09/02/2014 – Ephemeris – Viewing the first quarter Moon

September 2, 2014 Leave a comment

Ephemeris for Tuesday, September 2nd.  The sun will rise at 7:06.  It’ll be up for 13 hours and 11 minutes, setting at 8:17.   The moon, at first quarter today, will set at 12:52 tomorrow morning.

Tonight on the moon there are some very prominent craters on the terminator or sunrise line that’s cutting the moon in half.  From the top or north of the moon there’s Plato, which is also called a ringed plain because it has a flat floor.  South of there is Eratosthenes, at the end of the arc of the Apennines mountain chain.  At the south or bottom end of the moon are two other of my favorite craters.    First is the crater Tycho, that doesn’t look spectacular now, but will when the Moon is full with its rays of ejecta crossing a long way across the face of the moon.  A little bit farther south, partially entering sunlight is the large crater Clavius.  On my blog, bobmoler.wordpress.com, I’ll illustrate what the Moon’s image looks like in different types of telescopes.

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

Addenda

The moon tonight

The Moon tonight at 9 p.m. (September, 2, 2014). Created using Stellarium.

Image orientation in telescopes

The orientation of what one sees in an astronomical telescope depends on the type of telescope and the placement of the eyepiece.  The orientations shown are for observers in the northern hemisphere.  For the images below the moon shown is due south.

Erect image

The orientation of the Moon as seen with the naked eye, binoculars, spotting scopes and telescopes with an erecting eyepiece.

Mirror image

The orientation of the Moon as seen in a refractor or a Schmidt-Cassigrain or similar type reflector with a diagonal at the eyepiece end, and the eyepiece pointing up. This is a mirror image due to an odd number of mirror reflections in the telescope.

Inverted mirror image

The orientation of the Moon as seen with a refractor or Schmidt-Cassigrain and diagonal with the eyepiece oriented horizontally. It is a n inverted mirror image.

Inverted Moon

The orientation of the moon through a Newtonian reflector or a refractor without an eyepiece diagonal. It is an inverted image, an image rotated 180 degrees.

For southern hemisphere observers for these images to work the moon would be due north and all the images would have to be upside down.

 

09/01/2014 – Ephemeris – Previewing the month of September

September 1, 2014 Leave a comment

Ephemeris for Labor Day, Monday, September 1st.  The sun will rise at 7:04.  It’ll be up for 13 hours and 14 minutes, setting at 8:19.   The moon, 1 day before first quarter, will set at 12:02 tomorrow morning.

Let’s look at the skies for the month of September. The sun will moving at its greatest speed in its retreat to the south. Daylight hours in the Interlochen/Traverse City area and will drop from 13 hours and 14 minutes today to 11 hours 45 minutes on the 30th. The altitude of the sun above the southern horizon at local noon will be 54 degrees today, and will descend to 42 degrees on the 30th. The season of summer is getting short, so enjoy it while you can. Summer ends and autumn begins at 10:30 p.m. on September 22nd.  Saturn is retreating toward the sun now.  Mars is pushing on eastward.  On the 27th Mars will be north of the star Antares.  It will be a good time to compare their colors.

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

Addendum

September Star Chart

September star chart for 10 p.m. on September 15, 2014. Created by my LookingUp program.

The Moon is not plotted.  The planets are plotted for the 15th.  Mars will move eastward through the month and will approach Saturn.

Astronomical twilight ends at 10:05 p.m. on September 1st, decreasing to 9:01 on the 30th.

Add a half hour to 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.

Also shown is the Summer Triangle in red. Clockwise from the top star is Deneb in Cygnus, Vega in  Lyra and Altair in Aquila.

The green pointers from the Big Dipper are:

  • Pointer stars at the front of the bowl of the Big Dipper point to Polaris the North Star.
  • The arc of the dipper’s handle points to Arcturus.

08/29/2014 – Ephemeris – Twilight is shorter now than it was in June

August 28, 2014 2 comments

Ephemeris for Friday, August 29th.  The sun will rise at 7:01.  It’ll be up for 13 hours and 22 minutes, setting at 8:24.   The moon, half way from new to first quarter, will set at 10:09 this evening.

Here we are at the end of August already.  We have one more night to view the Milky Way in darkness after the moon sets, because the Moon sets at the very end of astronomical twilight.  By the way, astronomical twilight starts and ends when the sun is 18 degrees below the horizon, and the actual twilight glow is completely gone.  The sun sets more than an hour before it did in late June, which means that it gets dark much earlier.  Twilight lasted much longer in June than it does now because the Earth’s rotation now drops the sun below the horizon at a steeper angle.   As a matter of fact while the sun sets an hour earlier now than in June, twilight ends two hours earlier.  It sneaks up on you if you’re not paying attention to it.

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

Addendum

Tonight's end of astronomical twilight

Distance the Sun must travel from the horizon to 18 degrees below tonight, August 29, 2014. Created using Stellarium.

 Solstice end of twilight

Distance the Sun must travel from the horizon to 18 degrees below, the night after the June solstice, June 22, 2014. Created using Stellarium.

Categories: Ephemeris Program, Twilight Tags:

08/28/2014 – Ephemeris – The evening Moon will stay low in the sky for the next couple of weeks.

August 28, 2014 Comments off

Ephemeris for Thursday, August 28th.  The sun will rise at 7:00.  It’ll be up for 13 hours and 25 minutes, setting at 8:26.   The moon, 3 days past new, will set at 9:40 this evening.

Since we’re within a month of the autumnal equinox, coming up on September 22nd, something funny is happening with the Moon rise and set times near both new and full moon.  That is they aren’t changing very much.  Here we are with the Moon three days old, and it still sets before the end of astronomical twilight.  You may notice that for the next two weeks, that the Moon doesn’t get very high in the sky in the early evening.  It’s path stays close to the horizon.  Around first quarter next Tuesday the Moon will get to be just a little higher in the sky than the sun does on the first day of winter.  The next full moon is the Harvest Moon, being the full moon closest to the first day of autumn.  Then the day-to-day succession of rise times again will slow.

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

Addendum

Low Moon

The Moon on September 3, 2014 a day after first quarter. It will rise higher after that if one stays up long enough. Created using Stellarium.  Click on image to enlarge.

In the image above the Moon’s orbit is compared to the ecliptic, the plane of the Earth’s orbit to which it’s inclined by about 5º.  Note the two points where these lines cross.  The point where the Moon’s orbit crosses the ecliptic heading northward is called the ascending node.  The crossing point heading southward is the descending node.  The important thing about that is the when the moon passes a node while at new or full, an eclipse will occur,  which they will do in October.  There will be a total lunar eclipse on the morning of October 8th, then a partial solar eclipse on October 23rd as the sun is setting here in northern Michigan.  I’ll have more information as the events gets closer.

08/27/2014 – Ephemeris – Where are the bright planets for this week?

August 27, 2014 Comments off

Ephemeris for Wednesday, August 27th.  The sun will rise at 6:59.  It’ll be up for 13 hours and 28 minutes, setting at 8:27.   The moon, 2 days past new, will set at 9:12 this evening.

Let’s take our weekly look at the bright planets.  Reddish Mars is in the constellation of Libra the scales, skirting below, left of Saturn in the southwest as darkness falls.  It is in conjunction with Saturn today, as it passes due south of the ringed planet.  Mars will set at 11:07 p.m.  Saturn will set at 11:23 p.m.  Saturn viewing with a telescope will suffer because it’s getting close to the horizon but it’s still possible to see those fabulous rings and its large moon Titan.  Brilliant Jupiter will rise in the east-northeast at 4:44 a.m. tomorrow, followed by the brighter Venus, which will rise at 5:37 a.m.  Jupiter is increasing its distance from the sun, while Venus is retreating toward the Sun from our point of view.

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

Addendum

Evening planets

Saturn and Mars in conjunction at 9:30 p.m., August 27, 2014. Created using Stellarium.

Saturn

Telescopic Saturn. Do not expect to spot any other of Saturn’s moon other than Titan. 9:30 p.m., August 27, 2014.  Created using Stellarium.

Morning planets

Jupiter and Venus and the rising winter constellations at 6 a.m. August 28, 2014. Created using Stellarium.

Telescopic Jupiter

Telescopic view of Jupiter and its 4 Galilean moons at 6 a.m. on August 28, 2014. Created using Stellarium.

08/26/2014 – Ephemeris – The Great Rift

August 26, 2014 Comments off

Ephemeris for Tuesday, August 26th.  The sun rises at 6:57.  It’ll be up for 13 hours and 31 minutes, setting at 8:29.   The moon, 1 day past new, will set at 8:45 this evening.

High overhead the Milky Way is seen passing through the Summer Triangle of three bright stars.  Here we find the Milky Way split into two sections.  The split starts in the constellation of Cygnus the Swan or Northern Cross very high in the east.  The western part of the Milky Way ends southwest of the Aquila the eagle.  This dark dividing feature is called the Great Rift.  Despite the lack of stars seen there, it doesn’t mean that there are fewer stars there than in the brighter patches of the Milky Way.  The rift is a great dark cloud that obscures the light of the stars behind it.  Sometimes binoculars can be used to find the edges of the clouds of the rift, as stars numbers drop off suddenly.  This is especially easy to see in Aquila.

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

Addendum

The Great Rift in the Milky Way. Created using Stellarium.

The Great Rift in the Milky Way. Created using Stellarium.

08/25/2014 – Ephemeris – Cool treasures in the constellation of Lyra

August 25, 2014 Comments off

Ephemeris for Monday, August 25th.  The sun rises at 6:56.  It’ll be up for 13 hours and 34 minutes, setting at 8:31.  The moon is new today, and won’t be visible.

The bright star Vega will be nearly overhead tonight at 10 p.m.   It will be about 6 degrees south of the zenith.  That’s quite a stretch of the neck to spot, with its accompanying stars in a small parallelogram that make up the constellation of Lyra the harp.  Lyra has some interesting features for a serious observer with and without a telescope.  The bottom right star of the parallelogram, if south is toward the bottom, is a star called Beta Lyrae that changes brightness by a factor of 3 in a period of 13 days.  Another star near Vega looks like two close stars in binoculars, in telescopes each is again a double stars.  That’s Epsilon Lyrae.  The jewel of this constellation needs a telescope to find between the two bottom stars of the parallelogram, the famous Ring Nebula.

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

Addendum

A bi more stars than what will be seen in binoculars of the constellation Lyra.  Created using Cartes du Ciel (Sky Charts).

A bi more stars than what will be seen in binoculars of the constellation Lyra. Created using Cartes du Ciel (Sky Charts).

In the chart above:

The star designated α is Vega
The star designated β is Beta Lyrae
The stars designated ε1 and ε1 is Epsilon Lyrae
The object designated M57 is the Ring Nebula

Ring Nebula 1

The Ring Nebula. Visually one cannot detect the color. It takes a large telescope to see the central star. Credit: Stellarium.

The Ring Nebula, AKA M57 by amateur astronomers, is a planetary nebula.  The name planetary is a misnomer.  Many of these objects look like the dim planets Uranus and Neptune.  They are really stars like the sun, in their death throes puffing out their outer layers of gas at the end of their red giant stage.  See below the latest image of the Ring Nebula I recently found on the Phil Plait’s Bad Astronomy Blog.  It includes an explanation of what’s in the image.

Deep Ring Nebula

Photo by NASA, ESA, and C. R. O’Dell (Vanderbilt University) and Robert Gendler

Click on the image to get lost in the Ring Nebula!

 

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