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For some weeks I have been using a Canon EOS 10D digital camera, not only for normal photography but also for astronomical purposes. You can not make movies with this camera like a webcam but you can of course combine and process series of individual images with software like K3CCDTools and Paint Shop Pro to produce a single, better quality image.
I used this camera for
the first time in September 2004 during my vacation in southern
France so it will take some more time to explore the possibilities.
Exposure times with this camera range from 1/4000th of a second
to as long as you like. A remote control comes in handy for making
series of images. You can choose sensitivity manually, from ISO
100 to ISO 3200. It has a 6,3 Megapixel CMOS sensor. For more
details, see the Canon website.
The camera is very nice for imaging the night sky and constellations. I use different lenses for normal use. When you take the lens off, the camera can be attached to the telescope with an adapter ring. For telescope imaging I use focal reducers; f/6.3 is great, f/3.3 is a bit tricky because of vignetting. I still need a lot more practice to learn what is possible and especially what is not. Taking images in prime focus is more challenging because correct guiding is very critical.
When you attach your camera to a telescope, you get a pretty large magnification. For most deep sky objects you don't need that so using a focal reducer f/6.3 is strongly recommended. When you use full size images, 3072 x 2048 pixels are more than enough. Very often you just want to use a particular part of an image so simply crop images to the selection you need. Even then you probably have to resize the image even more. A smaller image will look sharper.
Everyone who does astrophotography knows the importance of perfect alignment and balance of the telescope. On vacation I had to set up the telescope again every evening I used it and that is not perfect at all. The results should improve when the telescope is used at home on its own mount in my home observatory. Another very important issue is the quality of the seeing. Longer exposure times have to be explored yet.
Needless to say that the images themselves are only the beginning. It takes a lot of time to process the images later on the computer and the result also depends on your patience and skill.
Another reason for choosing this digital camera (apart from the fact that it is a great camera for normal use!) is that it can produce single shot colour images. When I try this with my old CCD-camera, I have to use 3 different colour filters: red, green and blue. This means I have to take 3 images every time with long exposures. Each image has to be perfect and then aligned to produce one colour picture. If I would like to combine multiple colour CCD-images then this would take 3 times as much images compared to the Canon EOS 10D camera. That also means 3 times as much chances of having problems because of bad guiding.
That is the difficulty but a CCD-camera is more sensitive and can be cooled. There is less noise in the images. But it is much harder to "quickly" produce nice images, especially when you have to triple imaging. The Canon makes colour images and a series of "short" exposure images can be combined later. There is more noise that best can be reduced by stacking (a lot) more images. For the brightest nebula the Canon can be used but a CCD is needed for all those beautiful but faint deep sky objects.
Images with short exposure times bring out the colours of the stars very well. As far is I can tell now, a lot of deep sky objects are well within reach of this camera.
When I took most of the deep sky images, the seeing was not at its best. Nevertheless, the first results with the Canon are very encouraging, as shown below. Some images took a lot of computer processing though because of the relative short exposure times. Image processing can be great but it has its limits too. Do not forget: the better the raw images are, the better the end result will be. In other words: you can do (some) magic but no miracles.
I don't use autoguiding yet and I did no manual guiding as well on these images, so I depended on the telescopes drive and rough alignment alone. Therefore, exposure times were very limited. When you take images through the telescope, guiding is very, very critical. Piggy back imaging (camera on top of the telescope) is much easier. However, you need some time to be sure of proper focussing. Unfortunately this camera does not show a live picture on its LCD screen. However, you don't need that for astrophotography. It is a minor disadvantage for normal use but no reason not to choose for this camera at all.
Atmospheric optics
On this page you can also find images that are related to atmospheric
optics. The light of the Sun and the Moon interacts with water
droplets, ice cristals and our atmosphere. This interaction produces
all kinds of arcs, bows, halos and so on. Again, a digital camera
comes in handy. There is much more to be seen in the sky than
most people know and often it doesn't have to be dark or cloudless.
More information on how and when these phenomena form on Atmospheric
Optics.
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Prominence on 2006, april 4. Our Earth is added for comparison. Image with Daystar T-scanner H-alpha filter. | ||
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The flattening of the Sun at sunset. The disk of the Sun is distorted by the Earth's atmosphere. How much that will be, depends on the different layers in our atmosphere, with their different densities and temperatures. See Moon also. | ||
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The Moon with corona. To the left is the planet Jupiter. Above Jupiter is the star Porrima in the constellation of Virgo. Canon EOS 10D with 150mm telelens on a tripod at ISO 400. | ||
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Left: a beautiful Moonrise. Middle: the flattening of the Moon is obvious. In this image, it is about 17 percent. Canon EOS 10D with 500mm telelens on a tripod at ISO 800 and 2 seconds exposure time. Right: just a nice view, 3 seconds exposure time. | ||
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The Moon on September 9, 2004. Exposure time 1/2000 of a second at ISO 800. | ||
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Total lunar eclipse March 3 and 4, 2007. Left and right image with Canon EOS 10D and 500mm tetelens. For the center image, an 18mm lens was used. It shows the eclipsed Moon and Saturn to the right, among the stars of the constellation of Leo. | ||
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Images with a Canon EOS
10D and 500 mm Maksutov telelens on a tripod. Left: Venus, Mercury and Saturn on June 26, 2005, at 22.16 local time. Exposure time: 1/90 second, ISO 800. Middle: Venus and Mercury on June 26, 2005, at 23.09 local time. Exposure time: 1 second, ISO 800. Right: the close encounter on June 27. Final processing with Paint Shop Pro. |
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Venus, Mercury and Saturn
in binoculars in June and July 2005. June 27: closest approach Venus and Mercury. |
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Satur, Venus and Mercury on June 22, 2005. Canon EOS 10D with 161mm telelens on a tripod, exposure time 3 seconds at ISO 100, aperture value 8.0. Final processing with Paint Shop Pro. | ||
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Between June 19 and July 15, 2005, 3 planets are close to each other in the sky. June 27 will be their closest approach. All 3 of them are visible in the binocular field around that date. These Canon EOS 10D images were taken on June 19, 2005 | ||
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Many stars are beautiful coloured. The colours of some bright stars, can be seen with the naked eye. Most of them are too faint and you wil need binoculars or telescopes. Take pictures. It is fun and very easy. | ||
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Left 2 images: comet Schwassmann-Wachmann on April 28, 2006. Centre: animated gif; movement over 8 minutes. Right: celestial path from April 29-May 19. Image with Celestron C11 at f/6.3, Canon EOS 10D digital camera. Exposure time: 50 seconds at ISO 800. |
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Orbit of comet Machholz
(C/2004 Q2) in 2004 and 2005. Comet Machholz in Taurus on January 6, 2005. Canon EOS 10D digital camera piggyback on the telescope. Exposure time: 50 seconds at ISO 800 with an 123mm lens. |
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Machholz and the Pleiades, M45, on January 6, 2005. Compositions of 6 images with a Canon EOS 10D digital camera piggyback on the telescope. Exposure times from 15 to 50 seconds at ISO 800 with an 123mm lens. The images are just a part of the original large images and processed a bit more to bring out more details. |
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Machholz on January 6, 2005. Images with a Canon EOS 10D digital camera behind the Celestron C11 telescope and with a focal reducer f/6.3. Composition of 3 images each, exposure times from 14 to 26 seconds, at ISO 800. No tails visible. |
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The rapid movement of Machholz is shown here. Left: two images taken at 22.07 and 22.36 on January 6, 2005, were combined and shifted horizontally a bit. The positions of the background stars stay the same. The comet however has moved in its orbit around the Sun: 3 arc minutes in 29 minutes. Right: animated gif. |
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Images of comet Machholz (C/2004 Q2) on December 19, 2004. Left: Canon EOS 10D digital camera on a tripod, exposure time 10 seconds on ISO 1600 and a 102mm lens. Right: Celestron C11 with Canon EOS 10D digital camera, exposure time 21 seconds on ISO 800. | ||
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The Milky Way in Aquila, Scutum and Sagittarius. Composition of 3 images. This edge-on view of our own galaxy shows numerous starclouds and dark clouds of dust. An edge-on view of another galaxies, like NGC 891, shows how such fine dust lanes look like from a distance. The light pollution is obvious. | ||
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M8, the Lagoon Nebula. Composition of 10 images with a C11, focal reducer f/3.3 and the Canon EOS 10D digital camera. Images combined with K3CCDTools and further processed with Paint Shop Pro. Exposure times of the original images: 60 seconds at ISO 800. The seeing was not so good. Nevertheless, the core of the nebula and the galactic star cluster are very nice. | ||
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M17, the Omega Nebula, also called the Swan Nebula or the Horseshoe Nebula. Composition of 8 images with a C11, focal reducer f/3.3 and the Canon EOS 10D digital camera. Images combined with K3CCDTools and further processed with Paint Shop Pro. Exposure times of the original images: 60 seconds at ISO 400. | ||
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M20, the Trifid Nebula. Composition of 10 images with a C11, focal reducer f/3.3 and the Canon EOS 10D digital camera. Images combined with K3CCDTools and further processed with Paint Shop Pro. Exposure times of the original images: 60 seconds at ISO 1600. | ||
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M42, the Orion Nebula. Composition of 3 images with a C11, focal reducer f/6.3 and the Canon EOS 10D digital camera. Images combined with K3CCDTools and further processed with Paint Shop Pro. Exposure times of the original images: 45 seconds at ISO 800. The images to the right are processed further to bring out more detail in the nebula. | ||
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Double star cluster in Perseus. Celestron C11 with Canon EOS 10D digital camera and focal reducer f/3.3, exposure time 30 seconds at 800 ISO. | ||
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M45, the Pleiades in Taurus. Canon EOS 10D digital camera. To the left: exposure time 42 seconds, ISO 1600, telelens at afocal length of 200mm. To the right: exposure time 16 seconds, ISO 1600, telelens at afocal length of 102mm. | ||
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M11, the Wild Duck galactic star cluster. Celestron C11 with Canon EOS 10D digital camera and focal reducer f/6.3. | ||
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Globular cluster M13 in Hercules. C11, focal reducer f/3.3, Canon EOS 10D digital camera. | ||||
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M31, the Andromeda Galaxy. Its satellites M32 and M110 are also visible. C11, focal reducer f/3.3, Canon EOS 10D digital camera. | ||
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Our Milky Way. High clouds and orange street lights in the distance disturb the view of our galaxy when long exposure times are used. | ||
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NGC 6826, the "Blinking Planetary" in Cygnus, is a planetary nebula. Magnitude: +10. | ||
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NGC 7009, the Saturn Nebula in Aquarius. Composition of 15 images with a C11, focal reducer f/6.3 and the Canon EOS 10D digital camera. Images combined with K3CCDTools and further processed with Paint Shop Pro. Exposure times of the original images: 24 seconds at ISO 800. Although this is a composition image, the original images themselves were almost as good as this image, without processing. This camera is great for bright planetary nebulae. | ||
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Planetary nebula NGC 7662 in Andromeda. An excellent target for the Canon EOS 10D! Distance: between 1.800 and 5.600 light years. | ||
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NGC 6960, the Veil nebula, with a Celestron C11, Canon EOS 10D digital camera and focal reducer f/6.3. To the left is the unprocessed, raw image, at one third of its orininal size. In the middle is the same image, slightly enhanced in contrast. To the right: composition of 3 images, further heavely processed but at its original size this time. The whole scene is a small part of the original image (about 25%). | ||
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Drunk astronaut with crazy
satellite captured! He really should quit drinking or they will
shoot him down... Most satellites only show slight variations in brightness as they spin but follow a straight line. This one is probably a large rocket stage that is still tumbling through space. |
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A magn. -6 Iridium flare in the constellation of Hercules on June 8, 2005. The Iridium 75 satellite was launched on May 17, 1998 from Vandenberg Air Force Base in California. Orbit: 776 x 779 km. | ||
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These bright streakes in the sky are Iridium flares. Sunlight reflects from their solar panels. They can even get as bright as magnitude -9! Very impressive. Check out the Heavens Above website. Images with Olympus C-4000 ZOOM and Canon EOS 10D. | ||
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Iridium 35 on May 10, 2005: an impressive Iridium flare of magnitude -8! Very bright flares like this one can be seen in daylight. I took this image in early twilight. Very nice to watch! | ||
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On www.heavens-above.com you can find out when, how and where the International Space Station is visible, for your location on Earth. This example shows its predicted orbit and the image shows it was correct in all details. When the Sun is far beneath the horizon, you can see satellites suddenly dissappear in a few seconds as they enter Earth's shadow. The images were taken on May 8, 2005. | ||
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Sun images. These nice light phenomena can be seen when Sunlight is scattered by water droplets, ice cristals or dust particles. |
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Moon images. These nice light phenomena can be seen when Moonlight is scattered by water droplets, ice cristals or dust particles. |
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On a nice summer day in May 2005, this bright and beautiful corona was visible. The original image is on the left. The right image is the same but enhanced in contrast to show all of its details and colours. | |
| Bad weather doesn't mean you can't take nice pictures. Look for thunderstorms and try to catch the beauty of lightning. Such images can be pretty impressive (as long as you don't get hit on the head...). | |||||
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