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07/06/2015- Ephemeris – Today we are at our greatest distance from the sun.

July 6, 2015 Comments off

Ephemeris for Monday, July 6th.  Today the Sun will be up for 15 hours and 26 minutes, setting at 9:30.   The Moon, 2 days before last quarter, will rise at 12:23 tomorrow morning and tomorrow the Sun will rise at 6:04.

This is the day the we are the farthest we can get from the Sun for the year.  The point in the Earth’s orbit that it occurs is called aphelion.  Earth is closest to the Sun in January at perihelion.  The actual distance difference between perihelion and aphelion is 3 million miles out of roughly 93 million miles.  So now we’re roughly 94 and a half million miles from the Sun or 152 million kilometers., and will swoop down to 91 and a half million miles(91.4) or 147 kilometers from the Sun in early January.  Because Earth’s northern and southern hemispheres have different ratios and placement of land versus ocean I’m not sure you could correlate seasonal differences of the hemispheres with the Earth’s distance from the Sun.  Anyway the approximate time we reach aphelion will be 3 p.m. EDT (19 hr UT).

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

Addendum

The orbits of the inner planets. (P)erihelion - (A)phelion

The orbits of the inner planets. (P)erihelion – (A)phelion

The above is a diagram from three years ago, so the planets other than the Earth will be in different positions today.  The date of aphelion and perihelion move around over a greater range of dates than the equinoxes and solstices.  I’m not sure why without researching it, but I suspect that the Moon has something to do with it.

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06/26/2015 -Ephemeris – The latest sunset of the year

June 26, 2015 Comments off

Ephemeris for Friday, June 26th.  Today the Sun will be up for 15 hours and 33 minutes, setting at 9:32.   The Moon, 2 days past first quarter, will set at 2:57 tomorrow morning and tomorrow the Sun will rise at 5:59.

This evening we will experience the latest sunset of the year.  The sun has been setting within the same minute for a few days now.  Now the Sun will begin to set earlier and earlier,  at first imperceptibly, but soon with greater speed.  By the middle of August the Sun will set 45 minutes earlier.  Just in time to enjoy the summer Milky Way at a semi-decent hour.  The shorter days, or actually daylight hours, and the diminishing altitude of the Sun at noon will cause a decrease in the heat we receive from the Sun.  Still, right now we’re still warming up.  However there is a tipping point around mid to late July, when we will not get enough heat to keep getting warmer and we’ll start to cool.

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

Addendum

Average Monthly Climate Chart

Traverse City Climate Chart. The hottest day is around July 15, and coldest day is around January 20. Credit: http://www.usclimatedata.com

www.usclimatedata.com has monthly and daily average data for many locations in the United States.  They have code to embed this chart on your website.  However it didn’t embed properly in the blog, so I took a screen shot.

01/02/2015 – Ephemeris – Telescope Clinic tonight in Traverse City

January 2, 2015 Comments off

Ephemeris for Friday, January 2nd.  The sun will rise at 8:20, the latest sunrise of the year.  It’ll be up for 8 hours and 53 minutes, setting at 5:13.   The moon, 2 days before full, will set at 6:38 tomorrow morning.

Did you or someone in your family get a telescope for Christmas, or have one in a closet or attic because you don’t know how to put it together or operate?  Or maybe you are trying to figure out which one to buy.  Well, tonight’s your night.  The Grand Traverse Astronomical Society will host a telescope clinic at Northwestern Michigan College’s Rogers Observatory on Birmley Road, south of Traverse City starting at 8 p.m.  Telescope experts from the society will help you set up your telescope and give you observing tips.  So bring ’em if you’ve got ’em.  If it’s clear, at 9 p.m., there will be a star party to try out your telescope, or try them out on the lights of Traverse City.  Can’t make it?  We can help you after any meeting.

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

Addenda

Remember the Quadrantid meteor shower tomorrow evening and into Sunday morning:

The moon will interfere with the meteor shower, so only the brightest will be visible.  The radiant will rise from the northeast.  The radiant will be nearly overhead at the start of twilight.  On a dark night up to 120 meteors per hour may be seen according to the International Meteor Organization.

Quadrantid meteor shower radiant at 1:30 a.m.

 

The Earth will reach perihelion Sunday.
This is the closest the Earth gets to the Sun in its orbit this year.  The Sun will be 91,402,000 miles or 147,096,000 kilometers away at around 1 a.m. January 4th, 2015 EST or 6 hr UT January 5th 2015.  It makes winter the shortest season because the Earth is moving its fastest during perihelion.  It’s only by a few days.  And in northern Michigan where it seems that winter overlaps half of fall and spring besides, that few days difference is buried under snow.

01/01/2015 – Ephemeris – Happy New Year – a look at January

January 1, 2015 Comments off

Ephemeris for New Years Day, Thursday, January 1st.  The sun will rise at 8:20.  It’ll be up for 8 hours and 52 minutes, setting at 5:12.   The moon, 3 days before full, will set at 5:43 tomorrow morning.

Happy New Year.  Let’s preview the month of January.  We’re a day from the latest sunrise at about the same time as today, 8:20 a.m. and will back down to 8:02 by the 31st.  Sunset times are currently increasing by a minute a day from 5:12 p.m. today to 5:49 at month’s end.  Listeners near the shore of Lake Michigan will have about the same sunrise time in Ludington, Interlochen/Traverse City, Petoskey and Mackinaw City, but the sunset times will vary markedly.  The Quadrantid meteor shower whose radiant is near the end of the Big Dipper’s handle will reach peak on the 3rd, but it will have interference from the full moon,.  On the 4th the Earth will be its closest to the sun of the entire year.

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

Addenda

Monthly Star Chart

January 2015 star chart

Star Chart for January 2015. Created using my LookingUp program.

The Moon is not plotted.  The planets and stars are plotted for the 15th at 9 p.m.  That is chart time.

Evening astronomical twilight ends at 6:58 p.m. on January 1st, and increasing to 7:30 p.m. on the 31st.

Morning astronomical twilight starts at 6:34 a.m. on January 1st, and decreasing to 6:22 a.m. on the 31st.

Add a half hour to the chart time every week before the 15th and subtract and hour for every week after the 15th.

For a list of constellation names to go with the abbreviations click here.

The green pointer from the Big Dipper is the pointer stars at the front of the bowl of the Big Dipper that point to Polaris the North Star.

The Quadrantid meteor shower

The moon will interfere with the meteor shower, so only the brightest will be visible.  The radiant will rise from the northeast.  The radiant will be nearly overhead at the start of twilight.  On a dark night up to 120 meteors per hour may be seen according to the International Meteor Organization.

Quadrantid meteor shower radiant at 1:30 a.m.

Quadrantid meteor shower radiant at 1:30 a.m.

The Earth at Perihelion

This is the closest the Earth gets to the Sun in its orbit this year.  The Sun will be 91,402,000 miles or 147,096,000 kilometers away at around 1 a.m. January 4th, 2015 EST or 6 hr UT January 5th 2015.  It makes winter the shortest season because the Earth is moving its fastest during perihelion.  It’s only by a few days.  And in northern Michigan where it seems that winter overlaps half of fall and spring besides, that few days difference is buried under snow.

Quasi-conjunction between Venus and Mercury on the evening of January 10th.

A quasi-conjunction. Conjunctions occur when two solar system bodies have the same right ascension. Mercury will get to within 0.6 degrees of Venus before retreating back sun-ward.

Quasi-conjunction of Venus and Mercury

Animation of the Quasi-conjunction of Venus and Mercury. Time span 1/05/2015 to 1/15/2015 at 7 p.m. Created by Bob Moler using Stellarium and GIMP.

Comet C/2014 Q2 (Lovejoy)

Here is a finder chart for 9 p.m. for January.  Every other position is marked with the month-day and predicted magnitude.  Recently the comet has shown to be brighter than predicted by up to one magnitude.  Note that magnitudes in astronomy are like golf scores – the lower the number, the brighter the object.  So the comet should reach 4th magnitude.

Comet Lovejoy

Nightly plot of Comet Lovejoy (C/2014 Q2) for the month of January, 2015 at 9 p.m.
Created using Cartes du Ceil (Sky Charts).

 

09/22/2014 – Epmemeris – Autumn begins tonight

September 22, 2014 Comments off

Ephemeris for Monday, September 22nd.  The sun will rise at 7:29.  It’ll be up for 12 hours and 10 minutes, setting at 7:39.   The moon, 2 days before new, will rise at 6:54 tomorrow morning.

Welcome to the last, almost full, day of summer.  The Sun will reach the autumnal equinox point in the sky at 10:30 this evening.  At that moment the Sun will cross the celestial equator, a projection of the Earth’s equator, heading southward.  All locations on the earth except two will experience 12 hours of daylight and 12 hours of night.  Well they would if the Earth didn’t have an atmosphere and sunset and sunrise were defined differently.  The two locations that don’t experience equal night, which is what equinox means, are the north pole where the sun will be setting and the south pole where the sun will be rising.  For us in the northern hemisphere daylight hours will be shorter and the Sun will peak lower in the south each day until the December solstice.

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

Addendum

Autumnal equinox

The Earth as seen from the direction of the Sun as it crosses over the Earth’s equator heading south. Created using Celestia.

07/03/2014 – Ephemeris – Today the Earth is its farthest from the Sun for this year

July 3, 2014 Comments off

Thursday, July 3rd.  Today the sun will be up for 15 hours and 28 minutes, setting at 9:30.   The moon, 2 days before first quarter, will set at 12:35 tomorrow morning.  Tomorrow the sun will rise at 6:02.

Later today the Earth will pass a point in its orbit called aphelion.  This is the point where the Earth is its farthest from the Sun.  Astronomers measure it in terms of the astronomical units AU), the mean distance between the Earth and the Sun.  In astronomical units the Earth will be 1.01668 AU from the Sun at 6:59 p.m. (22:59 UT).  Converted to miles it is 94.51 million miles (152.1 million km).  The 1.7 percent farther distance from the Sun doesn’t really show up as making a difference in temperature.  It is swamped by the greater effect of the Earth’s axial tilt currently giving us our summer season.  The one thing about aphelion in summer gives us is a longer summer, than winter.  The Earth travels slightly slower when farther from the Sun than when closer to it, so summer is the longest season at 94 days.

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

Addendum

The orbits of the inner planets. (P)erihelion - (A)phelion

The orbits of the inner planets. (P)erihelion – (A)phelion

Note that the chart is from 2012.  The date of aphelion and perihelion varies by a day or two each year.  Mars and Mercury have the most eccentric orbits.

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