This morning on my way to work I paused to capture a few pictures of the waning crescent Moon near the planet Mercury. This is one of several pictures I took and its specs. are: 55 mm F9; ISO 100; 2 sec. With a 2-second shutter speed the headlights from west bound cars on Highway 50 become the streaks of light on the right side of the picture.
Thursday morning September 29th the 28-day old and very thin waning crescent Moon will be a few degrees below the innermost planet Mercury. New Moon is a few minutes past midnight Friday, 0:11 UT Saturday, so if you are able to see the Moon it will be close to the record for seeing the Moon close to new Moon phase.
Click here to read about the record sighting of a crescent Moon.
Wednesday September 28th the innermost planet Mercury reaches its greatest western elongation. At this elongation Mercury is to the right or the west side of the Sun as we see it from Earth. From western elongation Mercury moves eastward toward the Sun and superior conjunction next month on October 27th.
Wednesday September 28th the waning crescent Moon will be crossing the plane of the ecliptic moving north relative to the ecliptic. This is known as the ascending node, one of two intersections the Moon’s orbital path has with the ecliptic. The ecliptic is actually the Earth’s orbit and the Moon’s orbit is inclined about 6o from the ecliptic. So there are two node intersections, the ascending and descending nodes.
On the morning of the 28ththe Moon will rise as a very thin 27-day old waning crescent Moon.
Does our Moon actually go around the Earth as many graphics show? From our perspective on the Earth the Moon appears to circle around the Earth. However, in reality, the Moon orbits the Sun together with the Earth*
Read this very informative article about the Earth-Moon system and their orbital motions, written by Joe Hanson. “Do We Orbit the Moon?”
Monday morning September 26th the 25-day old waning crescent Moon will be within about 5o from the open star cluster M-44, also known as the ‘Beehive Cluster‘. This is a collection of several hundred stars with a combined apparent magnitude of around 4 making it bright enough to be seen with the unaided eye.
Even in moderately light polluted skies M-44 can be seen, and seen even better when viewed with binoculars.
Monday September 26th the planet Jupiter reaches conjunction with the sun, in effect behind the sun as we view the two from Earth. Jupiter will reappear later next month in the morning skies rising before the Sun rises.
A favorite pastime of mine is to watch the International Space Station orbit over my part of the world and when possible capture the flyover on film.
This picture is from Wednesday September 21st and is a time lapse consisting of about 80 separate pictures stacked together and processed as one picture.
The dashed line is the reflected light from the ISS and each dash represents 2.5 seconds of travel. The camera was more or less centered on Polaris, above the chimney, so as the Earth rotated stars around Polaris moved and the curved lines show the apparent circumpolar path they follow.
Thursday morning as I was walking my dog prior to leaving for work I spotted the ISS and whipped out my cellphone and captured some of its flight as a short video. The shaky motion comes from holding onto a 65 lb. dog on a leash with one hand and the cellphone in my other hand.
Click here to see the calculated path as done by the Heavens-Above web site.
This morning I set up for a time lapse series as I did on Wednesday. With large trees as my southern horizon this flyover past the constellation of Orion and the bright star Sirius was sort of a challenge. This is a series of 10 pictures stacked to show as one picture.
Click here to see the calculated path as done by the Heavens-Above web site.
Camera settings for all pictures: 18mm; f4.5; ISO 1600; 2.5 sec.
A shout-out to Mrs. Soukup’s online Astronomy students.
On a regular basis the Moon, at some point in its cycle of phases, passes above Orion’s head on its way to a traverse of the Gemini constellation. Often the Moon’s orbit takes it past the feet of the Gemini twins and sometimes near the open star cluster, M-35. This is a group of several hundred stars with an apparent magnitude between 5 and 6 that is fairly easily seen as a fuzzy patch of light – like an out-of-focus star.
However with the light from the nearby first quarter Moon brightening this part of the sky seeing M-35 will be very difficult.
On Thursday September 22nd at 14:21 UT, (9:21 am CDT) the Sun will have reached the astronomical coordinates of 0 degrees declination and 12 hours of right ascension, or RA. This places the Sun within the boundaries of the constellation Virgo the Maiden, or as some would say, “the Sun is in Virgo.” This is the actual position of the Astronomical Sun as opposed to the pseudoscience of astrology which has the astrological Sun entering the constellation of Libra the Scales.
Read a little more about how astrology has the Sun incorrectly placed in a previous blog, and in another blog discussing the effects of precession.
Declination is the astronomical equivalent to latitude measuring from 0 degrees at the equator to 90 degrees at either pole. Right ascension, or RA, is like longitude except that there is only east RA. The globe is divided into 24 sections, and like meridians of longitude, these hour circles are 15 degrees wide at the celestial equator and taper to a ‘point’ at the north and south pole respectively. In RA the ‘hour’ circles are counted from 0 hours to 23 hours. The 0 hour circle is at the intersection of the ecliptic and the celestial equator in the constellation of Pisces the Fishes.
In a class lesson about seasons today would be one of the two days during the year when the Sun would be described as being over the Earth’s equator. If you were at the Earth’s equator the Sun would have an altitude of 90 degrees, or straight up in your sky at your local time for midday. At that moment there would not be a shadow. However at any other latitude, north or south at midday, the Sun would be at an angle less than 90 degrees and there would be a midday shadow. (Midday is the local time when the Sun is halfway between local rising time and local setting time. At any midday the Sun is at its maximum altitude above the southern horizon in the northern hemisphere, or is at its maximum altitude above the northern horizon in the southern hemisphere.)
What is often noted about an equinox day is the reminder that equinox means equal night as a reference to there being equal amounts of daylight, and night. Also on an equinox day the Sun would rise due east and set due west for virtually everywhere on the globe. The times for sunrise and sunset would be approximately 12 hours apart, and the rising time would be around 6 am local time, and the setting time would be around 6 pm local time.
This short video shows students at Colegio Menor San Francisco de Quito, a school in Quito Ecuador, measuring the altitude of the sun hourly on the day of the 2004 September Equinox. They were taking part in Project SunShIP, Sun Shadow Investigation Project. There are also some pictures showing a local midday shadow from other participating schools in the United States and U.K.
Click here to go to the Qué tal in the Current Skies web site for more observing information for this month.
Over the next couple of nights or early mornings the waning gibbous Moon will pass across the stars of the Hyades, a v-shaped open star cluster that makes up the face of Taurus the Bull. Depending on your geographical location you may see the Moon either pass very closely to the reddish star Aldebaran.
From parts of Eastern Africa, Middle East, and South Asia the waning Gibbous Moon will be within 0.2o from Aldebaran.
Click here to go to the Qué tal in the Current Skies web site for monthly observing information, or here to go to bobs-spaces.