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Unformatted text preview: arize yourself with the main morphological types of galaxies, go to the Galaxy Zoo
website at http://www.galaxyzoo.org and then click on “STORY” and also on “CLASSIFY”. You can review the description of galaxy morphologies. Also see the corresponding
chapter in your textbook.
1. What are the typical colors of elliptical and spiral galaxies? Discuss why these classes
of galaxies tend to have the colors they have from what you know about the colors of
2. Sketch three examples of various ellipticals and four examples of various spiral galaxies
in your lab report indicating their type (spiral or ellipticals) and providing your best
guess for their sub-type according to Hubble’s classiﬁcation (e.g., E3, Sc, SBb, etc.).
See the diagram at
3 PHSC12000 V1.0 3 If you are curious and have time, explore the Galaxy Zoo website and help scientists in their
exploration of galaxies by performing some simple classiﬁcations in their ’Classify Galaxies’
section. Homogeneity of galaxy distribution on the sky
Start Google Earth and click on the “Saturn” icon on the top bar which switches to the Sky
portion of Google Earth4 on the lab computer (or on your laptop after you install Google
Sky and download the SDSS Galaxy Query kml plugin from the directory showed to you
by TA and activate the SDSS Galaxy Photometric Layer by clicking on it, make sure the
SDSS Galaxy Spectroscopic Layer is turned oﬀ (by unchecking it). Load the kml ﬁle
Hubble lab random SDSS fields.kml.
Find the corresponding folder in the Places window on the left hand side of the Sky window
and click on + to see the folder contents (field 1, field 2, ..., field 10). These are
ten random locations in the area of sky covered by the Sloan Digital Sky Survey away from
the plane of the Milky Way and in areas devoid of very big bright galaxies and stars (which
can block a signiﬁcant part of the ﬁeld of view).
Double click on the field 1 ﬁeld and the Sky will take you to the ﬁrst ﬁeld down to the
zoom level at wh...
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