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Archive for November, 2006

Digital Photography, Photoshop, and the Spaceship Under Glass

Friday, November 24th, 2006
Spaceship Under Glass
Spaceship Under Glass

Did you ever start out doing one thing and get distracted by something else? I was asked by the Adler Planetarium to teach a class about NASA’s Project Gemini – the frequently overlooked program wedged in between the Mercury and Apollo programs. I happily agreed. For more info about the class, see Gemini: Stepping Stone to the Moon (ST1).

As a part of preparing for the class, I went to the Adler armed with my Nikon D50 to take photographs of their “Return to the Moon” exhibit. The centerpiece of this exhibit is the Gemini 12 space capsule. This was the final mission of the Gemini program and carried James Lovell and Edwin “Buzz” Aldrin into space for a mission that lasted just shy of four days.

The lighting in the exhibit area was low, especially in the room housing the Gemini 12 capsule and flash photography was discouraged. Fortunately I had the foresight to bring my tripod with me so steadiness for long exposures wasn’t a problem. However lighting did present another challenge in that the spacecraft was housed within a large glass exhibit case. On the wall opposite the case were some brightly lit quotes. Unfortunately I did not notice the reflection that these quotations created on the glass case at the time. Last weekend upon a closer review of the photographs I took of the capsule’s interior, I was dismayed to discover the presence of these “backwards” quotes in a number of my shots. Fortunately I had taken photographs from a number of different angles and a few managed to come out clean. But I digress.

The real purpose of this story is to highlight the synergy of the camera and the computer. Synergy is the combination of two or more elements in which the net effect is greater than the sum of their individual effects, or the whole is greater than the sum of the parts. The marriage of the camera with digital image processing is one of the best examples of synergy that I can think of. I had always been interested in photography at an amateur level and I have worked with computer graphics off and on going back more than 20 years. It was my move from film to digital that renewed my interest in photography. Combining my love of computer graphics with the image capturing ability of the digital camera has led me in a new direction graphically speaking.

An example of this synergy is seen in the image used to illustrate this story. Titled “Spaceship Under Glass” I took the photo only to serve as a reference image of the Gemini capsule. Following my initial visual examination of the photo in Photoshop, my first thought was to just adjust the image to lighten the underside of the spacecraft. One thing led to another and before I knew it I had multiple adjustment layers and an image that was looking increasingly psychedelic. The true power of digital image processing is that it encourages experimentation.

One thing that I found very annoying in the original photograph was that the upper right quadrant of the glass case was obscured by a movie projection screen which was showing a movie about the Gemini mission. I could have cropped out the top of the image to get rid of it but that would have entailed cropping out all the lights as well and I was determined to keep them. Instead I resorted to a combination of the clone stamp tool, the healing brush tool, the eraser tool, and segments of the image copied to another layer and then blended in with the underlying layer to remove the intrusive movie screen. A companion screen was also present at the extreme left of the image. However, it only intruded over the background wall, rather than the glass case, and was easy to digitally “erase.” Note that the left portion of the photograph was cropped out of the version of the image shown here.

In summary, I began just wanting to use the photograph of the Gemini capsule as a simple illustration in the Open Office Impress presentation I was preparing. Instead of just making minor image corrections in Photoshop, I began a digital excursion that led me to an entirely unforeseen result. On the bright side, I suddenly found myself with the perfect title slide for my presentation along with some new image processing techniques under my belt.

Ad Astra, Jim

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Happy Birthday to First Lady Laura Bush

Saturday, November 4th, 2006

First Lady Laura Bush

Today is First Lady Laura Bush’s birthday so Happy Birthday Laura. You are certainly one of the best, if not the best, First Lady’s we’ve had in my memory, which dates back to the Nixon presidency.

One of the good things about the election season is that it brought First Lady Laura Bush to Schaumburg IL, a long way from both Texas and Washington DC. I was fortunate to be able to attend this campaign event which required advance reservations. I arrived a little more than two hours in advance of Mrs. Bush’s arrival and was able to move up to about three rows of people back from the front. It certainly was a long time standing.

This was a campaign event for the congressional campaigns of David McSweeney and Peter Roskam, and the gubernatorial campaign of Judy Baar Topinka. There is a Daily Herald story about the event that you can read to learn more.

Mrs. Bush gave a good stump speech about the various issues that are dominant this election season. Mrs. Bush was preceded by speeches from McSweeney, Roskam, Topinka, and IL state GOP Chairman Andy McKenna. Following her speech, the First Lady took time to walk along the front of the line giving autographs and having her picture taken. While I did get to say hi to her and get her autograph, I now kick myself for not turning over my camera and asking to have our picture taken. For some reason, it just didn’t seem right to me at the time – like too much of an imposition.

And Mrs. Bush: I must say that this is the first time that I have attended an event to see a celebrity who was neither an astronaut nor a scientist so consider yourself to be in exclusive company.

First Lady Laura Bush

I must add that I am very happy that I had a digital camera for this event, as opposed to my film camera. Many shots were spoiled due to the jostle of the crowd, some out of focus due to movement on my part as well as playing with focus and zoom settings. Knowing that I didn’t have to pay for film, pay for processing, or worry about changing rolls made it possible for me to be much more carefree when it came to taking pictures at the event.

Ad Astra, Jim

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Astrophotography and Large Telescopes Workshop

Saturday, November 4th, 2006
Doane Observatory Telescope

Last night was the first session of the “Astrophotography and Large Telescopes Workshop” class that I am taking at the Adler Planetarium. The class is being taught by astronomer Dr. Mark Hammergren and consists of three three hour sessions. The course description for the class reads as follows:

“Use research-caliber telescopes and specialized equipment to photograph your favorite deep-sky objects! Get hands-on access to the Adler’s 20-inch reflector in the Doane Observatory and remote control over the 150-inch reflector at the Apache Point Observatory in New Mexico. Learn to find and photograph faint asteroids, nebulae, galaxies, supermassive black holes and more.”

In last night’s class we discussed a variety of topics including:

  • competition for observing time at the major observatories
  • planning observing sessions at the major observatories
  • characteristics of CCDs
  • evaluating CCD performance
  • quantifying CCD irregularities via bias frames, dark frames, etc.
  • instrumentation (visual, IR, spectroscopy, etc.)
  • discussion of the telescopes that we will be using
  • elementary information on RGB and the creation of color images in Photoshop using the Hubble Space Telescope Eagle Nebula image as the example.

Following the lecture portion of the class we had the opportunity to go outside and see the Doane telescope in action. The Adler’s Doane Observatory is home to a 500-pound Cassegrain reflector with a 20-inch (0.5 meter) diameter mirror. The telescope uses a fork-style equatorial mount and its 0.5 meter diameter aperture and 4 meter focal length gives it a focal ratio of f/8 at prime focus. The mirror was created using the spin-cast technique. For instrumentation, there is a Finger Lakes Instrumentation 1024 x 1024 pixel CCD that has a 21 arcminute field of view.

According to Dr. Hammergren, in choosing targets for our Doane observing session we should focus on objects that are at least 30 degrees above the horizon; in the eastern part of the sky; and that are at least 15th magnitude for point sources or 13th magnitude for extended objects. Note that the Doane is open to the public during the planetarium’s Far Out Friday events. and for special observing events. Because this was a “Far Out Friday”, we had to be content to wait our turn to get a look through the telescope. The target this particular evening was our own Moon.

The picture at the top of this post was taken as I waited inside the dome for my turn to look through the telescope. Afterwards I headed outside to take some exterior shots of the observatory. One set that I was particularly pleased with was used to create the picture seen below. I dubbed it “Ghosts of Doane Observatory” because of the specter like appearance of the figures.

Ghosts of Doane Observatory
“Ghosts of Doane Observatory”

The second class in the series will be devoted to using the Adler’s Doane Observatory for making our telescopic observations, For this class, we will have exclusive use of the observatory. I can only hope that we will have a clear night for our class.

For the third and final class, we will get to use the Astrophysical Research Consortium 3.5-meter Telescope at Apache Point Observatory. In terms of instrumentation, we will be using either the SPICAM (Seaver Prototype Imaging camera) CCD camera or the DIS (Dual Imaging Spectrograph). SPIcam is a SITe 2048×2049 pixel CCD with a 4.78 x 4.78 arcminute field of view with 0.14 arcsecs per pixel. For details see Quick Guide to using Spicam. The Dual Imaging Spectrograph has a 4 x 6 arcminute field of view. Unfortunately I have no additional information about this instrument.

I am looking forward to the remainder of the class and with working on the images that we acquire doing our observing runs.

Ad Astra, Jim

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