Category Archives: Observing List

Posts describing the sky including lists of target objects.

The Sky for November 2013

The biggest advantage of winter for northern astronomers is it gets dark early. By mid November astronomical twilight is at 6:07pm EST and nautical twilight is 5:32pm. So observing the night sky is a lot easier than in late June when astronomical twilight is 11:24 EDT.

The moon plays a prominent role this month. Which is fine if you like looking at the moon, but not so good if you’re going to a dark site and want to hunt down some faint fuzzies. New moon is on Nov 3rd and will just be visible a couple days later in the western sky a few minutes after sunset. Try finding the young crescent moon on Nov 5th just after sunset which is at 4:45 est. The moon shows off the most detail when viewed along the terminator (line between light and dark). This is most true when viewing through a medium power telescope but also when using binoculars. So the moon is quite interesting to look at between new moon and 1st quarter – a waxing crescent –  also the waxing gibbous moon. (The waning moon also shows off a nice terminator but it transits much later at night.) The first quarter moon is Nov 9th when it rises 12:30pm est sets at 23:11. Full moon is on Nov 16 and rises 16:07 set the next morning at 6:55am and is a prominent object for the whole night. 3rd quarter is on Nov 25th when it rise 23:59. So its not until about Nov 23rd when the moon rises at 21:59 that it’s completely out of the way.

The chart below shows about 160° of the sky to the south on November 15th at 9pm. This corresponds to the same view at 10pm on Nov 1st and 8pm on Nov 30th.

November_2013_AllSky_Chart

Pegasus is now front and centre by mid-month, 2hrs earlier than in October. Cygnus is setting into the west and the winter constellations are starting to rise in the east with Taurus (the bull) first to appear. While not on the chart, the Big Dipper has sunk to its lowest point in the evening and is obscured from view unless you have an obstructed northern horizon.

M31_Andromeda_Galaxy_2010-11-08_v3_SJM
Last month’s feature object – the Andromeda galaxy (M31) – is now high in the southern sky at 9pm mid-month and so in a fine position to observe. (See the October Sky article for more info on the Andromeda Galaxy.)

The sky has rotated another 2hrs from the same time last month, so the reference stars to find M31 are in a slightly different orientation.

m31_finder_2013-11-15

Pisces_art
A challenging constellation to find is Pisces (the Fish). It is also due south at 9pm mid-month and just below the more prominent constellation Pegasus. It’s rather spread out with no obvious pattern to orient you. That and the stars are relatively faint and so hard to see, particularly from even a semi-rural sky. The main pattern is made up of stars that range in brightness from 3.6 to 5.2.

The best way find the whole constellation is to first locate the head of the bottom fish – the tight circle of 7 stars directly below Pegasus.
Pisces_chart
The square pattern in Pegasus is about 12° on a side – so a little larger than your hand (Hand Scale for Measuring Angles. The fish’s head is also about 12° below the bottom of Pegasus.

From there, try to trace the pattern of stars that form for the large v-shape.

The Sky for October 2013

The summer triangle formed by Altair, Vega and Deneb still dominates the south western sky but is slowing sinking towards the evening horizon now that we are officially into autumn. (The Equinox was on September 22, at 20:44 UTC.)

October_AllSky_2013
By mid month the constellation Cygnus (The Swan) will be high over head and a little to the west. The popular name for this constellation is the “Northern Cross” which is a more descriptive name making it easier to find. From a dark site the dark lanes of the Milky Way can be see passing through this constellation.

A little to the east, Pegasus (The Winged Horse) is high in the sky with Andromeda (The Chained Maiden) attached to upper left corner of the large square that forms the most identifiable feature of Pegasus. Therefore, the most noteworthy object in the evening sky this month is the Andromeda Galaxy (M31).
M31_Andromeda_Galaxy_2010-11-08_v3_SJM
The Andromeda Galaxy is 2.5mLy away, which puts it in our own back yard (The Local Group). M31 has the distinction of being the furthest object that can be seen without a telescope or binoculars and was the galaxy the Hubble used to establish that these objects were “island universes” and not part of the Milk Way. Even from a moderately light polluted sky it can be seen unaided as a distinct elongated smudge. With binoculars the edges become more defined and in a small telescope (80mm) the spiral arms and central bulge start to appear.

M31 is also referred to as our sister galaxy because it’s similar in size and shape to our own Milky Way. So looking at Andromeda, is like seeing the Milky Way as it looked 2.5 million years ago.

The chart below provides some tips on how to find it. Start with the star Alpheratz in the top left corner of Pegasus. Count three stars to the left to Mirach (with Alpheratz being star No 1). Then count three stars up (Mirach as No 1). The second set of 3 stars are faint so may not be obvious at first. M31 will be 4° to the right and elongated as shown.
finder_m31_star_hopping
On the other side of Pegasus, towards the meridian and 12° above the celestial equator, is the Pegasus Cluster (M1). It’s a small globular cluster that shows up in binoculars as a “non-stellar” object – meaning it looks like a fuzzy star. It is mag 7.5 and 31′ in diameter. In a 100 to 150mm scope it’s obvious that it’s a globular cluster. In 200mm+ scope many individual stars can be resolved with nice colour.

A bit lower sitting a half a degree below the celestial equator is M2. It is also mag 7.5 but smaller at 23′ in diameter. This means that it will appear brighter than M15 since magnitude is a measure of total brightness. A larger object means less surface brighteness since the available light is spread over a larger area.

A more challenging object for binoculars is the Helix Nebula (NGC 7293). Just 22° above the horizon (at the time for the chart), it requires a clear dark sky to see. In binoculars the mag 7.6, 13′ object will appear as a slightly brighter, diffuse spot. In large scopes the outer ring and central star become visible.
Astrophoto, Cluster, Open Cluster
More towards the north between Cassiopeia and Perseus is the Double Cluster  (NGC 869 and NGC 884 or Caldwell 14). These two bright open clusters can be seen in the same field of view of a 100mm scope. Unaided they show up as a distinct fuzzy patch.  Individual stars can be resolved in binoculars.

Venus is by far the brightest object in the early evening western sky and sets about 8pm by mid month.

Saturn now sets about 7pm so is pretty much gone for the year.

Uranus and Neptune are in a good position but hard to find and require a medium to large scope (100mm to 200mm). Neptune is a relatively bright magnitude 5.7 so can actually be seen in a small scope. But without any good reference stars to locate it, it can be a challenge. It does appear as blue-green to provide a clue that you’ve found it. In a large scope, the disk can just be resolved. Neptune is magnitude 7.8 but a little easier to find using the background stars in Aquarius as a reference.  Still, it’s best seen in a 200mm+ scope.

By mid-month Jupiter is rising at 11pm so is actually an accessibly object. It’s at opposition January 5th, when it will be due south at midnight.

Lastly, comet Ison is making the news. Still, it’s going to be a challenge. In early November when it’s going to be at its brightest, it’s also going to be close to the sun. So i am not planning any casual observing of this object just yet.

The Sky for September 2013

The fall Equinox occurs on September 22nd at exactly 20:44 UT (4:44pm edt). On this date and time the Sun crosses the equator making the day and night of equal length. After that, the daylight hours will get shorter and the nights longer – which is of course good if you’re an astronomer. At the start of the month, nautical twilight begins at 8:47pm – the time when the brighter stars can be seen (those used for navigation). By the end of the month, nautical twilight will be at 7:48pm – almost an hour earlier. Astronomical twilight – the start of the darkest part of the night – begins at about 9:26pm on Sept 1st. By Sept 30th, Astronomical twilight begins at 8:23pm.

Finder_Chart_South_2013-09-15By mid September at 9pm, the constellations Lyra (the Harp) and Cygnus (the Swan) are directly over head. Hercules is a little to the west but still in a good position to see. The large constellation Pegasus (the Winged Horse) is rising in the east. The tail of Pegasus is actually the constellation Andromeda (daughter of Cassiopeia) and home to the Andromeda Galaxy which will be featured next month. The Milky Way is still prominent in the south with Sagittarius (the galactic centre) a little west of the meridian.

Finder_Chart_Summer_Triangle_2013-09-15
The Summer Triangle – an asterism formed by the three bright stars Vega (Lyra), Deneb (Cygnus) and Altair (Aquila) is due south and stretches from the celestial equator to almost the zenith. These stars are in the top 20 list of the brightest stars and are the brightest stars in that area of the sky. So the “summer triangle” is easy to spot.

Finder_Chart_Coathanger_Area_2013-09-15
A fun binocular object is Brocchi’s Cluster (Collinder 399) but better known as the Coathanger. In 7×50 binoculars it looks like a perfectly formed coat hanger in the centre third of the FoV – albeit upside down. The Coathanger is in the lower third of the Summer Triangle along the Altair-Vega line. To find it, locate Altair with binoculars and then scan a third of the way towards Vega. The Coathanger should be easy to spot. (While Cr399 fits nicely between Sagitta and Vulpecula, these constellations don’t stand out well.)

Finder_Chart_Coathanger_2013-09-15

Another great binocular target is Ptolomy’s Cluster (M7). It’s a large open cluster that will occupy about a quarter of the FoV of 7×50 binoculars. It’s only 6° above the horizon though so requires an obstructed view.

M13 – the Hercules cluster and M92 are still the best bets for binocular globular clusters of the season. M27 and M57 are nice Planetary nebulae for moderate scopes either as visual or photography objects. The diffuse nebula of M8 and M20 are best seen in photographs due the red colour. Although the brighter reflection component of M8 is visible in small scopes and the open cluster M21 near M8 is also visible.

The photography project for this month is the Iris Nebula (NGC 7023, Caldwell 4) – a bright reflection nebula in the constellation Cepheus to the north. NGC 7023 refers to the open cluster while the nebula is LBN 487. The grouping is listed as mag 6.6 and 18′ in diameter. Although the region of interest is more like a degree wide. Images of it in real colour show it to be rather blue-purple with significant brownish dust lanes. The scope of choice is the AT106 with the Canon T2i which yields of FoV of 1.8×1.2°. 6-8hrs of imaging should be enough for a decent result which usually takes two clear nights to acquire.

The Sky for August 2013

Now that we are into August astronomical twilight starts at about 10pm EDT with dawn is around 4am EDT. This means being able to get outside to see some interesting stuff before bedtime and ample time to set up an imaging run. Identifying constellations and locating bright stars can be done shortly after nautical twilight which starts about 9:15pm EDT. Finder_Chart-Sagittarius_2013-08-17

The main feature of the sky in August and September is the Milky Way. In August it’s due south at 10pm with the brightest section – the Ophiuchus bulge – quite prominent. If observing for a moderately dark site, look for the dark  lane that runs down the middle.

Sagittarius is due south near the horizon. The galactic centre is about 1° south of 3 Sagittarii. Look there and you are looking at the “black hole” that lies at the centre of our galaxy.

This section of the milky way has several excellent binocular or small telescope targets. Using binoculars or a small scope, just scan up the Milky Way and you will see several interesting fuzzy objects (also known as deep sky objects – DSOs). A few noteworthy objects to look for are:

  • Lagoon Nebula (M8) – can sometimes be seen unaided. A small telescope will reveal a very bright patch with some dark lanes.
  • Trifid Nebula (M20) – Physically connected to M8, it’s a little harder to see due to its red colour. Look for the open cluster M21 just a little to the north east in the same binocular FoV.
  • Sagittarius Cluster (M22) – a mag 6.5 globular cluster which ranks as the third brightest in the sky.

Finder_Chart-Zenith_2013-08-17 At the zenith three easy to identify constellations stretch from east to west – Cygnus, Lyra and Hercules. Don’t forget to look for Delphinus (the Dolphin) – the small diamond shaped constellation near the ecliptic.

Hercules is home to two of the brightest globular clusters – The Hercules Cluster (M13) and M92. M13 is mag 7 and large enough to be seen unaided from a dark sky (limiting mag 5+). M92 will require binoculars.

Finder_Chart_Lyra The Ring Nebula (M57) is located in the south part of Lyra and is an excellent planetary nebula to view in small scopes. It’s only mag 9.5 so requires fairly dark skies, But at 1.7′ across, it’s large for a planetary nebula.

Just to the east of Vega in Lyra is Epsilon Lyra (ε) the “double double” – a multiple star system consisting of 4 stars arranged in two pairs.

Finder_Chart_Epsilon-Lyra
The two pairs have a separation of 3.5′ which can be seen in binoculars. The pairs have separations of 1.3″ and 2.3″ making them challenging doubles to split in a 4″ scope. However, the two pairs are oriented 90° with respect to each other making it easy to compare the star shapes and aiding in detecting the separation.