In the Sky This Week – April 30, 2019
Mercury, Venus appear very low in the eastern sky just before sunrise - if seeing Mercury was a challenge last week, it will be even harder this week. The waning crescent Moon joins the two planets until May 3rd.
- Mercury, Venus and a thin waning crescent Moon on the eastern horizon near sunrise on May 1st. Credit: Stellarium / Bob Trembley.
- Mercury, Venus and a VERY thin waning crescent Moon on the eastern horizon near sunrise on May 2nd. Credit: Stellarium / Bob Trembley.
Saturn, Jupiter and the star Antares appear southern sky early in the morning. In this image, I have the light pollution set to high - this is typically what I can see from a close suburb to Detroit.

Saturn and Jupiter high in the southern sky on Apr. 30th - with light pollution levels are set high. Credit: Stellarium / Bob Trembley.
This is the same patch of sky seen from a dark sky site.

The southern sky on Apr. 30th - with light pollution levels are set to none. Credit: Stellarium / Bob Trembley.
Mars and the star Betelgeuse are low on the horizon after sunset; the winter constellations will soon be gone.

Mars and the star Betelgeuse in the constellations Orion low in the western sky after sunset on May 6th. Credit: Stellarium / Bob Trembley.
M-109 - "Vacuum Cleaner Galaxy"
Messier 109 (also known as NGC 3992) is a barred spiral galaxy exhibiting a weak inner ring structure around the central bar approximately 83.5 ± 24 million light-years[3]away in the constellation Ursa Major. M109 can be seen southeast of the star Phecda (γ UMa). - Wikipedia
Where did the name "Vacuum Cleaner Galaxy" come from? It's not official; Stellarium refers to M-109 with that name, so I searched for it - I found it mentioned in an archived comment section on M-109 on Wikipedia.
The Moon is a waning crescent, visible low to the east before sunrise.
The new Moon occurs on May 4th.
After May 4th, the Moon will be a waxing crescent, visible toward the southwest in early evening.

The Moon from Apr. 30-May 6, 2019. Visualizations by Ernie Wright / NASA's Scientific Visualization Studio.
Moon History
Blagg crater is named after Mary Adela Blagg (1858-1944). A Moon mapper extraordinaire, Blagg standardized the names of lunar features and became one of the first 5 women inducted as a fellow into the Royal Astronomical Society. Rock star🌟. #WomenInSTEM https://t.co/H6g34q8Rr5 pic.twitter.com/i6Nb9JLNya
— NASA Moon (@NASAMoon) April 25, 2019
The Sun has been spot-free for 9 days; AR2738, if it still exists, it is on the other side of the Sun. Coronal holes are open at both poles, and a rather large coronal hole is in the middle of the Sun - just below the equator. SpaceWeather.com says: "A large hole in the sun's atmosphere is facing Earth and spewing a stream of solar wind in our direction. Estimated time of arrival: May 2nd. Minor geomagnetic storms are possible when the gaseous material arrives."
The eastern limb of the Sun has been hogging most of the prominences for the last few days.
The solar wind speed is 306.6 km/sec (↓), with a density of 5.9 protons/cm3 (↑).

Animated LASCO C2 Coronograph showing the solar corona above the Sun's limb (the white circle). Credit: NASA/JPL-Caltech
You 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
The quadruplet MMS spacecraft have finished 1000 laps 🏁 around Earth — which adds up to 163 million miles flown! 🛰 Their latest adventure took them beyond Earth's bubble of magnetic protection 🌐 and into the flowing solar wind. ☀️💨 https://t.co/nuq1vpfBco pic.twitter.com/3EdZuZVjvZ
— NASA Sun & Space (@NASASun) April 26, 2019
Upcoming Earth-asteroid encounters:
2019 HM3 |
2019-Apr-30
|
6.3 LD
|
5.2
|
15
|
2019 HO3 |
2019-May-01
|
13.8 LD
|
18.6
|
69
|
2019 HK |
2019-May-01
|
12.8 LD
|
12.9
|
51
|
2019 HW3 |
2019-May-01
|
16 LD
|
8.6
|
37
|
2019 HP |
2019-May-03
|
9.3 LD
|
5.7
|
26
|
2019 HV3 |
2019-May-04
|
12.4 LD
|
10.9
|
56
|
2018 KK1 |
2019-May-05
|
13.9 LD
|
13.9
|
71
|
2019 HQ3 |
2019-May-07
|
15.7 LD
|
12.7
|
28
|
2017 RC |
2019-May-09
|
14.5 LD
|
10.6
|
9
|
2008 HS3 |
2019-May-09
|
14.6 LD
|
5.3
|
162
|
2018 VX8 |
2019-May-12
|
6.2 LD
|
15.5
|
118
|
2019 GT1 |
2019-May-17
|
6.1 LD
|
3.9
|
36
|
2012 KT12 |
2019-May-18
|
3.3 LD
|
3.9
|
20
|
2015 KQ18 |
2019-May-25
|
10.7 LD
|
13.1
|
30
|
66391 |
2019-May-25
|
13.5 LD
|
21.5
|
1780
|
2003 LH |
2019-May-28
|
15.6 LD
|
7.4
|
32
|
2011 HP |
2019-May-30
|
12.3 LD
|
8.4
|
135
|
2014 MF18 |
2019-Jun-06
|
8.8 LD
|
3
|
22
|
441987 |
2019-Jun-24
|
7.7 LD
|
12.6
|
178
|
2008 KV2 |
2019-Jun-27
|
17.8 LD
|
11.4
|
195
|
Notes: LD means "Lunar Distance." 1 LD = 384,401 km, the distance between Earth and the Moon. Table from SpaceWeather.com
Potentially hazardous asteroids: 1967 (last updated Feb. 26, 2019)
Minor Planets discovered: 794,810 (+117)
Asteroid News
#ICYMI Do you have access to a 1-m telescope or larger? Then register to the @ESAGaia #asteroid alerts 👉https://t.co/KSQS9CniD3 to perform follow-up observations & help improve asteroid orbit determination or even discover new ones!
📷👉 https://t.co/VTyHcDqGC1 #PlanetaryDefense pic.twitter.com/zDaZcnPkqm— ESA Science (@esascience) April 30, 2019
LIVE: Speaking at the #PlanetaryDefense Conference https://t.co/uvjuqc6thj
— Jim Bridenstine (@JimBridenstine) April 29, 2019
On Apr. 29, 2019, the NASA All Sky Fireball Network reported 21 fireballs.
(19 sporadics, 2 eta Aquariids)

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.com
The Eta-Aquariid Meteor Shower is active
The Eta-Aquariid Meteor Shower is active and expected to peak next week.https://t.co/7clcC24nzp pic.twitter.com/Y56hILRSD0
— AMSMETEORS (@amsmeteors) April 29, 2019
This is the position of the planets and a couple bodies in the solar system:
- Position of the planets in the inner solar system, Apr. 30, 2019. Note: the Parker Solar Probe is almost to the orbit of Venus. Credit: NASA Eyes on the Solar System / Bob Trembley.
- Position of the planets in the middle solar system, Apr. 30, 2019. Credit: NASA Eyes on the Solar System / Bob Trembley.
- The outer solar system Apr. 30, 2019, with the orbit of trans-Neptunian object 2018 VG18 highlighted in red. Credit: Space Engine / Bob Trembley.
- Visualization of trans-Neptunian object 2018 VG18 – the first TNO discovered while beyond 100 AU (15 billion km) from the Sun. Credit: Space Engine / Bob Trembley.
Read more on: 2018_VG18
Juno - #CitizenScience Collaboration
#CitizenScience collaboration 📸🔬🎨 : I send home raw pictures of Jupiter, and talented people around the world turn them into everything from detailed scientific imagery to beautiful works of art. Full video: https://t.co/YIwpDufF6Q pic.twitter.com/ogkYKdw7HO
— NASA's Juno Mission (@NASAJuno) April 24, 2019
OSIRIS-REx - Detailed Survey: Equatorial Stations Phase
Look at these rocks on top of another rock. https://t.co/BJwDZROU06 pic.twitter.com/fm2LeU0A6T
— NASA's OSIRIS-REx (@OSIRISREx) April 29, 2019
Mars InSight - Winner of the Webby People's Voice Award
Martians, we did it! Your votes helped me win a #Webby People’s Voice award 🏆. Thank you for the love ❤️ and for supporting the work I’m doing on #Mars. Read all about @NASA’s Webby award wins: https://t.co/3hI3CiOvzQ pic.twitter.com/zO499yZnh3
— NASA InSight (@NASAInSight) April 24, 2019
Climate - NASA Earth Observatory, 20 Years
On April 29, 1999, NASA Earth Observatory (EO) started publishing science stories and imagery on the Web. So much has changed in those 20 years… https://t.co/OJ1iFx6WZC #NASAEO20 #EarthDayEveryDay #OTD ⏳ pic.twitter.com/zVpcyK4lzA
— NASA Earth (@NASAEarth) April 29, 2019
Data from the NASA Exoplanet Archive
Exoplanet News
Astronomers discover the first known exoplanet to survive a catastrophic collision with another planet. https://t.co/DNXHXLEliL pic.twitter.com/WhRPslrRXH
— Astronomy Magazine (@AstronomyMag) April 29, 2019
Exoplanet Artwork by Bob Trembley
- A hypothetical binary star in M-13, with a red giant and a neutron star companion. The neutron star has an accretion disk and polar jets. Credit: Space Engine / Bob Trembley
- A hypothetical exoplanet orbiting a binary star in M13. Credit: Space Engine / Bob Trembley
- “Blue Sunrise.” A neutron star rising on a hypothetical exoplanet. Credit: Space Engine / Bob Trembley
- “Red Sunrise.” A Red giant star rising on a hypothetical exoplanet. Credit: Space Engine / Bob Trembley
Nicknamed the Cheshire Cat galaxy group, this is the most popular example of gravitational lensing https://t.co/7lT87qbmaW pic.twitter.com/rhwhX08bPo
— Massimo (@Rainmaker1973) April 29, 2019
Apps used for this post:
NASA Eyes on the Solar System: an immersive 3D solar system and space mission simulator - free for the PC /MAC.
I maintain the unofficial NASA Eyes Facebook page.
Stellarium: a free open source planetarium app for PC/MAC/Linux. It's a great tool for planning observing sessions.
Universe Sandbox: a space simulator that merges real-time gravity, climate, collision, and material interactions to reveal the beauty of our universe and the fragility of our planet. Includes VR support.
Space Engine: a free 3D Universe Simulator for the PC. VR support coming soon!
Section header image credits:
The Sky - Stellarium/ Bob Trembley
Observing Target - Turn Left at Orion / M. Skirvin
The Moon - NASA/JPL-Caltech
The Sun - NASA/JPL-Caltech
Asteroids - NASA/JPL-Caltech
Fireballs - Credited to YouTube
Comets - Comet P/Halley, March 8, 1986, W. Liller
The Solar System - NASA Eyes on the Solar System / Bob Trembley
Spacecraft News - NASA Eyes on the Solar System / Bob Trembley
Exoplanets - Space Engine / Bob Trembley
The Universe - Universe Today