space station picture #1148683

some members wanted to know how I took picture #1148683 shown here
Here is the recipe. First, I took these three separate pictures of the same passage of the space station in the sky. Each picture is a 30 sec. exposure time at f/3.5 at 400 ISO with a 18mm lens. And you use manual focus, of course. The line in the last one is short because the station disappeared before the end of the exposure. The space station looks like a bright star in the sky and the line show its movement in the sky during the exposure. This is the same effect you have when you photograph cars at night on a road. The camera was on a tripod and I moved it to the right after each picture.
I used the software Microsoft ICE (Image Composite Editor) which can be downloaded free to do one panorama picture with the three ones. You can use any panorama software too. You have the result here.
As you can see, there are three separate lines in the sky. This is because I have to wait between each picture that it is processed in the camera and I can not take pictures during that time. To show the complete trajectory in the sky, I used Photoshop. First I tried with the "patch" tool and the "clone stamp" tool but I was not satisfied. What I did finally was to use the "lasso" tool to take the line on one of the original pictures and put it on the panorama with edit-copy-paste. After that, I used the "move" tool to place the line at the right place. When it is done, you go to layer-flatten image.I corrected the imperfections with the other tools. And you have the final picture.
To know when you can see the space station in your sky, you go to http://www.heavens-above.com and you will find the information. If they don't have your town, select the closest big town. You can also try with Calsky.com, but I prefer the first one.
To do that picture, it is better when the space station is at a maximum of about 30 degrees high and on an almost horizontal trajectory. You can also picture it when it goes very high in the sky but you will have only one short exposure picture. The exposure time can be between 5 sec. to 2 minutes. A short exposure is better if there are many lights in your area. If yo uhave a very dark sky, you can try a longer exposure time.