The “Noon At The Nerman” program connects artwork throughout the Johnson County Campus to the scholarly activities of the faculty here on campus. This past month, Dr. Doug Patterson, Professor of Astronomy, was invited to lead off the Fall Semester with a discussion of the Galileo’s Garden sculpture that now resides on the south lawn in front of the new Sustainability Building.
During Dr. Patterson’s talk, he refered to Prof. Paul Tebbe’s work with the analemma when the Galileo’s Garden sculpture was next to where the fountain between the SCI and GEB buildings is now. Thanks to Dr. Anita Tebbe, we rediscovered a video of Prof. Tebbe’s public talk demonstrating the analemma and the overlay he and his students made for the sculpture.
This is a perfect reason why we need to be focusing more effort into Space Weather research, and especially prediction. The STEREO-A spacecraft imaged a coronal mass ejection (CME) impacting the Earth in December 2008.
The corn is starting to dry out, so it must be time for the Fall semester to start up again. Here at JCCC, though, the work doesn’t stop just because its Summertime. This past summer term, I had an honors student that worked on astrophotography and differential photometry. Both were fun projects, and I’ll write more about the variable star photometry later. For now, let me show off some of the excellent images G. W. Francis took with our SBIG ST-8 CCD camera and his own Nikon D40.
Every Monday evening in June, it seemed, was cloudy, so we decided to take advantage of a sunny afternoon and image the Sun using an H-alpha filter. This filter only allows the one wavelength of red light emitted by hydrogen atoms which enables us to see features like the prominence shown above.
GW mounted his D40 onto the piggyback mount of our Celestron 8″ SC telescope and tried to take an image of the constellation Ursa Major. Most of what he got was the reflected light from the sodium vapor lamps in the parking lot. This was the last night of observing at the college. The light pollution was just too much for us.
GW mounted his Nikon D40 on a tripod and pointed it northward, centering Polaris in the field of view and collected 21 images each with a 30-sec exposure. By rotating and aligning each image, a detailed view of the Northern Night Sky is revealed. When the images are not rotated, but simply stacked and merged together, the rotation of the Earth becomes apparent as the stars leave trails through the sky. Notice that Polaris, which is very close to the North Celestial Pole, remains nearly fixed in place.
Before settling down onto the program variable star for the evening, the we targeted several Messier objects. M57, the Ring Nebula, is a planetary nebula. A star, not unlike our Sun, threw off its outer layers as it died leaving behind an expanding shell of gas and a small but staggeringly hot white dwarf in the center.
M16, The Eagle Nebula, made famous by the Hubble Telescope’s image Pillars of Creation, had to be imaged by peeking through the gaps in a maple tree near where we had setup the telescope. The location was chosen for optimum viewing of the variable star DY Her, not M16, but we got lucky. In the image you can make out the famous pillars in the top center of the image.
M13, the Great Cluster in Hercules, is one of the closest (relatively speaking) globular clusters to our planet. This dense cluster is home for around a million ancient stars.
Rather than using the SBIG ST-8 CCD camera, I opted for my Nikon D90 for these photos. In some respects its better, in other ways not so much. First stop: The Sun.
In this image, you can see the Sun’s chromosphere and a small prominence on the left side of the image. The camera doesn’t have the resolution nor dynamic range of your eyeball, so cool though this may be, nothing substitutes for seeing the Sun live. This image was taken through a DayStar H-alpha filter threaded to the back of our 12″ Meade on the roof of the CLB with my D90. I’ve tried doing solar imaging with the SBIG camera, but even at the fastest shutter speed, the image saturates. Even in the above image, the disc of the Sun is overexposed in order to make the chromosphere visible.
Alberio is a nice double star in the constellation of Cygnus. If you have a pair of binoculars, this is an easy target. The color difference between the two stars is due to their different temperatures. The bright blue star is extremely hot where as the yellow star is cooler (relatively speaking) with a temperature closer to that of our own Sun. This image is a single 30″ exposure with the D90 set at ISO3200. The noise isn’t too bad, but being a single shot, there’s more noise and less detail than one could get by taking multiple images and combining them. I’ll try that some time soon. With the D90 as opposed to the SBIG, the colors of the two stars are really easy to capture. With the SBIG, one would have to take three separate images through a red, a green, and a blue filter and combine them to form the color image. Doable, but definitely more work.
This image of the Great Cluster of Hercules, M13, is a single 30″ exposure like the image of Alberio, but with the much dimmer object comes a lower signal-to-noise ratio. Imaging objects like this is where the SBIG becomes vastly superior to a digital SLR like the D90. As with the Alberio image, this image could be improved by combining multiple exposures.
The Ulysses spacecraft is slowly dying, but its not quite finished yet! Its demise was slated for July 1, 2008, but even without its primary X-Band transmitter whose heatsink doubles as the heater for the fuel lines, its been surviving. Here’s the latest update on the health of the only spacecraft ever to explore the polar regions of the Sun.
Dear Ulysses colleagues,
Yesterday was mission day 6712 and we surpassed 400 days of S-band mission operations. Given that we thought the spacecraft would only survive a few months after the X-band transmitter failure on 15 January 2008, that’s pretty good going! The last month or so has seen a dramatic increase in data return. This is due in part to a request by NASA HQ for additional DSN coverage and also due to the fact that we can record and play back data again on board the spacecraft. That’s possible because the spacecraft-Earth distance is low enough to support a 1024 bps telemetry data rate at the moment (this situation will last until sometime in mid-March). I’ve attached a plot of our weekly data return percentages which clearly shows the recent improvements.
As far as the hydrazine is concerned, it’s obviously not frozen yet, but there can’t be very much left. Our estimate is that we have almost no fuel left even using our best-case estimates. However, it’s very difficult to get an exact figure of fuel usage over the mission given that we have had about 3 years of closed-loop conscan operations to control nutation when the spacecraft fired the thruster autonomously. During those periods, we had to estimate the number of pulses fired by monitoring the increase in catalyst bed temperature after each period of thruster activity which is not the easiest thing
to do. So the bad news is that we don’t have an exact estimate of how much fuel is left but the good news is that it’s still above zero! We hope that the data returned is continuing to excite you as the solar activity slowly begins to increase.
Here are two mosaics of the Sun stitched together with images collected on Wednesday afternoon. These images were taken with a Nikon D90 through a 12″ Meade SCT fitted with an H-alpha filter. The first mosaic is of the full disc of the Sun. There are some details, but the glare of the photosphere, even through the very narrow passband of an H-alpha filter, limits what can be seen in the chromosphere and corona. In the second image, the transfer curve for image was manipulated to eliminate the photosphere and highlight the chromosphere and corona. Notice on the lower right portion of the limb, there is one small, bright, prominence, and several faint and larger prominences. (since the image is inverted, this would be the north-eastern side of the limb.
Ok, it’s not the greatest picture, but we still are dealing with the wind shaking the telescope. You can see a couple of sunspots from, though. These are spots associated with the new solar cycle, #24. Note their latitude. Sunspots early in a solar cycle will form at high latitudes at first. Later in the cycle, these spots will appear at lower and lower latitudes as the Sun’s magnetic field gets more and more twisted. More Sun pics are coming, but it will take me a while to work through the processing.