WGN 46:4 out now!

WGN46-4
WGN 46:4 august 2018
Front cover photo: All-sky composite image of 2018 Perseids, photographed on 2018 August 12/13 and 13/14 from Tepličné, Slovakia.
Photo courtesy: Stanislav Kaniansky and Marek Harman.

The August 2018 issue of the IMO Journal is now in print. It will be mailed shortly and subscribers can also immediately access the journal in PDF format. The contents this month:

  • In Memoriam: Dr. Eduard Pittich (J. Tóth)
  • Compressive strength of a skirting Daytime Arietid – first science results from low-cost Raspberry Pi-based meteor stations (D. Vida, M.J. Mazur, D. Šegon, P. Kukić, A. Merlak)
  • Different definitions make a meteor shower distorted. The views from SonotaCo net and CAMS. (M. Koseki)
  • Results of the IMO Video Meteor Network — October 2017 (S. Molau, S. Crivello, R. Goncalves, C. Saraiva, E. Stomeo, J. Strunk, J. Kac)
  • Results of the IMO Video Meteor Network — November 2017 (S. Molau, S. Crivello, R. Goncalves, C. Saraiva, E. Stomeo, J. Strunk, J. Kac)

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Meteor Activity Outlook for 15-21 September 2018


Perseid meteor and Delta IV Heavy rocket trail over Cape Canaveral on August 16, 2018.
Credit & Copyright: Derek Demeter (Emil Buehler Planetarium

During this period the moon will reach its first quarter phase on Sunday September 16th. At that time the moon will lie 90 degrees east of the sun and will set near midnight local summer time (LST). As the week progresses the waxing gibbous moon will set later and later, shrinking the window of opportunity to view meteor activity under dark skies. The estimated total hourly meteor rates for evening observers this week is near 3 as seen from mid-northern latitudes and also 2 for those viewing from subtropical southern latitudes (25S). For morning observers the estimated total hourly rates should be near 14 for those viewing from mid-northern latitudes and 10 for those viewing from subtropical southern latitudes (25S). The actual rates will also depend on factors such as personal light and motion perception, local weather conditions, alertness and experience in watching meteor activity. Evening rates are reduced during this period due to moonlight. Note that the hourly rates listed below are estimates as viewed from dark sky sites away from urban light sources. Observers viewing from urban areas will see less activity as only the brighter meteors will be visible from such locations.

The radiant (the area of the sky where meteors appear to shoot from) positions and rates listed below are exact for Saturday night/Sunday morning September 15/16. These positions do not change greatly day to day so the listed coordinates may be used during this entire period. Most star atlases (available at science stores and planetariums) will provide maps with grid lines of the celestial coordinates so that you may find out exactly where these positions are located in the sky. A planisphere or computer planetarium program is also useful in showing the sky at any time of night on any date of the year. Activity from each radiant is best seen when it is positioned highest in the sky, either due north or south along the meridian, depending on your latitude. It must be remembered that meteor activity is rarely seen at the radiant position. Rather they shoot outwards from the radiant so it is best to center your field of view so that the radiant lies near the edge and not the center. Viewing there will allow you to easily trace the path of each meteor back to the radiant (if it is a shower member) or in another direction if it is a sporadic. Meteor activity is not seen from radiants that are located far below the horizon. The positions below are listed in a west to east manner in order of right ascension (celestial longitude). The positions listed first are located further west therefore are accessible earlier in the night while those listed further down the list rise later in the night.

Radiant Positions at 21:00 LST

Radiant Positions at 21:00
Local Summer Time

Radiant Positions at 01:00 LST

Radiant Positions at 0100
Local Summer Time

Radiant Positions at 5:00 LST

Radiant Positions at 05:00
Local Summer Time

These sources of meteoric activity are expected to be active this week.

The last of the chi Cygnids (CCY) are expected this weekend. The radiant currently lies at 20:12 (303) +32 which places it in central Cygnus, 2 degrees west of the faint star known as 39 Cygni. Rates are expected to be less than 1 per hour no matter your location. This radiant is best near 22:00 (10pm LST) when it lies highest in the sky. With an entry velocity of 15 km/sec., the average chi Cygnid meteor would be very slow.

The center of the large Anthelion (ANT) radiant is currently located at 00:28 (007) +03. This position lies in southern Pisces, 5 degrees southwest of the 4th magnitude star known as delta Piscium. Due to the large size of this radiant, Anthelion activity may also appear from northwestern Cetus as well as Pisces. This radiant is best placed near 0200 LST, when it lies on the meridian and is located highest in the sky. Hourly rates at this time should be near 2 no matter your location. With an entry velocity of 30 km/sec., the average Anthelion meteor would be of medium-slow velocity.

The September Epsilon Perseids (SPE) are active from September 3 through October 3 with the peak occurring on the night of September 10/11. The radiant is currently located at 03:40 (055) +40. This position lies just 3 degrees west of the 3td magnitude star known as epsilon Persei. The radiant is best placed near 0500 LST, when it lies highest above the horizon. Rates are expected to be near 1 per hour as seen from the northern hemisphere and less than 1 as seen from the southern hemisphere. With an entry velocity of 65 km/sec., most activity from this radiant would be swift.

The nu Eridanids (NUE) were co-discovered by Japanese observers using SonotoCo and Juergen Rendtel and Sirko Molau of the IMO. Activity from this long-period stream stretches from August 24 all the way to November 16. Maximum activity occurs on September 24th. The radiant currently lies at 04:38 (070) +05, which places it in southeastern Taurus, 3 degrees southwest of the 3rd magnitude star known as Tabit (pi 3 Orionis). This area of the sky is best seen during the last dark hour before dawn when the radiant lies highest in a dark sky. Current rates are expected to be near 1 per hour during this period no matter your location. With an entry velocity of 67 km/sec., the average meteor from this source would be of swift velocity.

The last of the eta Eridanids (ERI) are expected this weekend from a radiant located at 05:00 (075) -02, which places it in northeastern Eridanus, 4 degrees south of the 4th magnitude star known as pi 6 Orionis. This area of the sky is best seen during the last dark hour before dawn when the radiant lies highest in a dark sky. Current rates are expected to be less than 1 per hour during this period no matter your location. With an entry velocity of 65 km/sec., the average meteor from this source would be of swift velocity.

The Daytime Sextantids (DSX) are not well known due to the fact that the radiant lies close to the sun and these meteors are only visible during the last couple of hours before dawn. The radiant is currently located at 09:29 (142) +03. This position lies in western Hydra, 3 degrees northeast of the 4th magnitude star known as theta Hydrae. This area of the sky is best placed in the sky during the last hour before dawn, when it lies highest above the horizon in a dark sky. Since the maximum is not until September 29th, current rates would be most likely less than 1 per hour no matter your location. Spotting any of this activity would be a notable accomplishment. With an entry velocity of 33km/sec., most activity from this radiant would be of medium-slow speed.

As seen from the mid-northern hemisphere (45N) one would expect to see approximately 10 sporadic meteors per hour during the last hour before dawn as seen from rural observing sites. Evening rates would be near 2 per hour. As seen from the tropical southern latitudes (25S), morning rates would be near 7 per hour as seen from rural observing sites and 1 per hour during the evening hours. Locations between these two extremes would see activity between the listed figures. Evening rates are reduced during this period due to moonlight.

The list below offers the information from above in tabular form. Rates and positions are exact for Saturday night/Sunday morning except where noted in the shower descriptions.

SHOWER DATE OF MAXIMUM ACTIVITY CELESTIAL POSITION ENTRY VELOCITY CULMINATION HOURLY RATE CLASS
RA (RA in Deg.) DEC Km/Sec Local Summer Time North-South
chi Cygnids (CCY) Sept 13-14 20:12 (303) +32 15 22:00 <1 – <1 IV
Anthelions (ANT) 00:28 (007) +03 30 02:00 2 – 2 II
September Epsilon Perseids (SPE) Sep 10 03:40 (055) +40 65 06:00 1 – <1 II
nu Eridanids (NUE) Sep 24 04:38 (070) +05 67 07:00 1 – 1 IV
eta Eridanids (ERI) Aug 11 05:00 (075) -02 65 08:00 <1 – <1 IV
Daytime Sextantids (DSX) Sep 29 09:29 (142) +03 33 12:00 <1 – <1 IV

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Brazilian National Museum consumed by fire…

With a collection of 20 million items divided among the sectors of geology, paleontology, botany, zoology, biological anthropology, archeology and ethnology, Brazil and the world watched the flames consume the National Museum of Rio de Janeiro. The country’s oldest political institution, the National Museum, completed 200 years in June 2018. Its administration has been subordinated to the Federal University of Rio de Janeiro since 1946, at the end of the Estado Novo when the National Museum passed to the tutelage of the University. “The National Museum is an autonomous institution, part of the Science and Culture Forum of the Federal University of Rio de Janeiro, linked to the Ministry of Education.”
The National Brazilian Museum in 2004, before it went under fire. Credit: Paulo R C M Jr.
The National Brazilian Museum in 2004, before it went under fire. Credit: Paulo R C M Jr.
Created by D. João VI, on June 6, 1818 as the Royal Museum, it was initially based in Campo de Santana and aimed at promoting the cultural, scientific, intellectual and economic progress of the country.
In 1892, this museum was installed in the São Cristóvão palace, which was built in the early nineteenth century and housed D. João VI when he moved from Lisbon to Brazil in 1808. The palace was also home to D. Pedro I and D. Pedro II. Initially the palace belonged to a Portuguese merchant named Elias Antônio Lopes and he donated the house to D. João VI, claiming to worry about the welfare of the Portuguese king.
National Brazilian Museum under fire. By Felipe Milanez - Sent by the photographer -- OTRS-sent, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=72299257
National Brazilian Museum under fire. By Felipe Milanez
Throughout national history, the Palace of Saint Kitts witnessed remarkable moments, such as the signing of the decree of independence of Brazil by Maria Leopoldina (Empress Consort of the Empire of Brazil). Between 1889 and 1891, the Palace hosted the first republican constitution of Brazil. It is worth mentioning that many important names visited the place on trips to Brazil, such as Albert Einstein and Marie Curie, famous scientists of the twentieth century.
The museum had a large collection of items, including: the Egyptian collection, a collection of Greco-Roman art, a dinosaur from Minas Gerais, the oldest human fossil ever found in the country, known as “Luzia”, objects that showed the richness of the indigenous culture, Afro-Brazilian culture and cultures in the Pacific, a collection of shells, corals and butterflies, as well as a collection of meteorites found on Brazilian soil.
The Brazilian National Museum fire captured by a FRIPON video station from Rio de Janeiro Observatory. Credit: FRIPON
The Brazilian National Museum fire captured by a FRIPON video station from Rio de Janeiro Observatory. Credit: FRIPON
The fire in the National Museum began after 19:30 hours when the visits were closed, there were four guards at the scene who were able to leave before the fire reached a high level. “Much of the building’s structure was made of wood, and the building had a lot of flammable material – which made the fire spread quickly.” So far it is not known what actually caused the fire, it should be emphasized here that the museum lacked the attention of the competent bodies that should ensure its proper maintenance.
In a statement, the Institute of National Historic and Artistic Heritage (Iphan) expressed its indignation at the tragedy of international repercussions, highlighting the lack of commitment of the State to the preservation of national memory. Among the international media that reported the news stand out, BCC news, Ney York Times, Forbes, Le Monde, Associated Press, Clarin, The Daily Mail, CNN, El País, The Guardian, Spielgel Online.
Bendegó meteorite after museum fire. Image: Clever Feliz/Brazil Photo Press/Folhapress
Bendegó meteorite after museum fire. Image: Clever Feliz/Brazil Photo Press/Folhapress
Brazil and the world lose much of this tragedy. “A museum is a public or private institution that serves society and its development, which acquires, preserves, researches, communicates, displays or exhibits, for study and education purposes, art collections, scientific works, among others, always with cultural value”, according to the International Council of Museums.
And good news: among some collections, some of the meteorites that were on display have already been recovered and identified by the curatorship. The image of the meteorite Bendegó at the entrance of the Museum renews the hope of a future for the National Museum of Brazil.
Text:
Fabiana Barreto (Exoss/ROCG)
Luciana Fontes (Exoss)

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