First Experience With SSON

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.

Thanks Achut!

— 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!

Figure 1. M20 - Trifid Nebula [Credit: Achut Reddy]

Figure 1. M20 – Trifid Nebula [Credit: Achut Reddy]

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:

Figure 2. M20 with jet highlighted [Credit for inset Hubble image: NASA and Jeff Hester (Arizona State University)]

Figure 2. M20 with jet highlighted [Credit for inset Hubble image: NASA and Jeff Hester (Arizona State University)]

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.

 

Founding the Winer Observatory

Mark Trueblood and his Wife Pat founded and operate the Winer Observatory in Arizona. Since the 1980s Mark has been a pioneer in automated/robotic telescope technology. The Rigel Telescope housed in the Winer Observatory is part of SSON. I have been to the observatory a few times and Mark and Pat were gracious hosts when Kathy and I stayed at their house in Sonoita when we last visited Arizona. Because Mark is an expert in setting up observatories for remote operation I asked him if he would write an article about the Winer Observatory for my blog.

Thanks Mark!

—  Rich Williams
__________________

By Mark Trueblood

Winer Observatory in Sonoita, AZ

Winer Observatory in Sonoita, AZ

Introduction

Rich Williams asked me to write a blog article on the founding and operating of Winer Observatory. SSON shares time on the Rigel telescope, owned by the University of Iowa and located at our facility. Details of our observatory and its history can be found on our web site.

Moving to Tucson, Arizona

In the late 1990’s, the Goddard aerospace industry was evolving rapidly, so I decided it was time to move out west as Pat and I had discussed before we married. We had made a few brief trips to the southwest, so we knew what it was like. After looking at jobs at McDonald Observatory (west Texas) and the National Solar Observatory in Sunspot, NM, I finally accepted a job at the National Optical Astronomy Observatory (NOAO; the US national observatory that operates Kitt Peak) in Tucson in 1990. We moved to Tucson in May 1990, and a few days after our arrival, it hit 117°F, an all-time record. What a welcome to our new home! My first job was with the Tucson part of the National Solar Observatory (then a part of NOAO) on the Global Oscillation Network Group (GONG) project, and after leading the development of their data archive system, I moved over to the “night side” where I helped astronomer-managers oversee instrument development (mostly infrared instruments), first for the Gemini Observatory, then for NOAO’s 4-meter telescopes in Chile and Kitt Peak.

Founding and Building the Winer Observatory

Shortly after Pat and I married and while still living in the DC area, we founded Winer Observatory in 1983. It was named after Dr. Irvin M. Winer, who had been a professor and mentor at Wesleyan University while I was a graduate student immediately after graduating from college. Irv had a very interesting perspective on life, and was a great mentor and role model who died in middle age of cancer. A friend who graduated from Wesleyan suggested that I name the observatory after Irv.

At the time, Pat was a legal secretary for a large DC law firm, so she handled the paperwork to form a corporation in Maryland and to obtain IRS status as a 501(c)(3) non-profit public charity. She has served tirelessly ever since as a member of the Winer Board of Directors and Secretary-Treasurer of the corporation, doing all the paperwork I don’t have time for, bookkeeping, and serving as a trusted advisor.

While in the DC area, we both went on several lunar occultation and asteroid occultation expeditions with David and Joan Dunham. When we moved to Tucson in 1990, we continued those observations, but eventually we both became disinterested in occultations. During the first two years of living in Tucson, we searched for real estate far enough away from Tucson to enjoy dark skies, but still within a one-hour commute of where we worked. We bought our 20+ acres in Sonoita, in part because it was east of where we worked, so we would not be staring into the Arizona sun during our commute. We hired an architect and built a home for the two of us. We designed an observatory and began construction in 1995 by having 1000 cubic yards of earth removed where we would put our workshop, garage, and control room.

At first, progress was slow as it was limited by cash on hand. One day, I received a call from Prof. Robert Mutel of the University of Iowa who said he heard I was building an observatory in southeast Arizona and would I be interested in hosting his telescope? Shortly thereafter, we received a check from Iowa and another donation, so work proceeded more rapidly. Our original plan was that we would build a 25-foot square observatory on the south end of the 25 x 50 foot workshop, with the roof rolling on rails on top of the workshop walls. When Iowa called, we extended the observatory to 25’ wide by 35’ long on the drawings we used for our building permit. When the workshop was done, we decided to make the observatory 25 x 50 feet to accommodate more telescopes. We are now pretty much full, so that was a wise decision. With the 25 x 50 foot roof rolling to the north over a building of the same size, the northernmost pads do not have a view of Polaris for polar alignment. Everything we do for the first time, it seems, we know how to do so much better if we only had a second chance!

Pat and I both did some manual construction work on the observatory – I cut and bent about a mile (no kidding!) of #5 (5/8”) rebar, among other tasks. The contractor we hired was patient with us throughout this phase, and in July 1997, a crane hoisted wall frames and trusses into place for the rolloff roof. A few weeks of completing the welding and another month or so, and siding and decking covered the roof. During this time, I used lunch hours and the machine shop at work to make parts for the roof drive. I obtained donations of a large worm gear drive, drive chain, idlers, U-joints, pillow blocks, 3-phase inverters, and other items from Boston Gear, and of 25-pound crane rail and double flanged wheels from other vendors. I then built and installed the drive system myself – if this critical item didn’t work, I wanted only myself to blame.

I had things pretty far along and was attaching the drive chain to the roof late one night from the truck from Iowa showed up with their telescope. Perfect timing! A crane placed the Iowa 20-inch alt-az telescope on its pad the next morning, we routed various cables in the cable trough, and soon the telescope was moving under its own power. In September 1997, we officially began operations. The Iowa scope was joined by Tenagra Observatory’s supernova search a year later, then by Washington University in St. Louis, which had two telescopes at our site for several months, then one was shipped to India while the other remained here until 2010. We have also temporarily hosted a telescope and homemade spectrograph from Spectrashift.com a couple times while they were becoming the first amateur-led group to detect an exoplanet by the Doppler shift method. A complete history of the telescopes that are or were installed in the observatory is on our web site under History.

Rigel Telescope Installed in the Winer Observatory

Rigel Telescope Installed in the Winer Observatory

In 2002, the University of Iowa replaced their self-built 20” alt-az telescope with a Torus Technologies (now Optical Mechanics, Inc.) 14.5” fork mounted equatorial telescope. This is the telescope that SSON observers use. All telescopes are robotic (pre-programmed and controlled by computers) as opposed to remotely operated in real time by humans, due to limited Internet bandwidth in our remote location. Our site is miles away from cable TV or even DSL Internet – we pay hundreds each month for very limited bandwidth, while city dwellers enjoy 5 times our bandwidth for 1/50 the cost. Such is life in the boonies. We tried satellite connections a couple times, but they were very slow, almost equally expensive, and the time delay to go up and back to/from geostationary orbit made even simple remote login to a computer to do routine maintenance impossible, and some communications protocols just refused to work with such long delays.

We now serve four customers (University of Iowa, Ohio State University, a university in Poland, and NASA/Goddard Space Flight Center) and Pat has her 14-inch Meade mounted on a Paramount ME for public outreach and her own visual observing. Visitors are welcome with advance notice so you know we’re here. Come and check us out if you are in the area.

About Mark Trueblood

Mark Trueblood

Mark Trueblood

Born: February 23, 1948 Cincinnati, Ohio

High School: Finneytown HS, Cincinnati, Ohio

College: Brown University, BA and BS in Physics, cum laude 1971

Graduate School: University of Maryland, MS in Astronomy 1983

Research Interests: Near Earth Objects, Minor Planet Astrometry and Photometry, Occultations of Stars by Minor Planets, Extra-Solar Planet Discovery

Read Texereau’s book on telescope making at the age of 11, ordered a mirror making kit from Edmund Scientific, and made a 6-inch f/8 mirror at the age of 12.

Employed 1974-1990 in various aerospace companies in the Washington, DC area, first as a computer programmer, later as a project and program manager.

Program Manager at Ford Aerospace Corporation on the Hubble Space Telescope control center at NASA Goddard Space Flight Center, 1995-1998.

Employed by Association of Universities for Research in Astronomy (AURA, Inc) 1990-2012, first as a programmer and systems engineer for the National Solar Observatory Global Oscillation Network Group (GONG) project to design and develop a data archive capable of cataloging and storing 5 TB of data.

In 1994, became the Project Engineer in AURA’s National Optical Astronomy Observatory (NOAO) United States Gemini Program, overseeing the construction of instruments for the Gemini Observatory’s two 8-m telescopes by US teams. In 2010, became Project Manager for various optical and IR instruments for NOAO telescopes.

Since 1983, the Scientific Director of the Winer Observatory, founded to perform scientific research and public education in astronomy and light pollution, and just to have a whole lot of fun.

Mr. Trueblood is a member of the American Astronomical Society (Division for Planetary Sciences), International Dark-sky Association, International Amateur-Professional Photoelectric Photometry group, International Occultation Timing Association, Friends of the Monterey Institute for Research in Astronomy, and the Tucson Amateur Astronomy Association.

In 2001, the International Astronomical Union named minor planet number 15522 “Trueblood” in his honor.

The Sierra Stars Observatory Transmission Grating Spectrograph (TGS)

By Rich Williams

Introduction

I spent the last several months testing and experimenting with the transmission grating spectrograph (TGS) filters I installed on the Sierra Stars Observatory system. The system has two 600-line TGS blazed 50mm x 50mm gratings installed in two of the seven filter positions in the SSO filter wheel. One TGS has a plate with a slit that obscures all the light going to the CCD camera except for a 3mm-wide slot that blocks all light going to the camera except for what comes through the slot. This enables you to isolate the spectrum light from the target object (in the majority of cases) without light “polluting” the data from other nearby stars. The TGS without a slit enables you to potentially get spectra from multiple objects as long as there is a reasonable amount of space between objects to not overlap (and pollute) the spectrum light from other sources. In less crowded fields the TGS without a slit will work just as well. The SSO TGS system is now available to SSON users to schedule images.

Getting Your TGS Data

You schedule images to run on the TGS just as you do for “regular” SSON images selecting objects from our extensive online catalogs or setting your own coordinates for objects. You also set the amount of exposure time you want for each image. However, you need to make some extra decisions for TGS images to get acceptable results. This requires some learning on your part. I explain what you need to do and be aware of in the SSO TGS User’s Guide, which you can also read and download on the SSON website.

Now to the fun part. I’m going to show you some results I achieved using the SSON TGS to give you an idea what you might try on your own. Instead of demonstrating spectrum profiles of Vega (which is a standard for star spectrum calibration) and other commonly shown spectrum profiles I will use objects that show interesting information about the chemical makeup of unusual stars and the planet Uranus. For each case I describe a little about the object and specifics about the images used to create the spectrum profiles. I used MaxIM DL to process the FITS image data and RSpec to process the resulting images to create the spectra profiles. The profiles are all carefully calibrated using a non-linear process to get the greatest precision and then normalized. If this doesn’t mean anything to you right now, don’t worry. It will make more sense after you learn more about doing spectroscopy.

Betelgeuse (Alpha Orionis)

Betelgeuse is the brightest star in the constellation Orion. It is distinctly red in contrast to most of the other blue stars in Orion. It is a red supergiant star and very bright at approximately magnitude 0.4 (it is a variable star that can vary between 0.2 and 1.2 magnitude). By most estimates the star is at least ten times more massive than the Sun. The star is running out of hydrogen and as a result is nearing the end of its life. It’s evolved outside of the main sequence of “normal” hydrogen-burning stars and swelled to become a supergiant star. In the not too distant future (by astronomical standards) it will likely explode as a supernova and end up as a neutron star or black hole.

Spectroscopy of Betelgeuse

I created the spectrum profile in Figure 1 from a FITS image that is a composite of four images optimized with focus offsets that span the frequency range from 4000 to 8000 angstroms that were median combined (stacked) using MaxIM DL before creating a spectrum profile using RSpec.

Betelgeuse-Spectrum

Figure 1. – Betelgeuse Spectrum Profile and Image

I used four 1-second exposure images with focus offsets of 200, 400, 600, and 800 to achieve higher resolution throughout the spectrum. The SSO TGS User’s Guide explains what focus offsets are for and how to select values appropriate for the frequencies you want to best resolve. I used the software program MaxIM DL to stack the four images together using a median combine process. Figure 1 shows a cropped portion of the image.

The Betelgeuse spectrum profile shows many prominent absorption lines of heavy metals and even molecules such as titanium oxide (TiO) and vanadium oxide (VO). These molecules can exists in the star because the stars atmosphere cooled as the star swelled into its red supergiant phase. At higher temperatures the oxygen atoms would not be able to form stable bonds with the metal atoms to form molecules.

AG Pegasi

The star AG Pegasi (located in the constellation Pegasus) is an interesting binary star system comprised of a red giant star about 2.5 times more massive than the sun and a white dwarf approximately 0.6 the mass of the sun. The star system is now about magnitude 9. Astronomers have observed the star for over 150 years and in that short period (very short by astronomical standards) the binary star system has undergone a major transformation. Gas from the red giant star is being captured and accreted around the hotter white dwarf star. This has been happening for thousands of years. Since the beginning of the 20th century astronomers observed a surprising and swift transformation in the spectrum of the star system. As the hotter white dwarf accumulated hydrogen and began burning it the spectrum of the star transformed from types A to B to O and finally to the Wolf-Rayet spectrum it displays today. This is a star worth monitoring.

Spectroscopy of AG Pegasi

The predominate spectrum of AG Pegasi comes from the intense UV light from the white dwarf, which now has the spectrum of a Wolf-Rayet star. The UV light excites and ionizes the gases in the accreting material causing hydrogen to emit light at specific wavelengths. The hydrogen Balmer lines show up prominently in the spectrum of the star, especially the H-alpha line in the spectrum profile in Figure 2. Emission lines appear brighter than the continuum of the spectrum and display as upward “spikes” in the spectrum profile. The H-alpha line stands out strikingly in the image of the spectrum.

AG Pegasi-Spectrum

Figure 2. – AG Pegasi Spectrum Profile and Image

I used four 60-second exposure images with focus offsets of 100, 300, 500, and 700 to achieve higher resolution throughout the spectrum and median combined them to produce the spectrum image in Figure 2.

WR 136

The star WR 136 is a 7.5 magnitude Wolf-Rayet star located in the Crescent Nebula (NGC 6888) in the constellation Cygnus. It is about 15 times more massive and 250,000 times brighter than the Sun with a surface temperature about 70,000 degrees. Wolf-Rayet stars emit a massive amount of their gas continually generating a very strong stellar wind. This creates a huge expanding shell of gas that surrounds the star. They are among the largest and rarest of stars in our galaxy. The stars intense UV radiation excites the gas in the surrounding shell causing the atoms to emit light a specific wavelengths. The star has a spectral classification of WN6(h). The N indicates that the spectrum of the star emits nitrogen lines and the h indicates it has strong hydrogen emission lines.

Spectroscopy of WR 136

The spectrum profile of WR 136 in Figure 3 shows strong emission lines for hydrogen and nitrogen that show up prominently in the spectrum image.

WR-136-Spectrum

Figure 3. – WR 136 Spectrum Profile and Image

I used four 60-second exposure images with focus offsets of 100, 300, 500, and 700 to achieve higher resolution throughout the spectrum and median combined them to produce the spectrum image in Figure 3.

SU Andromeda

The star SU Andromeda is an irregular pulsating supergiant carbon star that has an approximate magnitude of 8.5. The atmosphere of carbon stars contain more carbon than oxygen because it is cool enough for carbon to combine with oxygen to form carbon monoxide (CO). This process consumes all the free oxygen leaving an excess of free carbon in the atmosphere. This creates a series of dominate carbon spectral lines called Swan bands. Helium fusion in the star also produces other metals such as barium and strontium that show up in the spectrum as well.

Spectroscopy of SU Andromeda

The spectrum profile of SU Andromeda in Figure 4 shows the characteristic carbon absorption lines of the Swan band as well as other trace elements.

SU Andromeda-Spectrum

Figure 4. – SU Andromeda Spectrum Profile and Image

I used four 60-second exposure images with focus offsets of 100, 300, 500, and 700 to achieve higher resolution throughout the spectrum and median combined them to produce the spectrum image in Figure 4.

Uranus

Unlike stars planets do not emit their own visible light. The light we see is sunlight reflected back to us. However, the returning reflected light is not the same as the light that left the sun. A planet’s surface and atmosphere absorb some of the light at various wavelengths before reflecting it back. This soaked up light shows up as absorption bands in the spectrum of the planet. The thick atmosphere of Uranus contains a large amount of methane as well as ammonia, hydrogen, helium and other gases. Methane produces strong abortion bands that show up in the spectrum of the planet.

Spectroscopy of Uranus

The spectrum profile of Uranus in Figure 5 clearly shows the methane absorption bands.

Uranus-SpectrumI used three 20-second exposure images with focus offsets of 400, 600, and 800 to resolve the methane lines and median combined them to produce the spectrum image in Figure 5.

Conclusion

I took the spectrum images over a period of several months as I set up and tested the TGS system. Starting out, my knowledge of spectroscopy and spectroscopes was limited. I’ve read a lot, researched a lot, and got a lot of help and advice from Dr. Robert Mutel. Robert installed the TGS system on the Rigel telescope in Arizona, which is part of SSON. As far as I know it was the first remote TGS spectroscopy system made publicly available for general users. I modeled the SSO TGS after Robert’s system as closely as possible. Besides explaining how a TGS system works and how to set them up he did many of the calculations I used writing the SSO TGS User’s manual and setting up the system.

I’m fascinated by how much information you can dig out of a star’s spectrum. It tells you a stars temperature, what it’s made of, how far its’ evolved, and more. There are many scientific investigations and projects you can do with this type of spectroscopy capability. Our SSON users are quite resourceful and curious. I expect to see some interesting “thinking outside the box” spectroscopy work by them. I’ve got some ideas of my own I want to work on.

Beautiful Image of New Supernova in M82

M82_SN_Arrow

This morning Adam Block, Manager of the Mt. Lemmon Sky Center observatories, sent me a message with a beautiful image of M82 that shows the bright supernova. Adam is a world-renowned astrophotographer who has won many awards for his work. He used the Mt. Lemmon Sky Center 0.81-meter telescope to take the image data to create his LRGB composite images. The powerful telescope is part of SSON and is available to all users for their own imaging and research projects.

Here is Adam’s message to me this morning verbatim, which includes the links to his latest images:

“here is my “press release” (meaning I send this to a small group of interested people)

Supernova!

I apologize if the following isn’t terribly well written… it is now quite early in the morning having just completed acquiring and processing data on M82 and its new supernova! It isn’t a perfect image (quick put together)… but here is what I got:

http://skycenter.arizona.edu/gallery/Galaxies/M82_Supernova

(click on the image for a larger version, click on the thumbnail for a version with an arrow!)

The direct links to the images are:

http://skycenter.arizona.edu/sites/skycenter.arizona.edu/files/M82_SN.jpg

and with the ARROW:

http://skycenter.arizona.edu/sites/skycenter.arizona.edu/files/M82_SN_Arrow.jpg

I look forward to showing guests to the SkyCenter a view of this through the telescope. Keep in mind this image is stretched in its brightness; the supernova is considerably brighter than any part of the galaxy and as it brightens it may outshine billions of stars in M82.


http://skycenter.arizona.edu
http://mirrorlab.as.arizona.edu
—-
Caelum videre iussit, et erectos ad sidera tollere vultus.
He bid them look at the sky and lift their faces to the stars.
–Ovid, Metamorphoses 1. 85-8″

Trying Remote Astronomy with the Sierra Stars Observatory Networks

Dr. David Galbraith started using SSON in April of 2013. He is the Head of Science at the Royal Botanical Gardens in Burlington, Ontario Canada and an active member of the Hamilton Amateur Astronomers (HAA). David wrote an article for the January issue of the  HAA online magazine Event Horizon with the title: Trying Remote Astronomy with the Sierra Stars Observatory Network.

It is a well-written and informative description of David’s experience using SSON and why he chose our network for his remote astronomy projects. If you are interested in trying out remote astronomy and want to read about one of our user’s experience trying out SSON, you can read David’s article here on the HAA web site.

— Rich Williams

Analyzing Comet Lovejoy

By Rich Williams

Figure 1

Figure 1 Comet Lovejoy

Last night I was able to fit in an hour’s worth of imaging time to get some data on Comet Lovejoy (also called C/2013 R1) on the SSO telescope just before the end of twilight. The comet is quite bright and were it not for all the media coverage of Comet ISON, which reaches perihelion on Thanksgiving days two day from now, Comet Lovejoy would probably be getting much more attention.

I scheduled six 240-second images without a filter (clear) and six 120-second images for B, V, and R filters. My original intent was to combine the data to create a LRGB composite color image (Figure 1). However, using various image processing techniques to analyze the image data I found some very interesting structure in the coma and tail of the comet.

One of the difficulties in working with comet image data is the great range of brightness between the area near the coma and the outer edges of the tail. Standard stretching of the images in various settings from very low to very high helps see more, but still a lot of the detail in the data is overpowered and hidden. I use MaxIm DL to analyze this type of data. Two image processing techniques that really help bring out fine detail in comet structure are digital development and rotational gradient filters.

Digital development processing does a nice job showing both bright areas and dim areas in objects like comets simultaneously. Figure 2 is a 24-minute total exposure (six four-minute stacked images) of the comet processed with digital development. It shows a lot of fine interesting detail around the coma and the tail. Most of the detail is not visible in raw data because it is overpowered.

Lovejoy-C-digital

Figure 2. Digital development processing of Comet Lovejoy.

A rotational gradient filter enhances low contrast structure radiating around the coma and in the tail. Figure 3 is a 12-minute total exposure (six two-minute stacked images) taken with an R filter. I then created the movie below from the six images processed with the rotational gradient filter to see if I could discern any movement in the comet’s structure. The series of images were taken between 12:43 and 13:11 UT on 11-26-2013 UT date. In just under a half hour span I didn’t expect to see much, if any, movement. To my surprise the comet is very dynamic and the undulating of the tail in such a short span of time is readily apparent.

Lovejoy-R-rotational

Comets are fascinating objects to observe. They change considerably from day to day and, as I found, even from minute to minute. I look forward to doing more of this work on Comet Lovejoy and of course Comet ISON, if it survives its close encounter with the sun on Thanksgiving Day.

 

Comet Lovejoy dynamics over a 29-minute period

Comet Lovejoy dynamics over a 29-minute period

 

Telescopic Observing Labs at Mesa Community College

One of the reasons I founded SSON was to make professional observatory facilities readily available to teachers and students. I saw an opportunity for teachers to use a network of remote telescopes regularly for astronomy class lab work and research. Several colleges and universities use SSON for these types of programs. Knowing they have access to our network of telescopes throughout the year ensures they can plan to use our facilities with confidence and get great results.

The following guest blog by Kevin Healy highlights how Mesa Community College uses SSON for their astronomy courses.

— Rich Williams

Telescopic Observing Labs at Mesa Community College

by Kevin Healy

The astronomy program at Mesa Community College (www.mesacc.edu/departments/physical-science) offers two introductory astronomy courses: one focusing on the Solar System and the other focusing on stars and galaxies. Each of these courses can be taken with or without the accompanying laboratory course.

As part of both of our lab courses, we introduced modern telescope imaging during the Spring 2012 semester. These lab exercises have provided students with the opportunity to plan telescopic observations and then use their requested images to look for asteroids or KBOs and construct color composite images of deep sky objects.

Our “Telescopic Observing” module involves two exercises completed in different lab periods. The first lab exercise introduces students to basic concepts of astronomical imaging such as the meaning of pixel values and image coordinates and the processes of image set alignment and color compositing.

At the end of this first exercise, students select two targets to be observed with a telescope in the Sierra Stars network. Their first target is a moving Solar System object while the second target is a Messier object. While I choose the exposure times and filters used for each object, the students must ensure that their chosen targets are up during darkness. This part of the planning is performed with the use of planetarium software, star atlases, star wheels, and/or the JPL Horizons “What’s Observable?” website (http://ssd.jpl.nasa.gov/sbwobs.cgi).

Lab instructors collect the observing targets and send them to me for telescope scheduling. In a typical semester we have 10 lab sections. Student groups of 2-3 mean that approximately a dozen Solar System objects and a dozen Messier objects are chosen. With the automated catalog search within the SSON website interface, scheduling these observations is quick.

For Solar System targets, I use 30-minute or 1-hour intervals between 30 second exposures (for asteroids) or 60 second exposures (for KBOs). Students have successfully identified many of the main belt asteroids and the larger KBOs.

For Messier targets, I typically use BVR or BGR filter sets for star clusters and galaxies with exposures in the range of 30-60 seconds per filter. This is enough to give the students enough detail to work with the images. If a student group selects a nebula, I typically add a longer H alpha exposure to replace the R filter image.

In the second lab exercise, students process their image sets. For the Solar System object image set, this involves aligning the stars in the images to look for motion against the star field. The Messier object image set is used to construct a color composite. We then ask students to present their final images to the other student groups. Each student is responsible for providing at least one fact about the Solar System and Messier object.

Students enjoy the hands-on activities and they see how real astronomical observing and image processing is done.

The image below is a composite of stacked images of the asteroid 32 Pomona taken Oct 25/26, 2012 at SSO. The asteroid is visible as a chain of 5 points in the center of the image. Each image was a 30-second exposure. The 5 exposures were spaced apart by 1 hour. They were added together to the form the final image. This is an excellent illustration of how an asteroid moves relative to the background star field. It is one of many examples of how I use SSON as a learning tool for my students.

Asteroid 32 Pomona Sequence

Asteroid 32 Pomona Sequence

 

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Dr. Kevin Healy
Residential Astronomy Faculty
Mesa Community College
Mesa, AZ

I am astronomy instructor and planetarium director at Mesa Community College in Mesa, Arizona. While the Arizona skies are often clear, the Phoenix metro area presents an obstacle to observing more than a few very bright objects. The SSON telescopes provide the opportunity for students to collect images they cannot get from our roof-top telescopes here at MCC. These images allow our introductory astronomy students a taste of astronomical imaging. I am very excited about the new opportunities for spectroscopy and for southern hemisphere observing made possible through a lot of hard work by the staff of the SSON telescopes.

SSON Update on Comet ISON

By Rich Williams

I took a series of 180-second exposures of Comet ISON using the Sierra Stars Observatory telescope in California last night (evening of March 4th California time/ March 5th UT date) to see how the comet was behaving. The comet hasn’t shown much of an increase in its brightness or in the length of its tail since my last blog about the comet on February 11. However, it is still out around the orbit of Jupiter and has a ways to go before approaching the sun.

Below is a composite image of Comet ISON created from seven 180-second images for a total of 21 minutes of exposure time. The telescope was guiding on the comet during the exposures. The comet is in the center of the 21 x 21 arc-minute field of view of the image.

Comet ISON March 5, 2013

Comet ISON March 5, 2013

The image below is a zoomed in area of the comet from the image above.

Comet ISON March 5, 2013 -- zoomed in

Comet ISON March 5, 2013 — zoomed in

 

Finally the video below shows the comet moving through a crowded star field in the constellation Gemini. You can see a few galaxies in the images as well. The total time from beginning to end of the sequence is about 40 minutes. The tail seems more apparent in this moving image of the comet.

 

 

 

Comet ISON Video March 5, 2013

Comet ISON Video March 5, 2013

 

Comet ISON Shows Its Tail!

By Rich Williams

I decided to start chronicling the changes in comet ISON as it approaches perihelion and beyond. On the night of February 12, 2013 UT date (Monday night February 11 California start time). I scheduled a series of 12 180-second images of ISON using on the SSO 0.61-meter telescope here in Markleeville, California. The seeing varied between 2.0 to 2.4 arc seconds that night. The telescope tracked on the comet selected from the SSON online MPC database. I downloaded my images from my SSON FTP directory after processing the SSON jobs for the night’s observing run. On first inspection I was delighted to see a discernible tail on the comet. This is pretty cool as the comet was still just beyond the orbit of Jupiter and more than 9 months from its extremely close grazing of the sun when it reaches perihelion. Comets coming out of the Oort are fresh and very unpredictable. Even so I think that an early tail like this is a good sign for a great show this fall and winter.

Comet_ISON_2-12-2013

Comet ISON showing early signs of tail.

I processed the 12 images using MazIm DL to create a movie loop of the series. Other than stretching the calibrated images no image processing was performed on the data. Above is one of the 180-second images of the comet. The field of view is approximately 21 by 21 arc minutes. The magnitude of the comet was approximately 15. The comet, while small, clearly shows a tail in the full image. The image below is a zoomed in cropped area around the comet from the same image.

ISON_2-12-2013-crop

Comet ISON zoomed in view

Finally the video below is a movie loop of the 12 images clearly showing the movement of the comet against the star field over approximately 40 minutes. I will try to image the comet regularly (every week or so weather and moonlight permitting) to monitor the brightness and changes in the comet as it approaches the. Sun. I’ll post my results here on this blog for you to see.

Comet ISON Video 2/12/2013

Learning How to Use the Rigel Transmission Grating Spectroscope (TGS)

By Alessandro Odasso 

The Rigel Telescope Transmission Grating Spectroscope (TGS) system has been made available to the SSON users thanks to the cooperation between Rich Williams and Dr. Robert Mutel (Iowa University). Quoting Rich’s words “The Rigel Telescope TGS system opens up a whole new field of inquiry for students, researchers, and curious people”.

I belong to the third group and I must say that when I first read his blog I was not only curious but also a bit puzzled. I was curious because I knew that the spectrum of a star is like a fingerprint, in a metaphoric sense it’s like the star’s own DNA. I was a bit puzzled because I was afraid that such a system would be too complicated to be used by a user with no specific experience.

During the Christmas holidays I decided to devote some time to read once again the blog and to pay attention to the user manual written by Dr. Mutel and I felt that, after all, it did not sound as complicated as I initially feared.

My first attempt in using the system was aimed at getting the spectrum of Merope, a star belonging to the Pleaides cluster. To do so required me to do two things:

1) I took an image of Merope(30 seconds exposure time)

2) I analyzed the FITS image with two different programs.

Phase 1 – Taking an Image

I decided to use the S filter, the one that has a slit to block out most light except for a narrow strip. You schedule to take TGS images on Rigel just as you do for regular images. However, you need to define two other parameters:

  1. The first parameter, “focus offest” is intended to tell the system which part of the spectrum you want to analyze with greater resolution. Having nothing specific in mind, I chose 402, a value that allows you to observe the H-alpha line with maximum spectral resolution.
  2. The second parameter, “RA offset” is a correction factor intended to have the star displayed on the left side of the image, just a trick to have the elongated black and white rainbow spectrum centered in the middle of the image. Again, not a problem: the manual gives you a very simple formula that calculates the RA offset, already expressed in RA seconds, taking into account the star declination.

Maybe, in the future, the SSON web page could be programmed so that this calculation is done automatically.

There is nothing different about the resulting FITS image. FITS is a standard so you can open the image with whatever FITS viewer, including Astrometrica (by H. Raab): you clearly see the spectrum spreading at the right of the slightly defocused zero-star and you can read the usual details in the FITS header.

Phase 2 – Analyzing the image and displaying the spectrum

My initial attempt to analyze the spectrum in my image was with RSpec, whose trial version can be freely downloaded from the vendor site.

I was impressed with RSpec’s very easy installation and very nice Graphical User Interface. Even without reading the manual, it is straightforward to open the FITS file and you are immediately rewarded by the system that displays a raw, not calibrated spectrum. In other words, the system displays a graph where the Y axis is related to the pixel brightness and the X axis represents the various pixels of the spectrum that you see in the FITS image.

The next step is to calibrate the graph so that the X-axis represents the wavelength expressed in nanometers (or Angstroms). The easiest calibration supported by the program is the one where you simply fill a field telling the system how many Angstroms / pixels must be taken into account. But here I was at a loss; I had no idea about the correct value!

The calibration technique is explained well in the video tutorials provided by RSpec. The idea is to identify a specific spectrum feature by simply clicking on it and by giving it the wavelength that you either know a priori or that you can get by clicking on the correspondent feature of a reference image of a star having a similar spectrum. The nice thing is that RSpec is shipped with a large reference library of star spectra.

As easy as this may seem, when I used the reference spectrum B6IV that should have worked with Merope… again I was at a loss! When I opened the spectrum of the reference image I was unable to compare it with my raw spectrum: the shapes were too different and I couldn’t determine which features matched in the two spectra!

At this point, to be honest, I felt confused. My learning curve was greater than I expected. While this learning process is certainly important, it is a bit frustrating, especially if you are a bit lazy as I am :-)

But here I have good news! Another nice thing about RSpec is that there is a Yahoo RSpec User Group where you can ask for help! This is a place where many technical issues are discussed and clarified. So I joined the forum and I am pleased to say that they helped me immediately sending me a calibration file that was a good starting point.

I guess the reason why RSpec calibration process is not automatic is simply due to the fact that RSpec needs to be very general, the software is not tailored to any specific hardware platform.

Rigel TGS Software for Linux and Mac Operating Systems

When I contacted SSON and Dr. Mutel asking for help calibrating my TGS images, I was given software that is designed specifically for use with the Rigel TGS. Almost no calibration is needed. This software comes in the form of a Python script that requires a Linux installation. I was lucky in this case as I happen to have a dual boot system with Debian installed on my computer.

Before running the script, I had to install a few libraries according to the instructions that I received. The whole installation process took less than 30 minutes and it was straightforward.

The nice thing about the program is that it is able to generate a bitmap showing the calibrated spectrum plus specific spectrum features in a complete automatic way and in just a few seconds!

You do not have to bother about details like, for example, the graph title and exposure time: this information is generated reading the data from the FITS file. Furthermore, you can choose which spectrum features you would like to be highlighted. Finally, the program is able to synthesize a second bitmap image of the colored spectrum rainbow. There is one important input that you must be careful to identify and enter: the zero-star pixel position.

The image below is the Merope spectrum that I obtained a few minutes after the installation of Dr. Mutel’ script:

Merope - 2013_01_06-spec

My experience proved to me that Dr. Mutel’s TGS software program is easy to use. It is only fair to note that when something like this is easy to use the reason is because other people spent a lot of time and effort to design and implement it. We must praise the Iowa and SSON teams for this!

Of course, this new tool does NOT transform us “curious people” into experts! However, thanks to this new tool and with appropriate guidance from professionals we may be in the position to give a little but not negligible scientific contribution in the framework of the so called pro-am collaborations or “citizen science projects”.

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Alessandro has been an avid SSON user since November 2009. He participates in several astronomy programs and projects. I thank him for giving me his personal experience using the new Rigel remote TGS system and sharing it on my blog.

I also would like to thank Dr. Mutel for his continued excellent work on the Rigel TGS system. He wrote the code for the Rigel TGS Software and continues to enhance it with features such as TGS Stitch, which enables you to combine two or more spectrum data optimized for different wavelengths into a single data graph. It’s very cool and useful!

For those of you who want to run the Rigel TGS software on a Windows system you can install the Ubuntu Linux operating system on Oracle VirtualBox. Both VirtualBox and Ubuntu are free to download. I have this set up on the Windows 7 laptop I’m writing this with. It’s easy to do following the installation instructions for both programs. After setting up Ubuntu (or another Linux OS) on VirtualBox, download the TGS Software and install it according to Dr. Mutel’s instructions.

Here are some links to quickly get you started installing the Rigel TGS Software on your system:

— Rich WIlliams