Messier 27 – the Dumbbell Nebula

Space is full of interesting objects. We often think of stars and galaxies, but there are other kinds of distant objects that have been discovered over the past 250 years. In 1764 the French astronomer Charles Messier found a whole new class of objects. He was hunting for comets, and had started to create a list of things in the sky that might look a little like a comet, but which didn’t move. The list, now known as the Messier Objects, was originally intended to help him and others find comets by confirming which things viewed though telescopes weren’t actually comets.

Nearly 250 years ago, he turned his telescope to the sky and found something he catalogued as the 27th object in his list. For some time the telescopes available showed objects like M27 as looking a bit like the distant, outer planets in our own solar system, and they picked up the general name “Planetary Nebulae.” Just what they were wasn’t explained for another century, when William Huggins was able to look at the light from one of these fuzzy, roundish objects. Through spectroscopy he realized that he wasn’t looking at light being reflected from an object like a planet, or light from a hot luminous object like a star, but light being generated by excited gasses.

Planetary nebulae are now known to be the spectacular remnants of a star that is throwing off vast quantities of gas late in its life. Some of them appear to be shedding multiple shells of gas. In the case of Messier 27, also called the Dumbbell Nebula, researchers have estimated that the bright gas we can see with telescopes likely was emitted from a star in the centre of the object about 10,000 years ago.

In early May 2013 I decided to try using the University of Iowa’s Rigel telescope at the Winer Observatory, southeast of Tucson, Arizona (http://www.winer.org/) to image M27. This telescope can be used by anyone over the Internet on the Sierra Stars Observatory Network (http://www.sierrastars.com), and I’ve been experimenting with it for the past few weeks.

To take an image of Messier 27 I first programmed the telescope to take a single shot of the nebula for 150 seconds, to get a feeling for exposures, which the telescope captured early on the morning of 7 May 2013. M27 is quite a bright object, and many people have fun finding it with a small telescope. It has a magnitude of 7.5, meaning that it’s just below the limit of objects you can expect to see on a dark sky with your eyes, but it’s well within the expected range of objects to see with a modest amateur telescope or binoculars.  It’s in the Vulpecula constellation (“the little fox”) just south of Cygnus, the swan. The 150 second exposure wasn’t overexposed for the nebula, and in fact looked a bit faint, so I decided to take a series of 300 second images. I set the telescope to take two 300 second exposures with no filter, and two more 300 second exposures with each of the red, green, and blue filters on the system. The images were captured early on the morning of Thursday 9 May 2013. Here’s the result, after combining the “black and white” frames first (“Luminance”) and then preparing the colour information (“RGB”), using free software called Fitswork4:

M27 imaged with Rigel

Messier 27, the Dumbbell Nebular, imaged with the 37 cm Rigel telescope owned by the University of Iowa, located in Arizona (the “Iowa Robotic Telescope Facility” or IRTF). The image was prepared from a series of monochrome pictures taken through colour filters (the “LRGB” process). combined with Fitswork4 and adjusted a bit with Adobe Photoshop Elements.

The Dumbbell Nebula sits about 1,360 light years away from earth, and is about one light-year across. It’s also notable because of the star that remains at its centre: it’s the largest-known white dwarf star.

This first try at M27 is encouraging, but I wasn’t able to get good registration, or alignment, of the red, green, and blue frames. As a result the colours I was able to produce in the combined image are a bit off. If I can improve the registration process the image should be a bit better. I need to do some more work on my “workflow” to process image files once I have them.

For more information on M27, check out Wikipedia: http://en.wikipedia.org/wiki/Messier_27

Copyright © 2013 David Allan Galbraith
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Peak at the Whirlpool (Galaxy, that is)

For International Astronomy Day (20 April) 2013, I decided to try the 61 cm f/10 Optical Mechanics Nighthawk CC06 Cassegrain telescope at the Sierra Stars Observatory in southern California to photograph M51, the Whirlpool Galaxy. M51 is relatively close to earth as galaxies go, and is a beautiful deep space object. It actually consists of two colliding galaxies.

The Sierra Stars Observatory is one of three observatories in the Sierra Stars Observatory Network, or SSON (http://www.sierrastars.com). I programmed the observations on the afternoon of the 19th of April and was delighted to see that the telescope had been able to make the photographs overnight, ready to download for the 20th.

To make this monochrome image, I took three 300 second exposures of M51 with the 61 cm telescope, and then used free software called FITSWork (http://www.fitswork.de/software/softw_en.php) to merge the three FITS-format images files. FITS files include both the image produced by an astronomical telescope camera and all of the data about the telescope’s position during the exposure. The combination of images reduces noise produced by the camera and effectively turns the result into a 900 second exposure. I then tuned up the resulting image for contrast and brightness by adjusting “levels” with Photoshop Elements 6. I feel I’m getting a little better at image processing, but I still have a lot to learn! It’s fun, though, and the remote observatory option is a way of taking your own images even when the local weather makes any stargazing impossible.

The Whirlpool Galaxy (M51)

The Whirlpool Galaxy (M51) photographed on 20 April 2013 with the 61 cm Sierra Stars Observatory.

M51 is located just south of Alkaid, the eastern-most star in the “handle” of the Big Dipper (formally named Eta Ursae Majoris). It is relatively bright and can be located with binoculars on a dark, clear night.

Because this is actually two interacting galaxies, M51 has a lot of red star-forming areas similar to the giant molecular cloud in Orion in our galaxy. Some are visible in this image as faint “knots” of light along the spiral arms of the galaxy. I’ll try imaging the galaxy with colour filters soon. These separate images can then be combined with the monochrome images I’ve already taken to produce a colour rendering. There’s a nice write-up on M51 on Wikipedia at: http://en.wikipedia.org/wiki/Messier_51.

The Whirlpool Galaxy is quite far north in the sky, and just about doesn’t set from the perspective of southern Ontario. It will certainly be on my list to see and try to photography myself once the weather and my availability make it possible.

Copyright © 2013 David Allan Galbraith

Finding Comet C/2012 S1 (ISON)

As I noted on a post a couple of days ago, I’ve recently joined the Sierra Stars Observatory Network to try some deep space imaging with research-grade telescopes. I thought I’d see if I could use a 37 cm telescope on the SSON to photograph a comet that’s on its way into the inner solar system, called Comet C/2012 S1 (ISON). This comet is predicted to be visible to the naked eye in November of 2013. It’s possible it will be a very spectacular sight.

Right now it’s much more humble from earth’s position. Various web sites are listing quantitative observations already of the brightness of this comet, describing it as between magnitudes 15 and 16 – in other words, it’s really, really faint.

Anyway, the SSON system makes use of an extensive database of the locations of deep sky objects to allow users to photograph them robotically. I sent in requests for two exposures of the comet of 300 seconds each (without any filters) on the University of Iowa’s Rigel telescope in southern Arizona, two days apart. It took a while to pin down the location of the comet in each of the two resulting images. I had to use software that allowed me to determine the position of objects on each image, but there it was! In this image I’ve pasted the 16 April 2013 image onto the background of the 14 April image, so that both are visible in one frame. I’ve added the little cross-hairs to indicate which wee blob is actually the comet. The added text is from the “FITS” files that are sent down by the telescope’s computer. The first line is the date and local time at the start of each 300 second exposure. The second line is the Right Ascension of the comet at that time (the coordinate corresponding to longitude in equatorial coordinates, expressed in hours, minutes, and seconds); the third is the Declination of the comet (the coordinate corresponding to latitude, or degrees, minutes, and seconds above the celestial equator).

Comet C/2012 S1 (ISON) photographed on 14 and 16 April 2013 with the University of Iowa's Rigel Telescope.

Comet C/2012 S1 (ISON) photographed on 14 April 2013 (lower) and 16 April 2013 (upper) with the University of Iowa’s 37 cm Rigel Telescope. The photos were set up over the Sierra Stars Observatory Network (SSON). Taken as separate images and made into a mosaic with Photoshop Elements. The inset image in the lower right is the 14 April image without any reduction in scale if the whole image is displayed at 800 pixels across.

I was pretty excited to actually find the comet in these two frames! The moon was a bit of a problem on the 16th. It was not too far from the location of the comet in the sky that night, and as a result there’s some background glow on the later of the two frames (mostly cropped out of this composite image).

It will be interesting to observe the comet again in coming days and weeks, to see how much it’s growing in size and brightness as it comes into the inner solar system. In the inset on the image above you can just about make out that there’s already a tail visible. Images taken with larger telescopes are already showing a distinct tail.

The images that you can take for yourself with the telescopes on the Sierra Stars Observatory Network (http://www.sierrastars.com) are carefully calibrated; if you wanted to use them for research purposes it would certainly be possible. For now I’m content to just see what I can do in terms of finding interesting objects and learning more about processing and improving the resulting images.

Copyright © 2013 David Allan Galbraith

Try Something New: Rent an Observatory for a Few Minutes

(Updated 21 April 2013)

Observatories can be very, very expensive undertakings. Some amateur astronomers have large disposable incomes and can buy and set up larger scopes – and even buy land for their own observatories. For others (I think the silent majority) using a large telescope can seem like an impossible dream.

Not any more.

It’s possible now to effectively rent a bit of time on an observatory from a distance, for either photographic purposes or even to undertake original research. Essentially, it`s astronomy time-share.

I’ve been interesting in trying this sort of thing for some time. You can find several services on-line that will let you join up and, from your home computer, direct a large telescope to do what you’d like it to do.

There are several approaches that these services take. Some are very consumer-oriented, such as the SLOOH Space Camera service (http://www.slooh.com/). SLOOH provides a lot of “added value” in astronomy, such as programmed events. Some other services allow users to take control of remote telescopes in real-time. With these services you need to be able to use a high-speed internet link and sophisticated software on your own computer to take control of all aspects of the distant observatory.

I’ve recently joined the Sierra Stars Observatory Network (SSON; http://www.sierrastars.com), which has a unique approach. The SSON consists of three different telescopes in the south-west USA, linked together with a scheduling service. The telescopes belong to educational or academic institutions, and are set up with sophisticated cameras. all that a user needs to do is to decide what to image. It’s not necessary – in fact it’s not possible – to run these telescopes yourself.

Using a very easy web-based form, users of SSON submit jobs to the telescope of their choice. The system operator cues up targets for the completely robotic observatory, and their computer takes care of the rest of it. When the images have been shot you’re sent an email message. You can then download the completed files from an FTP site. Not very hands-on, but very efficient and precise. The on-line scheduling system includes drop-down menus of thousands of celestial objects.

Membership programs like SSON can give you access to major, research-grade telescopes for a very small investment. An introductory membership package for SSON is $50 US, which gives you 83 credits. Subsequent credits are $1 each, unless you buy a lot of time, in which case the rate drops a bit. Charges are applied only for actual use of the telescope cameras – so if you take a five-minute exposure, you get charged only for that time. The rates run from about $1 per minute (actually $50 per hour) for the 37 cm Rigel telescope to $160 per hour for the 81 cm Mt. Lemon Sky Centre instrument.

There are some remote astronomy services that are less expensive per hour, but what convinced me to try SSON is the ease of submitting a request for imaging, and the fact that this is supporting research and educational telescopes.

I submitted two types of jobs to SSON to try it out this week. I sent in instructions to photograph M81, a lovely galaxy in Ursa Major, and also to try a photo of Comet S/2012 S4 (ISON), which might turn out to be a beautiful comet visible to the naked eye later this year. The observatory system ran my requests for exposure overnight between 13 and 14 April 2013. Here are two of the images taken by the Rigel 37 cm telescope, part of the SSON.

m81

My first shot of M81, a bright galaxy in Ursa Major, made by stacking several short images taken with the University of Iowa’s Rigel telescope… from my apartment in Hamilton, Ontario. This is pretty crummy; I still have a lot to learn about processing, and longer shots are coming, too. A start, though. M81 is a beautiful and very bright galaxy. Longer, better-planned exposures and better image processing will give nicer images in the future. This was produced by stacking 9 individual frames exposed without colour filters: 3×30 sec, 3×60 sec and 3×120 sec, for a total of 630 seconds. I am trying a second run of 5×300 seconds (1,500 seconds). I hope this will reveal some of the finer, more distance lanes of stars that extend out from M81. For those who have more experience with this than I, rest assured that the FITS files that come from this system are indeed 16 bit. This was a crude stacking attempt.

I was encouraged by the first shots of M81, but I didn’t set up the observatory to make very long exposures. The longest you can shoot on SSON is a 300 second individual exposure. I’ve re-programmed the 37 cm Rigel telescope for five exposures of 300 seconds each, for a total of 25 minutes of light-gathering. I hope to have these new frames in the next few days and will post updates.

Updated 21 April 2013: Here’s a much better version of the M81 image, prepared on the 21st from the second run of five 300 second exposures and a better job of managing the post-processing:

m81

Bodes Galaxy, M81, imaged using the 37 cm Rigel telescope on SSON by taking five 300 second exposures and combining them.

I did get a good-looking frame from the single request I sent for a photo of Comet C/2012 S1 (ISON), but I’m not 100% sure I know which object is the comet! I am looking into confirming the identity of the objects in the frame below. As of 16 April, I haven’t confirmed the location yet.

Update 21 April: Here’s the actual interpretation of my image from earlier in the week:

isoncr1

(Updated 21 April 2013) BLUE ARROW: The bright star in the middle of this field is not Comet C/2012 S1 (ISON) – but the comet should be somewhere nearby. In fact, it’s just at the tip of the RED ARROW. Photographed on the night of Saturday 13 April 2013 by the 37 cm Rigel telescope in the SSON. A single 300 second exposure with no filters, and with the guidance system set up to automatically find the comet.

Once I have a bit more of a handle on things like exposure times, I’ll also start shooting with colour filters. For now, I`m just trying the cameras without filters – essentially, black & white. I also have a challenge at the computer end of things. I need to upgrade my computer at home to allow running some better image processing software.Nothing can take the place of the thrill of actually seeing a celestial object live through a telescope. However, photography by remote control is also interesting, and accessible. I will be posting more updates on this process as I generate more results.

Copyright © 2013 David Allan Galbraith