Satellite Passes - Any tips?

[Chrissyo]

After capturing the ISS with my telescope (see here (http://www.iceinspace.com.au/forum/showthread.php?t=21834)), I've been practising for the next pass on some random satellites. I've been having fun with it too! It's nice and fast paced - its all about the chase. Good fun!:)

My criteria has been "they must have a high altitude, and their closest approach must be around 500-700km or so". So nothing too serious. I've added my results from the two passes below. I'm not sure if I got any specific details on either of them (but I wasn't really trying for detail on any of them as such, I was just practising hand tracking/capturing the objects on film. I don't even know if they were even big enough and/or close enough for details to be resolved?). The first one (TRMM) is fairly blurry all over, but it looks like there might be segments in some of the shots? Its pretty hard to tell though (and it doesn't really look anything like the satellite it should). The second one (Okean O Rocket) came out a bit better - I was able to capture a few frames of it 'stationary' (in respect to the movement of the camera). It looks like there is a protruding part that seems consistent in separate frames, but once again I can't really tell (and it's supposed to be a rocket body, what protruding part could there be?). Anyway, have a good laugh at my results. I could almost pass them off as squished bugs? :P

Anyway, I've had some annoying problems so I thought I might ask before the next ISS pass.

First problem (the second image) - it seems very difficult to capture a single non-trailed image. Most of the frames are blurred longways (kind of like star trails). Using my dob mount for tracking I don't think this will get any better because my video camera doesn't seem to have anyway to increase FPS rate. Does anyone have any ideas on how I could improve this?

Second problem (the third image) - Again, I'm not sure if I'll actually be able to fix this but when I transfer the AVI from my camera to my computer and use VirtualDub to split all the frames up, they are all half ghosted and interlaced. I suspect this is also partly due to the first problem I have. Does anyone know of any program that might be better for capturing video from a video camera to a computer? Or something that might just fix it in some way? :P

And just otherwise, has anyone attempted anything similar before? Any general tips you can give me? I think I've got to experiment with exposure values a bit (I was MUCH happier with the exposure of the Okean O rocket, it was set a fair bit lower than the other objects). Does anyone have any hints for this?

Also, does anyone know of any good websites (apart from Heavens Above) for information on satellites, rocket bodies, etc? Specifically a site that will give the size of the actual object and/or a picture or diagram of the actual object?

Thanks in advance! :D

[joe_smith]

to fix the "half ghosted and interlaced" problem you can use the Virtualdub filter "Deinterlace" then save it to a new avi then split in frames will fix the interlace problems if thats what they are.

[iceman]

Hi Chris, those are excellent.

Unless you can capture a shorter exposure (regardless of frame rate), the speed the object moves is always going to result in some blurring I guess.

Do you know what the exposure time is? 1/30s? What's the frame rate?

[Chrissyo]

I actually tried that - it didn't seem to work. I only tried one of the deinterlace types though (the one that said like "blend both fields - recommended") so I might have a better play around with it.



I can lower the exposure, though I think it might just be a digital effect. The camera defaults at 1/50 and goes into the thousands (ie. 1/2000). The second satellite I captured had the lowest exposure setting (at about 1/125 I think), so I suppose that might be the reason why it did seem to have better frames?

I'm not really sure of the frame rate of the camera... I just always assumed it was 30 fps. Regardless, it seems VirtualDub only wants to capture video at about 8-10fps - which could be the problem with a lot of the 'two ghosted images on one frame' issues (ie. the computer is trying to shove more frames into the slot for only one frame). I'm not sure if this is just a computer limitation (as in, whether my computer doesn't have enough CPU or whatever to transfer the file at full capacity).

I think my biggest fix to the long blurring images will be to just get out more often and practise hand tracking the satellites. The more smooth my motion the more stationary (relative to the camera movement) frames I'll be able to capture.