf planet Eris looking back at the planets; I kept the orbit line (red) to show its inclination to the plane of the ecliptic.
Hypothetical view of dwarf planet Eris. Credit: SpaceEngine / Bob Trembley.
Hypothetical view from the surface of Eris. Credit: SpaceEngine / Bob Trembley.NASA’s Interactive Real-Time Web-based Orrery:
[iframe src=’https://eyes.nasa.gov/apps/orrery/’ height=600 percent=100 style=””]
