06/24/2018 – Ephemeris Extra – Mars Summers

June 24, 2018 Leave a comment

This is a reprint of “Mars Summer” which I wrote for the Grand Traverse Astronomical Society newsletter Stellar Sentinel’s June 2018 issue.

The planet Mars has oppositions from the Sun about every 26 months more or less. These oppositions are a time when Mars is closest to the Earth for its position in orbit. It’s distance at these times range from 34.6 to almost 63 million miles, a range of almost 2 to 1. This is because Mars has a very elliptical orbit as can be seen below.

Mars closest approaches

Mars closest approaches to the Earth from August 27, 2003 to July 31, 2018. Diagram created using Bob Moler’s LookingUp program.

Especially close approaches to the Earth occur every 15 or 17 years in the latter half of summer in those years. My first close approach was September 7, 1956. It was a famous one for the time. Professional astronomers of that time were pretty sure that Mars didn’t have canals, features that were ‘discovered’ by Giovanni Schiaparelli in 1877. To him the features were grooves or channels. Unfortunately the Italian word for them was canali. The world press proclaimed that there were “canals” on Mars. Canals by definition are artificial and require canal builders, Martians by inference.

Like I said, professional astronomers had discounted them by 1956. But science fiction read by young impressionable amateur astronomers like myself talked about old races of Martians hoarding every last drop of water. So maybe we believed. With my 5 inch reflector I observed the polar cap and the large dark feature Syrtis Major.

My next close approach of Mars was August 12, 1971. That summer I was working out of town and in the midst of a move from Grand Rapids to Traverse City, so was unable to observe Mars properly.

In the summer and autumn of 1973 I was able to do an observing program of Mars when it was almost as close as in 1971, drawing its features. I found out that to really observe a planet it takes time to educate the eye and brain to see faint, fuzzy detail. And since I didn’t believe in canals by this time, I didn’t see them.

The next close approach was September 22, 1988. The first “Mars Night” held by the society. We had a great turnout. But Mars was tiny as seen in telescopes. At best it was 23.81 seconds of arc in diameter. The Moon and Sun are about 1,800 seconds in diameter. It would be a bit larger than half the apparent diameter of Jupiter at average distance.

On August 27, 2003 Mars came closer than at any time in 50,000 years some astronomers said. The society held its second “Mars Night” at the Rogers Observatory, and wow, the lines of people ran down the drive and onto the shoulder of the road. As in 1988, I was stationed on the lawn at the front of the observatory with the portable Celestron 11 telescope, which actually gave clearer views than the 14 inch telescope in the dome. (Hot bodies in dome make for lousy seeing.)

2003 is also memorable or rather infamous for the “Mars Hoax” email. Proclaiming that Mars would appear as large as the Moon on August 27th. This hoax has been propagated every two years since. I expect 2018 to be a banner year for the resurrection of the hoax.

We come to this year, 2018, 15 years after the 2003 closest approach. Mars will reach opposition on July 27th. It’s closest approach to the Earth will be on July 31st, at the distance of 35,784,000 miles. The reason the dates aren’t the same is that Mars will still be a month before reaching perihelion, its closest to the Sun, so it’s getting even closer than at the time of opposition.

The Mars oppositions of October 2020, December 2022, January 2025 and February 2027 will be of increasing distances up to 63.0 million miles. This will be followed by oppositions of decreasing distances in March 2029, May 2031, and July 2033 leading to another close approach on September 11, 3035 at 35.4 million miles.

However by 2035 there may be humans on Mars waving back at us. It’s odd that anyone on Mars at the time probably wouldn’t be able to see the Earth at that time. Martian oppositions for us, are the time of inferior conjunctions of Earth with the Sun. We’d be lost in the Sun’s glare.
For the very closest views of Mars get on the Internet and search for Mars Curiosity, Mars Opportunity and Mars Hirise. No telescope required.

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06/22/2018 – Ephemeris – Sun ‘n Star Party scheduled for tomorrow June 23

June 22, 2018 Leave a comment

Ephemeris for Friday, June 22nd. Today the Sun will be up for 15 hours and 34 minutes, setting at 9:32, and it will rise tomorrow at 5:57. The Moon, 2 days past first quarter, will set at 3:25 tomorrow morning.

Tomorrow afternoon and evening will be what we call a Sun & Star Party at the Sleeping Bear Dunes National Lakeshore. This event will be held at the Dune Climb. From 4 to 6 p.m., the Sun will be featured using two types of telescopes, one showing the sun’s photosphere in what we call white light, hoping the Sun will produce a sunspot of two, and another showing the chromosphere above it in the light of hydrogen giving a completely different view with possibly more activity. Starting at 9 p.m. will be a star party, actually really a planet party, viewing the planets Venus, Jupiter and Saturn, plus the Moon. There will be other objects visible in the deepening twilight.  The event is due to the cooperation of the Grand Traverse Astronomical Society and the park rangers.

Update:  The Sun and Star Parties are subject to cancellation separately based on weather.  Check back to this here if there is a cancellation or call the park at 231-326-4700.  The park’s web page for this event is here.   If Saturday night star party is cancelled, some members of the society will hold their own observation session at the Dune Climb Sunday night.  Notification will be posted by 7 p.m. here if that event will take place.  We also invite anyone with a telescope and experienced in its use to join us.  For anyone who wants to have us look at their telescope or give them tips, come to our NMC Rogers observatory star parties which are listed on our society web site: http://www.gtastro.org. Those star parties are less hectic.

The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Dune Climb Setup

This in the beginning of setup for the October 21, 2917 star party at the dune climb. Taken early while there was enough light. The dune blocks up to 12 degrees from the southwest to northwest, but the rest of the horizon is quite low. Venus will be high enough to clear the dune for most of the evening.

Setting up my telescopes at the Dune Climb

My equipment at the Dune Climb on October 21, 2017. My 11″ Dobsonian is in the foreground. The tripod for my Celestron 8 is laying on the ground behind it yet to be set up.
I pointed the Dobsonian at a variety of deep sky objects, while the C8 was pointed to Saturn and tracking that night.

06/21/2018 – Ephemeris – Yay, summer is here!

June 21, 2018 Leave a comment

Ephemeris for Thursday, June 21st. Today the Sun will be up for 15 hours and 34 minutes, setting at 9:32, and it will rise tomorrow at 5:57. The Moon, 1 day past first quarter, will set at 2:57 tomorrow morning.

Welcome to summer! It began at 6:07 this morning. If you remember back to winter and the beautiful constellation of Orion. Some folks could trace the club he was holding over his head off the red star Betelgeuse. The Sun now appears above that. If you remember Gemini the twins, well the Sun is off Castor’s big toe. That’s all pretty high in the sky and giving us 15 hours and 34 minutes of daylight. That’s why summer’s so hot. This despite the fact that in two weeks we will be the farthest we get from the Sun all year. The 3 million mile difference in the Sun’s annual distance is peanuts compared to the seasonal fluctuations caused by the tilt of the Earth’s axis.

The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

The Sun with its position with the stars at the summer solstice

The Sun with its position with the stars at the summer solstice, June 2018. Click on the image to enlarge. Created using Stellarium and GIMP.

Summer Solstice

The sun’s daily path through the sky from horizon to horizon on the first day of summer, the summer solstice. Grid lines are 15° apart. The Sun os plotted at 15 minute intervals. Credit: My LookingUp program.

 

06/20/2018 – Ephemeris – Let’s check out the bright planets for this week

June 20, 2018 Leave a comment

Ephemeris for Wednesday, June 20th. Today the Sun will be up for 15 hours and 34 minutes, setting at 9:31, and it will rise tomorrow at 5:57. The Moon, at first quarter today, will set at 2:29 tomorrow morning.

It’s Wednesday again and time to look for and at the bright planets. Three of them are in the evening sky. The brilliant beacon of Venus will be visible in the western twilight from about 9:50 p.m. until it sets at 11:59 p.m. Mercury is far below and right of it, setting at 10:48 p.m. Jupiter will be in the south as it gets dark. Jupiter is only outshone by Venus and the Moon. And after Venus sets will have the night to itself as the brightest star-like object until it sets at 3:34 a.m. Binoculars will show it to be bigger than star-like in size. Saturn will rise at 9:46 p.m. in the east-southeast. Mars will rise at 12:07 a.m. and is now outshining Saturn, and in July and August will even outshine Jupiter.

The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Venus and Mercury

Venus and Mercury at 10 p.m., about a half hour after sunset, June 20, 2018. Created using Stellarium.

Evening Planets

Venus, the Moon and Jupiter at 10:30 p.m., about an hour after sunset, on June 20, 2018. Created using Stellarium.

Telescopic Venus

The phase exhibited by Venus in a telescope on June 20, 2018. Created using Stellarium.

Binocular Moon

The moon as it might be seen in binoculars at 10:30 p.m. June 20, 2018. Created using Stellarium.

Jupiter and moons

Jupiter and moons at 10:30 p.m. June 20, 2018. The image shows Europa in transit of Jupiter. A satellite is normally invisible against the face of Jupiter, but its shadow can be seen falling on the planet. Created using Cartes du Ciel (Sky Charts).

Satellite  Event        Local Date/Time       Universal Date/Time
Europa:   Transit start 20 Jun 2018  9:06 pm  21 Jun 2018 1:06
Europa:   Shadow start  20 Jun 2018 10:57 pm  21 Jun 2018 2:57
Europa:   Transit end   20 Jun 2018 11:20 pm  21 Jun 2018 3:20
Europa:   Shadow end    21 Jun 2018  1:12 am  21 Jun 2018 5:12

Source of satellite events:  https://www.projectpluto.com/jevent.htm

Morning planets

Morning planets at 5 a.m. June 21, 2018. Click on image to enlarge. Created using Stellarium.

Mars and Saturn telescopicly

Saturn and Mars with the same magnification with an inset of Mars at higher magnification at 5 a.m. June 21, 2018. Created using Cartes du Ciel (Sky Charts).

Note on the inset image.  The south polar cap is probably larger than shown.  Also with the dust storm in progress the dark features may be obscured.  The dust storm clouds appear brighter than the normal surface of the planet.

Planets and the Moon at sunset and sunrise of a single night

Planets and the Moon at sunset and sunrise of a single night starting with sunset on the right on June 20, 2018. The night ends on the left with sunrise on the 21st. Click on the image to enlarge. Created using my LookingUp program.

 

 

06/19/2018 – Ephemeris – The Mars rover Opportunity is facing its greatest challenge

June 19, 2018 Comments off

Ephemeris for Tuesday, June 19th. Today the Sun will be up for 15 hours and 34 minutes, setting at 9:31, and it will rise tomorrow at 5:57. The Moon, 1 day before first quarter, will set at 2:01 tomorrow morning.

The Mars Exploration Rover-B, named Opportunity landed on the Red Planet on January 25, 2004 for a mission hoping to last 90 Martian days or sols. It has been going strong for over 5,000 sols, or nearly 14 ½ Earth years, and has driven over 28 miles. Now Oppy, as its controllers affectionately call it, is meeting it’s greatest challenge. A huge dust storm, threatening to engulf the entire planet is building up. It has cut off the sunlight that power’s Oppy’s solar panels. Day has become night. The Jet Propulsion Laboratory controllers have put Oppy in deep sleep mode, powering only its clock to wait out the storm. They are awaiting Oppy’s phone home call scheduled for 11 a.m. at its local time each sol.

The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Mars global scans

An animation of Mars global scans by the Mars Reconnaissance Orbiter over the period of May 31 to June 11, 2018. Two dust storms, one from the north, and another from the south converge and threaten to go global. Click on the image to enlarge. Credit: NASA/JPL-Caltech/MSSS.

Lights out for Oppy

Lights out for Oppy. The Sun photographed by Opportunity over several sols. Credit NASA/JPL-Caltech.

Below, the News Conference about Opportunity and the dust storm, recorded June 13, 2018.

06/08/2018 – Ephemeris – A second Moon race?

June 18, 2018 Comments off

Ephemeris for Monday, June 18th. Today the Sun will be up for 15 hours and 34 minutes, setting at 9:31, and it will rise tomorrow at 5:56. The Moon, 2 days before first quarter, will set at 1:30 tomorrow morning.

The Moon as a destination is becoming a hot topic among the space faring nations. Who will land humans first in this second wave since the United States landed there in the late 1960s and early 1970s: The Chinese, Russians, us? Or maybe someone else? Next year July 20th will be the 50th anniversary of Neil Armstrong’s first step onto the lunar surface. The goal this time is not to just visit, but to stay. The lunar surface is a harsh environment of extremes in temperatures and radiation from the Sun, and from the universe beyond. There is shelter beneath the surface, in lava tubes. There is one lava tube with a collapsed roof, a skylight, which could provide access in a place called the Marius Hills.

The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Marius Hils

An oblique view of the Marius Hills from the Lunar Orbiter 2, with an inset look into a skylight into a lava tube from the Lunar Reconnaissance Orbiter at the lower left. Click on image to enlarge. Credit NASA, Lunar Orbiter 2, Lunar Reconnaissance Orbiter.

The picture above was posted on Astronomy Picture of the Day (APOD) 2017 October 2017:  https://apod.nasa.gov/apod/ap171025.html, where there is more information.

06/15/2018 – Ephemeris – Earliest sunrise and a look at Venus

June 15, 2018 Comments off

Ephemeris for Friday, June 15th. Today the Sun will be up for 15 hours and 33 minutes, setting at 9:30, and it will rise tomorrow at 5:56. The Moon, 2 days past new, will set at 11:25 this evening.

Today saw the earliest sunrise of the year at 5:56 a.m. We’re 6 days from the summer solstice.

The two day old Moon tonight will appear below and to the right of Venus. Tomorrow night it will have moved to be left and above Venus. This weekend it will be fun to look at Venus and the Moon in binoculars or a small telescope. In a small telescope Venus, though small is definitely not round. It has a gibbous phase and appears 75% illuminated by the Sun. It’s still a bit farther than the Sun, at 109 million miles (175 million km). By the end of October it will come to less than a quarter that distance from us and be invisible in the Sun’s glare. Its phase will get skinnier as its size grows in our telescopes until then.

The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Venus and the Moon

Venus and the Moon tonight June 15, 2018 at 10:30 p.m. Created using Stellarium.

Venus apparent sizes

Comparison of apparent sizes of the planet Venus, tonight June 15 and near Inferior conjunction. I was 2 days late using my memory. The date will be October 26th. Created using Stellarium.