Heads UP! for Early July 2016

The planet Jupiter is still outstanding in the evening sky. It’s the brightest object in our sky, even though Jupiter looks 4% smaller by the end of the month.  It’s still a great time to get any telescope out and look for the dark cloud bands and Jupiter’s four brightest moons.  If you are lucky or plan well, you can see the Great Red Spot.  It’s smaller than it used to be, but looks much redder than the darker cloud bands – almost orange.

 

Here’s a photo from the Juno spacecraft from earlier this week.  What it shows is what we can see in our humble telescopes.

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Photo from Juno, released by NASA and labeled by the Planetary Society.

(But we don’t see a ‘half Jupiter’ – our view is a fully lit Jupiter.)  Juno is preparing to enter orbit around Jupiter on July 4th  .  While its camera is small, it’s primary mission is to measure the strength of microwave radiation from the interior of Jupiter.  This is like weather radar, where microwaves are used to measure water in Earth’s air.  In this case, Jupiter is the source of the microwaves.  Data from Juno will allow scientists to learn about what the inside of Jupiter is made of.  From Earth’s point of view, Jupiter is 4 percent smaller by the end of the month, but worth watching to see if the Great Red Spot keeps its recent brightening and if the darker cloud belts stay constant.

Mars and Saturn are low in the southern sky as seen from the northern hemisphere.

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Mars and Saturn 1/3 of the way up from the southern horizon. Sky and Telescope chart.

Venus and Mercury are close to the Sun in the sky. See this photo from the Solar and Heliospheric Observatory of the sky near our Sun.

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The International Space Station returns to the dawn skies starting on the 6th.

On July 4th, at local noon in the Eastern United States, the Sun is furthest from the Earth for 2016.  Doesn’t that make you feel cooler?

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Rough weather before a nice holiday weekend

Before the holiday weekend starts, nature is going to do some rough sweeping through our area. Be alert for showers, thunderstorms and the possibility of strong, damaging winds later this afternoon and evening.

After that, the weekend looks warm, but nice, with next chance of rain depending on a system passing to our Monday night and early Tuesday.

 

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHERN CONNECTICUT
...NORTHEAST NEW JERSEY AND SOUTHEAST NEW YORK.

.DAY ONE...TODAY AND TONIGHT.

THERE IS A CHANCE FOR SEVERE THUNDERSTORMS THIS AFTERNOON AND
EVENING. THE MAIN THREAT IS DAMAGING WINDS. THERE IS A SMALL
CHANCE FOR LARGE HAIL AND ISOLATED TORNADOES...MAINLY FROM THE NEW
YORK CITY METRO AREA ON WEST AND NORTH.
From the National Weather Service Forecast Discussion: The threat for storms falls off fairly rapidly from west to east
this evening (maybe lingering into the first part of the overnight
hours far eastern zones), as the surface cold front reflection of
the upper trough pushes to the east.

How to find Mars!

The fourth planet from the Sun, Mars is a bright reddish dot in our night skies. To find it, look low the southeast sky after the sky gets dark.

Southeast is on the other side of the sky from where the sun sets. By 9:30 pm local daylight time, about the time it gets dark out, Mars will have risen above the southeastern horizon.  It will rise a bit earlier each night.  Mars will be highest in the sky about midnight in May and by 11pm in June.

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Mars and Saturn low in the southeast sky at 9:30pm Daylight Time.

You can use the star chart above from the heavens-above.com or the map for May (and June, when it’s published) to find Mars in the sky.

What will you see in a telescope?

If you point a telescope of any size at Mars and focus it carefully, you’ll see a tiny reddish dot.  Once you get the planet centered in the eyepiece, take a good long look and see if you can pick out any gray or light colored areas.  Then use a higher power eyepiece to see how much detail you can see on Mars.  It’s still going to be small.  How much power can you use?  A good rule of thumb is to find out the highest power you can use is to measure the opening where the light comes though in millimeters and multiply it by 2.  A 2.4 inch objective (where the light comes into the telescope) is about 60 millimeters wide.  Multiply that by 2 and the maximum usable power is 120x.  See if your telescope came with eyepieces marked with power ratings or if the materials with your telescope tells you what power the eyepieces can give. If you have a ‘barlow’ lens, multiply the power by the ‘2x’ or ‘3x’ stamped on the side to get the total power.

If Mars is very fuzzy, it’s either a night with a turbulent jet stream overhead or you are using too much power.  The gray areas are areas of volcanic rock where the reddish dust has blown off the solid rock.

While you are in the neighborhood, Saturn rises about an hour and a half after Mars rises, so check out the ringed planet.  While you are waiting for Mars to get above your trees, look for Jupiter, just as bright as Mars higher in the southwest sky.  They are also on the sky maps.

Added May 23rd… A more detailed discussion of what your telescope can see on Mars is at astrobob in Duluth, MN: http://astrobob.areavoices.com/2016/05/21/what-will-your-telescope-show-on-mars/

Happy hunting!

 

 

 

Use the Solar Observatory to See the Pleadeas In Daytime

The lovely Pleiades  star cluster is not visible in our nighttime sky, because it’s lost in the glare of the Sun.  But it’s fun to look for it while it moves past the Sun in our skies.  And we can do that with the SOHO solar telescope.  SOHO (Solar & Heliospheric Observatory) is a joint USA and European Space Agency space mission to study our star.

SOHO has special cameras, some of which block out the Sun so we can see the Sun’s outer atmosphere and how the Sun’s magnetic field affects it.  SOHO blocks out the Sun so well, we can see stars and planets passing through the glare of the Sun.

Check this week and watch the Pleiades, that star cluster that looks like a little dipper, or nameplates on older Subaru cars, pass through the view of the C3 camera .  Here’s a sample from yesterday:

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The Pleiades are in the upper left of this scene and will move to the lower right this week. The incredibly bright object on the right is the planet Venus.

Here’s a movie of the past three days, showing the Sun moving in front of the star field and Venus racing to keep up.

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Watching a tiny dot on the Sun

May 9th – the Transit of Mercury across the Sun.  I couldn’t see the last one, several years ago, since the sun was so dimmed by haze, after the solar filter, there was no sunlight left.
The sun broke through the stratocumulus clouds about 7:10am and I used my 8-inch dobsonian reflector telescope to watch Mercury move onto the solar disk. Because of turbulence and thermals, the edge of the sun looked very wavy, as if the sun had a scalloped edge.  Mercury seemed to stay attached to the edge of the sun for a long time, well after the entire disk was in front of the sun.
I took a few photos with my Canon XS camera in place of an eyepiece (‘prime focus’) and a white light solar filter (see below).
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Mercury in that tiny dot in front of the Sun in this Canon XS camera exposure at prime focus 1/125 second exposure at ISO 400.

Then I drove to work with my 60mm f/11 Orion refractor. I was surprised I didn’t have to convince security that it was ‘take our telescope to work day’.  Viewing diagonally through the laminated glass and various thicknesses of cirrus clouds was difficult, since the sun was getting high in the sky by 10:30.  I found the best way to see a faint impression of the sunspot group and Mercury was to project the image of the sun onto a white sheet of paper tacked up on a partition in shade – something hard to do outdoors.  The 25mm (low power) eyepiece was best, but contrast and resolution was poor. By noon, a layer of altostratus clouds moved in from the south and covered the sky where the sun was, ending our viewing.
While I drove to work, it was fun to hear the FM stations talk about the transit.  WCBS-FM’s morning show host was complaining his co-hosts were very quiet, ‘looking at a tiny dot on a computer screen’, because they were fascinated by NASA and Space.com’s coverage of the transit.
PS I’ve done astronomy through the glass at work before. We’ve observed the Moon, a comet and last December, the Moon next to Venus.  IMG_0732 crop blue
 Click to see Venus as the dot to the upper left of the Moon. Dec 7 2015 250mm Canon XS 1/640 second exposure at f/11 and ISO 400.

Mercury and Venus in the SOHO Solar Observatory

As Mercury moves toward its passage across the Sun on Monday*, it was visible on the SOHO C3 camera.  The C3 is on the SOHO spacecraft, which watches the Sun from it’s post a million miles out from Earth.  The C3 has a shade to block out the Sun so it can see the Sun’s outer atmosphere.  It can also see stars in the background and the occasional planet that photobombs the scene.

This month, Mercury moved in from the left side of the C3 scene, dimming as the sunlight side turns away from us. Now you can’t even see it.  Venus is coming in from the right side, on the far side of the Sun, far away but still very bright.  The glare from Venus overloads the sensor and makes a big ‘splash’ on the sensor.

mercury and venus may 2016 soho

Follow the path of Mercury on this movie of recent photos from the C3 camera. The bright streaks are where the Sun’s magnetic field heats up the Sun’s outer atmosphere.  The ‘puffs’ emitted from are coronal mass ejections from the Sun.

current_c3 movie

Mercury is the tiny dot on the left moving a bit faster than the background stars (roughly on the path on the still photo above).

 

* Don’t view the Sun without a proper solar filter, firmly fixed to the open end of the telescope.  See Sky and Telescope, or our Westchester Astronomers newsletter for details on the Transit of Mercury across the Sun.

 

High tides from an invisible moon

The new moon on the Friday the 6th is near the time the moon is closest to us.  The combined effect of the line up of the sun and moon and the moon being closer than normal enhances the range of tides.  This new moon we can’t see induces large-than-normal tidal ranges from the 6th through the 9th.  (See the NYC NWS office to see if this sun/moon alignment and lunar perigee will produce coastal flooding.)

Conversely, the moon is farthest away this month near the time of full moon – furthest full moon this year.  Thus, May will have the smallest-looking Full Moon of 2016. If the largest full Moon on November 14 is a ‘supermoon’, is the smallest full Moon on the 21st a ‘minimoon’?  Photos taken with the same camera and settings at the same time of night can show a slight, but noticeable, difference in size.