Archive
09/22/2016 – Ephemeris – Autumn will begin this morning
Ephemeris for Thursday, September 22nd. The Sun will rise at 7:30. It’ll be up for 12 hours and 8 minutes, setting at 7:39. The Moon, 1 day before last quarter, will rise at 12:06 tomorrow morning.
Fall is about to a, well… fall upon us and in a few weeks so will the leaves. At 10:21 (14:21 UT) this morning the Sun will cross the celestial equator heading south. The celestial equator is an imaginary line in the sky above the earth’s equator. At that point the sun will theoretically set at the north pole and rise at the south pole. The day is called the autumnal equinox and the daylight hours today is 12 hours and 8 minutes instead of 12 hours exactly. That’s due to our atmosphere and our definition of sunrise and sunset. The reason for the cooler weather now and the cold weather this winter is that the length of daylight is shortening, and the Sun rides lower in the sky, spreading its heat over a larger area, thus diluting its intensity.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum

The Earth as seen a couple of days ago from NOAA,s DSCOVR satellite located near the Sun-Earth L-1 point 1 million miles sunward from the Earth. Credit NOAA/NASA.

The Sun’s path through the sky on the equinox day from Traverse City, MI. Created using my LookingUp program.
09/21/2016 – Ephemeris – Mercury escaped to the morning sky and Jupiter will soon follow
Ephemeris for Wednesday, September 21st. The Sun will rise at 7:29. It’ll be up for 12 hours and 11 minutes, setting at 7:41. The Moon, 2 days before last quarter, will rise at 11:15 this evening.
Tonight we have four of the five bright classical planets in the evening sky. Mercury crossed into the morning sky last week, and Jupiter will follow next Monday. Jupiter is too close to the Sun to be seen. We are left with Venus, Saturn and Mars. Venus is briefly visible after sunset, low in the west. It will set at 8:42 p.m., following the Sun’s earlier setting times. Mars, Saturn and the star Antares start the evening in the southwestern sky in a lengthening triangle, with Saturn on top, Mars below and way out to the left, and Antares below Saturn. Saturn, spectacular in telescopes with its rings, will set at 10:52 p.m. And Mars, moving rapidly to the east against the stars will set at 11:31 p.m.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum

Looking very low in the west at 8:01 p.m., 20 minutes after sunset, September 21, 2016. To see how Venus’ position changes from week to week, check out the last few Wednesday’s posts. I’m using the same landscape for each which is supplied by Stellarium. Created using Stellarium.

The lengthening Mars-Saturn-Antares triangle and the background constellations at 9 p.m., September 21, 2016. Created using Stellarium.

Saturn and some of its moons at 9 p.m. September 21, 2016. Created using Cartes du Ciel (Sky Charts).

Planets and Moon at sunset and sunrise of a single night starting with sunset on the right on September 21, 2016. The night ends on the left with sunrise on September 22. Mercury has escaped to the Morning sky and will rise at 614 a.m. on the 22nd. If you are using Firefox right-click on the image and select View Image to enlarge the image. That goes for all the large images. Created using my LookingUp program.
09/20/2016 – Ephemeris – The twilight zone
Ephemeris for Tuesday, September 20th. The Sun will rise at 7:28. It’ll be up for 12 hours and 14 minutes, setting at 7:43. The Moon, 3 days before last quarter, will rise at 10:29 this evening.
It’s getting a lot darker a lot earlier now than it did a month or so ago. We see the same thing in the morning sky. Now astronomical twilight, that’s when the last vestiges of the twilight glow disappear, ends before the time of sunset we had back in June. Tonight that’s at 9:21 p.m., when the Sun reaches 18 degrees below the horizon. Useful stargazing usually starts by nautical twilight which will occur at 8:46 p.m. when the Sun is 12 degrees down. This is the time when navigators could see the bright stars and the horizon with their sextants to make a star fix. It is a time when all the naked eye planets and the brighter constellations can be made out. Twilight lasts the longest near the summer solstice due to the shallow angle of the Sun’s setting path.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Below is the twilight table for September through December. This is a calendar function from Cartes du Ciel (Sky Charts), a free program, which can be downloaded from the panel on the right of this page. This is, of course, for the Interlochen/Traverse City, Michigan area. If you’re from somewhere else, download the program, and put in your location to create your own table. The last two columns on the right are times that the sky will be dark, without moonlight.
| Interlochen/ Traverse City | Time zone=EDT/EST | ||||||
| Morning twilight | Evening twilight | Dark night | |||||
| Date | Astronomical | Nautical | Nautical | Astronomical | Start | End | |
| 2016-09-01 | 5h26m | 6h04m | 21h27m | 22h05m | 22h05m | 5h26m | |
| 2016-09-02 | 5h28m | 6h06m | 21h25m | 22h03m | 22h03m | 5h28m | |
| 2016-09-03 | 5h29m | 6h07m | 21h23m | 22h01m | 22h01m | 5h29m | |
| 2016-09-04 | 5h31m | 6h09m | 21h21m | 21h59m | 21h59m | 5h31m | |
| 2016-09-05 | 5h33m | 6h10m | 21h19m | 21h56m | 22h24m | 5h33m | |
| 2016-09-06 | 5h34m | 6h11m | 21h17m | 21h54m | 22h55m | 5h34m | |
| 2016-09-07 | 5h36m | 6h13m | 21h15m | 21h52m | 23h29m | 5h36m | |
| 2016-09-08 | 5h37m | 6h14m | 21h13m | 21h50m | – | 5h37m | |
| 2016-09-09 | 5h39m | 6h15m | 21h11m | 21h48m | 0h07m | 5h39m | |
| 2016-09-10 | 5h40m | 6h17m | 21h09m | 21h45m | 0h50m | 5h40m | |
| 2016-09-11 | 5h42m | 6h18m | 21h07m | 21h43m | 1h39m | 5h42m | |
| 2016-09-12 | 5h43m | 6h19m | 21h05m | 21h41m | 2h34m | 5h43m | |
| 2016-09-13 | 5h44m | 6h20m | 21h03m | 21h39m | 3h35m | 5h44m | |
| 2016-09-14 | 5h46m | 6h22m | 21h01m | 21h37m | 4h40m | 5h46m | |
| 2016-09-15 | 5h47m | 6h23m | 20h59m | 21h35m | – | – | |
| 2016-09-16 | 5h49m | 6h24m | 20h57m | 21h33m | – | – | |
| 2016-09-17 | 5h50m | 6h26m | 20h55m | 21h31m | – | – | |
| 2016-09-18 | 5h51m | 6h27m | 20h53m | 21h28m | – | – | |
| 2016-09-19 | 5h53m | 6h28m | 20h51m | 21h26m | 21h26m | 21h47m | |
| 2016-09-20 | 5h54m | 6h29m | 20h49m | 21h24m | 21h24m | 22h28m | |
| 2016-09-21 | 5h56m | 6h31m | 20h47m | 21h22m | 21h22m | 23h15m | |
| 2016-09-22 | 5h57m | 6h32m | 20h45m | 21h20m | 21h20m | – | |
| 2016-09-23 | 5h58m | 6h33m | 20h43m | 21h18m | 21h18m | 0h06m | |
| 2016-09-24 | 6h00m | 6h34m | 20h41m | 21h16m | 21h16m | 1h02m | |
| 2016-09-25 | 6h01m | 6h36m | 20h39m | 21h14m | 21h14m | 2h01m | |
| 2016-09-26 | 6h02m | 6h37m | 20h37m | 21h12m | 21h12m | 3h03m | |
| 2016-09-27 | 6h04m | 6h38m | 20h36m | 21h10m | 21h10m | 4h05m | |
| 2016-09-28 | 6h05m | 6h39m | 20h34m | 21h08m | 21h08m | 5h08m | |
| 2016-09-29 | 6h06m | 6h41m | 20h32m | 21h06m | 21h06m | 6h06m | |
| 2016-09-30 | 6h08m | 6h42m | 20h30m | 21h04m | 21h04m | 6h08m | |
| 2016-10-01 | 6h09m | 6h43m | 20h28m | 21h02m | 21h02m | 6h09m | |
| 2016-10-02 | 6h10m | 6h44m | 20h26m | 21h00m | 21h00m | 6h10m | |
| 2016-10-03 | 6h11m | 6h45m | 20h24m | 20h58m | 20h58m | 6h11m | |
| 2016-10-04 | 6h13m | 6h47m | 20h22m | 20h56m | 21h28m | 6h13m | |
| 2016-10-05 | 6h14m | 6h48m | 20h21m | 20h55m | 22h04m | 6h14m | |
| 2016-10-06 | 6h15m | 6h49m | 20h19m | 20h53m | 22h45m | 6h15m | |
| 2016-10-07 | 6h16m | 6h50m | 20h17m | 20h51m | 23h31m | 6h16m | |
| 2016-10-08 | 6h18m | 6h52m | 20h15m | 20h49m | – | 6h18m | |
| 2016-10-09 | 6h19m | 6h53m | 20h14m | 20h47m | 0h21m | 6h19m | |
| 2016-10-10 | 6h20m | 6h54m | 20h12m | 20h46m | 1h19m | 6h20m | |
| 2016-10-11 | 6h21m | 6h55m | 20h10m | 20h44m | 2h20m | 6h21m | |
| 2016-10-12 | 6h23m | 6h56m | 20h08m | 20h42m | 3h26m | 6h23m | |
| 2016-10-13 | 6h24m | 6h58m | 20h07m | 20h40m | 4h36m | 6h24m | |
| 2016-10-14 | 6h25m | 6h59m | 20h05m | 20h39m | 5h49m | 6h25m | |
| 2016-10-15 | 6h26m | 7h00m | 20h03m | 20h37m | – | – | |
| 2016-10-16 | 6h28m | 7h01m | 20h02m | 20h35m | – | – | |
| 2016-10-17 | 6h29m | 7h03m | 20h00m | 20h34m | – | – | |
| 2016-10-18 | 6h30m | 7h04m | 19h58m | 20h32m | 20h32m | 21h07m | |
| 2016-10-19 | 6h31m | 7h05m | 19h57m | 20h31m | 20h31m | 21h58m | |
| 2016-10-20 | 6h33m | 7h06m | 19h55m | 20h29m | 20h29m | 22h54m | |
| 2016-10-21 | 6h34m | 7h07m | 19h54m | 20h27m | 20h27m | 23h54m | |
| 2016-10-22 | 6h35m | 7h09m | 19h52m | 20h26m | 20h26m | – | |
| 2016-10-23 | 6h36m | 7h10m | 19h51m | 20h24m | 20h24m | 0h56m | |
| 2016-10-24 | 6h37m | 7h11m | 19h49m | 20h23m | 20h23m | 1h59m | |
| 2016-10-25 | 6h39m | 7h12m | 19h48m | 20h22m | 20h22m | 3h01m | |
| 2016-10-26 | 6h40m | 7h14m | 19h46m | 20h20m | 20h20m | 4h02m | |
| 2016-10-27 | 6h41m | 7h15m | 19h45m | 20h19m | 20h19m | 5h02m | |
| 2016-10-28 | 6h42m | 7h16m | 19h44m | 20h17m | 20h17m | 6h02m | |
| 2016-10-29 | 6h43m | 7h17m | 19h42m | 20h16m | 20h16m | 6h43m | |
| 2016-10-30 | 6h45m | 7h18m | 19h41m | 20h15m | 20h15m | 6h45m | |
| 2016-10-31 | 6h46m | 7h20m | 19h40m | 20h14m | 20h14m | 6h46m | |
| 2016-11-01 | 6h47m | 7h21m | 19h38m | 20h12m | 20h12m | 6h47m | |
| 2016-11-02 | 6h48m | 7h22m | 19h37m | 20h11m | 20h42m | 6h48m | |
| 2016-11-03 | 6h49m | 7h23m | 19h36m | 20h10m | 21h26m | 6h49m | |
| 2016-11-04 | 6h51m | 7h24m | 19h35m | 20h09m | 22h14m | 6h51m | |
| 2016-11-05 | 6h52m | 7h26m | 19h34m | 20h08m | 23h08m | 6h52m | |
| 2016-11-06 | 5h53m | 6h27m | 18h33m | 19h07m | 23h07m | 5h53m | |
| 2016-11-07 | 5h54m | 6h28m | 18h31m | 19h06m | – | 5h54m | |
| 2016-11-08 | 5h55m | 6h29m | 18h30m | 19h04m | 0h09m | 5h55m | |
| 2016-11-09 | 5h56m | 6h31m | 18h29m | 19h03m | 1h15m | 5h56m | |
| 2016-11-10 | 5h58m | 6h32m | 18h28m | 19h03m | 2h24m | 5h58m | |
| 2016-11-11 | 5h59m | 6h33m | 18h27m | 19h02m | 3h36m | 5h59m | |
| 2016-11-12 | 6h00m | 6h34m | 18h26m | 19h01m | 4h50m | 6h00m | |
| 2016-11-13 | 6h01m | 6h35m | 18h26m | 19h00m | – | – | |
| 2016-11-14 | 6h02m | 6h36m | 18h25m | 18h59m | – | – | |
| 2016-11-15 | 6h03m | 6h38m | 18h24m | 18h58m | – | – | |
| 2016-11-16 | 6h04m | 6h39m | 18h23m | 18h57m | 18h57m | 19h38m | |
| 2016-11-17 | 6h06m | 6h40m | 18h22m | 18h57m | 18h57m | 20h39m | |
| 2016-11-18 | 6h07m | 6h41m | 18h22m | 18h56m | 18h56m | 21h43m | |
| 2016-11-19 | 6h08m | 6h42m | 18h21m | 18h55m | 18h55m | 22h47m | |
| 2016-11-20 | 6h09m | 6h43m | 18h20m | 18h55m | 18h55m | 23h52m | |
| 2016-11-21 | 6h10m | 6h45m | 18h20m | 18h54m | 18h54m | – | |
| 2016-11-22 | 6h11m | 6h46m | 18h19m | 18h54m | 18h54m | 0h54m | |
| 2016-11-23 | 6h12m | 6h47m | 18h18m | 18h53m | 18h53m | 1h56m | |
| 2016-11-24 | 6h13m | 6h48m | 18h18m | 18h53m | 18h53m | 2h55m | |
| 2016-11-25 | 6h14m | 6h49m | 18h17m | 18h52m | 18h52m | 3h54m | |
| 2016-11-26 | 6h15m | 6h50m | 18h17m | 18h52m | 18h52m | 4h52m | |
| 2016-11-27 | 6h16m | 6h51m | 18h17m | 18h52m | 18h52m | 5h51m | |
| 2016-11-28 | 6h17m | 6h52m | 18h16m | 18h51m | 18h51m | 6h17m | |
| 2016-11-29 | 6h18m | 6h53m | 18h16m | 18h51m | 18h51m | 6h18m | |
| 2016-11-30 | 6h19m | 6h54m | 18h16m | 18h51m | 18h51m | 6h19m | |
| 2016-12-01 | 6h20m | 6h55m | 18h15m | 18h50m | 19h11m | 6h20m | |
| 2016-12-02 | 6h21m | 6h56m | 18h15m | 18h50m | 20h03m | 6h21m | |
| 2016-12-03 | 6h22m | 6h57m | 18h15m | 18h50m | 20h59m | 6h22m | |
| 2016-12-04 | 6h23m | 6h58m | 18h15m | 18h50m | 22h00m | 6h23m | |
| 2016-12-05 | 6h24m | 6h59m | 18h15m | 18h50m | 23h03m | 6h24m | |
| 2016-12-06 | 6h25m | 7h00m | 18h15m | 18h50m | – | 6h25m | |
| 2016-12-07 | 6h26m | 7h01m | 18h15m | 18h50m | 0h08m | 6h26m | |
| 2016-12-08 | 6h26m | 7h02m | 18h15m | 18h50m | 1h17m | 6h26m | |
| 2016-12-09 | 6h27m | 7h03m | 18h15m | 18h50m | 2h26m | 6h27m | |
| 2016-12-10 | 6h28m | 7h03m | 18h15m | 18h50m | 3h40m | 6h28m | |
| 2016-12-11 | 6h29m | 7h04m | 18h15m | 18h50m | 4h54m | 6h29m | |
| 2016-12-12 | 6h30m | 7h05m | 18h15m | 18h51m | 6h09m | 6h30m | |
| 2016-12-13 | 6h30m | 7h06m | 18h15m | 18h51m | – | – | |
| 2016-12-14 | 6h31m | 7h06m | 18h16m | 18h51m | – | – | |
| 2016-12-15 | 6h32m | 7h07m | 18h16m | 18h51m | 18h51m | 19h21m | |
| 2016-12-16 | 6h32m | 7h08m | 18h16m | 18h52m | 18h52m | 20h28m | |
| 2016-12-17 | 6h29m | 7h04m | 18h13m | 18h48m | 18h48m | 21h35m | |
| 2016-12-18 | 6h30m | 7h05m | 18h13m | 18h48m | 18h48m | 22h40m | |
| 2016-12-19 | 6h30m | 7h06m | 18h13m | 18h49m | 18h49m | 23h44m | |
| 2016-12-20 | 6h31m | 7h06m | 18h14m | 18h49m | 18h49m | – | |
| 2016-12-21 | 6h31m | 7h07m | 18h14m | 18h50m | 18h50m | 0h45m | |
| 2016-12-22 | 6h32m | 7h07m | 18h15m | 18h50m | 18h50m | 1h46m | |
| 2016-12-23 | 6h32m | 7h07m | 18h15m | 18h51m | 18h51m | 2h44m | |
| 2016-12-24 | 6h32m | 7h08m | 18h16m | 18h51m | 18h51m | 3h43m | |
| 2016-12-25 | 6h33m | 7h08m | 18h17m | 18h52m | 18h52m | 4h40m | |
| 2016-12-26 | 6h33m | 7h09m | 18h17m | 18h53m | 18h53m | 5h37m | |
| 2016-12-27 | 6h34m | 7h09m | 18h18m | 18h53m | 18h53m | 6h32m | |
| 2016-12-28 | 6h34m | 7h09m | 18h19m | 18h54m | 18h54m | 6h34m | |
| 2016-12-29 | 6h34m | 7h09m | 18h19m | 18h55m | 18h55m | 6h34m | |
| 2016-12-30 | 6h34m | 7h10m | 18h20m | 18h56m | 18h56m | 6h34m | |
| 2016-12-31 | 6h34m | 7h10m | 18h21m | 18h56m | 19h53m | 6h34m | |
09/19/2016 – Ephemeris – How did the pirates of long ago navigate?
Aye matey, Barnacle Bob here with Ephemeris for Talk Like a Pirate Day, Monday, September 19th. The Sun will rise at 7:26. It’ll be up for 12 hours and 17 minutes, setting at 7:44. The Moon, 3 days past full, will rise at 9:47 this evening.
We tend to romanticize things of the past like the Pirates of the 16th, 17th and 18th century, not so much the Somali pirates of today. The problems of getting around and finding your way around were difficult in the seas and oceans before the use of the Harrison Chronometer made the precise determination of longitude possible in the late 18th century. It did require an almanac of star and planet positions plus the chronometer must be set to some time standard of a particular place of known longitude. Among the Islands of the Caribbean I imagine, though don’t know for certain, that one could dead recon between the islands and crudely navigate that way. Latitude determination was easy using the Sun.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum

John Harrison’s (1693-1776) First attempt at a chronometer (1735), which he called H1. Credit: Solarnavigator.net.

John Harrison’s (1693-1776) fourth attempt at a chronometer (1759), which he called H4. It passed its sea trials. It’s not much bigger than a pocket watch. Credit: Solarnavigator.net.
09/16/2016 – Ephemeris – The Harvest Moon is slightly eclipsed for everyone but the Americas
Ephemeris for Friday, September 16th. The Sun will rise at 7:23. It’ll be up for 12 hours and 27 minutes, setting at 7:50. The Moon, at full today, will rise at 7:59 this evening.
Tonight’s full Moon is the Harvest Moon, the nearest full Moon to the autumnal equinox. For the next few nights the Moon will rise later each night by much less than the average 50 minutes later each night effectively lengthening twilight for those gathering in crops. Also this afternoon there will be a penumbral lunar eclipse visible, well not here in Michigan… because the Moon won’t be up. Actually just about the whole world except North America and most of South America will be able to see the eclipse. A penumbral eclipse is what I call a 5 o’clock shadow eclipse. You wouldn’t know it unless someone pointed it out to you, when the Moon dips into the Earth’s outer shadow and the sunlight falling part of it is diminished by a little bit.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum

The not so full Moon of Monday night and its reflection on the waters of Suttons Bay after the schooner Inland Seas docked after an evening sail. Credit: the author.

The penumbral eclipse of the Moon centered on 2:25 p.m. Eastern time, 18:54 UT, for an hour and a half before and after. Only near the middle of the eclipse will anything be visible of the effect. I find that wearing sunglasses reduces the brightness of the moon and enhances the penumbral shadow. Credit: NASA/GSFC/ Fred Espenak.
For the full-page pdf of the above click here: http://eclipse.gsfc.nasa.gov/LEplot/LEplot2001/LE2016Sep16N.pdf
09/15/2016 – Ephemeris – SpaceX has an explosion in its Falcon 9 second stage
Ephemeris for Thursday, September 15th. The Sun will rise at 7:22. It’ll be up for 12 hours and 30 minutes, setting at 7:52. The Moon, 1 day before full, will set at 7:01 tomorrow morning.
The rocket company SpaceX had one of its Falcon 9 Rockets explode as it was being fueled for a test firing to check out its booster engines on September first. The second stage, which was being loaded with fuel exploded. Even if a tank had been ruptured, there should be no ignition source to cause the explosion. Unfortunately the satellite, AMOS-6 a communications satellite destined for geosynchronous orbit, was already mounted on the rocket, and can be seen falling off the rocket just after the explosion. This is the second failure of a Falcon 9. In June of last year a helium tank inside the liquid oxygen tank in the second stage broke loose and ruptured the tank, while still being boosted by the first stage. It took a few seconds after the rupture before the fuel ignited causing the explosion that ended the mission. SpaceX has issued a request for videos or anything that might shed light on the latter accident.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum

A sequence of photographs of the Falcon 9 explosion. Credit: US Launch Report.
09/14/2016 – Ephemeris – Then there were four… Evening planets that is.
Ephemeris for Wednesday, September 14th. The Sun will rise at 7:21. It’ll be up for 12 hours and 33 minutes, setting at 7:54. The Moon, 2 days before full, will set at 5:49 tomorrow morning.
Tonight we have only four of the bright classical planets in the evening sky. Mercury crossed into the morning sky Monday, Jupiter will follow shortly. Jupiter is impossible to spot being very close to the direction of the Sun. We are left with Venus, Saturn and Mars. Venus is briefly visible after sunset, low in the west. It will set at 8:52 p.m., following the Sun’s earlier setting times. Mars, Saturn and the star Antares start the evening in the southwestern sky in a triangle, with Saturn on top, Mars below and to the left, and Antares below Saturn and right of and below Mars. Saturn, spectacular in telescopes with its rings, will set at 11:18 p.m. And Mars, moving rapidly to the east against the stars will set at 11:39 p.m.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum

Looking very low in the west at 8:14 p.m., 20 minutes after sunset, September 14, 2016. Created using Stellarium.

The Moon and the lengthening Mars-Saturn-Antares triangle at 9:30 p.m., September 14, 2016. Created using Stellarium.

Saturn and some of its moons at 9:30 p.m. September 14, 2016. Created using Cartes du Ciel (Sky Charts).

The Moon tonight as it might be seen in binoculars at 9:30 p.m. September 14, 2016. Created using Stellarium.

Planets and Moon at sunset and sunrise of a single night starting with sunset on the right on September 14, 2016. The night ends on the left with sunrise on September 14. Mercury has escaped to the morning sky. If you are using Firefox right-click on the image and select View Image to enlarge the image. That goes for all the large images. Created using my LookingUp program.
09/12/2016 – Ephemeris – Mercury passes inferior conjunction with the Sun today
Ephemeris for Monday, September 12th. The Sun will rise at 7:18. It’ll be up for 12 hours and 39 minutes, setting at 7:58. The Moon, 3 days past first quarter, will set at 3:34 tomorrow morning.
Today the Planet Mercury will pass inferior conjunction, that is move between the Earth and the Sun. Unlike last inferior conjunction, when it passed directly in front of the Sun on May 9th. This time it will pass below the Sun. The term inferior means it is between the Earth and the Sun. A superior conjunction is when Mercury passes the back side of the Sun. Mercury will be moving into the morning side of the sky, and toward the end of the month it will be much easier to spot than it was last month when it was low in the west. On autumn mornings the ecliptic, the path of the Sun and planets, sticks up, close to vertical, while in the evenings it lies close to the horizon, which is also why Venus sets so soon after the Sun now.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum

Mercury last August 16 at greatest eastern elongation. Note how low Mercury is to the horizon at sunset. Created using Cartes du Ciel (Sky Charts).
Note in the charts above and below the line passing through the Sun, and the one the planets hang around is the ecliptic, the projection of the Earth’s orbit on the celestial sphere. The grid line running through the west compass point at the horizon is the celestial equator. I’m allowing us to see below the horizon. As planets rise, move across the sky and set they will appear to move parallel to the celestial equator.

Mercury this coming September 28 at greatest western elongation. Note how high Mercury is to the horizon at sunrise. Created using Cartes du Ciel (Sky Charts).
Note too that Mercury appears farther from the Sun on August 16th than at September 28th. And it is. On August 16th Mercury appears 27.4 degrees from the Sun. On September 28th, it’s only 17.8 degrees. That’s a big advantage for observers in the southern hemisphere. The best times to see an eastern elongation of Mercury is on winter and spring evenings, and the best times to see a western elongation of Mercury is on summer and autumn mornings. Since the seasons are reversed from the northern hemisphere to the southern hemisphere. Our not so good August 16th elongation of Mercury was a really good one for folks south of the equator. We’ll return the favor September 28th. But the best southern hemisphere greatest elongations are always greater in the separation of Mercury from the Sun than northern ones because Mercury has a markedly elliptical orbit.
09/09/2016 – Ephemeris – There’s a star party tomorrow at the NMC Rogers Observatory
Ephemeris for Friday, September 9th. The Sun will rise at 7:15. It’ll be up for 12 hours and 48 minutes, setting at 8:03. The Moon, at first quarter today, will set at 12:50 tomorrow morning.
For the sixth weekend in a row the Grand Traverse Astronomical Society will host an observing event. Just one this weekend. It will be a star party at Northwestern Michigan College’s Rogers Observatory tomorrow night, Saturday night the 10th from 9 to 11 p.m. The observatory’s and GTAS members telescopes will be used to view the Moon and the planets Saturn and Mars. Some of the brighter deep-sky objects of the summer sky will also be visible. There will be an alternate program available if it’s cloudy. Last weekend’s star party , out at the Sleeping Bear Dunes was a perfectly clear night with and nearly 1800 folks showed up to view the wonders of the Milky Way. The society and the park thank all who attended.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
09/08/2016 – Ephemeris – The Moon tonight: Two mountain ranges
Ephemeris for Thursday, September 8th. The Sun will rise at 7:14. It’ll be up for 12 hours and 51 minutes, setting at 8:05. The Moon, 1 day before first quarter, will set at 12:07 tomorrow morning.
The planet Saturn will appear below the nearly first quarter Moon tonight. The southern part of the Moon shows lots of craters in a pair of binoculars or small telescope. The area is called the lunar highlands. Most of the northern part of the Moon contains the lunar seas or maria. There is some interesting terrain there for the small telescope, including the mountain range the Alps to the North and the Apennines south of them. Lunar mountain ranges are named after Earthly ones. The two ranges are part of the broken ramparts around Mare Imbrium, the large Sea of Showers. In it are a few large craters that were created by impacts since the sea itself was created by a huge asteroid impact over 3.8 billion years ago.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum

The Moon tonight at 9 p.m. September 8, 2016. Created using Stellarium.

A closer look at the emerging mountains on the Moon at 9 p.m. September 8, 2016. Created using Stellarium.
More of these mountains will be revealed in coming nights.