All posts by AstroJim

Jim has been an astronomy and space exploration enthusiast since early grade school. As the result of a renewed interest in astronomy in 2012, he bought his first "real" telescope and mount. He has since ventured into astrophotography, and continues to acquire equipment, skills, and knowledge to improve his capabilities.

2020 Astronomy Guide

As things do from time to time, new ideas pop into my head, and a pursue what of them that I can. Writing a guide like this seems like a great way to gather many sources into one, easy to use location.

As can be seen in this article, and in the Events Calendar, 2020 will be an astronomically busy and interesting year!

The Best Meteor Showers

Meteor showers occur as a result of Earth passing thorough a comet’s orbital path, which is strewn with debris that were left behind as its ices vaporized during close passes of the Sun. Some key points to note when going out to observe a meteor shower is the date and and time of day for peak meteor rates, Moon’s phase, meteors per hour and location in the sky. Some showers begin a week or more before the peak, but the peak will be the best opportunity for a great show. The time of day is important, and most are best observed around midnight, or in the pre-dawn hours. As most meteors are quite dim, the Moon’s phase/location in the sky is a factor. If the Moon is full, which means that it is bright and up all night, at the time of a shower many meteors will be washed out. A dark sky location is important for this same reason. The important clue to the location in the sky is the meteor’s name. All meteors associated with a named shower will appear to radiate from the constellation for which it is named. Leonids’ radiant, for instance is in the constellation Leo. Concentrating on the area of the sky halfway between the radiant and the zenith seems to work best for most showers. And a word about comfort. Dress warmly and perhaps use blankets or a sleeping bag. It is colder than you think, even in the summer. Also, a patio lounge chair will eliminate strain on the neck.

Planets

The planets can be observed wandering among the stars. Movements of the fast-moving inner planets, Mercury and Venus, can be detected from one night to the next. Mars, slower and farther out, can be seen to move in the course of a month. Jupiter and Saturn require several months before noticeable movement is detected. This movement, always close to the ecliptic, occasionally results in interesting conjunctions with other planets, the Moon, or bright stars that lie along the ecliptic.

An interesting position for the inner planets is greatest elongation (from the Sun). Because Mercury and Venus’ orbit lies inside Earth’s, the size of their orbit limits how far these two planets can be separated from the Sun as they wander. Mercury is most easily seen within a few days of this event, and Venus is near its brightest.

An interesting position for the outer planets is opposition (from the Sun). This is the point where the Sun, Earth and a planet fall in a straight line with Earth in the middle. Where ever the Sun is, look in the opposite direction to see the planet at opposition. This is when the planet is closest to Earth, and therefore it appears larger and more detailed in the telescope, and it is at its brightest.

Planetary Movements to Watch.

Mercury will make three evening appearances in the western twilight and three morning appearances in the pre-dawn eastern twilight. Look for this elusive planet about 15 minutes after sunset, or 30 minutes before sunrise at the times of it’s greatest elongation from the Sun.

Greatest eastern elongations (evening) are March 23, July 22, November 10.

Greatest western elongations (morning) are February 10, June 3, and October 1.

Venus will already be two months into an evening apparition as 2020 begins. It will be bright well-placed for observation until mid-April, at which time it will be at its greatest elongation, and appear telescopically as a “half” Venus. Venus will coincidentally be near its brightest near greatest elongation. As it continues along its orbital path, it will grow larger, and will present an increasingly thinner crescent as it begins to grow dimmer and move closer to the Sun as this apparition ends in May. It will be prime for telescopic views as it enters its crescent phases in mid-April.

Mars begins the year as a morning object in an apparition that will last until 2021. Look for a lunar occulatation in February. It starts the year rising at 4 am, and it will continue to rise earlier each morning until it begins rising before midnight, thus becoming an evening object in mid-May. Mars reaches opposition in mid-October, which is when it will be closest to Earth, and it will present its brightest appearance. Near opposition, amateur astronomers with modest telescopes can observe the redder and darker areas of the planet to detect its daily rotation, and polar ice caps can be observed.

Jupiter begins apparition in that will last into 2021 when it emerges from behind the Sun in mid-January. It rises earlier each morning until it becomes an evening object rising before midnight on May 11th. Jupiter reaches opposition on July 13, when it is closest to Earth. Watch Jupiter as it is chased across the sky by Saturn all summer and fall, culminating in a spectacular and exceedingly close conjunction at about 1/10° separation on December 21st. Telescopically, changes in Jupiter’s bands, transits of The Great Red Spot, and movements of the Galilean moons are among the most interesting planetary phenomena for amateur astronomers.

Saturn also begins its next apparition in January, just a few days after Jupiter. It reaches opposition on July 20th, just a week after Jupiter. Read about Jupiter in the paragraph above for information about Saturn – Jupiter interaction this year. Saturn’s rings are the solar system’s show stopper, even in small telescopes. Bands on the planet’s surface, and some of its moons can be observed with a modest telescope.

This site’s Events Calendar can be monitored for dates of the events described here, and others.

SpaceX Starlink 2 Mission

The SpaceX Starlink 2 mission launched 2020-1-6 @ 21:14, and released 60 Starlink satellites at about 22:16. Packed one against the other as they were released at 350 km above the Earth’s surface, these satellites will disburse as they attain higher orbits over time. As this disbursement progresses, the “train” appearance of the 60 satellites will diminish.

Starlink 1 Satellite Train. Reddit. 2019-12-15

To find opportunities to view the Starlink 2 train, use a satellite tracker to determine when favorable passes occur for your location. I use me.cmdr2.org/starlink, which is designed specifically for Starlink passes. Using lat/lon coordinates rather than selecting a city will give you better precision. I use N39.14/W77.00 for my location in central Maryland.

To actually observe the train, use the time and direction information provided in the tracker to determine when and where to look. The train should be clearly visible with the unaided eye. I wouldn’t recommend anything stronger than binoculars if a closer look is desired.

Using me.cmdr2.org/starlink and accounting for weather forecasts in my area, I arrived at two possible opportunities to observe passes. These can be seen in the Events Calendar. As the satellites’ orbital characteristics are changing, I expect that he times of these events could change. If so, I will update theses events in the calendar, and I will add more events to the calendar if they appear in the tracker.

An Interesting Astronomical Observation Project

Most people intuitively know that days are shorter and nights are longer during the winter months, and days are longer and nights are shorter during the summer months. For those people who don’t know why, but would like to develop an understanding of why that is, here is an interesting observation project that begins to tease out the answer.

As I write this on December 23, 2019, we are just two days past the winter solstice, or the astronomical first day of winter. This event coincides with the shortest day and longest night of the year. And, at around this time, the sun rises and sets at its southernmost point on the horizon. This is a great time to begin the project, and observe the rise and set points move northward over the next six months.

This project can work with observing just sunrises, just sunsets, or both. After deciding when events you can observe, the first thing to do is select one or two observation points that are readily and repeatedly available. One should be toward the east in the mornings for sunrises, and the other toward the west in the afternoons for sunsets.

For the most casual observer, make a mental note of the sunrise or sunset point of the horizon, and the time. This first observation is your baseline. Make this observation every couple of days, and compare them with your baseline observation. During the period between the winter solstice (around December 21st) to the summer solstice (around June 21st), an observer should note that the rise or set point moves northward as the winter and spring progress. The sunrise time should be earlier and the sunset time should be later during this progression. By the time you get to June, you’ll be surprised at how much the rise or set points have moved, and how much the time has changed as well. From June 21st back to December 21st, the rise or set point should be moving southward on the horizon while the rise time gets later and the set time gets earlier.

More sophisticated observers can use a compass to record the azimuth of the sunrise or sunset, and record their observations in a spreadsheet for later analysis. A magnetic compass that can read degrees or a smartphone app can do the job. If you’ve never used a compass, they are not difficult to learn, and there are many online resources. Also, be sure to record the time in Universal Coordinated Time (UTC) to eliminate any confusion that daylight savings time might impose.

As an example for us in the eastern time zone, to convert standard time (EST) to UTC, add five hours. To convert daylight savings time (EDT), add four hours. Be aware that from early May until mid-August, sunset times of 8 pm EDT (and later) will use the next days date. For instance, sunset at 8:36 pm on June 21st might be recorded as 2020-06-21 20:36 EDT. Converting this to UTC by adding four hours pushes the time past midnight, and results in 2020-06-22 00:36 UTC.

If anyone actually does the observations, and would like an interpretation of the results, I would be glad to work with you, or write more on this topic, just let me know.

Did I Image 2I/Borisov this Morning?

Bottom line up front, at this point I have no idea if I photographed 2I/Borisov, (the comet, hereafter) or not.

Here’s what I have to go on so far. The first image depicts a Stellarium rendering of the star field in which the comet was located when I imaged it this morning. Its computed location is indicated with a red X.

Stellarium frame rendering of Comet 2I/Borisov’s star field as of 20191207 0514EST. Annotations by Jim Johnson, December 7, 2019.

Next is an actual telescopic image from this morning. It is annotated to guide the reader through this discussion.

Annotated image of Comet 2I/Borisov taken 20191207 0514EST by Jim Johnson.

The frame scale and orientation are almost exactly the same for both the Stellarium rendering, and this morning’s photograph. Also in both images are green lines that highlight groupings of stars I used to determine that I had at least photographed the star field that should contain the comet.

In the actual photograph, I have placed a red circle in approximately the same relative location that the Stellarium rendering expects the comet to be, but I cannot see anything in this location.

I have also circled in blue two objects in the photograph that are not in the Stellarium rendering, and that are brighter than I expect the comet to be. I believe that these two objects are not stars, because I have done a lot of detailed comparisons between Stellarium renderings and actual photographs of the same star field. I have never found Stellarium to miss a star.

But I cannot say that they are the comet. That there are two unidentified objects instead of one in the photograph is suspicious.

Their brightness is suspicious too. The comet is projected to be 15.6 magnitude. Keeping in mind that a larger number equates to a dimmer object this would be a very dim object, even if it were a star. But comets are diffuse objects, not pinpoint objects like a star. This means that a comet’s reflected light is spread out over a wider area than a star, thus making it appear dimmer than a star of the same magnitude.

In the annotated photograph, I marked the magnitudes of three reference stars in orange. All three of these stars are of a lower (brighter) magnitude than the comet is projected to be, but even so, two of these three stars appear dimmer than the two circled objects. The third (11.2 magnitude), suggests that both of the unexplained objects in the blue circle are roughly 11th magnitude.

As I confessed at the beginning of this article, I do not know if I captured Borisov or not, but I have some guesses. One thing that could account for the separation between the blue circle (actual location of something), and the red circle for the computed location is that cometary data are updated periodically, and perhaps a future update will provide a more accurate computed location that places them within the blue circle. Another possible scenario that I would assess as highly unlikely, is that the comet broke into two pieces, and all of the freshly exposed ices caused the comet to flare up in brightness. Still not probable is that the flare up pushed the comet off of its original path, thus creating the discrepancy between the blue and red circles.

I will keep an eye out for news and cometary data updates for the next few days and report any new findings.

Jim Johnson’s Total Solar Eclipse of the Sun Experience

At about 1327 CDT on August 21, 2017 near Gordonsville TN, I stood less than 100 yards off of the center of the path of totality, waiting for the moon’s shadow as it raced across the earth’s surface, and I stood within that shadow for about two minutes and 39 seconds. A combination of many things put me in that time and place. Perhaps luck, skill, and drive were among them. Many have asked me to describe the experience, and my first words have included the word “beautiful”, and something like “words cannot describe. This article will be of few and inadequate words.

Astonishment is the single word that is probably most descriptive of my reaction. I had read a lot about eclipses, and I thought that I knew what to expect. Nonetheless, I was completely astonished at how quickly and how deeply the final darkness set in from the time that I could last see stark shadows on the ground, and then no shadow at all. The reappearance of light and shadows at the end of totality happened equally as fast.  I was astonished at how bright and how large the sun’s corona appeared, and equally astonished at how vastly black and empty the moon appeared at the center of the corona. Gazing upon the combined effect felt to me as if a hole had opened up in the fabric of the universe. I actually felt a moment of panic.

I did manage to see Venus and Jupiter. I looked for, but could not see Mars nor Mercury. I could see parts of the “360 degree sunset” anywhere that I had a clear view of the distant horizon.

I made an effort to observe a phenomena called earthshine, where sunlight falling on the earth’s surface is reflected up to the moon, and back to the earth again. As I said before, I was astonished at how utterly black the moon appeared at the center of the sun’s rather bright corona.

I tried to observe the approaching umbral shadow of the moon, but could only see indirect evidence of it as light changed in and on the distant clouds. I also tried to view shadow bands against a white shirt that I had dropped onto the ground – nothing there either. All in all, no big deal.

I did not think to try to observe prominences on the sun. This is understandable as I had just lost my mind.

I visually observed first contact, the first bite that the moon took out of the sun, through a filtered telescope. I took peeks at it off and on in this manner, and with eclipse shades for the 90 minutes from first contact to totality. I did not observe anything after third contact when the sun emerged from the other side of the moon’s disk.

I managed to see the diamond ring effect just prior to totality and just after totality. I did not see anything that I could identify as Baily’s Beads.

I was able to observe solar crescents resulting from the pinhole effect of leaves in a tree just prior to totality. I noticed that the quality of the light changed, and shadows appeared to sharpen. And certainly, I could feel the sun’s intensity drop from early in the partial phase of the eclipse.

I did not notice any animals, so no behavioral changes were noted.

Secondarily to the eclipse, I devised an automated method of taking some images prior to and during totality. I clicked a Start button, and did not have to fiddle with the camera/telescope until after the imaging run was complete. Some preliminary, pre-processed images follow below.

The first image is of the diamond ring that appears in the final seconds before totality. In addition to the brilliant diamond, there are some features of interest to note in this photo. All three regions of the sun’s atmosphere can be seen. The white area from the reddish area just above the diamond to the reddish area just below the diamond is the photosphere. This region of the atmosphere is closest to the sun’s surface, and the white light that we observe from the sun originates here. The chromosphere is the next highest region of the sun’s atmosphere. It can be seen in the two reddish areas previously mentioned. Also, at about 2:30 and 4:30, promeninces rising out of the chromosphere can be seen. And finally, everything else, and the bright parts of the other two images are the outer region of the corona, which is the main event for a total eclipse of the sun. A final, processed image will be available shortly.

My travel plan was to arrive at Louisville, KY on the day before the trip, assess the weather, and choose an observing location on the morning of the eclipse.  This reduced my risk of being locked into a location that would be clouded out on the day of the eclipse. Gordonsville TN was the location that I choose and drove to that morning. They skies had been crystal clear all day but cumulus clouds rolled in just as the moon’s disk began to cover the sun. Since there was enough clear skies between the clouds, and they were moving along at a pretty good clip, I felt confident that I would be able to get a glimpse of totality, if not see all of it. As it turned out, the sky became crystal clear again before totality arrived.

The entirety of the driving was arduous, and I put a lot of effort into planning for the trip. In short, it was well worth the effort, and I will put myself in the path of the moon’s shadow at every opportunity.  The next total eclipse of the sun occurs on April 8th, 2024, just a little over six years from now. I encourage everyone to plan to travel to the path of totality to see this astonishing event.

The Great American Eclipse - Diamond Ring
The Great American Eclipse – Diamond Ring

 

The Great American Eclipse - Corona
The Great American Eclipse – Solar Corona

 

The Great American Eclipse - Solar Corona
The Great American Eclipse – Solar Corona

Catching Up

It has been a while since I have written in Jim’s AstroLog, but I have been busy. Here’s a brief run down what what I have been up to. Maybe I’ll add more to fill in the blanks as time permits. I should say that I am enjoying writing again, even after these few words.

Federal Employee

Work and a long commute consumed just about every minute that I could have otherwise had to pursue my own interests.  The last two years with my former agency were among my best, but even that  (not to mention myself) was getting old. So I moved on.

Retiree

Big news – I retired (again) at the end of April, 2017, and I have been busy getting used to that. I kinda like it. I am probably working harder that I’ve ever worked, but with the difference being that I am doing the things that I have always wanted to do, which is especially nice.

HAL Officer

I was elected to the Howard Astronomical League as secretary for the Boards’ 2015 term, and served in that capacity again for the 2016 term. I was elected president for the 2017 term, and I am now in my second term in that capacity. Big news for the club during my tenure as president is accepting a Takahashi TOA 150 and an Astro-Physics 1200GTO mount from David Illig, and embarking on a project to upgrade the club’s observatory. This equipment is installed in the observatory and is being readied for the club’s members use. I expect to write more about this.

www.howardastro.org

Professor

In the last few days before I was retired, the opportunity to teach and I found each other – I have taught three semesters of astronomy at Howard Community College. I had absolutely no interest in working after retirement, but this has been a dream job that I never thought that I could find. I am really enjoying this gig! The SET department and I have been discussing the addition of an honors section to the course, and I am looking forward to bringing it on line and teaching it. Definitely more to write about here.

Master Gardener

Gardening is my other hobby. I enrolled in the Montgomery County Master Gardener Program with the 2018 class of interns. Still serving as an intern for the rest of this year.

Astronomer

With the exception of a trip to the Almost Heaven Star Party in West Virginia in September 2016, and to Kentucky/Tennessee to view the total eclipse in August 2017, I have doing very little of my own astronomy since I last wrote.

I finally cleared the decks and put my own personal astronomy ahead of just about everything else.  The impetus was signing up for the Almost Heaven Star Party 2018. Much to write about here, so expect another article.

Buying More Aperture

I have written about my bout with aperture fever on this site, and how I overcame the affliction – at least temporarily. To be fair to myself, I did a through assessment of why I bought the Televue NP101 (4″ apochromatic refractor), and I came to terms with why it is a fine instrument. I am by no means abandoning this telescope. It has a place in my collection, and it can do things that the light bucket that I am about to describe could never dream of doing. I expect to use it often for as long as I am able to engage in my hobby.

Please indulge me for one more paragraph before I describe what I am buying. I have also written here about why I bought the NP101 in the first place – I am preparing to enjoy my life-long love of astronomy in my retirement. The acquisition that I am presently pursuing will add another dimension to my enjoyment of my hobby, and to my ability to share my hobby with others. And to be sure, this new instrument can do things that the NP101 can never dream of doing. There is plenty of room for both instruments in my collection.

The telescope that I have ordered is a Meade LX200 12-inch f/8 Schmidt-Cassegrain reflecting telescope. Unlike others I know who have purchased Meade or Celestron Schmidt-Cassegrain reflectors, I chose to forgo the Meade fork-style mount, and chose instead the Losmandy G-11 German equatorial mount (GEM) with the Gemini II goto system.

This telescope weighs 56 pounds, which exceeds the capacity of my Losmandy GM-8. I chose Losmandy mount over a Meade fork-style mount, because I intend to do astrophotography. A fork style mount is simple to use and is great for visual astronomy. It is, however, completely inadequate for astrophotography. This, and my familiarity with Losmandy made the G-11 a natural choice. And since finding objects with an instrument of this focal length (much narrower field of view) will be exceedingly more difficult than with my NP101, I ordered the Gemini II goto system to reduce the amount of time time required for find the object that I might be trying to visually observe or photograph.

I expect to take delivery of the telescope and mount in six to eight weeks. I will not be sharing the news of my telescope’s arrival with my amateur astronomer friends, because they will most undoubtedly hold me accountable for the many cloudy nights that are sure to follow its arrival. Meanwhile, I must maintain my sanity by being calm and forgetting that I have a new telescope on order.

© James R. Johnson, 2016
jim@jrjohnson.net.

 

August 2015

INTRODUCTION

This is the hottest and most humid month of the year in Maryland. Don’t be discouraged though. There will be that occasional night when the hot weather breaks, and getting reacquainted with the night sky will be an exhilarating experience. So keep your eye on the weather and take advantage of those wonderful nights. Be sure to look for the Summer Triangle, which a large triangle of bright stars that is nearly directly overhead at nightfall. These stars are Vega in the constellation Lyra, Altair in the constellation Aquila, and Deneb in the constellation Cygnus.

About Scope Out      How to begin Observing the Night Sky

THE CONSTELLATIONS

The sky map below represents the sky as it will appear in mid-August at the end of astronomical twilight, or the arrival of complete darkness, at about 9:30pm EDT. The Scope Out monthly focus is on the constellations that are  just to either side of the meridian, which is near the 18th hour (18h) of right ascension line in the August sky map below. For a primer on how to use this sky map, please read How to begin Observing the Night Sky.

Scope Out divides the celestial sphere into three zones to aid in finding constellations:

1. Circumpolar Constellations: Find Usra Minor standing up on its tail, and Draco in the northern sky above Polaris.

2. Northern Constellations:  Find August’s remaining northern constellations, Corona Borealis, HerculesLyraAquila, and Cygnus near the zenith.

3. Southern Constellations: The best-placed constellations in April are Ophiuchus, Serpens, Scorpius and Sagittarius. Some of these, Scorpius and Sagittarius, for example, never rise very far above the horizon because of their deep southern declination.

The August Night Sky, Jim Johnson, December 14, 2014.
The August Night Sky, Jim Johnson, December 14, 2014.

THE PLANETS
planets
Colors of the planets. This picture is not to scale. Image from NASA’s Planetary Photogrounal at http://photojournal.jpl.nasa.gov/

Mercury is an evening object most of this month, appearing low on the western horizon as darkness falls. Mercury will be in conjunction with Jupiter on August 6th, and Jupiter, Mercury and the bright star Regulus can be seen within 1° of one another on August 7th. Mercury reaches this apparition’s brightest magnitude (-1) on August 21st, and its greatest eastern elongation on August 31st. Venus can be glimpsed by a determined binocular viewer early in the month. It will be very low on the horizon, and it will set just a few minutes after sunset. By mid-month, Venus will be lost in the sun’s glare, and thus a spectacular evening apparition ends. By month’s end, Venus will be on the other side of the sun as viewed from earth, and can be seen low on the eastern horizon about 30 minutes before sunrise. Jupiter also ends its evening apparition this month as it slips into the sun’s glare early in August, not to be seen again until it reappears as a morning object in September. Mars is a morning object, rising on the eastern horizon just before sunrise. Saturn, the sole bright planet that is easily visible, steals the planetary show this month. Look for it low in the southern sky near the distinct head of Scorpius. Uranus and Neptune are still morning objects that rise above the eastern horizon in the wee hours of the morning They can be seen by a determined binocular observer.

THE LUNAR CALENDAR

moon_phases_small_lastqtr August 6
3rd Quarter
moon_phases_small_new August 14
New Moon
moon_phases_small_firstqtr August 22
1st Quarter
August 22
Conjunction with Saturn
moon_phases_small_full August 29
Full Moon

Events

Very close grouping of Mercury, Jupiter and Regulus – August 7th

These three objects will be positioned within 1° of one another providing a pretty grouping with the unaided eye, or within a telescopic field of view at low magnification.

Perseid Meteor Show – August 11 to 14.

The moon, a waning crescent, is well positioned to provide a dark sky for observing the Perseids this year.

© James R. Johnson, 2015
jim@jrjohnson.net

July 2015

INTRODUCTION

Summer’s heat is here and it is vacation season. Vacations are often an opportunity to get away from the city lights, so if you happen to be so lucky, be sure to take advantage of every opportunity to enjoy a much darker, and hence starrier night sky than what you might be accustomed to at home. In addition to being prepared for the cool nights that occur even during the summer, be sure to bring along something to keep the bugs away.

About Scope Out      How to begin Observing the Night Sky

THE CONSTELLATIONS

The sky map below represents the sky as it will appear in mid-July at the end of astronomical twilight, or the arrival of complete darkness, at about 10pm EDT. The Scope Out monthly focus is on the constellations that are  just to either side of the meridian, which is near the 12th hour (12h) of right ascension line in the July sky map. For a primer on how to use this sky map, please read How to begin Observing the Night Sky.

Scope Out divides the celestial sphere into three zones to aid in finding constellations:

1. Circumpolar Constellations: Find Usra MinorUrsa Major and Canes Venatici in the northern sky above Polaris.

2. Northern Constellations:  Find July’s remaining northern constellations, Leo, Leo Minor, Coma Bernices, Bootes and Corona Borealis near the zenith.

3. Southern Constellations: The best-placed constellations in April are Crater, Corvus, and Virgo. Some of these, Crater and Corvus, for example, never rise very far above the horizon because of their deep southern declination.

July
The July Night Sky, Jim Johnson, December 2014.

THE PLANETS
planets
Colors of the planets. This picture is not to scale. Image from NASA’s Planetary Photogrounal at http://photojournal.jpl.nasa.gov/

Mercury begins the month as a morning object, just past its peak for optimal viewing. Look for it in the eastern morning sky about 75 minutes before sunrise. It quickly dives back into the sun’s glare and is lost by month’s end. Venus and Jupiter are the bright pair in the western sky just after sunset.  They are just one day past a very close conjunction as the month begins, and they will travel together while remaining in relatively close proximity to one another. They will  appear just a bit closer to the western horizon with the passing of each evening. Venus‘ telescopic appearance will change dramatically during the month, beginning as a rather thick crescent, and then closing the month as a fingernail crescent. Venus’ apparent disk will appear noticeably large as well as the month progresses. Mars begins to emerges as a morning object by month’s end, and will be difficult to see without binoculars. Look for it near Mercury about 45 minutes before sunrise on the eastern horizon on July 16th. Saturn is just past its optimum viewing position with respect to disk size and brightness. It is placed higher in the sky for easier viewing at nightfall. Uranus and Neptune are morning objects that rise just before dawn.

THE LUNAR CALENDAR

moon_phases_small_full July 1
Full Moon
moon_phases_small_lastqtr July 8
3rd Quarter
moon_phases_small_new July 15
New Moon
July 18
Conjunction with Venus and Jupiter
moon_phases_small_firstqtr July 24
1st Quarter
July 25
Conjunction with Saturn
moon_phases_small_full July 31
Full Moon (aka Blue Moon)

Events

Earth reaches Aphelion – July 6

The Earth reaches its farthest distance from the Sun during its annual orbit about the Solar System’s star. There are no direct observables for the casual astronomer, but if the Earth were at perihelion, or the closest distance to the Sun, on this date, northern hemisphere summers would be noticeably warmer.

Very close grouping of Moon, Venus and Jupiter – July 18

Look for a very pretty grouping of a fingernail crescent Moon with Venus and Jupiter low on the western horizon right after sunset.

Blue Moon – July 31

The occasion of a second full moon during a calendar month is known as a “blue moon.” July’s first full month was on July 1st.

© James R. Johnson, 2015
jim@jrjohnson.net

June 2015

INTRODUCTION

Summer arrives this month, and with it, those seemingly endless days. Summer nights, of course are exceedingly short. In fact, Civil Twilight, which is not very dark, ends at 9:50 pm and begins at 4:30 am around the Summer Solstice on June 21st. Summer nights are only about 6 1/2 hours long! Compare this to winter nights, which are about 12 1/2 hours long. If we astronomers could only have both summer weather and winter-length nights at the same time.

About Scope Out      How to begin Observing the Night Sky

THE CONSTELLATIONS

The sky map below represents the sky as it will appear in mid-June at the end of astronomical twilight, or the arrival of complete darkness, at about 10pm EDT. The Scope Out monthly focus is on the constellations that are  just to either side of the meridian, which is near the 12th hour (12h) of right ascension line in the June sky map. For a primer on how to use this sky map, please read How to begin Observing the Night Sky.

Scope Out divides the celestial sphere into three zones to aid in finding constellations:

1. Circumpolar Constellations: Find Usra MinorUrsa Major and Canes Venatici in the northern sky above Polaris.

2. Northern Constellations:  Find June’s remaining northern constellations, Leo, Leo Minor, Coma Bernices, Bootes and Corona Borealis near the zenith.

3. Southern Constellations: The best-placed constellations in April are Crater, Corvus, and Virgo. Some of these, Crater and Corvus, for example, never rise very far above the horizon because of their deep southern declination.

May
The June Sky at Nightfall, Jim Johnson, December 2014.

THE PLANETS
planets
Colors of the planets. This picture is not to scale. Image from NASA’s Planetary Photogrounal at http://photojournal.jpl.nasa.gov/

Mercury begins a morning apparition at the beginning of the month, and it is best observed at its peak western elongation on June 24th. Look for it in the eastern morning sky about 45 minutes before sunrise. Mars in now hidden in the sun’s glare and will not be visible until it emerges as a morning object later this summer. Venus is the very bright object in the western sky after sunset. It is near its peek elongation from the Sun, and telescopically presents an appearance similar to a crescent moon. The crescent will become thinner, and the planet’s disk will appear to grow larger through the remainder of its evening apparition. Jupiter is the bright object that appears nearly overhead at nightfall. Read about its coming conjunction with Venus below. Saturn is just past opposition, and can be found above the eastern horizon at sunset. It remains showy both visually and telescopically. Uranus and Neptune are morning objects that rise just before dawn.

THE LUNAR CALENDAR

moon_phases_small_full June 2
Full Moon
moon_phases_small_lastqtr June 9
3rd Quarter
moon_phases_small_new June 16
New Moon
June 19
Conjunction with Venus
June 20
Conjunction with Jupiter
moon_phases_small_firstqtr June 24
1st Quarter
June 28
Conjunction with Saturn

Events

Summer Solstice – June 21

Summer officially begins when the sun reaches its northernmost point on the celestial sphere at 12:38pm on June 21st. At local noon, when the sun reaches the meridian, it will be at its highest point in the sky for observers north of the Tropic of Cancer. The longest day of the year and the shortest night of the year occur within a few days of this date.

Conjunction of Venus and Jupiter – June 30

Venus and Jupiter have been visible together in the evening sky since March, with Venus on the western horizon and Jupiter on the eastern horizon. These two planets have been slowly approaching one another these past few months, and will finally meet at month’s end. They begin the month about 20° (about a hand’s length) apart. Venus will be near Gemini’s two brightest stars, Castor and Pollux, and these three objects will appear in a nearly straight line on June 1st. Jupiter will be to their east. The moon will move through this area just after mid-month, passing Venus on the 19th, and Jupiter on the 20th. The two planets will reach conjunction on June 30th, appearing just 1/3° apart, which is the same field of view of most telescopes.

© James R. Johnson, 2015
jim@jrjohnson.net