Author Topic: Image Reveresed/Flipped between Gzoo and SDSS  (Read 2969 times)

Bubba Ho tep

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Image Reveresed/Flipped between Gzoo and SDSS
« on: May 14, 2013, 06:28:27 pm »
Hi ,
Ive tried to find the answer elsewhere on here so apologies in advance if it has already been covered. When looking at this image

Gzoo image http://talk.galaxyzoo.org/objects/AGZ0005m96

I wanted to look into it further using SDSS and got this image

[urlhttp://skyserver.sdss3.org/dr8/en/tools/chart/chart.asp?ra=24.27121604&dec=25.51542368][/url]

The image of the same object is flipped, Im sure there must be a good reason, I was just wondering if anyone could tell why ?

thx

NGC3314

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Re: Image Reveresed/Flipped between Gzoo and SDSS
« Reply #1 on: May 15, 2013, 06:42:54 pm »
Early in GZ Classic, the relative numbers of CW and ACW spirals showed a statistical difference, which would be hugely important if real. As a powerful test for where this came from, the Zoo started to serve up a subsample of galaxy images flipped or rotated (which demonstrated that at least most of the difference is in our brains rather than the sky). This did cause some consternation because there was no way to get the word out to all Zooites about this. (I wasn't actually aware that they were still being served in flipped versions, come to think of it).

ElisabethB

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Re: Image Reveresed/Flipped between Gzoo and SDSS
« Reply #2 on: May 15, 2013, 07:25:54 pm »
Early in GZ Classic, the relative numbers of CW and ACW spirals showed a statistical difference, which would be hugely important if real. As a powerful test for where this came from, the Zoo started to serve up a subsample of galaxy images flipped or rotated (which demonstrated that at least most of the difference is in our brains rather than the sky). This did cause some consternation because there was no way to get the word out to all Zooites about this. (I wasn't actually aware that they were still being served in flipped versions, come to think of it).

Are you sure that is the reason ?
Because every (and it is really every) SDSS image in the Hubble zoo is rotated ?

Budgieye

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Re: Image Reveresed/Flipped between Gzoo and SDSS
« Reply #3 on: May 15, 2013, 08:47:19 pm »
In Hubble images, north is on the right. I have always wondered why they do that.
So if you put your head down on your right shoulder, the image is now the same orientation as SDSS, which puts north at the top.
« Last Edit: May 15, 2013, 08:55:59 pm by Budgieye »

ElisabethB

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Re: Image Reveresed/Flipped between Gzoo and SDSS
« Reply #4 on: May 15, 2013, 08:49:15 pm »
Aww, bless you !  :D
Tx , Christine !

Edd

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Re: Image Reveresed/Flipped between Gzoo and SDSS
« Reply #5 on: May 17, 2013, 05:25:11 am »
We take our images from the field frames, rather than the reprojected JPEGs the SDSS navigator and explorer etc. use. This means we're orientated so that field (the outline of which can be turned on in the navigator form the x-y axes.
You can see the field we took it from here:
http://skyservice.pha.jhu.edu/DR9/ImgCutout/getjpegcodec.aspx?R=8056&C=2&F=94&Z=0
which puts East as the direction nearest vertical, and North to the right.
When I look up at the night sky and think about the billions of stars out there, I think to myself: I'm amazing. - Peter Serafinowicz

NGC3314

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Re: Image Reveresed/Flipped between Gzoo and SDSS
« Reply #6 on: May 17, 2013, 05:52:58 am »
The alert reader will note that I committed a professorial act above, writing something which was technically correct but irrelevant to the application at hand...


Budgieye

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Re: Image Reveresed/Flipped between Gzoo and SDSS
« Reply #7 on: May 17, 2013, 06:56:21 am »
?

:D

 :)

Bubba Ho tep

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Re: Image Reveresed/Flipped between Gzoo and SDSS
« Reply #8 on: May 19, 2013, 07:10:18 pm »
hi thank you for the answers,
I am now tilting my head as per Budgieyes instructions................

 :)

Budgieye

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Re: Image Reveresed/Flipped between Gzoo and SDSS
« Reply #9 on: May 19, 2013, 08:09:44 pm »
« Last Edit: May 19, 2013, 08:53:05 pm by Budgieye »

elizabeth

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Re: Image Reveresed/Flipped between Gzoo and SDSS
« Reply #10 on: May 19, 2013, 08:30:40 pm »
 :D :D :D LOL

Bubba Ho tep

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Re: Image Reveresed/Flipped between Gzoo and SDSS
« Reply #11 on: May 19, 2013, 08:38:39 pm »


 :) ;)
« Last Edit: May 19, 2013, 08:40:13 pm by Bubba Ho tep »