Supernova SN 2014J in Ursa Minor

On 22 January 2014, S. J. Fossey discovered a supernova, designated SN 2014J, in the Cigar Galaxy, Messier 82. It’s turned out to be the brightest of its type visible in the Northern Hemisphere in living memory. M82 is in Ursa Major, nice and high in the night sky for those of is in the Great White North! It is not visible to the unaided eye, clocking in at about Magnitude 11.5, but that’s well within the capability of a home telescope on a dark night to spot, and especially with a short exposure with a digital camera on a 4″ or 5″ telescope.

I wanted to see if I could take an image of the supernova from my livingroom couch, and so used a simple web form to request an image be taken by the MicroObservatory Network in Arizona. Anyone can use this free educational system, using the on-line forms at: http://mo-www.harvard.edu/MicroObservatory/

The simple icon-driven menu asks for subject, field of view, and exposure time. All the rest is automated. I sent the request in on 25 January, and on the afternoon of the 26th I received an email message from the system indicating that an image was ready. Here’s the result. The supernova is the bright star to the right of centre of the irregular galaxy.

Supernova SN 2014J is visible between the hair lines along the right side of this image. The cloudy mass is the Cigar Galaxy, Messire 82, in Ursa Major. This is an uncropped image as provided by the MicroObservatory Network. See the text for description. Click on the image to see it scales a little better.

The fact that the galaxy is so far over to the right side of the frame is the result of errors in the on-line system. It amounts to perhaps a 10th of a degree or less, but that’s enough to put things way off of centre. Given that this is a free, public-access system, you can’t complain too much! I wish I had had access to a system like this as a child – this and other robotic telescope systems now available to the public would make for amazing science fair projects! I have an article in a forthcoming issue of the Hamilton Amateur Astronomer’s newsletter The Event Horizon on robotic observatories, which I find a very nice way of avoiding the cold outside conditions of astronomy in Canada in the winter. Yes, I’m a wimp, but I’m a warm wimp.

Copyright © 2014 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