Cassiopeia – the W in the sky

Some constellations are easier to spot than others.  Cassiopeia with its distinctive W is visible year round in the northern hemisphere above the 34th parallel. In the image below it easily stands out from the fainter background stars.

Cassiopeia above the three line - Benoit Guertin

Cassiopeia above the three line – Benoit Guertin

The five stars drawing a W in the sky are all naked eye magnitude 3 and brighter stars, and in the image above I used a layering technique to increase the color and brightness of those stars to really make them stand out.

  1. Duplicate your base image, and set this layer to lighten only
  2. Apply a blur to the top layer(about 8-12 pixels)
  3. Increase the color saturation and brightness.  Play with the curves to brighten the bright stars, but not the background sky.
  4. Use a mask as required to filter out the bright foreground elements, such as light reflecting off a building roof-line in my image above.

Canon Rebel XTi
17mm f/4
4 x 20sec ISO800

 

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This Weekend: 4 Planets in Plain Sight

If you are able to get out of bed early before sunrise and the sky is clear, you can catch a view of our three closest planets, and if you include Earth that makes 4.  Mercury was at the greatest elongation on September 12th (furthest from the Sun when viewed from Earth) which makes it a good time to spot without the glare of the Sun.  But it happens that Mars and Venus are also on that same side of the Sun, making a chanced planetary alignment.

The sky map below [click for larger] shows the position of Mercury, Mars and Venus for the morning of the 16 to the 19 of September.  Bright star Regulus and our Moon are also there to make this a worth-while event, especially on Monday the 18th.

September_AlignmentMars and Mercury will be closest on the 16th, while the 18th will probably be the most photogenic as the Moon will be a thin crescent in the middle of this alignment.

Ursa Major

Ursa Major, or Big Dipper is one of the most recognizable constellation in the Northern hemisphere. People often use it to locate Polaris, the North Star.  Can you find Polaris? (Hint: upper right)

Ursa Major (Big Dipper) low in the sky in late summer around 11pm

Ursa Major (Big Dipper) low in the sky in late summer around 11pm

Canon Rebel XTi (450D)
17mm f/4
Stacking of 4 x 20 seconds @ ISO800
Post processing with GIMP

Moonlit Mountain Under the Stars

When I took the four shots to create this image below the Moon was just starting to rise above the tree-line behind me.  A full moon may be 1,000,000 times dimmer than the Sun it’s still bright enough to cast shadows and considerably light up the scene in a long exposure photo.

Over the mountain top a loose grouping of stars identified as Melotte 111 open star cluster.  These are about 40 bright stars laying 280 light years away all moving together.  It lies in the Coma Berenices constellation.

ComaBerenices_2017-08-10

Canon Rebel XTi (450D)
17mm f/4
20sec @ ISO800
The sky is a stack of 5 x 20sec.  The foreground is a single 20sec shot.

Next Year: Lights Out For the Perseids

Yesterday, even if I’m located in the light polluted Montreal suburb, I decided to head out at quarter to midnight to see if I could by chance spot one or two bright meteors from the Perseids shower. As luck would have it in the 15 minutes doesn’t looking around Cassiopeia I spotted two before clouds and a rising moon sent me indoors.

But during that time scanning and waiting, it got me thinking… It took me a good minute to find a suitable spot in my backyard free of the light from the neighbours’ houses and street lights. If there was less light pollution we could have darker skies and everyone could enjoy the show.

During Earth Hour people are asked to turn off the lights for one hour to support the fight for climate change. But I always found that pretty pointless.  If you want to fight climate change, it’s an every day affaire, in your daily routine and the choices you have as a consumer, not one hour in an entire year. So the one hour lights out is more of a gimmick, doesn’t really benefit anyone. But if we had an evening of lights out during the peak of the Perseids meteor shower wouldn’t that be great!

The Perseids falls in August when it’s warm and sitting outside past sunset in the cooling air is enjoyable. Kids don’t have school so they can stay up late. And the patio furniture is out, that’s all the required equipment.

So what do you say? Light out for the 2018 Perseids? I think that’s a worthwhile collective movement.

This Weekend – Best Time to See Jupiter

This weekend is the best time to see Jupiter of all 2017, because the planet is at opposition, meaning it is exactly opposite to the Sun and the Earth-Jupiter separation is also at its closest.

The photo below was taken during the September 2010 event and I happened to fall upon a fantastic low turbulence window in the atmosphere. Look closely and you’ll see the shadow of one of those moons on the Jupiter’s surface.

Jupiter_17sep2010

Jupiter – Benoit Guertin

Photos of Jupiter with the moons are a little tricky. Capturing the smaller moons require more exposure or gain, but at the risk of over-exposing the planet and turning Jupiter with those wonderful cloud bands into nothing more than a white sphere. It is always better to take a series of images or videos with different settings and review them at a later time on the computer.  Some information on planetary imaging and processing is provided in my blog on imaging with a webcam.

Planetary imaging is all about controlling turbulence.  Air turbulence whether within the optics, telescope, near the ground or high atmosphere will give you a blurry view. Hence some simple tips are:

  1. Allow your equipment to cool down a few minutes such that the equipment temperature can stabilize and match the outdoors.
  2. Past midnight is better as this allows time for the ground to cool especially after a sunny afternoon, reducing convective currents.
  3. Wait until Jupiter is high in the sky, that way there is less atmosphere between you and Jupiter. By looking straight up, you will be looking through a smaller “air column”.

A good time will be on April 10th when the Moon will next to Jupiter.  See the sky chart below showing the southern part of the sky at 10pm EDT.  The planet will track west as the night advances.

April 10th 2017 Sky Chart

April 10th 2017 Sky Chart

 

Tomorrow Evening: Moon, Mars and Venus

Great photo opportunity tomorrow evening, January 31st, with a thin crescent Moon in a close formation with Mars and Venus.  As the sky darkens simply look between South-West and West and you won’t miss them.  However don’t wait too late, by 9pm they will have disappeared below the horizon.

Early Evening Sky (7pm) - Look WSW for this close formation

Early Evening Sky (7pm) – Look WSW for this close formation

The Moon will be a thin crescent.  Here it is as photographed of the Moon tonight at 5:40pm just a little less than 3 days old.

Crescent Moon - 30-JAN-2017 (5:40pm)

Crescent Moon – 30-JAN-2017 (5:40pm)

No high-resolution photo for this one.  Took it quickly through an open window simply by hand-holding the telescope, and using Venus to quickly find focus through the camera view-finder.

Skywatcher 80ED
Canon XTi (1/50s at ISO400)
Registax6 to align, stack and wavelet on the best 3 frames (out of a dozen)