Data Acquisition

The Search for Data

I knew that there must be numerical data for the positions of the stars that can be seen at night. I had no clue, however, what form it might be in and how to get it into ArcView. Because of this, I was surprised at how quickly I found data (it took me just two days).

As an undergraduate, I had done research on the Tarantula Nebula in the Large Magellenic Cloud (the nearest galaxy outside of the Milky Way (which is our own galaxy)) under Gary Bernstein. That project involved alot of number crunching, so I figured he probably wouldn't know where the data I needed was, but would probably know where I could find it. Unfortunately, I quickly received eMail back from the notorious mailer-daemon very quickly. I knew I had to either track Gary down or find someone else I might contact.

I next tried eMailing Joel Bregman, a professor I had had at the University of Michigan as a senior for High Energy Astrophysics (HEAP), a course I highly recommend to anyone who enjoys astronomy. He eMailed me back two days later with a web site and how to use it.
Joel's eMail

Hello Daniel,

It's good to hear from you. You probably only want bright stars, and you might do a Google search for that, but another way is to use the NASA archive services.

Go to . Under "Popular Catalog Choices", click "Hipparcos Main" then at the bottom, click "More options." At the next screen, unclick the things you don't want and click on the things you want. So if you only want positions and a magnitude (V, for example), only click on "ra", "dec", and "vt_mag". You might have it sort by ra by clicking the other button next to it. Now if you only want stars brighter than some amount, such as 3rd mag, put "< 3" in the box next to "vt_mag".

Then, down at the bottom, use the pull-down menue from "Output Format" to select the format you want.

That should do it.

Good luck,
Joel Bregman

Downloading the Data

I started with the search engine Joel sent me to, and choose stars with a magnitude ("vt_mag") less than 6 (only those stars visible to the human eye). I'm not as interested with the motion of stars, so I deselect pm_ra, pm_dec. I'm also not interested in color (although I may change my mind about that), so I didn't deselected spect_type.


Now that I've got my data, it's time to import it.

Urban Planning: Final Project, Presentation Outline
Data Acquisition, Star Chart Creation, Calculating on a Web Site
Home Page, About Me, ePortfolio, Lesson Plans, Papers, Old Site

Daniel D. Slosberg |
December 1, 2003