Bob B.
Bob the Excel Guru?
Posts: 3,072
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Post by Bob B. on Aug 28, 2008 20:45:13 GMT -4
Due to requests made in another thread, I’ve plotted a circumlunar trajectory showing spacecraft position at regular time intervals. Below is the link: Circumlunar Free Return TrajectoryI’m very pleased with the results of the simulation. I was able to find an aim point that returned the spacecraft to Earth with the optimum entry angle needed for a survivable reentry. I particularly like the spacecraft-moon encounter and how the spacecraft loops around the backside of the Moon. I might plot a second set of illustrations zooming in on this area and using a shorter time increment. Anyone know how to and is willing to make an animated GIF out of this? If so, I can probably provide more illustrations to make a smoother looking animation.
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Post by LunarOrbit on Aug 29, 2008 0:02:18 GMT -4
Anyone know how to and is willing to make an animated GIF out of this? Here you go
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Post by lennison on Aug 29, 2008 0:07:29 GMT -4
Anyone know how to and is willing to make an animated GIF out of this? Here you go Lunar Orbit, that is great! May I ask what software you use to produce these, and whether it takes a lot of effort to learn?
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Bob B.
Bob the Excel Guru?
Posts: 3,072
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Post by Bob B. on Aug 29, 2008 0:14:59 GMT -4
Great, thank you! Ditto what lennison said; how'd you do that?
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Post by LunarOrbit on Aug 29, 2008 1:07:06 GMT -4
I'm glad you like it. I used Macromedia (now Adobe I guess) Fireworks. It's not that hard to figure out, I learned it on my own. I just had to import each of Bob's images (the hard part was done for me) as separate frames, adjust the delay between changes, and then export it as a GIF. I also added the elapsed time info.
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Post by Ginnie on Aug 29, 2008 1:17:50 GMT -4
I'm glad you like it. I used Macromedia (now Adobe I guess) Fireworks. It's not that hard to figure out, I learned it on my own. I just had to import each of Bob's images (the hard part was done for me) as separate frames, adjust the delay between changes, and then export it as a GIF. I also added the elapsed time info. ha ha. Seems we both were busy! I made one too, on the John Lear thread I thought I would do one quick without a lot of detail... Used gimp. I thought I might work on another one for fun, with a space background, a realistic earth and moon, but it would take awhile because I want to have the spacecraft fly in a smooth flight path.
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Post by LunarOrbit on Aug 29, 2008 1:39:22 GMT -4
I never thought of trying Gimp, forgot it had animation capabilities. It's a good free option, but it did require a bit of research to figure out how to change the delay between frames.
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Al Johnston
"Cheer up!" they said, "It could be worse!" So I did, and it was.
Posts: 1,453
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Post by Al Johnston on Aug 29, 2008 6:32:33 GMT -4
It's fascinating to get such a visceral impression of how far ahead of the Moon they had to aim and how briefly the two bodies were in proximity.
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Post by Ginnie on Aug 29, 2008 8:37:19 GMT -4
I never thought of trying Gimp, forgot it had animation capabilities. It's a good free option, but it did require a bit of research to figure out how to change the delay between frames.
I didn't use it by choice. I need something easier for LInux.
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Bob B.
Bob the Excel Guru?
Posts: 3,072
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Post by Bob B. on Aug 29, 2008 9:43:18 GMT -4
I think I've just discovered that Photoshop has the ability to make animated GIFs, though I'm having trouble figuring it out how to create the layers. I'm at work now so I can't waste anymore time on it. Hopefully I'll figure it out tonight. If so, I'm going to try to come up with a smoother animation using more images.
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Post by Ginnie on Aug 29, 2008 12:08:00 GMT -4
Bob, I have what may be a silly question. The Earth would have moved around the Sun during the trip, right? So I would imagine that seeing that trajectory that you did - it displays it in relation to where the Earth is? What I mean is that seeing that the Earth would have covered a few degrees of its orbit around the Sun - then in real space the trajectory's path would look different? So what I'm saying is that to properly display it, you would also have the Earth moving along the orbital path instead of being static? Why I'm mentioning this is that I might take on a pet project of animating the trajectory in a more realistic manner with the Earth moving (and spinning perhaps). I know it wouldn't be as informative - just prettier.
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Post by JayUtah on Aug 29, 2008 12:30:27 GMT -4
I use both Gimp (or properly, "the Gimp") and Adobe Photoshop as the requirements dictate, but not yet for any aspect of my life that requires orbital mechanics. That's an excellent animation and an excellent illustration of what some people find to be a difficult concept to grasp. I know from reading my posts it doesn't sound like I think a picture is worth a thousand words, but I really love this illustration.
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Post by Ginnie on Aug 29, 2008 12:51:00 GMT -4
I'm thinking of something like this: Now, this is a very crude representation of what I'm thinking of. ...and I'd have to figure out the actual distance the earth would travel on its orbit (a little over one degree a day?). But I just using this to show what I'm talking about. 92 955 807 (distance from sun) X 3.141 = 291,974,189.787 miles divided by 365 days = 799,929 miles per day (approx) Whoah, that seems like a lot! I'd need a huge canvas to plot that! EDIT: Oops, forgot the moon.
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Post by Ginnie on Aug 29, 2008 12:54:40 GMT -4
I use both Gimp (or properly, "the Gimp") and Adobe Photoshop as the requirements dictate, but not yet for any aspect of my life that requires orbital mechanics. That's an excellent animation and an excellent illustration of what some people find to be a difficult concept to grasp. I know from reading my posts it doesn't sound like I think a picture is worth a thousand words, but I really love this illustration. I'm finding OpenOfficeDraw very helpful in doing animated gifs, because I can make objects, move them around and they aren't "painted" down. I can use a combo of image files plus vector graphics. When I have it the way I like it, I can group what I want, and export it to become one frame of my animation.
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Post by dmundt on Aug 29, 2008 12:56:45 GMT -4
I see what you are saying, Ginnie. That would be a very different looking path. Is it necessary, though? Doesn't the orbit have to take into account one fixed position -- and in this case it is the Earth? I'm sure someone here knows.
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