
The Sloan Digital Sky Survey - dnetesn
http://alliance.nautil.us/feature/278/taking-to-the-stars
======
antognini
For anyone interested in astronomy who would like to try their hand at some
small projects using real data, the SDSS website has some guides to help you
through a few projects here:

[http://skyserver.sdss.org/dr14/en/proj/projhome.aspx](http://skyserver.sdss.org/dr14/en/proj/projhome.aspx)

Some of the advanced projects are to make an HR diagram, classify stellar
spectra, and calculate the redshift of quasars. Of course, all the data is
public so the guides are just a start --- you can keep going in any
interesting direction. It doesn't take long to get to the point where you're
doing real research.

It's pretty cool that thanks to this project anyone with an Internet
connection can reproduce fundamental astronomical results for themselves.

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anon1253
Even for a simple amateur astrophotographer [1] the SDSS data is invaluable.
It powers most of the target selection, and provides accurate coordinates for
most astronomical objects. Combined with Plate Solving, it makes my life much
easier [2]. Take for example a well known tool "Sequence Generator Pro", I
only have to type in a name and I can start imaging [3]. I can't thank the
people enough who worked on this. I'm soon upgrading the telescope with a set
of Sloan photometric filters (used in the survey) [4], and particularly
interested in expanding my images with Near Infrared data. Which can also give
very pretty pictures [5]

[1]: my 2017 images
[https://www.flickr.com/photos/joelkuiper/38496747325/](https://www.flickr.com/photos/joelkuiper/38496747325/)

[2]:
[http://cosmo.nyu.edu/hogg/research/2006/09/28/astrometry_goo...](http://cosmo.nyu.edu/hogg/research/2006/09/28/astrometry_google.pdf)

[3]:
[https://www.flickr.com/photos/joelkuiper/24582661547](https://www.flickr.com/photos/joelkuiper/24582661547)

[4]:
[http://astrodon.com/store/p12/Astrodon_Photometrics_Sloan_Fi...](http://astrodon.com/store/p12/Astrodon_Photometrics_Sloan_Filters.html)

[5]
[http://trappedphotons.com/files/tmp/Making%20Pretty%20Pictur...](http://trappedphotons.com/files/tmp/Making%20Pretty%20Pictures%20from%20Scientific%20Data.pdf)

~~~
geokon
The second link is fascinating. I've never come across this algorithm. What a
clever solution!

I'm a bit unclear on how the "quads" are chosen (ie. which 4 stars are grouped
together). I assume your image and the sky-survey database you're comparing to
are at a completely different detail-level. Choosing every combination of 4
stars seems not practical. If you just choose groups of 4 that are next to
each other then you may find the database has dozens of stars in between your
quad's stars (b/c it's at a higher detail level)

The slides acknowledge this by saying " Finally, there is the additional
problem of distractor & dropout stars", but I don't see their solution :)

Maybe this is a clue "Cycle through all possible valid* quads (brightest
first) and compute their corresponding codes" but there are no details.

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mandarg
Nearly 10 years ago (wow, time flies), as a weedy undergraduate, I was
fortunate enough to do a research project [1] under one of the scientists [2]
who worked on this survey. It was pretty cool to just be able to submit
arbitrary SQL queries and get nice CSV files back.

With my imperfect knowledge of astrophysics and hacked-up scripts, it was
pretty intimidating to stand up and present my "interesting-but-will-probably-
need-more-detailed-research" to a bunch of people with literally decades of
experience in the field and have them take me seriously and ask questions.

I do other things now, but it's a pleasant surprise from the past to see this
on here :)

[1] [https://mandarg.com/vsrp-talk.pdf](https://mandarg.com/vsrp-talk.pdf)

[2]
[http://www.ncra.tifr.res.in/~yogesh/](http://www.ncra.tifr.res.in/~yogesh/)

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davidmr
I worked with probably a dozen or so scientists and engineers who were
building the SDSS telescope and the associated data analysis infrastructure
(full disclosure: my role was very nearly entirely nothing compared to
everyone else).

It's really a technological marvel, and some truly brilliant engineers and
scientists were working on it. I'm intensely gratified that the survey has
been such a smashing success; they all deserved it.

The part I was always most impressed with was they way they took the spectra.
As mentioned in the article, the survey was twofold: the image survey over the
vast swaths of the sky and somewhere around 2,000,000 spectra taken of distant
objects.

Every single one of those spectra was taken by use of a fiber optic cable at
the focus point of the telescope. They would take a metal plate, drill holes
in it where the objects would appear, and plug the holes by hand with the
cables: [http://blog.sdss.org/wp-
content/uploads/2014/05/twitter5.jpg](http://blog.sdss.org/wp-
content/uploads/2014/05/twitter5.jpg)

2 million times!

~~~
antognini
I was pretty lucky to be in a department that was one of the SDSS members. The
metal plates they had were only used a few times since each one was unique to
the field it was designed for. After they were done with them they sold them
to some of us grad students for $20 (the price they would have gotten as
scrap). When I move into a house I'm going to mount mine on a wall so I have a
little piece if scientific history to look at. :)

One thing to add, too, is that the plates are pretty big! Each one is about
three feet across and maybe 1/8 inch thick!

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indescions_2018
On the radio astronomy side. The Jansky VLA survey has only just begun data
collection ;)

[https://science.nrao.edu/science/surveys/vlass](https://science.nrao.edu/science/surveys/vlass)

[https://sciencesprings.wordpress.com/2017/12/28/from-nrao-
th...](https://sciencesprings.wordpress.com/2017/12/28/from-nrao-the-very-
large-array-sky-survey-vlass-this-is-huge-with-many-great-videos-at-the-end/)

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dnautics
The most recently run catalog of the sdss has some very interesting coding
techniques associated with it:

[https://youtu.be/uecdcADM3hY?list=PLP8iPy9hna6QpP6vqZs408etJ...](https://youtu.be/uecdcADM3hY?list=PLP8iPy9hna6QpP6vqZs408etJVECPKIev&t=1718)

