Galaxy Zoo Forum

The site and the science => Analysis Tips => : Antirius August 01, 2007, 02:57:45 PM

: Do you classify part or all of the image?
: Antirius August 01, 2007, 02:57:45 PM
http://cas.sdss.org/astro/en/tools/explore/obj.asp?id=587736543086379123

This seems to be somehing at the edge of or behind the galaxy.
: Re: Object at edge of galaxy
: Halibut August 01, 2007, 09:07:28 PM
With these ones, we've been told by the zookeepers to classify the whole of the galaxy as one instead of just the object in the corss hairs, which zoomed out looks like a spiral edge-on.
: Do you classify part or all of the image?
: fluffyporcupine August 10, 2007, 08:35:31 PM
This seem sto get asked a lot, Zookeeper kevins reply was:
Hi,

Please classify the morphology of the HOST GALAXY. In this case, a spiral.

We will add this to the FAQ.

Thanks!

it was in this thread: http://www.galaxyzooforum.org/index.php?topic=325.0

Hope it helps!
: Re: Do you classify part or all of the image?
: Jaina August 10, 2007, 08:41:39 PM
I move to sticky this topic so that people can find it more easily.
: Re: Do you classify part or all of the image?
: Megalodon99 August 10, 2007, 09:55:18 PM
I also move to sticky it.
: Re: Do you classify part or all of the image?
: Alice August 10, 2007, 10:40:15 PM
All right, all right, I'll stickify this thread  ;D
(Zookeepers - if you object I'll unstick it. I'm not stuck-up about my moderating.)
: Re: Do you classify part or all of the image?
: Jaina August 10, 2007, 11:07:09 PM
Horray!  Many thanks, Alice!  8)
: Re: Do you classify part or all of the image?
: Alwaysthinking August 14, 2007, 12:43:59 AM
I thought you were supposed to classify whichever one was in the middle… :-\
: Re: Do you classify part or all of the image?
: speedymarie August 14, 2007, 04:37:28 PM
I thought you were supposed to classify whichever one was in the middle… :-\
Sometimes a part of a galaxy will be targeted, especially when the galaxy is very nearby. For example, I got a target that was a bright blue, heavy star-forming, outer arm of the Pinwheel Galaxy. Looking at the target I was presented, zoomed way in, it looked like a blue irregular. But if you zoomed way, way out, you discovered that it was an outer arm of a large, nearby galaxy. In that case, I would classify the entire galaxy (a spiral), rather than just the arm that was my target (what looked like a blue irregular close up).

Now, if you get a picture that has several different galaxies in it, then yes, you'd classify whichever was in the middle, the target.

Hope that helps!
: Re: Object at edge of galaxy
: Kukakokeke August 17, 2007, 05:32:23 AM
I have the same picture today. In my opinion it is maybe merger or overlapped pair of galaxies. In inverted picture you can see second nucleus on object in lower right edge.

(http://casjobs.sdss.org/ImgCutoutDR6/getjpeg.aspx?ra=202.22428169&dec=10.03308714&scale=0.1980635&width=512&height=512&opt=I&query=&InvertImage=on)

Sorry Halibut, but I don't agree your opinion for classify in this case. In case that object is one piece of galaxy, your comments are right.
: Re: Do you classify part or all of the image?
: carwotcar August 20, 2007, 04:00:49 PM
In some cases galaxies have smaller satalite galaxies as does our galaxy that is what you might be seeing
: Re: Do you classify part or all of the image?
: altymczuk September 09, 2007, 08:11:00 PM
See neither an overlap nor a merger. CW spiral.
: Re: Do you classify part or all of the image?
: buck1127 July 24, 2008, 02:20:10 AM
I'm not sure if this topic is covered elsewhere, though I feel it probably must be since it is something I have questions about rather frequently.  My question is:  How can you tell when the target might be a distant galaxy behind the larger host galaxy?  As such, I wouldn't think classification of the host is what they're looking for.

Other cases include ones where forground stars are pinpointed as the targets inside a larger host galaxy, so when you see these, you might assume it's targeting a part of the galaxy and classify it rather than noticing it's actaully a STAR.

the one below is one that falls in this category

(http://casjobs.sdss.org/ImgCutoutDR6/getjpeg.aspx?ra=143.05534128&dec=21.53061401&scale=0.79224&width=512&height=512&opt=&query=)
http://cas.sdss.org/astro/en/tools/explore/obj.asp?id=587741709406896132

If you click on the link it shows in SDSS that the targeted object is a STAR, so shouldn't it be classified as S/DK??

.....and if the target specClass is "GALAXY", how can you be sure that it isn't gating on a distant galaxy behind (or maybe even in front of) the larger one?????

Any clarrification would be greatly appreciated........and, if this has already been addressed elsewhere, please forgive me.

thanks
: Re: Do you classify part or all of the image?
: rat February 15, 2009, 10:20:42 PM
I'm not sure if this topic is covered elsewhere, though I feel it probably must be since it is something I have questions about rather frequently.  My question is:  How can you tell when the target might be a distant galaxy behind the larger host galaxy?  As such, I wouldn't think classification of the host is what they're looking for.

Other cases include ones where forground stars are pinpointed as the targets inside a larger host galaxy, so when you see these, you might assume it's targeting a part of the galaxy and classify it rather than noticing it's actaully a STAR.

the one below is one that falls in this category

(http://casjobs.sdss.org/ImgCutoutDR6/getjpeg.aspx?ra=143.05534128&dec=21.53061401&scale=0.79224&width=512&height=512&opt=&query=)
http://cas.sdss.org/astro/en/tools/explore/obj.asp?id=587741709406896132

If you click on the link it shows in SDSS that the targeted object is a STAR, so shouldn't it be classified as S/DK??

.....and if the target specClass is "GALAXY", how can you be sure that it isn't gating on a distant galaxy behind (or maybe even in front of) the larger one?????

Any clarrification would be greatly appreciated........and, if this has already been addressed elsewhere, please forgive me.

thanks

We've been told to classify without looking at the SDSS data: http://www.galaxyzooforum.org/index.php?topic=273214.msg226225#msg226225
: How do I go back to correctly classify a galaxy?
: david walland August 14, 2009, 12:58:09 PM
I was whizzing through galaxies when up came what looked exactly like a star, but without the usual 4 "spikes".  So I classified it as a star or artifact.

When I could go into the image and zoome out, I quickly realised that this was not a star but the centre of a nearby elliptical galaxy.  How do I go back to the thing and put a correct and meaningful classification in place of the nonsense I have written?  How do I zoom in and out *before* classifying?

Regards

David Walland
: Re: How do I go back to correctly classify a galaxy?
: AlexandredOr August 14, 2009, 01:06:37 PM
I was whizzing through galaxies when up came what looked exactly like a star, but without the usual 4 "spikes".  So I classified it as a star or artifact.

When I could go into the image and zoome out, I quickly realised that this was not a star but the centre of a nearby elliptical galaxy.  How do I go back to the thing and put a correct and meaningful classification in place of the nonsense I have written?  How do I zoom in and out *before* classifying?

Regards

David Walland

Welcome to the Zoo !
To "go back" I think you have only to click on the icon, in the lower row, you've just choosed. The choice is proposed again. But corrections are possible only while classifying, not after...
To zoom in and out before classifying, I think it's no possible...
: Re: Do you classify part or all of the image?
: ElisabethB August 14, 2009, 01:08:25 PM
Hi David
in GZ1 you could zoom in/out before classifying. In GZ2 this is not possible.
And I'm afraid you can't go back and redo a classification.
But don't worry, lots and lots of people will get the same galaxy to classify.
Welcome to the Zoo and happy hunting  :D
: Re: Do you classify part or all of the image?
: Alice August 14, 2009, 03:18:15 PM
Welcome to the zoo David! And don't worry, because if something doesn't match up with what people are saying about it, the zookeepers can use their own checks to find out why.

Very early on, nearly 2 years ago I should think, zookeeperKate did an Object of the Day of 3 beautiful, close-up galaxies which had mostly been classified as stars - because they needed zooming out on.

What your classification tells them is to adjust the image to zoom it out more for future classifiers, if that is possible.

You can change your mind during the classification process but not afterwards, sorry. Even so, don't worry if you have made a mistake, we all do now and then.
: Re: Do you classify part or all of the image?
: Bruno August 27, 2009, 04:19:41 PM
Welcome to the zoo David! And don't worry, because if something doesn't match up with what people are saying about it, the zookeepers can use their own checks to find out why.

Very early on, nearly 2 years ago I should think, zookeeperKate did an Object of the Day of 3 beautiful, close-up galaxies which had mostly been classified as stars - because they needed zooming out on.

What your classification tells them is to adjust the image to zoom it out more for future classifiers, if that is possible.

You can change your mind during the classification process but not afterwards, sorry. Even so, don't worry if you have made a mistake, we all do now and then.
quoting  Jack Lemmon "nobody's perfect" ;D
: Re: Do you classify part or all of the image?
: AbuMaia October 11, 2009, 08:49:58 PM
I just got this one: (http://s3.amazonaws.com/zoo2_extra/318406.jpg)
I marked it Smooth, In Between, Yes, Other, based on the large galaxy at the middle bottom, even though there was nothing at the "center."  Was this correct to do, or should I have clicked Star/Artifact instead?
: Re: Do you classify part or all of the image?
: ElisabethB October 11, 2009, 08:56:41 PM
Hi AbuMaia
you should always classify what's in the centre of the image, so in this case star/artefact would've been correct.
Could you please post the ref.number in future posts, that makes it easier to check things.
Welcome to the Zoo and have fun !  :D
: Re: Do you classify part or all of the image?
: AbuMaia October 12, 2009, 04:44:17 AM
sorry 'bout that.  that one was SDSS 8647474690343764057
: Re: Do you classify part or all of the image?
: JeanTate June 22, 2010, 01:32:12 PM
(http://s3.amazonaws.com/zoo2_extra/355966.jpg)
Just what am I expected to classify?

The small yellowish blob near the center? Or the faint ((blueish?) haze which covers much of the field?
: Re: Do you classify part or all of the image?
: ElisabethB June 22, 2010, 04:22:11 PM
Hi Jean,
I'd go for star /artifact as there is no galaxy in the middle of the picture.
And if you want to classify the nebula it's also star/artifact.
You can't win 'em all !  ;D
: Re: Do you classify part or all of the image?
: pete 53 January 08, 2011, 01:28:02 PM
I have a dilema. I classifid this as haveing lumps (4+, clump Ect ) and I then intended to state about the spiral, but found I could not. So in this situation what is more importent. Classafing the Galaxy or whats in it.
(http://zoo-hst.s3.amazonaws.com/12020321.jpg)AHZ10002dx  :-\
: Re: Do you classify part or all of the image?
: Alice January 08, 2011, 01:32:01 PM
It'll ask you what shape the clumps are in - click "spiral"! :)
: Re: Do you classify part or all of the image?
: pete 53 January 08, 2011, 01:53:09 PM
It'll ask you what shape the clumps are in - click "spiral"! :)
Should of thought of that I was just seeing them all pushed to one side (ie A Clump)