Skywatcher's Guide: April and May 2018
- Stars and Constellations
- Solar System
- Calendar of Night Sky Events
- Deep Sky
- Frequently Asked Questions
Stars and Constellations
In April, the spring sky is now prominent in the east, along with the familiar Big Dipper. The Big Dipper is high in the northeast, and the two stars at the end of the bowl can be used to find Polaris, our north star. Also, the handle can be used to "arc to Arcturus", a bright star in the constellation Boötes. Next, Leo the lion is very high in the east, approaching the middle of the sky now, with the constellation Virgo just below. The winter constellations are also visible, now in the west. Taurus the bull is getting lower in the west, near Orion the hunter to the west-southwest. Canis Major (the big dog), along with the bright star Sirius, is also getting low in the southwest. Gemini the twins is a little higher in the west, along with Auriga the charioteer in the west-northwest and Canis Minor (the little dog) in the southwest. The winter Milky Way is now getting lower in the west as well. Far to the south we can see some constellations making up part of Jason's Argo Navis, which we only get to see briefly since it is so far south. Finally, there is still a small portion of the fall sky still visible just for the first hour or so of the night. Cassiopeia the queen is in the north-northwest, and Perseus the hero is in the northwest.
In May, the winter constellations are lower in the west, and Orion, Taurus, and Canis Major are already in the process of setting at the beginning of the night, along with Cassiopeia and Perseus to the northwest. The spring constellations are higher now, and we can see the rest that weren't up this time last month. Hercules is below Boötes in the east-northeast. Some of the summer constellations are also getting ready to come up and will be visible a few hours after sunset.
Interesting Stars Visible in April and May (during observatory hours)
|Name / Designation||Apparent Magnitude
(lower = brighter)
|Regulus||1.36||77||means "Little King"|
|Almak||2.1 / 5.0 & 6.3||355||triple star system w/ 64 yr orbit|
|Albireo||3.2 / 5.8 & 5.1||390 / 380||possibly a triple star system|
|Eta Cassiopeiae||3.5 / 7.4||19||480 yr orbit|
Mercury is passing between us and the sun in early April, but will emerge in the morning sky by the end of the month. It will then begin to disappear again in late May.
Venus keeps rising higher and higher in the evening sky throughout April and May.
Mars rises earlier and earlier each night, eventually coming up before midnight by late May.
Jupiter rises a little after sunset in April, and then a little before sunset in mid and late May.
Saturn rises earlier and earlier each night, coming up before midnight by the end of April.
Jupiter Great Red Spot Transits during April and May (when the Flandrau dome is open)
Note: The GRS is visible on the disk of Jupiter for 50 minutes before and after meridian transit time.
|Date||Meridian Transit Time|
|04/01/18||Mercury at inferior conjunction. — Between us and the Sun.|
|04/02/18||Appulse of Mars and Saturn. — Separated by 1.3°.|
|04/08/18||Last Quarter Moon.|
|04/18/18||Uranus at conjunction. — Passing behind the sun.|
|04/22/18||Peak of Lyrids meteor shower.|
|04/22/18||First Quarter Moon.|
|04/25/18||Appulse of Mars and Pluto. — Separated by only 1.4°.|
|04/29/18||Mercury at greatest western elongation. — Visible in the morning before sunrise.|
|05/07/18||Peak of Eta Aquariids meteor shower.|
|05/07/18||Last Quarter Moon.|
|05/08/18||Jupiter at opposition. — Best time to see our largest planet.|
|05/13/18||Appulse of Mercury and Uranus. — Separated by 2.2°.|
|05/21/18||First Quarter Moon.|
The winter Milky Way is now getting low in the west, but there are still several interesting objects we can see here. The Pleiades (Seven Sisters, M45) is close to the west-northwest horizon right next to the Hyades (C41), which makes the face of Taurus the bull. The constellation Auriga is a little bit higher, where we can see M36, M37, and M38, which are visible with binoculars. The Double Cluster (C14) in Perseus is low in the north-northwest. Higher in the sky we have the Beehive (Praesepe, M44) in Cancer the crab and Coma Berenices (Bernice's Hair) near the tail of Leo.
We are now beginning to see some globular clusters coming up in the east. M3 is towards the east, in the constellation Boötes. Nearby, the famous Hercules Globular (M13) is low to the east-northeast.
For nebulae, we have the spectacular Orion Nebula (M42) now now getting low to the west-southwest. This is the closest star-forming region to our solar system. We also have some good planetary nebulae, which come from dying stars. The Eskimo (C39) in Gemini is high in the west, the Owl (M97) in Ursa Major is high in the northeast, and the Ghost of Jupiter (C59) is to the south in the constellation Hydra.
And now the galaxies: In Ursa Major to the north we have Bode's Galaxy (M81) and the Cigar Galaxy (M82), close enough to be seen together in a low-power telescope. Nearby in the constellation Canes Venatici we have the Whirlpool (M51), which is a pair of colliding galaxies. The Pinwheel Galaxy (M101) is also nearby near the handle of the Big Dipper. Then the Sombrero Galaxy (M104) is in the southeast in the constellation Virgo.
Interesting Deep Sky Objects to Observe during April and May (during observatory hours)
|Designation||Name||Apparent Magnitude||Apparent Size||Distance
|Messier 45||Pleiades||1.6||110'||440||open cluster|
|Messier 44||Beehive Cluster||3.7||95'||577||open cluster|
|Messier 42||Orion Nebula||4||85' x 60'||1400-1600||diffuse nebula|
|Messier 33||Triangulum Galaxy||5.7||67' x 42'||3,000,000||spiral galaxy|
|Messier 3||(in Canes Venatici)||6.2||18'||34,000||globular cluster|
|Messier 81||Bode's Galaxy||8.5||21'||1,200,000||spiral galaxy|
|NGC 3242||Ghost of Jupiter||8.6||25"||1400||planetary nebula|
|Messier 82||Cigar Galaxy||9.5||14'||1,200,000||galaxy|
What can we gain by studying astronomy?
Because space is "out there" (literally) it might be hard to see how looking into the cosmos can benefit humanity here on the Earth. But there are a lot of things we can gain by studying astronomy.
First off, Earth is of course located in space, so it is good to watch out for other things that might affect us — what we call space weather. This includes asteroids and comets that come near to us, as well as solar storms that might send charged particles our direction. There are various times in history where space weather has affected our technology, or even life itself. If we are aware of potential threats, we can at least think about ways we can protect ourselves, rather than just waiting for something to happen.
Another way that astronomy benefits us is by refining our knowledge of physics. The conditions on Earth are very tame in terms of pressures, temperatures, radiation, speed, gravity, etc, compared to a lot of other places in the universe. By looking at these types of places, we can see if the equations we use to model physics on Earth still hold true at these extremes. Pushing these equations to the limits can give us more insight into how things work and can fuel research into other areas such as particle physics, quantum mechanics, acoustics, hydrodynamics, etc.
Finally, one way that astronomy research has benefited humanity is through our technology. For example, the cameras we find in our smart phones are basically simplified versions of the cameras first developed for use with telescopes and satellites. Many things that were originally designed for use on spacecraft or by astronauts in space have found their way into everyday use. A quick internet search led me to this article with several examples.
If you have any questions you'd like me to answer in the next issue of SWG, please let me know. I'm also happy to take suggestions or comments, and also pictures if you'd like to send them. Happy viewing!
- Cornelius, Geoffrey. The Starlore Handbook: an Essential Guide to the Night Sky. San Francisco, CA: Chronicle, 1997. Print.
- Ottewell, Guy. Astronomical Calendar 2012. Raynham, Mass: Universal Workshop, 2011. Print.
- Ottewell, Guy. Astronomical Calendar 2013. Raynham, Mass: Universal Workshop, 2012. Print.
- Ottewell, Guy. The Astronomical Companion. 2nd ed. Raynham, Mass: Universal Workshop, 2010. Print.
- Astronomy Magazine. February 2013. Volume 41, No 2.
- Astronomy Magazine. February 2013. Volume 41, No 3.
- Sky & Telescope. February 2013. Volume 125, No 2.
- Sky & Telescope. March 2013. Volume 125, No 3.