Public Access Astronomy: the MicroObservatory Robotic Telescope Network

The MicroObservatory Robotic Telescope Network, operated by the Harvard-Smithsonian Center for Astrophysics OWN “Observing With NASA” program allows free, public access use of 6″ reflecting telescopes located at the Whipple Observatory in Amado, Arizona. If you are a teacher interested in introducing astronomy in a hands-on way, a parent wanting to show kids that they can also take astrophotos, or just interested in experiencing with Internet-based remote observatories, making use of this free system is well worth a try. This system has been in use for over a decade and is a lot of fun.

The network can be reached at: http://mo-www.cfa.harvard.edu/MicroObservatory/

Guest users can select from a pre-set menu of target objects. In December 2013 I tried shooting images of several deep space targets over successive nights. The 6″ reflectors (identified as Ed, Ben and Cecilia, Donald) are programmed with a simple web form. Once images are captured, users are sent an email message with instructions on how to retrieve the files. The files are all returned as 650 x 500 FITS files. The network also supplies MicroObservatoryImage, a free program based on Java that processes FITS files, including stacking RGB images, optimised for the small images the system produces.

The web site is well worth exploring, as there are several resources there of interest to teachers, especially.

Here are three images I captured with this system in December 2013. The images I was able to capture did suffer from several artifacts, including diffraction spikes, and “blooms” produced by very bright stars.

The Cab Nebula (Messier 1) imaged with one of the educational telescopes of the
MicroObservatory Robotic Telescope Network. Three images were taken, one each through a red, green, and blue filter, and then they were combined with the MicroObseervatoryImage software supplied by the network.

NGC5457, Messier 101, imaged with the MicroObservatory Robotic Telescope Network. This was taken as a single 60 second exposure, taken at 5:37 AM local time on 31 December 2013. The area imaged is approximately one degree of arc across.

The Great Nebula in Orion (M42) imaged in three colours using the MicroObservatory system. The colour image was assembled as described above for the image of the Crab Nebula. This image is slightly retouched to reduce artefacts created by both diffraction effects (spikes) and also “blooms” or smears produced by very bright stars.

Copyright © 2014 David Allan Galbraith

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:

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

A Quick Look At 1 Ceres

Is it a giant asteroid? Is it a dwarf planet? Is there a difference?

1 Ceres has been classified as both. Ceres is the largest object in the Asteroid Belt between Mars and Jupiter – something like 900 km across. We will get our first really good look at it in about 2 years when NASA’s Dawn spacecraft arrives in its orbit. It was in fact the first “asteroid” discovered, in 1801. It ranges from magnitude 7 to 9, so is almost never visible to the unaided eye, but it’s also pretty easy to find with most telescopes.

I thought I’d take a look using the University of Iowa’s Rigel telescope in Arizona, using the web-based Sierra Stars Observatory Network. Here’s a shot of 1 Ceres captured during the night of 1 May 2013. Ceres is the bright “star” in the middle of the frame. It’s so bright (around magnitude 8) that it’s actually quite overexposed on this cropped image. The image here was made by stacking three 150 second exposures.

The dwarf planet 1 Ceres photographed early on the morning of 1 May 2013 using the University of Iowa Rigel Telescope in Arizona. Ceres is the brightest object in this image, in the centre of the frame. It’s so bright compared to the many background stars that it’s actually over-exposed here. A composite of three stacked 150 second exposures without filters taken with the 31 cm robotic telescope, over the Sierra Stars Observatory Network.

The particulars from the FITS file of the first of three images taken by Rigel:
DATE-OBS= '2013-05-01T03:25:00.311' / UTC, start of exposure
LST     = '10:39:31'           / Local sidereal time at exposure start
POSANGLE= '  70:48:39'         / Position angle, degrees, +W
LATITUDE= ' 31:39:56'          / Site Latitude, degrees +N
LONGITUD= '-110:36:05'         / Site Longitude, degrees +E
ELEVATIO= ' 38:22:26'          / Degrees above horizon
AZIMUTH = '283:31:10'          / Degrees E of N
OBJRA   = '  6:39:18.3'        / Target center J2000 RA
OBJDEC  = ' 28:48:59.6'        / Target center J2000 Dec

 

Copyright © 2013 David Allan Galbraith

Trying LRGB Colour

Our eyes see a composite image of the world around us. If your vision is “normal” the colours you see every day are composed of four type of information: brightness, plus red, yellow, and blue information, each coming into your brain from difference cells in your retinas.

Colour images taken with large telescopes are assembled from the same four channels. Advanced cameras used in astrophotography are monochrome, or “black and white.” Colour comes into these images through combining multiple exposures, some done with red filters, blue filters, green filters, and some done with no colour filters at all. The result is an “LRGB” or Luminance-Red-Green-Blue image.

I tried this process recently by using (again) the Sierra Stars Observatory’s 61 cm telescope in California, accessed over the internet on the Sierra Stars Observatory Network (see my posting from 21 April 2013 for monochrome results). Combining monochrome images with others taken with red, green, and blue filters, using software called fitswork, and the tuning things a little in Photoshop Elements, I was thrilled to see an attractive image of Messier 51, the Whirlpool Galaxy, materialize! Might be a bit heavy on the blue channel, but the arms of M51a are known for regions of hot, young stars, and its companion, M51b, is redder because of a higher number of older, redder stars.

Messier 51, the Whirlpool Galaxy in Ursa Major, imaged using the 61 cm Sierra Stars Observatory in California. A composite colour image prepared by using monochrome images captured on 20 April 2013 and additional exposures for red, green, and blue information on 22 April 2013.

Copyright © 2013 David Allan Galbraith

Why “Post-Processing” Matters

We’re very used to having great photos delivered by our digital cameras these days. Point and shoot is the order of the day. Astrophotography is a little different, because of the tiny amount of light involved, and the specialized, custom nature of the photographic and telescope equipment.

I thought an example might indicate what I mean. The image below is of Bode’s Galaxy, M81, which is a large, bright galaxy close to us. I set up the Rigel 37 cm telescope in the Sierra Stars Observatory Network (http://www.sierrastars.com) to take five shots of M81, each one being a five-minute exposure. I then used software to combine the images, and to adjust the contrast and brightness of the resulting “stacked” image. These sorts of images are taken with monochrome cameras – or black and white – that are sensitive to all frequencies of visible light.

Here’s what the “tuned up” image of M81 looks like:

A processed image of Bode’s Galaxy, M81, created by stacking five 300 second exposures taken with the 37 cm Rigel Telescope in Arizona. This bright galaxy is relatively close to earth and can be located on a clear night with binoculars or a small telescope in the constellation Ursa Major.

Here’s one of the five original 300 second exposures, displayed more or less as it looked when it was delivered by the telescope and camera. The fine details of the finished image are in there, but in order to see them the brightness and contrast needs to be “stretched” a bit. This process changes the relationship between the light values recorded by the camera and the shade of gray displayed on the image, to show the fainter light of the outer edges of the galaxy.

An unproccessed frame of M81, one of five taken as a 300 second exposure without filters on the Rigel Telescope in Arizona on the evening of 15 April 2013.

I’m feeling a little more confident about monochrome images now, but I still need to update my computer for doing this sort of “Post-Processing.” My next step will be to take some images of M81 and other objects with these remote telescopes using colour filters. By shooting images with colour filters on monochrome cameras like those on this sort of telesope, you can reconstruct a colour picture in post-processing.

Copyright © 2013 David Allan Galbraith

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) 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 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