#messier objects

The debate over the correct Messier number for the Ship of Theseus is ongoing.

Messier Objects [Explained]

Transcript Under the Cut

by Kat Troche of the Astronomical Society of the Pacific

What Are Messier Objects?

During the 18th century, astronomer and comet hunter Charles Messier wanted to distinguish the ‘faint fuzzies’ he observed from any potential new comets. As a result, Messier cataloged 110 objects in the night sky, ranging from star clusters to galaxies to nebulae. These items are designated by the letter ‘M’ and a number. For example, the Orion Nebula is Messier 42 or M42, and the Pleiades are Messier 45 or M45. These are among the brightest ‘faint fuzzies’ we can see with modest backyard telescopes and some even with our eyes.

Stargazers can catalog these items on evenings closest to the new moon. Some even go as far as having “Messier Marathons,” setting up their telescopes and binoculars in the darkest skies available to them, from sundown to sunrise, to catch as many as possible. Here are some items to look for this season:

M44 in Cancer and M65 and 66 in Leo can be seen high in the evening sky 60 minutes after sunset. Credit: Stellarium Web

Messier 44 in Cancer: The Beehive Cluster, also known as Praesepe, is an open star cluster in the heart of the Cancer constellation. Use Pollux in Gemini and Regulus in Leo as guide stars. A pair of binoculars is enough to view this and other open star clusters. If you have a telescope handy, pay a visit two of the three galaxies that form the Leo Triplet - M65 and M66. These items can be seen one hour after sunset in dark skies.

Locate M3 and M87 rising in the east after midnight. Credit: Stellarium Web

Messier 3 Canes Venatici: M3 is a globular cluster of 500,000 stars. Through a telescope, this object looks like a fuzzy sparkly ball. You can resolve this cluster in an 8-inch telescope in moderate dark skies. You can find this star cluster by using the star Arcturus in the Boötes constellation as a guide.

Messier 87 in Virgo: Located just outside of Markarian’s Chain, M87 is an elliptical galaxy that can be spotted during the late evening hours. While it is not possible to view the supermassive black hole at the core of this galaxy, you can see M87 and several other Messier-labeled galaxies in the Virgo Cluster using a medium-sized telescope.

Locate M76 and M31 setting in the west, 60 minutes after sunset. Credit: Stellarium Web

Messier 76 in Perseus: For a challenge, spot the Little Dumbbell Nebula, a planetary nebula between the Perseus and Cassiopeia constellations. With an apparent magnitude of 12.0, you will need a large telescope and dark skies. You can find both M76 and the famous Andromeda Galaxy (M31) one hour after sunset, but only for a limited time, as these objects disappear after April. They will reappear in the late-night sky by September.

Plan Ahead

When gearing up for a long stargazing session, there are several things to remember, such as equipment, location, and provisions:

Do you have enough layers to be outdoors for several hours? You would be surprised how cold it can get when sitting or standing still behind a telescope!

Are your batteries fully charged? If your telescope runs on power, be sure to charge everything before you leave home and pack any additional batteries for your cell phone. Most people use their mobile devices for astronomy apps, so their batteries may deplete faster. Cold weather can also impact battery life.

Determine the apparent magnitude of what you are trying to see and the limiting magnitude of your night sky. You can learn more about apparent and limiting magnitudes with our Check Your Sky Quality with Orion article.

When choosing a location to observe from, select an area you are familiar with and bring some friends! You can also connect with your local astronomy club to see if they are hosting any Messier Marathons. It’s always great to share the stars!

My first post on this tumblr was the Lagoon Nebula! I was fortunate to take another picture of this beautiful nebula last night. ✨✨✨

The Lagoon Nebula’s distinct shape is mainly due to a dark band of gas and dust running down its center. This nebula is the birthplace of many stars, which is seen by the presence of dark Bok globules that collapse to create protostars! 🌊🌊🌊

(Above: The well-known Leo Triplet consists of three spiral galaxies with the names Messier 65, Messier 66, and the Hamburger Galaxy (NGC 3628). All three galaxies will fit within the field of view of a telescope at low magnification. NASA APOD for April 18 2019 by Marcus Bauer)

Hello, Stargazers!

Here are your Astronomy Skylights for the week of May 12th, 2019 by Chris Vaughan. Feel free to pass this along to your friends and send me your comments, questions, and suggested topics. I repost these emails with photos at http://astrogeoguy.tumblr.com/ where all the old editions are archived. You can also follow me on Twitter as @astrogeoguy! Unless otherwise noted, all times are Eastern Time. Please click this MailChimp link to subscribe to these emails. If you are a teacher or group leader interested joining me on a guided field trip to York University’s Allan I. Carswell Observatory or the David Dunlap Observatory, visit www.astrogeo.ca.

I can bring my Digital Starlab inflatable planetarium to your school or other daytime or evening event. Contact me and we’ll tour the Universe together!

Public Astro-Events

At 7:30 pm on Wednesday, May 22, the RASC Toronto Centre will hold their free monthly Recreational Astronomy Night Meeting at the Ontario Science Centre, and the public are welcome. Talks include The Sky This Month, a do-it-yourself telescope project, and student project about gravitational waves. These meetings are also streamed live on RASC-TC’s YouTube channel. Check here for details. Parking is free. 

Every Monday evening, York University’s Allan I. Carswell Observatory runs an online star party - broadcasting views from four telescopes/cameras, answering viewer questions, and taking requests! Details are here. On Wednesday nights they offer free public viewing through their rooftop telescopes. If it’s cloudy, the astronomers give tours and presentations. Details are here. 

On Monday, May 20 from 5 to 7 pm, guests aged 19+ are invited to attend A Pint of Science at Artwood Artbar in Hamilton, ON. This session will focus on A Trip to Quantumland. Registration and details are here. 

On Friday, May 24 at 8 pm, RASC - Mississauga will present a free public talk by Dr. Renée Hložek, Assistant Professor, Dunlap Institute for Astronomy & Astrophysics entitled Echoes of Our Beginnings. Details are here. 

On Friday, May 24, starting at 7 pm, U of T’s AstroTour will present their planetarium show Grand Tour of the Cosmos. Tickets and details are here. 

The next RASC Family Night at the David Dunlap Observatory will be on Saturday, May 25. There will be sky tours in the Skylab planetarium room, space crafts, a tour of the giant 74” telescope, and viewing through lawn telescopes (weather permitting). The doors will open at 8:30 pm for a 9 pm start. Attendance is by tickets only, available here. If you are a RASC Toronto Centre member and wish to help us at DDO in the future, please fill out the volunteer form here. And to join RASC Toronto Centre, visit this page. 

The Moon and Planets

This is the week of the lunar month when our natural satellite, fresh from yesterday’s full moon, will wane and rise later, eventually arriving at its Last Quarter phase next Sunday after mid-day. By that time, the moon will have set in the west for us in the Eastern Time zone. Last Quarter moons always rise near midnight and linger into the daytime morning western sky. 

Here are the rest of the moon doings for this week… 

When the waning gibbous moon rises from the southeastern horizon just before midnight local time on Monday, it will be positioned a palm’s width to the lower left (east) of bright Jupiter. As the pair crosses the sky together, the moon’s orbital motion will carry it farther away from Jupiter. You can watch both of them until Jupiter fades from view just before sunrise. At that time, they will be positioned over the southwestern horizon.

(Above: This week the waning gibbous moon will have encounters with the two bright, gas giant planets Jupiter and Saturn. I've shown it here at 5 am local time on Tuesday morning, but you can see the pairing starting several hours earlier. On Thursday morning, the moon will dance with Saturn instead, and parts of the world will see the moon pass in front of the ringed planet.)

The moon will also dance with Saturn this week. When the moon rises from the southeastern horizon after 1:30 am local time on Thursday, it will be positioned 4 finger widths to the lower left (east) of yellowish Saturn. As before, the moon’s orbital motion will carry it noticeably farther from Saturn over the following hours. They will remain visible until about 5 am local time, when they will sit in the southern sky. Hours earlier, observers in the southern tip of Africa, parts of eastern Antarctica, Kerguelen Islands, most of Australia, and southern New Zealand will get to see the moon pass in front of (or occult) the Ringed Planet. 

You still have some evenings to catch a glimpse of Mars’ bright, reddish pinpoint in the western evening sky before it transitions fully into the sunset. This week, Mar is tickling the toes of Gemini (the Twins) and sets at about 11:30pm local time.

(Above: On Sunday evening, May 19, Mars' eastward orbital motion will carry it close past the bright star cluster designated as Messier 35. Binoculars will show the cluster and Mars once the sky has darkened, as shown here at 10 pm local time.)

In the north-northwestern sky this evening (Sunday), Mars will be positioned only 0.25 degrees (or half of a moon’s diameter) to the right of the prominent open star cluster known as Messier 35 and NGC 2168. Mars and the star cluster’s many stars will all fit together into the field of view of a backyard telescope at medium magnification. Binoculars will also show this cluster under moderately dark skies. Look for another, dimmer open star cluster designated NGC 2158 sitting southwest of Messier 35. 

The bright planet Jupiter will rise in the east at about 10:30 pm local time this week. It’s gradually making its way into position for our summer evening stargazing! For now, if you are walking through the house in your pj’s during the wee hours, Jupiter’s bright beacon might catch your eye through a south-facing window. Jupiter will reach its highest position, over the southern horizon, at about 3 am local time, and then it will descend towards the southwest as dawn arrives. If you’d like to see the famous Great Red Spot in your telescope, it will be crossing the planet around midnight on Sunday and Friday, and before dawn on Wednesday. No matter when you look, you can see the four bright Galilean moons arrayed to either side of Jupiter. Sometimes you’ll only see two or three of them if the rest are hidden by Jupiter itself. 

Yellowish Saturn will be rising about 2 hours after Jupiter all summer, which positions it about 2.5 outstretched fist diameters to the lower left (east) of Jupiter in the pre-dawn sky and just to the left (east) of the stars that form the teapot-shaped asterism of Sagittarius (the Archer). Saturn will officially enter the evening sky on Friday, when it will rise a few minutes before midnight. Dust off your telescope because even a small telescope will show its rings! 

(Above: Low in the eastern predawn sky on Monday, Venus' orbital motion toward the sun will carry it close past distant Uranus, as shown here for 4:55 am local time. Unfortunately, dim Uranus will be swamped by the dawn twilight.)

Distant and dim, blue Neptune is in the southeastern pre-dawn sky, among the stars of Aquarius (the Water-Bearer). The planet will rise at about 3 am local time. But I’d wait for summer, when it will be available in the evening sky, to look for it. 

Distant Uranus will sit a few finger widths above our next-door neighbour Venus in the east-northeastern sky on Monday morning. But the dawn twilight will make seeing the planetary pairing extremely difficult.

(Above: The sky between Leo and Ursa Major, shown at 10 pm local time, features a number of galaxies that can be seen in backyard telescopes under very dark skies. The sky to the upper left of Leo's star Denebola, toward Virgo, contains thousands more.)

Dark Sky Galaxies

Towards the end of this week, the waning, late-rising moon will leave the evenings nice and dark worldwide – ideal for hunting for dimmer targets such as the spring galaxies in Leo (the Lion) that are observable in backyard telescopes. The well-known Leo Triplet consists of three spiral galaxies with the names Messier 65, Messier 66, and the Hamburger Galaxy (NGC 3628). All three galaxies will fit within the field of view of a telescope at low magnification. Their visual magnitudes range from 8.9 to 10.3, and all three have good surface brightness due to their near edge-on orientations.

(Above: The constellation of Leo, the Lion is in ther western evening sky, as shown here at 10 pm local time. It contains many galaxies (coloured ovals), including the Leo triplet at upper left, near Chertan, and another grouping positioned just under the lion's belly.)

Find the trio about 3 finger widths to the lower left (southeast) of the medium-bright star Chertan, which marks the lion’s rear foot. Another group of prominent galaxies is positioned about midway between the triplet and the bright star Regulus. The close pair of Messier 105 and NGC 3384 resembles headlights in the fog when viewed in a telescope. Two more galaxies, Messier 95 and Messier 96, are located a finger’s width below those “eyes”.

(Above: If you draw an imaginary line across the Big Dipper's bowl and continue it beyond the star Dubhe, you'll arrive at the pair of spiral galaxies known as Bode's Nebula, labelled near the bottom of the picture. Other ovals represent additional, dimmer galaxies. During evening in late May, the Dipper is inverted. But it rotates a  little every month.)

Although Ursa Major (the Big Bear) is a circumpolar constellation, it moves to a location very high in the northern sky in late evening during late May – a position ideal for observing the galaxy showpieces within it. The Big Dipper makes up most of Ursa Major. Drawing a line through the dipper’s bowl to connect the bright stars Phecda to Dubhe, and then extending the line by an amount equal to their separation, brings one to a pair of spiral galaxies called Bode’s Nebula. The larger and brighter galaxy is named Messier 81. It’s a magnitude 6.9 spiral galaxy oriented not quite face-on to Earth. The other galaxy, named Messier 82, is located half of a finger with to the lower right of Messier 81. It is smaller - but bright due its nearly edge-on orientation. Several other galaxies can be found within a few finger widths of Bode’s Nebula.