Jupiter rises late in the evening.
Processing a captured AVI movie from a camera like a canon EOS attached to the C14 is rather easy. We just load up Registax 6 which is free software with the AVI movie and toy with the adjustments a bit. It's a little more work than I'll mention here, but the computer does most of the work.
The real challenge is not learning how to use Registax, it's getting a good photo or movie to begin with. The c14 is a great telescope and the observatory can provide great images. When objects are low and near the horizon the light must pass through perhaps as much as 100 miles of atmosphere. There is a lot of particles and humidity often in the sky and that causes distortion in the images you gather.
The top photo below was captured late last month, 9-26. It was captured using backyard EOS and a 2 x Barlow. A 5x digital crop of the sensor data zoomed in the image further giving us 1250x for the image. That is a tremendous amount of magnification and most times this image will break down from something like the c14 at that kind of power. That kind of power is usually not usable because the seeing and transparency isn't good enough. But the morning I took this Jupiter was high in the sky and conditions were good. So the too image was taken around 6am in the morning. Jupiter doesn't show as much detail as I'd like it to show, but for a one shot camera and our setup, it's pretty good.
The second image is Jupiter with 5x the normal focal length of 625x when we have the canon EOS t1i attached to the f11 c14. Native power is 125x with a t mounted 3/4 inch sensor. 3911 divided by 50 times 1.6 gives us the effective power. When I multiply this by five, The 5x digital magnification setting in backyard EOS software that I used, we get 625 power.
So the second photo is half the power of the first. And the image maybe slightly zoomed a bit with processing. The states powers are close to the actual power we see with a normal 100 image display.
Why does the second image look much worse, than the first?
Te second image looks worse because Jupiter was photographed at about 2am in the second photo. Jupiter was much lower in the east and still rising. It was only 18 or so degrees above the horizon. There was more dew and humidity in the air. I was also looking through half the shutter and half of the telescope was aimed at the wall. Jupiter hadn't risen far enough to be fully visible in the shutter, but I tried to get the photo anyway. I was hoping to get an image of the triple shadow transit last week with the second photo, but the shadows of three moons of Jupiter were moving across the face of the planet when it was only 3 degrees above the horizon as the event started.
I could not see the shadows on the planet with a different telescope outside aiming low at the planet. The air was unsteady and Jupiter was fuzzy in the telescope. By the time Jupiter was hi enough to get a capture with the C14 one of the shadows of one of it's moons was already off the face of the planet.
A triple shadow transit only happens a couple of times a decade, so they are rare. I was hoping to get a photo of this or see it visually. If I was in Europe under clear skies I probably could have seen the event. But it was over and Jupiter was to low for our area.
This shows the most important thing in getting a good astrophotograph. You have to have an object high above the horizon and get those images when the object is 30 degrees or higher in the sky. Lower targets can be seen and photographed, but they won't look as good.
Later in the year near December Jupiter will be high in the sky near opposition at midnight. We will get the best views and photos of it at that time, around midnight, when it's highest in the sky, and closer to earth.
- Posted using BlogPress from my iPad
No comments:
Post a Comment