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 Evening With The Stars this spring had a great turn out. Thanks to all who came out. Leo gave a great talk, and I’ve heard from many of the attendees that they really enjoyed the evening. Unfortunately, the weather was not as cooperative and clouds ruined our planned observing. We’ll try again in the Fall when we have our EWtS event again. Here are some pictures from the evening.
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 is a mosaic of the first quarter moon taken this last Wednesday, March 5th. The individual images were collected with a Nikon D90 threaded to the Meade 12″ SCT. The separate images were then assembled using GIMP, an open-source image manipulation program.
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.
Want to do space science, but don’t have a billion dollar spacecraft, or an 80-m radio telescope in your backyard? Check out SpaceHack.org. There you’ll find a variety of resources and projects especially suited for the armchair scientist!