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Supernova 2006aj

February 22, 2006

Some 440 million years ago an explosive extremely high energy event occurred in the distant universe. The initial energy released by the blast sped across the emptiness of space unimpeded until February 18, 2006 when it excited the electronic sensors of the Swift satellite instruments orbiting Earth. Almost immediately thereafter, Swift telemetry streams signaled worldwide alerts to astronomers. Ground-based telescopes swung into action to study the region of space where the signal emerged. Additional alerts were sent to amateur astronomers via the Internet. One of those messages arrived in the inbox of the Cedar Amateur Astronomers (CAA) group. The group "Stellar Commitee" leader issued a call to members to try to observe and possibly image the optical component of an anticipated supernova.

For many years, gamma ray bursts puzzled astronomers. The cause of such extremely high energy levels was mind-boggling. All sorts of theories emerged to explain them from neutron star mergers to mysterious magnetars. In his book Extreme Stars, James Kaler refers to gamma ray bursts (GRBs) as "the ultimate violence". The problem astronomers faced was locating the GRB sources accurately and quickly with as much scientific gear as could be mustered. With the availability of the Swift satellite astronomers are gathering more data and evolving more definitive theories. This recent gamma ray burst (GRB060218) occurred at 03:34:30.97 Universal Time. Large ground based telescopes detected a supernova energy signals 3 days later. It was suggested that a dim and "nearby" object may be detectable with amateur telescopes and CCD cameras. With the CAA Stellar committee chair's call I went to see what I could find.

My first information source was the American Association of Variable Star Observers (AAVSO) web site. Plenty of information is available in AAVSO Special Notice #8. From the notice I learned the celestial coordinates of the burst and acquired a star chart indicating the precise location of the "optical afterglow". The notice detailed photometric techniques and filter types that would benefit further research. Although I'd like to contribute scientifically valuable data, I'm not yet equipped or experienced enough to do so. My goal was challenging enough: locate a beacon of light energy from the emerging supernova a mere 440 million light years away.

I opened my observatory dome on the evening of February 22 near 9:00pm. By 9:50 I was recording the first frames of the target area. I decided on 5 minute exposures using high resolution. Following the first exposure I performed an image link with the TheSky Version 6 planetarium software. The image link attempts to align the image with precise coordinates of bright catalogued stars. To my surprise the first image link was successful. My telescope was right on target. I then instructed the CCD imaging software to record another 6 images of 5 minutes each. After 4 images were accumulated I began aligning and combining them to learn whether or not an object signal existed at the target location. This is the time when reality sets in. Is a 10" telescope capable of resolving a point source of light 440 million light years distant? Well as a matter of fact yes it can! After only 15 minutes of combined exposure time a faint speck of a star-like image appeared. The trick was to continue imaging until a convincing signal developed above the background sky brightness. After 25 minutes the light source was convincing but I kept going to further increase the signal to noise ratio. After 35 minutes I had my results. To make sure the image quality was optimal I recorded bias and flat frames to substract unwanted electronic noise and dust moats from the final composite. Click on the image to view Supernove 2006aj.

Read AAVSO Special Notice #8 http://www.aavso.org/publications/specialnotice/8.shtml
Read more about the Swift Telescope at http://swift.sonoma.edu/about_swift/instruments
If you'd like to read more about GRB060218 see http://www.dsi-astronomie.de/SN_2006aj_2006-03-02.805.htm

Contact Cedar Amateur Astronomers http://www.cedar-astronomers.org/

Messier 100 Supernova 2006X

Posted March 21, 2006 | Updated April 23, 2006

Located along the border of the constellations Coma Berenices and Virgo is a rich cluster of Messier catalog galaxies. Among this group in the southwest region of Coma Berenices is the face-on spiral Messier 100. On February 4, Supernova 2006X was discovered by Shoji Susuki and M. Migliardi. The Type Ia supernova was initially imaged at magnitude 17 and appears to have peaked near magnitude 13.6 on February 23. This 21 minute image taken March 22 by a shows Supernova 2006X is still a bright component of Messier 100's spiral arms. Also captured in this image are two distant elliptical galaxies. Numeric labels indicate stellar magnitudes of nearby stars for comparison. On April 23, I took a follow up image. You can see a noticable reduction in the supernova magnitude compared to the March 21 image.

Caldwell 30

Monday, 6 November 2004

In early September, I set up my LX200 for CCD imaging. I didn’t plan to image any particular astronomical object. I usually thumb through Stephan James O’Meara’s The Messier Objects and The Caldwell Objects for potential candidates. The books include a wealth of Messier and Caldwell object celestial locations, magnitudes, photographs, histories and observing tips. This night, I fortuitously opened the Caldwell book to Caldwell 30. My eyes were immediately drawn to a label Stephan’s Quintet in the lower right of the included photograph. Stephan’s Quintet is a stunning example of gravity at work on a gigantic scale. Three of the galaxies show evidence of interaction (let’s just say they are mixing it up). Without further delay (or reading of the text) I entered one of the galaxy’s New General Catalog (NGC) number, 7319 into the LX200 hand controller’s GOTO command. My telescope’s computerized targeting slewed the LX200 to a location in northwest Pegasus.

When CCD imaging of new targets, I lead off with short exposures of a few seconds to verify the position of the object in the field of view. I may nudge the pointing north-south/east-west to center the object before proceeding with longer exposures. After centering the faint “fuzzies” of the Quintet, I activated the Software Bisque’s CCDSoft program’s auto-guiding mode and took two 60 second images. Satisfied with the auto-guiding accuracy I followed with a 300 second guided image. To assess the resolution of this collection of galaxies, I combined the 3 images to produce a 420 second exposure. See the results in Figure 1. More magnification (in this case removing the focal reducer) would improve the image. Changing the magnification is disruptive time-wise so, with a sigh, I decided to table Stephan’s Quintet for another night.

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