¿dónde están Venus y Mercurio

   So where are Venus and Mercury?
   Friday, 1 November, these two inner planets will be at one of their four respective and specific locations along their orbital path around the Sun relative to the location of the Earth along its orbital path around the Sun.

orbits-above   Firstly, the innermost planet, Mercury, is not in transit as the banner graphic at the top of the page suggests. However Mercury is between the Earth and the Sun as this graphic shows. And, for either Mercury or Venus, when that happens the inner planet is said to be at inferior conjunction, but not necesarily in transit, or crossing directly in front of the Sun. Because the orbital paths of the planets are inclined away from the plane of the ecliptic, or the Earth’s orbit, the two inner planets ‘behave’ more or less as our Moon does when it reaches new Moon phase. When these objects come between the Earth and the Sun they are more often than not above or below the plane of the ecliptic and are therefore not in transit or eclipse. This is because of the planets inclination to the plane of the ecliptic. There are only certain times when the circumstances for a transit of either Mercury or Venus. The most recent and basically the last for a long time, was the Venus transit of 2012. I went to Tucson Arizona to view the event. And with my sister-in-law we joined a small group of like-minded people to view the transit from the observatory on the summit of Mt. Lemmon.

venus-orbit-ani   The other inner planet, Venus, has reached the point in its orbit around the Sun where Venus is as far ‘out’ from the Sun as we see the two near the horizon. This is measured as the angle between the Sun, Venus, and the Earth. This animated graphic shows Venus above the horizon then crossfades to show Venus in its current orbital position. This orbital position is called an elongation, and since Venus is in the evening sky to the east from the Sun, and setting after the Sun, ‘we’ would say that Venus is at greatest eastern elongation. At this elongation Venus is 47.1 degrees from the Sun.

Click here to go to the Mercury Chaser web page to see the Mercury elongation calculator.

Click here to go to the Seeing Venus in the Daylight web page, then scroll down to see the Venus elongation calculator.

   
   
   
telescopeClick here to go to the Qué tal in the Current Skies web site for more observing information for this month.

Sun Enters Libra Today

Click on graphic to see it full size.

Click on graphic to see it full size.

   Today, 30 October, the Sun in its apparent eastward motion along the ecliptic, moves out of the constellation Virgo the Harvest Maiden and into the constellation of Libra the Scales. This is the true or actual position of the Sun as opposed to the pseudoscience of astrology which usually has the astrological Sun one constellation ahead or east from the Astronomical Sun’s position.

   
   
   Click here to go to the Qué tal in the Current Skies web site for more observing information for this month.

Moon, Mars, and Regulus

Click on graphic to see it full size.

Click on graphic to see it full size.

   An hour or so before sunrise local time on Tuesday morning (29 October) the thin 24-days old waning crescent Moon will rise in between Jupiter and the star Regulus in Leo the Lion. If you have a good view that includes the north look to the left from the Moon for the familiar star patterns of the two dippers.

   
   
   
   Click here to go to the Qué tal in the Current Skies web site for more observing information for this month.

Daytime Jupiter Sighting

Jupiter Moon Conjunction

Jupiter Moon Conjunction 10/25

   As a follow-up to my post the other day about seeing Jupiter during the daytime here is a cropped portion of one of the pictures I took of the waning gibbous Moon and Jupiter. The Moon, in this picture, is somewhat overexposed in order to include Jupiter.
   This picture was taken sometime after 7:30 am CDT so the sky was fairly bright but knowing where to look for Jupiter made it an easy naked-eye daytime sighting. Jupiter is the dot in the upper left corner.

Jupiter-Moon Conjunction 10/26

Jupiter-Moon Conjunction 10/26

   This is a cropped portion of one of the pictures I took earlier this morning around 7:15 am CDT. Jupiter is the faint dot in the upper right corner. I would have waited a little longer to take these pictures but high cirrus clouds were moving in and covering the area of the sky where the Moon and Jupiter were located.

   
   
   
   Click here to go to the Qué tal in the Current Skies web site for more observing information for this month.

October Apogee Moon

october-apogee   Our Moon orbits around the Sun with the Earth and from our perspective on the Earth the Moon appears to circle Earth each month. The Moon also has a slightly elliptical-shaped orbit allowing for the Moon to have a furthest (apogee) and closest (perigee) distance from the Earth each month.

25 October - 14 UT (9 am CDT)

25 October – 14 UT (9 am CDT)

   This month the 20.9 days old waxing crescent Moon reaches perigee today, 25 October at 14 UT (9 am CDT), and will more or less be at a distance of 31.7 Earth diameters (403,945km or 227,708 miles).

Click here to go to the Qué tal in the Current Skies web site for more observing information for this month.

   
   
   
   Click here to go to the Qué tal in the Current Skies web site for more observing information for this month.

Daytime Sighting of Jupiter

Click on graphic to see full size.

Click on graphic to see full size.

   Late this evening or tomorrow morning, depending on your time zone, the waning gibbous Moon will be rising near the planet Jupiter. The two will be around 7 degrees apart as the banner graphic at the top of the page shows, or as is shown in this graphic which is set for 25 October at 6 UT (1 am CDT).

Click on graphic to see it full size.

Click on graphic to see it full size.

   If you are a later in the morning person, or would like a sort of challenge, the Moon will be over the southern horizon at sunrise and still near Jupiter. Jupiter is bright enough to still be visible even at around 7 am local time as this graphic shows. Find the Moon and then look straight above and a little to the left for a bright ‘star’ and you will have found Jupiter. For a challenge, a daytime observation, wait for an hour or so after the Sun has risen and see if you can still find Jupiter, but now in the daytime.

   
   
   
   Click here to go to the Qué tal in the Current Skies web site for more observing information for this month.

Sun Not In Scorpio Today

oct-sun-ani   According to the pseudoscience of astrology the Sun enters the constellation of Scorpio the Scorpion today, 23 October. When in fact the actual position of the Sun today is within the boundary of the constellation of Virgo the Harvest Maiden, as the banner graphic at the top of the page shows. This animated graphic shows the Sun’s apparent eastward motion along the ecliptic at 5-day intervals during October.
   Read a little more about how astrology has the Sun incorrectly placed in a previous blog, and an another blog discussing the effects of precession.

   
   
   
   Click here to go to the Qué tal in the Current Skies web site for more observing information for this month.

When the Moon Hits You In The Eye…

   This evening the 17.75 days old waning gibbous Moon rises in the face of Taurus the Bull as the banner graphic shows. hyades1-aniThe Moon is very close to the open star cluster the Hyades, a v-shaped grouping of stars that form the face of the bull. The reddish star Aldebaran is one of the eyes and its reddish color signals an angry bull. The bottom or point of the v-shape is the nose and the star at the top of the v-shape across from Aldebaran is the other eye.

Close-up View with 7x50 Binoculars

Close-up View with 7×50 Binoculars

   The Hyades is a large open star cluster consisting of several hundred stars all of about the same age and at a distance of around 150 light years. The brighter reddish star Aldebaran, at a distance of about 70 light years, is not part of this open star cluster but is coincidentally in the line of sight toward the Hyades.

   
   
   
   Click here to go to the Qué tal in the Current Skies web site for more observing information for this month.

Mom and the Kids

   This evening the 16.8-day old waning gibbous Moon rises within about 7 degrees from the open star cluster, the Pleiades, marking the shoulder of Taurus the Bull. Off to the left, or toward the north is the pentagon-shaped star of Auriga the Charioteer.
capella-bino   The alpha, or brightest star in Auriga is Capella which from Latin means something like ‘female-goat’. The three nearby stars to Capella, Almaaz, Hoedus I, and Hoedus II, are called the ‘kids’ as these are the babies from their mother goat Capella. Capella at a distance of 42 light years is the 6th brightest night time star, and Capella is actually a double pair of stars.
auriga-ani   Within the pentagon-shape of Auriga lie two open star clusters, M-36 and M-38. Both are about 7th magnitude in apparent brightness and are within 2-3 degrees of each other meaning that both are visible within the field of view of binoculars or with a telescope and a low power wide-field eyepiece.

   
   
   
   Click here to go to the Qué tal in the Current Skies web site for more observing information for this month.

Harvest or Hunter’s Moon?

Clip Art by George Reed. Used with permission.

Clip Art by George Reed. Used with permission.

   Each full Moon has a name, or actually several names depending on the culture or part of the world. In the United States the full Moons of September and October are both named for practical reasons in that one is called the Harvest Moon while the following one is called the Hunter’s Moon. Unfortunately the definition of the Harvest Moon apparently may be either the full Moon closest before the September Equinox, or the closest full Moon after the September Equinox.
   It would be much simpler if this were determined by the full Moon closest to the September Equinox, making this year’s Harvest Moon in September and the following full Moon which is today, 18 October, the Hunter’s Moon.

kc_chiefs_moon   So what exactly is a Harvest or a Hunter’s Moon, and what makes them more significant (if they are) over other full Moons? The significance lies in the idea that September is typically harvest time at mid-latitudes in the United States and that once the fields are cleared the Hunter’s can more easily spot and ‘bag’ their prey. It is also significant in how the Moon rises each evening around the time of full Moon in September and October.

ecliptic-ani   The path or angle
the Moon rises is less steep than at other months so for a few days the Moon rises only about 30 minutes later rather than the 50 or so minutes of later rising time during other months. This in effect means more bright full moonlight later into the evening allowing farmers and hunters to take advantage of the extra light. The change in the angle that the Moon rises, and conversely sets, varies as the angle of the ecliptic changes as the Earth revolves around the Sun going through the cycle of seasons. As this animated graphic is showing this angle changes each month for the same reason that we have seasons – the axial tilt of the Earth.

Like 2 salt grains in the ocean here are two useful resources about the Moon out of the ‘Sagans’ of lunar resources that are out there. (1 Sagan = “billions and billions”
   Download the Lunar CRater Observation and Sensing Satellite (LCROSS Storybook)
   Download the Lowell Observatory Moon Clock. (PDF 79 Kb)

   ‘Rock it’ to the Moon in an animated simulation of a crewed Constellation Program mission to the Moon. This is actually a combination of two separate videos that I cut apart and spliced back together to reduce the length. (5m49s)

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   Just enjoy it!! (1m49s)

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   And of course Neil Young singing “Harvest Moon”

   
   
   Click here to go to the Qué tal in the Current Skies web site for more observing information for this month.