UPSIDE-DOWN?

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Denise
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Joined: Fri Aug 04, 2006 8:04 pm
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UPSIDE-DOWN?

Post by Denise »

This is the second time I've spent an hour or two star-dusting. The first time (after doing the training session) I was fairly happy that I knew what I was doing. I got one calibration image wrong and decided that was the stars' way of telling me to go to bed. Tonight I've probably been through another 30-40 (missed another calibration unexpectedly early) but towards the end I became sure that I had seen 2, maybe 3 "upside-down" images - at least one of which I'm sure was a calbration image (they tend to have a "shoreline", it seems to me at this early stage). I logged them as "bad focus" - and in fact have started to log bad focus when the focus only seems to come in right at the top of the range. On the assumption that if surface focus only starts there, there's not much chance for sightings below the surface. Am I right to do this? Also, is it possible for some images to be upside-down (whether accidentally or on purpose)?
Thanks, Denise :)
anyone got the key?
icebike

Re: UPSIDE-DOWN?

Post by icebike »

Denise wrote: I logged them as "bad focus" - and in fact have started to log bad focus when the focus only seems to come in right at the top of the range. On the assumption that if surface focus only starts there, there's not much chance for sightings below the surface. Am I right to do this?
I think you got it backwards....

If the surface comes into focus only when the mouse is over the TOP of the focus bar, its a perfectly good movie. You get an added bonus of being able to peek deeper than usual into the areogel with such a movie.

If the surface comes into focus with the mouse at the bottom of the focus bar, you can't see anything IN the aerogel, and that is a bad focus movie.

Once you find the point where the surface is in focus, there is no point in searching higher (upward on the focus bar). You should concentrate your efforts below the surface (downware on the focus bar.
icebike

Re: UPSIDE-DOWN?

Post by icebike »

Denise wrote: Also, is it possible for some images to be upside-down (whether accidentally or on purpose)?
Thanks, Denise :)
Do you mean having the frames stacked in the wrong order or do you mean the image is flipped so that north is south?

As to the later, (flipped), it doesn't matter, because you are looking straight down onto and INTO a chunk of aerogel. Does not matter if you walk around the other side and peer into the gel.

If you are suggesting image stacked in reverse order, I don't think so. There are many optical illusions due to lighting of these microscopic images.
fjgiie
DustMod
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Location: Hampton, SC, US

Circular tracks

Post by fjgiie »

Hi Denise,

Please go to the tutorial and look at:

Page 0. Read the bottom of this page about size of tracks.
Page 1. Here use the VM and see a circular track.

Page 11. We do not know what these tracks look like for sure. On this page use the VM and see the best picture of what the Stardust Team thinks an interstellar dust track looks like.

I would not worry about a track being upside down. They should be roughly circular or oval shaped. When a grain or speck of aerogel goes out of focus it will appear to get larger. Tracks will stay in focus under the surface of the aerogel for the most part, just like you see in the tutorial.

Thanks,

fjgiie
Denise
Posts: 26
Joined: Fri Aug 04, 2006 8:04 pm
Location: London
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Post by Denise »

Well, thank you Ice - but I have to admit I'm now confused... When I did the test, I'm sure I did it the way I'm doing it now, starting from the bottom of the grid and gradually moving up. I scored 100% on the test. Now I've dropped 3 out of about 36 calibrations, but my "upside-down" comment fits in with what you've just said... But it doesn't make sense - I've been perfectly happy watching things come into focus and go out of focus, looking for the strange one which then starts to sharpen. And my calibration score would tend to reinforce this...
But I have been working far too many hours these last ten days or so since I star-dusted for the first time, so perhaps it's me that's upside-down...
anyone got the key?
Denise
Posts: 26
Joined: Fri Aug 04, 2006 8:04 pm
Location: London
Contact:

Post by Denise »

:? Yes, yes, yes. It is me that's upside-down. I've just gone back to the tutorial. Apologies and thanks. Well, we all have to be stupid some of the time... (don't we?)...
anyone got the key?
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