ELAIS-N2-P1

A few crops from a 1x1 degree mosaic image, composed from g, r and z-band data in the SpARCS ELAIS-N2-P1 field (as B, V and R channels). Total exposure time is about 3h, with the MEGAPRIME camera installed on the 3.6m Canada-France Hawaii Telescope. 

The original image is 4.7 Gb, so I had to crop some more interesting regions. 

Nicely disturbed galaxy

 Galaxy string

Hundreds of galaxies in just a few arcminutes

The power of a 4m class telescope is still great! :) More images to come soon, as I see interesting regions in the data I have. 

The bolides of Teide

       After ascending to 3100m to Tenerife's Pico Viejo on last Saturday (10th of November) and descending at night, the whole party of five was quite tired (after all, the sign at the beginning of the path was marked with the "Extreme difficulty" distinction). We laughed in the face of danger. Although the initial plan was to spend the night under the stars together, the others gave in to thirst, hunger and tiredness but I could only ask them to leave me closer to the Teide Observatory: it was a night close the Taurid meteor shower maximum and some bright meteors were promised. At least for my effort I should of been a bit rewarded.

     So, they brought me to within 1 km of the observatory and packed me with blankets, warm clothes and the rest of the food and water, leaving me alone in starlight. Fortunately, Etienne was a great guy and promised to pick me up in the morning, otherwise I was supposed to walk about 10 km or so to the main road and take the bus at 16:00 back to Puerto de la Cruz. And he did, so I got a lot more sleep on Sunday :)

I was initially planning to take a long time-lapse, until dawn, but when I went to check the camera after some time I realized that some clouds/fog (basically the same thing there) passed by and ruined the whole idea. Scanning quickly through the images revealed though that the fireball (bolide) I barely saw some time earlier was indeed in one of the images. Oh, joy!! It is probably the brightest meteor I have ever photographed and I used for that a 8mm fisheye lens at 5.6, ISO 1600 on a Canon 600d and 45s exposure time. 

The winter Milky Way rises, meteors fall

     Today I played a bit with the lightcurve and reached the graph below. I took a 58x670 pixels crop of both the meteor and Castor and Pollux, plotting on the X axis the pixel number and on the Y axis the values in counts of all the 58 pixels of the line perpendicular to the meteor trajectory and the Castor-Pollux line. 

Then I averaged the values of the three CCD channels (RGB) and multiplied the result with 256, for convenience. The red shows the meteor lightcurve and the black the spatial lightcurve of the two standard stars used, Castor and Pollux.

 After performing a little statistical analysis of the values I equalized the backgrounds of the meteor image and of the standard stars to have the same zeropoint and therefore a meaningful comparison. Calculating the FWHM of the stars in pixels which allowed the transformation to arcminutes, using the pixel scale of the camera-lens combination.

 Assuming an angular velocity of 15 degrees per second for the meteor, it is then possible to calculate the time the meteor took to cross 3 arcminutes.  As the flux ratios of Castor and the maximum brightness of the meteor seem about the same, the ratios of the exposure times/3arcminutes should give us the flux ratios.

 The meaning of the values cited in the figure are: V is the pre-atmospheric velocity (km/s), the elevation h_b (degrees), the altitude H_b (km) of its start point, and the angular distance between its end point and the radiant D (degrees). 

As I mentioned I barely was it and it seemed quite (angularly) fast to me, so an Andromedid label is excluded and the Taurid origin is out of the question also from the track orientation, at least at first sight.

And that's how I got an approximate magnitude of -8.5m for this fireball :)

There were other meteors and this is the second (and last) bolide I captured on camera that night. The analysis above cannot be performed though, as the meteor track is saturated and only a minimum magnitude can be obtained in that way. 

Venus and the Moon joined the show :)

 A 100% crop of the meteor captured above. It's kind of wiggly and I wonder if it's a sampling effect or a true physical effect. 

Comet C/2012 S1 (ISON) & Co

The comet season is here!

After the great comet of 2007, comet McNaught and the great comet of 2011, comet Lovejoy, we might be due to another Great One. Comet C/2012 S1 (ISON) was discovered on the 21st of September 2012 by Vitali Nevski and Artyom Novichonok, working with the International Scientific Optical Network (ISON). The preliminary orbit predicts that the comet will pass 1.8 million kilometers away from the Suns center and 1.1 million kilometers above it's surface on the 28th of November 2013.

This very close approach will melt and vaporize parts of the comet and it might develop a spectacular tail, with the potential of being much brighter that the Full Moon (some predictions reach magnitude -16). It is also well placed for observations from the Nothern Hemisphere, unlike the previous two great comets of this century. But let's not forget comet Kohoutek, which was another bright hope that ended in darkness: comets are notoriously unpredictable. 

Just one more interesting "coincidence". The orbit of comet C/2012 S1 looks quite similar to that of the Great Comet of 1680. It might be that they had the same parent body, which fragmented a long time ago. Hopefully we'll have the fun Newton had while he observed it. 

Right now it is beyond the orbit of Jupiter and looks like a very faint smudge at magnitude 17.5 V, but mark your calendars for late 2013 as you might be in for the show of a lifetime!

I observed this comet last night, with the 0.5m Argelander Institute telescope (as usually).

But there are other icy snowballs visiting the inner solar system :) 

One of them is comet C/2010 S1 (LINEAR), now shining at magnitude 13.3. It brighten to magnitude 13 or so in mid-2013 an then it will slowly fade away. A much more discreet visitor than comet ISON!

The second one is Comet C/2012 K5 (LINEAR), which will brighten to magnitude 8 in late December 2012 - early January 2013.  Right now it is at magnitude 11.1. Northern observers will have the best view, as it will silently slide from Ursa Major to Taurus in this time. As the comet was moving rather fast, I had to stack the images by centering all of them on the comet: that is the reason for which the stars look like trails while the comet looks just fine :) There was a gap in the observations and that's why the star trails come in pairs.

These last two comets were observed on the 24th of June 2012.

UPDATE: 13 January 2013
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The comet C/2012 K5 (LINEAR) has indeed brightened up to magnitude 8 during the last few months. An animation of the comet sliding among the stars can be seen below. The magnitude of the nucleus only as reported by Astrometrica is 14.8 V. 

Wavy Perseid trail

Meteors are the blazing trails that smaller than one would expect dust leave while entering our atmosphere at huge velocities (from about 20 to 70 kilometers per second). A millimeter sized particle would produce a very bright meteor, probably not unlike the -8m one that left the trail pictured below. Sometimes these ionized gases remain visible for so long that high atmosphere winds distort them in funny ways:

The picture was taken in August 2008 during the maximum of the Perseid meteor shower from the top of the Omu Peak in the Romanian Carpathians.

The Andromeda galaxy

One chance. Once chance to get it right, with sooo many things that could go wrong! 

Almost ten years ago I could use for a night a telescope on an equatorial mount to piggyback my Canon T70 with a 200mm f/4 lens and ISO 400 film :D 

One of the targets was of course M31, the Andromeda Galaxy. It was a lot of fun, as one could not see what he's doing and manually guiding 30 minutes it's not an easy task: the slightest mistake could and would of ruined the picture.

But I kept my hand steady, my eye sharp and prayed to the control towers to divert planes from my field of view:

   Take a good look at it as we're going to crash with this giant galaxy in no time (~4 billion years!).  

Milky Way over Las Campanas

The center of our galaxy rises over the Las Campanas Observatory, with the twin 6.5m Magellan telescopes visible at the bottom of the image. It's not too far from the Cerro Tololo Inter-American Observatory and if you're around there, visit them both!

From the eye of the lama to the little horse, it's all there.

Winter cone

  The famous Cone Nebula can be found in the constellation of Monoceros and it's one of those star forming factories in our galaxy which already created a very young star cluster (the Christmas tree, NGC 2264 :) ). S Monocerotis is responsible lighting up the last remains of the "mother - gas cloud". 7 light years across (10 arcminutes) and 2700 light years distant, the Cone Nebula is part of a huge star forming complex in the winter skies, a blend of dark and excited gas and dust clouds.

 

 I have always wished for a Christmas Tree like this. 

Cosmic dance and elegance

In their way through space, galaxies usually meet and interact, creating new structures. Thirty years ago a Canadian astronomer (Paul Hickson) created a catalogue of 462 such closely interacting systems, most often composed of 4-5 galaxies as closely packed together as the galaxies in the center of  some clusters of galaxies. We don't know precisely yet how many of  the galaxies in these systems are interacting and how many are just chance alignments, but studies have shown that for about half there is some physical connection involved. 

A theory suggests that these systems are on their way of creating an elliptical galaxy, so stay tuned! 

   Below, the cosmic dance brought together in HCG 44 three spirals and a small elliptical galaxy, NGC 3190, NGC 3193, NGC 3185 and NGC 3187 and signs of their interactions abound (tidal tails, disc distortions...)

Meanwhile in Pegasus, ~40 million light years away, edge-on spiral galaxy NGC 7814 elegantly displays her slightly warped edge-on disc. It is also called Little Sombrero after her closer and larger brother M 104. There are many faint galaxies seen around it and as their light passed through the halo of the galaxy is gets a little redder.

      Elegant, isn't it?

All images taken through the 0.5m Argelander Institute for Astronomy Institute in Bonn.