International Dark Sky Week Virtual Activities (April 19-26, 2020)

By Jim Knoll

Often referred to as one of the most brilliant and beautiful winter open clusters, M37--my saltshaker cluster--is the brightest of the Auriga clusters (M36, M37,M38) NASA Image — Often referred to as one of the most brilliant and beautiful winter open clusters, M37–my saltshaker cluster–is the brightest of the Auriga clusters (M36, M37,M38)
NASA Image

A few virtual events happening this week (April 19 – 26, 2020) in support of International Dark Sky Week on Facebook Live & You Tube. The Facebook pages below are public pages, so you do not need to have a Facebook account to view them. If you miss any live events, they will probably be available under Facebook Video’s.

Tuesday April 21. 11:30 am Arizona Time (GMT-7 or Pacific Timezone) on the Grand Canyon Conservancy Association (GRCA) Facebook Page (https://www.facebook.com/grandcanyonconservancy/). Ranger Rader Lane will discuss GRCAs journey to become an International Dark Sky Park.

Tuesday April 21. 8:00 pm Arizona Time (GMT-7 or Pacific Timezone) on our TAAA Facebook Page, we will be doing a Virtual Star Party, observing about 12 objects for an hour and half. TAAA Facebook Page: https://www.facebook.com/TucsonAstronomy/. The live event may be located under the Videos section.

Thursday April 23. 12 pm (Noon) Arizona Time on the GRCA Facebook Page. Dean Regas will do a Live Virtual Tour of the Universe. If you don’t immediately see the live video when you go to the Facebook page at the appointed time, look under the Live or Video section of the page.

Friday April 24. 7 – 8:15 pm Arizona Time on the Fred Lawrence Whipple Observatory. A nation-wide livestream Star Party. it will be presented on You Tube. The Whipple webpage is: https://nightsky.jpl.nasa.gov/event-view.cfm?Event_ID=112413

All Week. Log into the International Dark Sky Association International Dark Sky Week page for a schedule of presentations all week long. Many are specific for children and would be good for kids or grandkids. The link to the webpage is: idsw.darksky.org. Once there select schedule.

Solar System

Planets of the Month: APRIL

by Erich Karkoschka

Venus is 40 degrees high at sunset and close to its brightest possible (Magnitude -4.5). After its passage through the Pleiades on the 3rd and 4th, it moves toward Alnath in Taurus. It is visible late into the evening and sets around 10:30 pm. By the end of the month, it is relatively large (39 arch seconds) and 25 % illuminated.

On April 15, the Last Quarter Moon joins the three morning planets in the predawn sky. On April 26, it is closest to brilliant Venus in the evening sky. First Quarter Moon is April 1 and 30, Full Moon April 7, Last Quarter April 14, and New Moon April 22.

Mars is the third planet to rise in the morning sky, following very close to Saturn at the beginning of April but sepertated by about 20 degrees by the end of the month. Mars is at Magnitude +1.

Jupiter rises at 2 am, dominating the morning sky at a magnitude of -2.

Saturn follows Jupiter and is 5 degrees to the east in the morning sky abut the same brightness as Mars at a magnitude of +1.

General Astronomy, Star Parties

Celebrate the Night Sky

by Jim Knoll

Since we don’t have any star parties to talk about and many are at home doing projects, this might be a good time to evaluate your home outdoor lighting to help preserve the dark skies. As many of you know, the International Dark Sky Association (IDA) is located right here in Tucson. Their website is: https://www.darksky.org and they have lots of resources to help you out. Here are some tips to evaluate your own lighting.

– Install lighting only when and where it’s needed.

– Use energy saving features such as timers, dimmers, and motion sensors on outdoor lights. Timers work great to get your attention when they come on.

– Make sure your lighting is shielded so light shines down, not up and does not trespass on your neighbor.

– Educate your friends and neighbors about the importance of good lighting for our health, economy, and environment.

— Artificial light at night can interfere with ecological interactions like predator-prey relationships, interrupts habitat connectivity, influences species’ ability to detect seasonality, and interferes with the human circadian rhythm.

International Dark Sky week is April 19-26, 2020. Join IDA for daily virtual celebrations at: idsw.darksky.org.

Please share with your family and friends.

Spiral galaxies, M77 (face-on) and NGC 1055. Nasa image — Spiral galaxies, M77 (face-on) and NGC 1055.
Nasa image

Astronomical Events

April Astronomy Observing

by Jim Knoll

April has a lot of interesting astronomy events and they are all visible with just your eyes.

April 2 morning. Mars and Saturn are very close in the morning sky (1.5 degrees) with Jupiter another 6 degrees to the upper right. View around 5 or 5:30 am.

April 3 evening. To the west, Venus (brightest object in the night sky in that area) will have a conjunction (get very close) to the Pleiades or 7 Sisters Cluster. In fact, Venus will be in the cluster. View around 7 or 7:30 pm.

Throughout April in the morning around 5 or 5:30 am. Mars (red), Saturn, and Jupiter form a nice line of planets with Mars closest to the horizon and Jupiter furthest with Saturn in the middle. The Moon joins the group April 14 – 16.

April 21-22. The evening or April 21 or even better the morning of April 22 will be the Lyrid Meteor Shower. Toward the east after 10 pm or early in the morning around 5 am look straight up. The shower radiant will be near the star Vega in the constellation Lyra and in the constellation Hercules right next door. Might see up to about 20 meteors per hour.

Sorry, no TAAA Public star parties in April and May. After the Monsoon, we will start them up again. Check our TAAA Website calendar for more info (tucsonastronomy.org) or follow a particular event here on our Facebook Page.

Clear skies and stay safe.

The nebulosity associated with M45 is not the progenitor of the cluster. Instead, it is a nebula through which M45 is passing. NASA Image, Robert Gendler — The nebulosity associated with M45 (Pleiades) is not the progenitor of the cluster. Instead, it is a nebula through which M45 is passing.
NASA Image, Robert Gendler

General Astronomy, Solar System

Planets of the Month: MARCH

by Erich Karkoschka

Mercury is just visible at dawn. Its greatest western elongation is the 23rd.

Venus is 45 degrees high at sunset, its best once every eight years. Greatest elongation from the sun is on the 24th, when it is half illuminated. On April 3 it will be inside the Pleiades (M45). At magnitude -4.5, it can be seen during the day if one can find it. The Moon visits Venus on March 26 & 27. Uranus is only 2 degrees from Venus on March 8 (within a binocular view).

Moon. First Quarter: March 2. Full: 9. Last Quarter: 16. New: 24. The Moon will visit Venus March 26 & 27.

Mars. Rises around 4 am at magnitude +1. Mars rises first early in the month, Jupiter is 5 degrees behind, and Saturn another 8 degrees behind. By the 18th Mars has almost caught up with Jupiter and the Moon is very close to both of them. Between the 20th & 31st, Mars will be between Jupiter and Saturn and within 7 degrees of each other. A Mars/Jupiter conjunction is on the 20th and a Mars/Saturn conjunction is on the 31st. After the 31st, Mars will have passed Saturn and will move on while Jupiter and Saturn stay within 6 degrees of each other.

Jupiter. Rises around 4 am at magnitude -2. See Mars write-up for positioning.

Saturn. Rises around 4 am at magnitude +1. See Mars write-up for positioning.

Uranus. Only 2 degrees from Venus on the 8th.

Neptune. Not visible. Solar Conjunction (in the glare of the Sun) is March 8.

The Vernal (Spring) Equinox is March 19 at 9 pm MST. This is when the Sun crosses the celestial equator (an imaginary line in the sky above the Earth’s equator). This happens on March 19, 20, or 21 every year in the Northern Hemisphere.

32 inch Cassegrain Project, Solar System

Planets of the Month: FEBRUARY 2020

by Erich Karkoschka

Mercury is easily visible in the first half of the month during dust in the west. It disappears after the 18th.

Venus is 40 degrees high at sunset and even 44 degrees by the end of the month. This is close to the maximum possible. It sets after 9 pm. The Moon will visit Venus on the 27th, a beautiful sight.

MAIN EVENT. Occultation of Mars by the Moon on the morning of February 18, well visible from Tucson before dawn in the southeast. It starts about an hour after Mars rises and lasts for another hour. Mars disappears behind the bright side of the Moon at 4:38 am and will reappear at 5:40 am along the dark side. The disappearance will be visible in binoculars as Mars slowly becomes invisible at the bright limb of the Moon. The reappearance will also take about 20 seconds. Since it occurs at the dark limb, it can be observed with the naked eye.

Uranus is 60 degrees high after dusk, visible in binoculars or a telescope.

Morning Sky. Mars rises at 4 am. Jupiter follows at 5 am, and Saturn at 6 am. These three planets will get closer to each other as the month progresses.

General Astronomy, Solar System

Planets of the Month: JANUARY, 2020

by Erich Karkoschka

	Mercury starts to be visible far below Venus in the West on the 26th. It will be well visible in early February.
	Venus is extending its visibility in the West from 2 to 3 hours and sets after 9 pm by the end of the month.
	The thin lunar crescent after New Moon in the West will be near Mercury on the 26th and near Venus on the 27th & 28th.
	Mars rises at 4 am. On the 18th & 19th, it will be 5 degrees north of Antares. Two red objects near each other.
	Jupiter will slowly appear in the morning sky starting the 11th.
	Saturn is not visible. It get occulted by the Sun on the 13th.
	Uranus is 70 degrees high after dusk in the SW.
	Neptune in Aquarius gets visited by Venus on the 27th with a separation of only 10 arc minutes, makiong it possible to fit two planets in the filed of view even at high magnification.
	Minor planet #4, Vesta, is further near Uranus in Cetus and still brighter than 8th magnitude.

Astronomical Events, General Astronomy, Solar System

Planets of the Month: DECEMBER, 2019

by Erich Karkoschka
Planets for December 2019

	Mercury will be visible until December 19th, rising just after Mars (15 degrees below) before dawn.
	Venus is in the evening sky, getting higher and more obvious.
	New Moon will be at Christmas, last visible in the morning of the 24th and coming back in the evening sky on the 27th below Venus and the 28th right next to Venus, a beautiful pair.
	Mars rises before dawn in Libra, followed by Mercury 15 degrees below.

	Saturn is to the upper left of Venus in the evening sky until December 10 & 11, when Venus passes two degrees south of Saturn. At that time, Pluto is right next to both planets, but 15 million times fainter than Venus and not an easy target. After Christmas, Saturn will be too close to the Sun to be visible.
	Uranus is well placed in the evening for observers with binoculars or a telescope.
	Neptune is well placed in the evening for observers with binoculars or a telescope.
	Pluto is next to Venus & Saturn December 10 & 11 but is 15 million times fianter and not an easy target. The brightest minor planet, Vesta, is not too far from Uranus and only slightly fainter.

32 inch Cassegrain Project, General Astronomy, Star Parties

December 2019 Events

We have two Tucson public observing events this month.

– Agua Caliente Park (NE Tucson) on December 21st: CANCELLED
– Tucson Mountain Park Ironwood Picnic Area (SW Tucson) on December 28 from 6 – 8 pm. Follow the Facebook event for real-time updates.

Meteor Shower. The Geminids peak early morning on December 14th or late evening on the 14th. There will be a bright Moon in the sky very close to Gemini which will limit what you can see. If possible put the Moon to your back and look for meteors in the opposite direction.

General Astronomy, Solar System, Star Parties

Mercury Transit Across the Sun (November 11, 2019)

by Jim Knoll

Monday November 11, 2019 (Veterans Day). This is a school holiday and a work holiday for many. Don’t pass up this “seldom-in-a-lifetime event”. A Mercury Transit (passing in front of) will NOT be visible again in the U.S. until May 7, 2049. Transits occur only 13-14 times per century. A Mercury Transit is too small to see without a properly filtered solar telescope. When you observe a transit, you see a small black circle (the planet Mercury) moving across the Sun. This event is visible throughout the U.S. TAAA will have several solar telescopes to safely view the Transit at Brandi Fenton Memorial Park (3482 E River Rd, River & Alvernon) on November 11 from 7:30 – 11 am (Mercury mid-transit when it is crossing the middle of the Sun is at 8:20 am Tucson time). Sunrise November 11 is 6:49 am and the Transit will already be underway. You can follow the Mercury Transit event on our Facebook page (facebook.com/tucsonastronomy) for real-time weather updates. This event requires a clear view of the Sun (no cloud cover). CAUTION: Never look at the Sun without a proper solar filter or you can damage your eyes.

For more information, email: astronomy-events@tucsonastronomy.org.