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Posts Tagged ‘astrophotography’

Comet Lovejoy

Comet Lovejoy

On the night of November 27th 2011 amateur astronomer and comet hunter Terry Lovejoy from Australia discovered something that he marked as “probable reflection” with his telescope. He checked back and it wasn’t a reflection at all, it was a comet. This comet named after his discoverer C/2011 W3 Lovejoy  belongs to what is known as the “Kreutz Sungrazers” family, comets with orbits bringing them really close to the sun, the theory is that these comets are fragments of a larger comet that was fragmented thousands of years ago.

Comet Lovejoy started then a journey of amazing highlights for the astronomical community. It’s the first comet of the Kreutz group to be discovered from the ground in 30 years, usually they are discovered using NASA’s solar telescopes such as SOHO or STEREO. After initial calculations the comet body was estimated to be as big as a football field, not enough to survive a close approach to the Sun. Comet Lovejoy was doomed.

Lovejoy Approaching the Sun

Lovejoy Approaching the Sun

While approaching the Sun Lovejoy brightened to magnitude -4, that’s as bright as planet Venus making it the third brightest object in the sky after the Sun and the Moon. It wasn’t visible to the naked eye because the comet was too close to the Sun, lost in the glare. This was supposed to be all, after perihelion the little comet would be destroyed into tiny fragments never to be seen again.

But comets are like a box of chocolate, you never know what you are gonna get. The astronomy world was amazed when the comet emerged from behind the Sun.

It's Alive!

It's Alive!

The comet emerged from behind the Sun and looked smaller and had lost its tail. It was a miracle for the little comet to have survived perihelion but that was only a small thing compared to what was coming. The comet re-formed it’s tail and brightened and now astronomers started to discuss the possibility of the comet being visible to the naked eye.

Due to its orbit Lovejoy is only visible to observers in the south hemisphere it started very close to the sun so astronomers and photographers had to hunt for it a few minutes before dawn, as soon as it cleared some degrees away from the Sun the show started.

Lovejoy at the Milky Way

Lovejoy at the Milky Way

The comet became visible to the naked eye before dawn, it was easy to see on December 23rd, I went to a rural location and at around 3am the tail of the comet rose from behind the trees at the horizon, it was a fantastic sight. It quickly brightened and its two tails were easy to spot with the naked eye and magnificent in photos.

The Two Tails of Comet Lovejoy

The Two Tails of Comet Lovejoy

The main tail curves above the horizon and is made of dust, the secondary tail is made of ionized gas and rises straight from the horizon. As said before both tails were easy to see with the naked eye.

As photos started to come from Australia, South Africa and Argentina the comet became bigger and brighter, people compared it with comet McNaught from 2007 and with Ikeya-Seki from 1965, the brightest comet in the history of mankind and also a member of the Kreutz family. Lovejoy wasn’t that bright, you had to go to rural areas to see it but it was really big with its tail extending for more than 20 degrees.

The Great Comet of 2011

The Great Comet of 2011

There is no formal definition of “great comet” but in some places they say that a comet needs to be bigger than 15 degrees and visible to the naked eye. If we take that definition then Lovejoy is without a doubt the great comet of 2011. It’s huge and bright enough to be an easy naked eye object from rural areas. In my estimations it was brighter than the Milky Way and as bright as the Magellan Clouds but the clouds were very high in the sky and the comet close to the horizon so it’s probably brighter.

Dawn of the Comet

Dawn of the Comet

Lovejoy will now begin to travel fast away from the Sun towards the south celestial pole. It will be fainter each day and it will be higher in the skies of the south hemisphere. By January 8th the comet will be circumpolar at latitude 35 degrees south, that means it will be visible the whole night. It will not be visible by the naked eye but with binoculars or telescopes it promises to keep being a fantastic target.

This comet, discovered by an amateur astronomer, was supposed to be destroyed at perihelion it survived and displayed a fantastic show. It was a great christmas gift for all the people that like the beauties and surprises of the night sky.

You can find my photos of Comet Lovejoy at the special gallery I created on my website: http://www.luisargerich.com/lovejoy

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The Emu in the Sky

The Emu in the Sky

What happens when you find yourself standing in the middle of the night at 800 meters high, with little or no humidity and more than 200km away from the nearest artificial light-source? Welcome to one of the best nigh skies in the world, at the Somuncura plateau in the Argentinian Patagonia.

There is a scale to measure the quality of the night sky called “the Bortle  Dark Sky Scale” in that scale Somuncura is a class 1 zone, there’s not a single lightbulb in hundreds of kilometers around you!

From Scorpius to Orion

From Scorpius to Orion

If you are used to the horrible pink glow of urban or suburban skies you will notice several differences in a class 1 sky. The first one is that you can’t see! And I really mean it, on a moonless night you can put your hand in front of your face and you won’t see it. Interesting!. Several deep sky objects are easily seen with the naked eye. The Magellan clouds are very bright and the Milky Way is stunning. The Orion Nebula is fuzzy and easy and of course you see thousands of stars. Something that really caught my attention was how the dark coalsack  nebula next to the southern cross contrasted against the Milky Way. It was deep black against an ocean of stars.

The Light of the Milky Way

The Light of the Milky Way

The Milky Way is so bright that it casts shadows and can be used as a light-source. This panorama is Milky-Way lit, no moon, no artificial lights no other light source in hundreds of kilometers. I blogged about this before in a post called “The Light of the Milky Way“.

The Celestial Equator

The Celestial Equator

One inmediate effect of darkness is that you can take a really long exposure photo without blowing the sky, at the place where I live I can expose the sky for about 30 seconds, at Somuncura I could expose for 2 hours and the photo had still room for more photons! This is very nice but caught me totally off guard and I run into several technical problems with my remotes, batteries and supporting gear because I wasn’t trained for such long exposures.

Meteor at Somuncura

Meteor at Somuncura

My final paragraph is for meteors or shooting stars. I visited the plateau in March far away from any significant or even small meteor shower. Even then it was very easy to catch a few sporadic meteors jut by grazing at the sky for some time. I even got a nice bolide in one photo jus by pure luck. I can’t imagine how a meteor shower would look under these skies but I would love to be there for one.

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The Light of the Milky Way

The Light of the Milky Way

In my trip to the Somuncurá Plateau in Patagonia, Argentina I found that a very dark sky can be a very good and very bad thing at the same time. The Plateau is one of the most isolated places on earth, the nearest town is more than 200km away and there are no light sources of any kind. On a moonless night you can’t see a hand in front of your face. It was also for me the first time without battling against some kind of glare in the horizon, even if you are at the countryside a city 100km away can create a nasty glow in the horizon making starry landscapes difficult to expose.

So this is probably one of the best skies in the world, dark, dry, at 1000 meters of altitude and without any light source,  that’s the good part. The bad thing is that the total absence of light makes exposures much more difficult, even in dark locations there is always “some” light to make the landscape show up in a long enough exposure, here I could expose for minutes and minutes and all I could get was darkness.

The photo is titled “The Light of the Milky Way” because that is the main light source for the landscape, averaging magnitude -5 the Milky Way can be used as a light source and can even cast small shadows if you are in a really dark location. I used the brightest part of the Milky Way at Scorpius-Sagitarius as the light source for the lagoon here, that’s the brownish reflection you see on the water.

The photo is a panorama made from 5 portrait oriented shots at 14mm 30” F2.8, Orion and the Milky Way are at the center, the Magellan Clouds on the left. You can even see the Tarantula Nebula as a bright spot next to the Large Magellan Cloud and the cumulus 47 Tucanae as a diffuse star next to the Small Magellan Cloud. The Magellan Clouds are satellite galaxies of our own Milky Way and even if they are bright they are also very diffuse and impossible to observe from a light polluted place.

Image at my website

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The last time a total Lunar eclipse took place on the 21 of December was 1648 years ago. In 2010 the event repeated, a total lunar eclipse was visible in most of the Americas during the summer or winter solstice depending on which hemisphere you live.

The 2010 Solstice Eclipse

The 2010 Solstice Eclipse

From my location: Buenos Aires, Argentina the eclipse started at 3:27am in the morning with the moon setting, moonset was during the totality stage so we only saw half of the eclipse. Fortunately the other half is just symmetrical to the first part but in reverse order and as the moon approached the horizon an optical illusion made it seem bigger than what it really was. A giant red moon looming over the horizon, that’s something you have to see!

Totality

Totality

I took photos every 2 minutes with a Canon T2i (550D) and a Canon 400mm F5.6 lens, the 1.6x crop factor of the 550D combined with the 400mm lens gave me a field of view of 640mm. I decided not to use the 1.4x teleconverter as it would make my lens go from F5.6 to F8 and the totality phase of the eclipse would take a long exposure time resulting in a blurry photo due to the Moon movement. The moon moves quite fast in the sky, I had to chase it with my camera from shot to shot. A micrometric head like the Manfrotto 410 helps a lot in that task.

Before and After

Before and After

During totality the moon is in the Earth’s shadow so it is not lit by the sun but from Earth’s own light, when the atmosphere is clear the moon turns very red, in years with volcanic eruptions the moon can turn brown chocolate or be completely black. During this eclipse the stratosphere was very clear resulting in a bright red moon during the totality phase.

Solstice Eclipse Starscape

Solstice Eclipse Starscape

It’s very difficult to take a photo of the stars with the moon included in the frame, the moon is so bright that gets totally overexposed producing flares glare and diminishing the stars. During the totality phase of the eclipse the moon was very dim allowing the capture of the moon against a background of stars in the same field of view.

You can check more photos at my site: http://www.luisargerich.com

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Geminid Bolid at Mercedes

Geminid Bolid at Mercedes

A meteor shower is produced when Earth glides across debris from a comet or asteroid, the tiny fragments that are only a few inches long burn in the atmosphere producing meteors. Sometimes a bigger fragment grazes thru the atmosphere producing a bolide: a bigger, brighter meteor but even those are not big enough to reach the surface. In the case of the geminids the debris was originated by an asteroid named 3200 Phaeton, it’s the only meteor shower not originated from a comet. The first photo shows a bright bolide above the setting moon.

The Geminids are usually the best meteor shower of the year. In the southern hemisphere the radiant is not very high in the sky but high enough to produce many meteors and the temperatures are warm as the event takes place on summer time.

The Geminids at Orion

The Geminids at Orion

The photo shows the Orion belt with the flame nebula and horsehead nebula and the big and bright M42 nebula. 10 meteors crossed the field of view in a 20 minutes time span. That’s a high rate and was probably the peak of the meteor shower from my location. The gaps in the meteor trails are produced by a 1 second delay between exposures and in some way help to see the speed of the meteors. The one in the top left corner was specially bright and fast.

Geminid Meteor at the Pleiades

Geminid Meteor at the Pleiades

This meteor crossed the pleiades cluster M45 coming from the Geminids radiant in the Gemini constellation. It has a notorious green tint, geminids are usually yellow/green. Not all the meteors came from the radiant there were many errant meteors. The best way to make sure you don’t miss a meteor is to use a fisheye lens pointed straight up at the zenit to make sure you cover as much of the sky as possible. I’ll try that approach next time to see how many meteors I can get.

Geminid Meteor at Mercedes

Geminid Meteor at Mercedes

This ultra wide view shows a bright bolide near the horizon. The sky features several constellations and objects including Orion, Taurus with the Pleiades and Hyades cluster, Gemini, Hydra and more. This was just before dawn and the horizon was starting to get bright so the meteor must have been really big and bright.

Meteor showers are fun to watch and fun to photograph, it’s a hunting exercise as you have the camera constantly shooting trying to get a meteor, they are so fast that the only way to get them involves a little luck. For unknown reasons the Geminids are getting better and better year after year so we can just start to wait for the 2011 show.

For more photos you can always check my website: http://www.luisargerich.com

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The Moon October 19th 2010

The Moon October 19th 2010

This post shows some simple results of what can be done with a DSLR without a telescope in the field of planetary astrophotography. While the results can never be compared to the results obtained with a telescope I think most photographers are unaware of what can be achieved just with the camera and a long lens. For this examples I used a Canon 550D camera, a 400mm F5.6 lens and a 1.4x teleconverter. Longer lenses and a 2x teleconverter can achieve even more magnification for even better results. Glass quality is fundamental a good 400mm lens can be better than a cheap 800mm mirror lens.

Jupiter and its Moons

Jupiter and its Moons

For the moon and Jupiter I used the camera, the 400mm lens and the 1.4x teleconverter. Aperture was fixed at F11 for maximum sharpness, ISOs between 400 and 800 are more than enough to get shutter speeds such as 1/200 or 1/100 those are enough to freeze the movement of the moon or Jupiter across the field of view.

Six Degrees of Separation

Six Degrees of Separation

To improve noise, resolution and magnification several images can be taken and then stacked. Registax is a very good free software for planetary stacking.  For Jupiter and its moons two different exposures are needed as the planet will be overexposed if the moons are displayed and the moons will be invisible if Jupiter is properly exposed.

Jupiter without a Telescope

Jupiter without a Telescope

This last example was done with the Video Mode of the 550D. The 550d has a 7x 640×480 video mode that acts like a digital zoom, a short video can then be decomposed by registax into hundreds of frames that can be stacked to improve noise and resolution. Jupiter shows enough detail to see its bands and the red spot, I think the resolution is high enough to show Venus phases and it will be great to show Saturn and its rings, probably the most interesting target for this unpretentious kind of photography.

I hope this small article encourages more photographers to make tries at the moon and the planets, it can be done even if you don’t have a telescope.

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