"I think I've found a track, what do you think?"

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caprarom
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Re: "I think I've found a track, what do you think?"

Post by caprarom »

Well, Klemek, assuming I'm looking at the correct spot, that looks more to me like two unrelated inclusions. However, take a gander at the vertical feature running from about 80/0 down to about 80/35. It's at the very end of the focal range, unfortunately, but looks interesting.

Mike C.
DanZ
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Re: "I think I've found a track, what do you think?"

Post by DanZ »

fjgiie wrote:Is that a midnight track at 100, 375?
Since it came up fjgiie, here's the view from below 7974893V1: 9012914V1

Dan
jsmaje
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Re: "I think I've found a track, what do you think?"

Post by jsmaje »

Thanks Dan for your efforts in obtaining the adjacent/overlapping movies to mine and fjgiie’s, which indeed leave no doubt as to their fiducial nature. It makes all the difference to feeling positive about participation in the project when one is treated as an intelligent and interested observer rather than simply a coordinate-producing drone!

In which regard, I (and Elaine Keefe, who’s also had a go) have had trouble matching up the movies you imply are immediately adjacent to the right & below-right of 6263991V1(9992091V1 & 2462846V1), which contain another fiducial track.

If nevertheless actually adjacent, how come two fiducials would/could be placed a mere ~500 microns apart? I suspect rather than adjacent, you may have meant nearby? In which case, just how nearby?
To my knowledge we’ve not been allowed knowledge of the strategy of fiducial placement – correct me if I’ve missed something somewhere.

If I may say so, these pesky needle-pokes cause not only confusion for dusters, but also a hell-of-a-mess of the aerogel! Let’s hope none obscure genuine tracks. Do the team have any concerns in that respect?
I understand why they were considered necessary for determining the orientation of extracted tile sections and hence any embedded tracks, but were no subtler ways possible and considered?

Only asking!
John
DanZ
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Re: "I think I've found a track, what do you think?"

Post by DanZ »

jsmaje wrote:Thanks Dan for your efforts in obtaining the adjacent/overlapping movies to mine and fjgiie’s, which indeed leave no doubt as to their fiducial nature. It makes all the difference to feeling positive about participation in the project when one is treated as an intelligent and interested observer rather than simply a coordinate-producing drone!

We try! :wink:

In which regard, I (and Elaine Keefe, who’s also had a go) have had trouble matching up the movies you imply are immediately adjacent to the right & below-right of 6263991V1(9992091V1 & 2462846V1), which contain another fiducial track.

I agree I don't see obvious overlap, but they certainly look like the same general area to me (similar surface features, etc.). I imagine that there might be a bit of edge that is missing, or perhaps there simply aren't any obvious features that are shared between them

If nevertheless actually adjacent, how come two fiducials would/could be placed a mere ~500 microns apart? I suspect rather than adjacent, you may have meant nearby? In which case, just how nearby?
To my knowledge we’ve not been allowed knowledge of the strategy of fiducial placement – correct me if I’ve missed something somewhere.

I was under the impression that each tile received one needle poke, but let me find out if I misunderstood and get back to you.

If I may say so, these pesky needle-pokes cause not only confusion for dusters, but also a hell-of-a-mess of the aerogel! Let’s hope none obscure genuine tracks. Do the team have any concerns in that respect?

That was one of my first questions as well! But I was told that the risk was so mathematically small, that it was deemed acceptable.

I understand why they were considered necessary for determining the orientation of extracted tile sections and hence any embedded tracks, but were no subtler ways possible and considered?

The whole extraction business was the result of an environmental malfunction at the storage/examination facility in Houston. I think, therefore, they wanted to extract as soon as possible (which allows for better controlled storage), and the fiducial (once deemed safe enough) was the quickest way to go.

Only asking!
John
DanZ
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Re: "I think I've found a track, what do you think?"

Post by DanZ »

I wrote:
I was under the impression that each tile received one needle poke, but let me find out if I misunderstood and get back to you.
Turns out I was completely wrong on that. In the early days, fiducials went in as "triplets" - up to 15 of them per tile (thus a possible 45 needle pokes total). And the distance between some of these was on the order of a couple hundred microns, so yes, they can be very close. Now, however, they are using less and each extracted tile is only getting either 6 or 15 needle pokes (Dr. Westphal wasn't exactly sure at the time I asked).

But also, I had originally gotten the impression that these fiducials were mostly about marking the original orientation of the tile before it was removed. Turns out I somewhat misunderstood that too, and what they are really telling the scientists is what is happening to the aerogel when it is removed - i.e., the amount of distortion. This is because the tiles were originally packed in the collector array under significant pressure on all sides. Keeping the pressure on the tiles the same as it was before during removal is the goal, but there is bound to be some change, and the fiducials help identify where that may have happened.

I hope that clarifies things a bit. Just realize there are lots of these, and you will know doubt continue to encounter them on a fairly regular basis.

Dan
jsmaje
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Re: "I think I've found a track, what do you think?"

Post by jsmaje »

Thanks for that Dan.
Your helpful and detailed responses to my queries in fact served to resurrect a lost memory of all this business actually having been explained over a year ago by Andrew Westphal, here:

http://stardustathome.ssl.berkeley.edu/ ... 30c#p17647

I’m sure the team must despair when we forget what has been previously explained!
Sorry, but forgetting seems to be my latest hobby.
At least I, you, and hopefully others are that little bit wiser.
And apologies to the team if I have wasted any of their time.

John
DanZ
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Re: "I think I've found a track, what do you think?"

Post by DanZ »

Wow, even I forgot about that! No worries, but I should use this forum's search function (which isn't half bad) a little more myself before I pass on some of these questions.

Oh well, thanks for the concern John, it's appreciated.

Dan
fjgiie
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Re: "I think I've found a track, what do you think?"

Post by fjgiie »

  


          Two tracks in one movie!

(sortalike tracks)
caprarom
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Re: "I think I've found a track, what do you think?"

Post by caprarom »

Wow! Is that fiducially responsible!? (Sorry, had to say it.) I think you must merit some kind of special award for that, fjgiie.

Mike C.
jsmaje
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Re: "I think I've found a track, what do you think?"

Post by jsmaje »

Fjgiie & caprarom, how nice to see at least a larger part of the triplets of what have variously been termed "witness tracks", "needle-pokes" and (officially) "fiducials".

They are described here as being 'configured in an "L", 500 microns apart, and they are each 200 microns deep. There are 15 triplets in a 3 by 5 array on the aerogel tile surface.'

Presumably the two in that movie serve to indicate the north/south axis, though seemingly less than 500 microns apart?? I guess the third would be positioned at right-angles to one or the other to indicate the east/west axis.

It would be fun to see the surrounding movies to get a complete picture of an "L".
And I wonder if it may be possible - geometrically, and given the scanning regime - to see evidence of all three triplet tracks in a single movie?

John
propriome
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Re: "I think I've found a track, what do you think?"

Post by propriome »

I'm not the one who found it (8th on 24 viewers to report it), but i'd like to know what do you think about this one: 432212V1
fjgiie
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Re: "I think I've found a track, what do you think?"

Post by fjgiie »

propriome wrote:I'm not the one who found it (8th on 24 viewers to report it), but i'd like to know what do you think about this one: 432212V1
That is the bottom part of the "L".

  I
  I   _

I rated it a 10 and my comment was:     fiducial.
Berkeley rated it the same with comment:    fiducial, confirm

So, it is a needle mark.
jsmaje
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Re: "I think I've found a track, what do you think?"

Post by jsmaje »

fjgiie wrote:That is the bottom part of the "L".
Fjgiie - it would be nice to think that propriome's track completes the third part of the local L-shaped jigsaw along with your previous two verticals, though it could of course have come from another part of the tile.

At least I now have a mind-picture of the scale, orientation and appearance of these fiducial L's.
John
fjgiie
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Re: "I think I've found a track, what do you think?"

Post by fjgiie »

 

    Find the big old track!

    You think?

 
nitram819
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Re: "I think I've found a track, what do you think?"

Post by nitram819 »

Yep, nice long 4:00 track.
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