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ISS and Capella photo op planning

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#26 Mike Phillips

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Posted 30 November 2012 - 09:21 AM

Great 1st try Tim!!! Glad you got something.

Mike

#27 tjensen

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Posted 30 November 2012 - 09:57 AM

Thanks guys.

Actually, other than the focus going off (not sure how that happened) I'm rather pleased with this as a first attempt. I learned quite a bit. The exposure time wasn't bad, so I have a handle on that now.

I'll double check collimation, and make sure to lock the mirror down tonight in the hopes that tomorrow morning will cooperate... though it isn't looking promising right now.

Thanks to everyone that contributed their technical and emotional assistance. It was a fun little adventure and definitely worth another try.

Cheers
Tim

#28 FoxK

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Posted 30 November 2012 - 12:19 PM

Tim..don't give up yet........reload that series of frames in registax....checkmark the frames you want included (make sure the box for "Frame List" is checked) and try, instead of manual alignment, use the option for "align using Centre of gravity".other options you want checked are "track object" and "predict track"

I'm not convinced its even out of focus...bad stacking will result in an effect that can mimic bad focus. Perhaps you can load your video into registax and go through the frames and make an image of the best single frame. It appears to me that your image is just stacked poorly.....I believe I can see the radiators which tend to often be the brightest parts, and they appear pretty focused but multiple images of it (as expected by a bad stack)

Also, do yourself a favor....write down the brightness of that overflight and write down what you used here as far as shutter speed, and gain so you have a frame of reference for next time. We can get a better idea for adjustment after looking at the single best frame if possible....also....If I stop responding, I am leaving to go crab fishing in Alaska on Saturday so will be unable to help any further so hopefully we can get some results tonight.I will check later.


#29 tjensen

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Posted 30 November 2012 - 01:03 PM

Hey Fox,

Thanks for the encouragement. Alas, I do think it is a focus issue... mixed with the thin fog I was shooting thru. I ran the avi thru VirtualDub and selected the frames that contained the ISS. It was out of focus in each frame. But maybe close? Anyway, the longest stretch I got was 16 frames, I ran that thru Castrator and then stacked with AS!2.

I have the record log from FireCapture so I know the camera settings. I don't plan to give up just yet. Not sure what I want to try differently for the next go (tomorrow morning at 5:34). I've never tried the satellite tracking feature of the LX200GPS. Don't know how well that works. I had the scope equitorially mounted. I might change that to alt az. I'm going to stay with the Flea3+0.5X FR for now for the high sensitivity and fast frame rates. As posted above, my other option is the T2i, but I think the transfer rate is too slow.

I have another window on Sunday morning and possibly another short one on Monday. Other passes are below the treeline. I won't get another chance 'til 12/10.

Enjoy your fishing trip north. One of my dreams is to take a kayak out on Great Slave Lake in the NWT for a couple of weeks.

#30 FoxK

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Posted 30 November 2012 - 03:24 PM

Thanks Tim.....good luck....In a few more tries, it'll be easy for you to capture once you get into the groove. Just some info...............because of its orbital trajectory, you should expect the ISS to alternate between overflights in early evening and then it switches over to many passes in the early morning. Besides exposure.....you see how critical focus is....best bet is to do one more focus on a star 10 minutes before the overflight.....changing temperatures in a scope can really change the focus over time...I have a lil set screw I can use to lock the focus but just the pressure it puts on the foccus tube knocks the focus out enough to be useless so I do the 10 minutes before method and be VERY CAREFUL not to touch anything in the focal train. One more thing to watch for is sometimes with the cam etc attached, and the scope pointing near up at the ISS's brightest...the weight can pull the focus tube enough to ruin the shot......be aware.......ok.....that's all the advice I have lol........i'm sure you'll get it next try or the next.

Fox

#31 tjensen

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Posted 30 November 2012 - 04:00 PM

Thanks Fox. I'm hoping the weather will cooperate for tomorrow. Fingers crossed. I think I messed up the focus when I started to manually slew... I bumped the camera.
Live and learn.
T

#32 zAmbonii

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Posted 30 November 2012 - 04:26 PM

You might not have been out of focus. When manually tracking You need a pretty high shutter speed so it doesn't smear. Also the ISS is going to change orientation and size as it moves across the sky and that is going to affect a final stack if there was a bit of time between the images you caught on chip.

What do your single frames look like?

#33 Jim Chung

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Posted 30 November 2012 - 07:05 PM

It looks like too slow a shutter speed to me as well and not a focus problem.

#34 tjensen

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Posted 30 November 2012 - 07:41 PM

I know the orientation changes... the stack was of 18 consecutive frames.

Could be a slow shutter speed... capture log indicates 116 fps with a shutter speed of 0.7ms (1/1428) I have no idea what others use.

Here is a composite of 6 of the 18 images that went into the stack.

So I'm curious... what techniques work?

Attached Files








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