Achut Reddy is a recent SSON user with a keen interest in creating the finest aesthetically appealing astronomy images he can. Knowing about the fantastic results Adam Block gets using the Mt. Lemmon 0.8-meter Schumann telescope he chose the instrument for gathering image data to create a composite image of M20. I asked him if he would be willing to write a blog about his experience and results for our SSON users. He agreed and submitted the article in this blog.
— Rich Williams
By Achut Reddy
Like most amateur astronomers, I started out doing astronomy on my own equipment. However having had a chance to work on (and being spoiled by!) larger telescopes than I could ever hope to own myself, located in places with much better seeing than I could ever hope for where I live, I’ve come to realize that remote astronomy using telescopes maintained by others is a far better option and would give me much more impressive results. No more staying up all night in the freezing cold; I could now do astronomy from the comfort of home, in my hot tub
I recently signed up with a number of different remote telescope networks, including SSON. I chose as my first target an easy object – M20, the Trifid Nebula. In my opinion, the Trifid is one of the very prettiest objects in the sky, at least in the Northern Hemisphere. It’s full of rich colors and fine details in the dust lanes and gaseous structures. But not all images of M20 succeed in capturing all of that. It would take a certain amount of luck (for good weather and seeing conditions) and careful image processing to get the most out of the data. My goal was to create a beautiful picture that was comparable to some of the best M20 images out there and that I could blow up and hang on my wall.
For my instrument I chose the Schulman 32-inch Telescope at the Mount Lemmon SkyCenter in Arizona. As far as I’m aware, this is the largest telescope available on any public remote astronomy network. This is a fabulously powerful instrument, and capable of truly stunning images.
For my observing plan, I chose an RGB 3-channel model with 16 exposures each of Red @ 300 secs, Blue @ 225 secs, and Green @ 180 secs. M20 is bright enough that I skipped the Luminance channel entirely and relied on the color channels themselves to deliver the detail. I’ll admit I was a bit nervous about submitting my first job on SSON. Was my observing plan a sound one? Did I get the coordinates correct?
I also learned of a few restrictions regarding the telescope parameters for jobs submitted through SSON. Namely:
1. Exposures are unguided
2. All exposures are binned 2×2
The telescope has excellent precision tracking and #1 would not be problem, as long as exposures are kept to 300 seconds or less. But I was concerned about #2. Binning trades off resolution for increased sensitivity. (In retrospect this was probably a good trade-off for this project, but I didn’t know this beforehand. The increased sensitivity resulted in brighter, more vivid colors.)
The web interface to create observing jobs is simple and easy to use, though it is somewhat bare bones (lacking some of the polished user interfaces on the other networks). There were also a number of minor software glitches. However Rich Williams and Adam Block on the Mount Lemmon side were extremely proactive and helpful, and all issues were quickly resolved. There was also no setting to do dithering of images, but Adam graciously enabled this setting for me anyway. So I submitted my job, and crossed my fingers. With SSON, your job is run asynchronously depending on availability of the instrument and seeing conditions, so you don’t know in advance exactly when it will be run.
When I received notification that my job ran, I anxiously downloaded the results and set about to process the images. The images came pre-calibrated so I could skip the Calibration step. Then I followed the usual procedures: Global Registration, Per-channel Normalization, Data Rejection, and Summing, and finally combining the color channels together into one full-color image. Then with the helpful input of an expert graphic designer, Dominic Urbano, I made further refinements in Photoshop to reduce noise, sharpen the details, and improve the colors in the image. I was blown away by the result; the image was stunning!I was especially pleased with the details in the dark dust lanes, the range of colors in the emission and reflection parts of the nebula, and the overall 3D appearance of the puffy clouds. Then, another surprise. While examining the image in detail I noticed a tiny but clear straight line jutting out from one of the clouds near the bottom. Was that an artifact, or could it be… ? I checked the Hubble archive and found what I was looking for – a high resolution close-up of the region in question and sure enough, it was an actual stellar jet! This was the first time I had captured anything like this and it was the icing on the cake:
The jet itself is quite interesting:
“A stellar jet [the thin, wispy object pointing to the upper left] protrudes from the head of a dense cloud and extends three-quarters of a light-year into the nebula. The jet’s source is a very young stellar object that lies buried within the cloud. Jets such as this are the exhaust gases of star formation. Radiation from the massive star at the center of the nebula is making the gas in the jet glow, just as it causes the rest of the nebula to glow.
The jet in the Trifid is a “ticker tape,” telling the history of one particular young stellar object that is continuing to grow as its gravity draws in gas from its surroundings. But this particular ticker tape will not run for much longer. Within the next 10,000 years the glare from the central, massive star will continue to erode the nebula, overrunning the forming star, and bringing its growth to an abrupt and possibly premature end.”
– Hartmut Frommert & Christine Kronberg (SEDS)
The shorter spike pointed about 45° clockwise from the jet is a knot of denser material resisting the stellar wind “blowing” the less dense material around it.
This is certainly my best astronomical image so far. I feel that it met my goals, and it will shortly be mounted on my wall! The experience overall was very satisfying and I look forward to doing more projects with SSON.
Achut Reddy is a Software Engineer in “Silicon Valley”, California. He has several hobbies/interests including astronomy & astrophotography, paleontology, archaeology, languages, scuba diving, and traveling.