Monday, November 9, 2009

Red Giant become a video star

Below is a video showing the planets and a few stars to scale. One of the last stars in the video is Herschel's Garnet Star mentioned in the post below. The star is also known as Mu Cephei. Mu Cephei is so huge that if the Sun were to exchange places with it, the Earth would be inside the star. This red supergiant would also swallow up Mars and Jupiter and almost reach out to the orbit of Saturn.


Red Giant meets Red Nebula


Click on each image for a large view
IC1396 is cataloged as a star cluster embedded in a nebula. Right in the middle of the nebula, the star cluster is easy to see in binoculars, but in this long exposure photograph it is overpowered by the nebula. This is a very large nebula, about 2.5 degrees across (5 full moons would span across it), but it is very far way (2,450 light-years) and very hard to see visually.
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The bright star at the top is one of the largest known red supergiants in the Milky Way. William Herschel described it as "a very fine deep garnet color" and is therefore commonly know as "Herschel's Garnet Star". So why is it yellow and not red in the picture? The main reason is that in long exposure images bright stars tend to get overexposed and loose their color. In this case yellow was the result. Astronomers who view this star through large telescoes see it more orange that red.
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The bottom image was a very nice surprise! I wanted to create an image with legends pointing to the various known objects in the nebula, so I turned into in a black-and-white image. When I did this I tried using a red filter. The result was a much brighter nebula that constrasted nicely with all the dark dusty regions (5 of them are Barnard Dark Nebulae). On the right side is a dark globule known as the "Elephant's Trunk" and vdB142.
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Technical Photo Info
Camera: Q453 CCD
Lens: 300mm f/4 L IS
Apeture Setting: f/4
Exposures: 9 X 10 minutes (90 minutes)
Darks: 2 darks to create dark pixel map
Flats: 0
Biases: 20
Mount: Celestron CGE
Guide Camera: CCD-Labe Q-Guider
Guidescope: 400mm Tasco refractor
Calibrated, Aligned and Stacked in Nebulosity
Final processing in Photoshop

Tuesday, November 3, 2009

Not So Clear Sky Imaging

Click on image for a larger view
What to do, what to do? My imaging equipment is all set up for the night, but here comes the clouds. High cirrus are sailing across what was a clear and cloudless sky while I was setting up. I really want to try out my new lens on the sky, so I decide to try a few shots anyway. I take six shots, ten minutes each. By the time the last exposure is done, the sky is pretty well covered with clouds. As they come into my laptop I see that each image has halos around each star, with the last image having the largest halos. As I shut down the computer, I'm thinking that will be the last see of those pictures.
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That was two months ago. Today I saw an image by Rogelio Bernal Andreo on the Astronomy Picture of the Day website that had practically the same framing and image scale of what I took that night. My my, what a picture it is. Here is the link to his picture: http://tinyurl.com/yj3txu2 After seeing this I decided to process my images to see what I had (a single image doesn't show much, only when they are aligned, combined and processed does the detail come out). My picture doesn't go as deep as Mr. Adnreo, for a lot of reasons, but I am happy the way it came out. The glow around the stars give the picture a mystical quality, and the Califonia Nebula and the Plieades Star Cluster still show through. The dusty dark nebulae throughout this part of the sky is also evident. The dark nebulae are labeled in the second image above, but as you can see, they are actually spread all over the area.
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Technical Photo Info
Camera: Q454 CCD
Lens: Canon 70-200mm f/2.8 L IS
Focal Length Setting: 70mm
Apeture Setting: f/4
Exposures: 6 X 10 minutes
Darks: 2 darks to create a dark pixel map
Flats: 0
Biases: 0
Mount: Celestron CGE
Guide Camera: CCD-Labs Q-Guider
Guidscope: 400mm Tasco refractor
Calibrated, Aligned and Stacked in Nebulosity
Final processing in Photoshop