Green Comet and Globular Cluster

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The image above is of Comet Garradd as it went by the globular cluster M71 in the constellation Sagitta back on August 26, 2011.  This is the brightest comet in the sky right now, easily visible with a pair of binoculars, but with a couple of provisions.  You need to view it away from the city lights and you need to know exactly where to look.  Because comets are constantly on the move, you will need a star chart for the evening that you go out into the countryside.  Click here to get some printable star charts for the next 6 months (courtesy of Sky and Telescope magazine) as it heads closer to the sun.  Comet Garradd will be visible for quite a long time, so there should be no excuse of not having enough time to see it.

Are you wondering why the comet is green?  One of the few green objects in the night sky, the color is caused by the Sun's ultraviolet light striking the cyanogen gas surrounding the star-like nucleus of the comet making it glow.  The tail is composed of gas and dust, pushed away from the nucleus, by the pressure of light particles from the sun.

The globular cluster, M71, looks to be fairly close to the comet, but not really.  At the time of the picture, the comet was about 130 million miles away from Earth.  M71 is 13,000 light years away.  To make it easier to compare the difference in distances, lets convert the comets distance in miles to light years.  Light travels 186,000 miles per second.  Dividing 130 million by 186,000 gives about 700 seconds.  Now you can really see the difference:  Light takes about 11.6 minutes to get from the comet to our eyes, but from where M71 is located, it takes light 13,000 years to travel from where it is located.

Technical Data:

• Date Taken: Aug 26, 2011
• Location: ASKC Dark Sky Site
• Telescope: 190mm, f/5.3 Maksutov Newtonian
• Camera:  Q453 CCD (similar to QHY8)
• Exposure: 30 minutes (consisting of 15 - 2 minute shots)
• Calibration: 20 Bias, 20 Flats, 1 Dark
• AutoGuider: Q-Guider with 50mm Finderscope
• Mount: Parallax Instruments HD 150C
• Capture Software: Nebulosity
• Calibration Software: Nebulosity
• Final Processing Software: Photoshop CS3

Supernova Erupts in the Pinwheel Galaxy

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On August 24, the Palomar Observatory discovered a supernova in M101, the Pinwheel Galaxy.  The supernova has been getting brighter every day since its discovery.  I took this picture on the evening of August 30.  The star is brighter than the nucleus of the galaxy, which is composed of millions of stars.  M101 is a large face-on spiral near the Big Dipper with an apparent size of the Moon.  It can just barely be seen with a pair of binoculars from a very dark sky, but now the supernova will be brighter than the galaxy, at least until the explosion dies away in a few days.

Click on the image below to show you a labeled picture pointing out the location of the supernova and a few supergiant star forming areas in the galaxy. Three galaxies near M101 are also labeled.  They are NGC5471, NGC5473 and one that almost looks like a star, PGC49919.  They look smaller than M101 only because they are much further away from us.  M101 is 23 million light years away and 170,000 light years across.  This supernova, designated 2011fe, is being studied by the scientific community.  The early detection, combined with the relative closeness of M101, makes this a spectacular find for professional researchers.  Here's a light curve of magnitude measurements (visual, R, V, and B) that the America Association Variable Star Observers has received.

The Needle Galaxy - NGC4565

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Commonly known as the "Needle Galaxy" because of its narrow edge-on appearance, this spiral galaxy is formerly labeled NGC4565 in the constellation Coma Bernices. Another way to imagine it: Think of a dinner plate with a glob of mashed potatoes in the middle of it, then look at this plate from the edge.  The mashed potatoes is the bulge of stars at the center of the disk.  The plate is the rest of the galaxy consisting of blueish areas of star formation and massive lanes of  dark dust and gas circling the disk.  The "Needle" spans 100,000 light years in diameter and is 30 million light years from Earth.  One of the prettiest edge-on galaxies in the night sky.

Many other galaxies, much further away and therefore fainter and smaller are strewn throughout the image.  I have labeled some of the brighter ones in the image below.  If you can't see these galaxies, then your monitor is too dark.

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Technical Data:

• Date Taken: 04-02-2011
• Location: ASKC Dark Sky Site
• Telescope: 190mm, f/5.3 Maksutov Newtonian by Orion
• Camera: Q453 CCD, 3032(h) X 2016(v) pixels
• Exposure: 1 hour (consisting of 4 - 15 minute shots)
• Calibration Exposures: 20 Bias, 0 Flats, 1 Dark used to make a "Bad Pixel Map"
• AutoGuider: Q-Guider with 50mm Finderscope
• Mount: Parallax Instruments HD 150C
• Capture Software: Nebulosity
• Calibration Software: DeepSkyStacker
• Final Processing Sofware: Photoshop CS3

Milky Way

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This is our home galaxy, which we call the Milky Way.  The 10mm lens I used gives  a 107-degree diagonal view.  From the horizon to just past overhead.  The whole thing extends across the whole sky and circles underneath our feet in one huge ring.  We see the part under our feet in the Winter sky.

Only from a dark site, away from the light pollution of our cities, can you see it in all its glory.  But even when you can see the Milky Way from a dark site, you won't see it quite this way.  Our eyes see with a bit more subtlety.  Only in photographs do we see it with this much color and contrast.  The clouds of stars, nebulae and dark dusty areas are very easy to see.

The above image took almost 3 hours to take.  I piggybacked my Canon Xti with my 10-22mm lens (set to 10mm at f/5) on top of my telescope and took 22 eight minute pictures.  I combined, aligned and stacked them in DeepSkyStacker then processed it in Photoshop.

I have outlined the major constellation in the annotated image below.

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How To Take Star Trails Around The North Star

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Star trails are easy to take with your digital camera, but before I tell you how I created the above image, a few things about the picture.  The image is a 5.5 hour long exposure of the northern sky centered at the "north celestial pole" of the Earth.  As we rotate with the Earth during the night, the stars seemingly rotate counter-clockwise.  They rotate in smaller circles around a point near the "North Star".  This point is the axis of the Earth extended to the sky and is called the north celestial pole.  Also notice that the North Star is not exactly at this point.  The red glow centered above the tree line is the light pollution glow from Kansas City, about 50 miles away.  The brighter white glow on the left is from the La Cygne power plant, about 5 miles distance.

The image is NOT one long exposure, but a combination of eighty one, 4 minute shots.  I started the first exposure at 10:54 p.m. and the last exposure ended 5 hours, 30 minutes later, just after atronomical twilight at 4:24 a.m.  All taken with my 10-22mm wide-angle lens set to 10mm on my Canon XTi digital.

A little bit of forethought is required to take a shot like this.  You can take one long shot, but if you do, you are more likely to get a very bright, over exposed picture.  It is better to take shorter exposures and combine them later.  This is what I did:

• Before dark, I put the camera on a tripod.  I replaced the camera's battery with its AC-power adapter (I didn't want the battery to run out of power in the middle of the shots).
• I set the lens at its widest view, 10mm.  I then auto-focused the lens on the distant horizon.  I turned off the auto-focus switch (you don't want to use the auto-focus feature because the stars are too dim for the lens to focus on).  Being careful not to bump the focus setting.  I then set the shooting mode to M (Manual) and dialed the shutter speed to Bulb.
• Once it got dark, I composed the picture by taking a few test shots.  I settled on individual 4 minute shots, with the lens set at f/4 and the camera at ISO 400.  A little bit of math told me that I would need about 75 shots for the 5 hours of darkness.  I used a "timer remote controller", setting the remote to take 99 shots, each shot set at 4 minutes with a 2 second interval between shots to allow each image to be saved to the memory card.  I pressed the Start button on the timer and walked away.

There is one thing that can ruin a shot like this, and that is dew.  If the night is humid, the lens will fog over with dew.  I get rid of dew by attaching a dew heater around the lens.  The heater is usually run with power from a battery.  Even a simple 9-volt battery will work.  I make my own dew heating straps using resistors.  The other thing that I have done is to blow away the dew every once in a while with a hair blower.  That being said, I did not have a dew problems.  There was just enough of a breeze to keep it at bay.

Now comes the easy part, combining all eighty one pictures. How can that be easy, you might be saying?  It is easy because someone has created a program that does it all automatically. Achim Schaller, from Germany, created the program and it is "Free".  Here is the website: http://www.startrails.de/html/software.html  All you do is load the images, press a button, and in a few minutes it is done.  It's supposed to create a video also, but I couldn't get it to work.

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Above are the first and last frames from the eighty one images.  You can see how much the sky has rotated in 5.5 hours

Colorful Nebulae around the Antares and Ophiuchus Region

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This is one of the most colorful regions in the Milky Way.  Visually, even with the largest telescope, you won't see it anything like this.  It takes long exposure photographs to bring out the beautiful colors, and is why I like to take pictures of the night sky.
Known as the Rho-Ophiuchus Nebula Complex, it consists of blue reflection nebulae, red emission nebulae, dusty, dark nebulae and a rare yellow-orange reflection nebula surrounding the Red Giant star Antares at the lower-left of the image.  The triple star Rho and the blue reflection nebula surrounding it is located in the middle-lower section of the image.  The colors of these nebulae are fascinating, but what is really amazing to me are the "Dark Nebulae".  These filaments of dark-brown regions consist of light years of dust.  So much dust they block the Milky Way starlight in the background.  Dark Nebulae were discovered by the pioneering astrophotographer Edward E. Barnard in the late 1800s.  He created a catalog of 349 dark nebulae.  Each has a number with the letter B in front of it.
Other objects in the image include Globular Clusters.  M4 is largest and easiest to see.  It is the big ball of stars located below Antares.  Very much smaller is NGC6144, just to the right and a little below Antares.  Three others, even smaller globulars are in the image, but look like large stars (To see where they are, take a look at the annotated image below).

Technical Data:

• Date Taken: 06-04-2011
• Location: ASKC Dark Sky Site
• Lens: Canon 28-200mm f/2.8 L IS (set to 100mm at f/4)
• Camera:  Q453 CCD, 3032(h) x 2016(v) ~ 6.11M pixels
•  Field of View: 13.6 degrees X 9.0 degrees
•  Calibration Exposures: 20 Bias, 0 Flats, 1 Dark used to make a "Bad Pixel Map"
•  Exposure:  2 hours (consisting of 8 - 15 minute shots)
•  Calibration Exposures: 20 Bias, 0 Flats, 1 Dark used to make a "Bad Pixel Map"
•  AutoGuider: Q-Guider with 50mm finder
•  Mount: Parallax Instruments HD 150C
•  Capture Softwar: Nebulosity
• Calibration Software: DeepSkyStacker
• Final Processing Software: Photoshop CS3

ISS Passing Overhead

 
Last evening I set up my Canon XTi with a new 10-22mm f/3.5 lens to capture the International Space Station as it crossed almost directly overhead here in the Kansas City area.  The Moon was shining brightly and it was not quite dark, so there was quite a bit of nice blue color in the sky as well as some fast moving clouds.  Here it is on YouTube: