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https://github.com/jeff1evesque/interview-nrao
Calculate time spent performing astronomical observations using input file
https://github.com/jeff1evesque/interview-nrao
Last synced: 3 days ago
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Calculate time spent performing astronomical observations using input file
- Host: GitHub
- URL: https://github.com/jeff1evesque/interview-nrao
- Owner: jeff1evesque
- Created: 2014-10-03T03:07:29.000Z (over 10 years ago)
- Default Branch: master
- Last Pushed: 2014-10-04T23:59:45.000Z (about 10 years ago)
- Last Synced: 2024-11-08T06:06:16.480Z (about 2 months ago)
- Language: Python
- Homepage:
- Size: 949 KB
- Stars: 2
- Watchers: 2
- Forks: 0
- Open Issues: 1
-
Metadata Files:
- Readme: README.md
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README
interview-nrao
=====================
I had an interview with the [NRAO](http://www.nrao.edu/) (National Radio Astronomy Observatory) for a *Software Engineer II* position, and was given a coding exercise to calculate the amount of time spent performing astronomical observations. This exercise was written in [Python](http://en.wikipedia.org/wiki/Python_(programming_language)), and emphasized to be [object oriented](http://en.wikipedia.org/wiki/Object-oriented_programming).
###Definition
Azimuth: is the angular distance along the horizon to the location of the object. By convention, *azimuth* is measured from north towards the east along the horizon.
Elevation: sometimes called *altitude*, is the distance of an object appears to be above the horizon. The angle is measured up from the closest point on the horizon.
- http://astrosun2.astro.cornell.edu/academics/courses/astro201/alt_az.htm
Flux density: is a non-[SI](http://en.wikipedia.org/wiki/SI) unit (jansky, or Jy) of spectral [flux density](http://en.wikipedia.org/wiki/Flux_density). One jansky is equivalent to 10^(-26) [watts](http://en.wikipedia.org/wiki/Watt) per [square metre](http://en.wikipedia.org/wiki/Square_metre) per [hertz](http://en.wikipedia.org/wiki/Hertz). It was created for and is still most frequently used in reference to electromagnetic energy, especially in the context of radio astronomy. The brightest [astronomical radio sources](http://en.wikipedia.org/wiki/Astronomical_radio_source) have flux densities of the order of one to one hundred janskys.
**Note:** The Sun *at 10 GHz* has *4,000,000* Jansky (JY).
- http://en.wikipedia.org/wiki/Jansky
###Overview
This exercise simulates telescope motion as it observes its sources. Using *input* data, `scanner.py` calculates the length of time taken performing various *scans* during it's observations.
Three important files were provided during this exercise, now located within the `given/` subdirectory:
- `coding-project.pdf`: defines, and provides description on the given exercise
- `input.txt` : given input data
- `output.txt` : given sample output data
##Configuration
###GIT
Fork this project in your GitHub account, then clone your repository:
```
cd /var/www/html/
sudo git clone https://[YOUR-USERNAME]@github.com/[YOUR-USERNAME]/interview-nrao.git interview-nrao
```
Then, add the Remote Upstream, this way we can pull any merged pull-requests:
```
cd /var/www/html/interview-nrao/
git remote add upstream https://github.com/[YOUR-USERNAME]/interview-nrao.git
```
###File Permission
Change the file permission for the entire project by issuing the command:
```
cd /var/www/html/
sudo chown -R jeffrey:sudo interview-nrao
```
**Note:** change 'jeffrey' to the user account YOU use.
##Execution
This repository / exercise contains `scanner.py`, which is responsible for running the necessary *validation*, and *calculation* scripts, contained within the `lib/` subdirectory.
To calculate the amount of time spent performing an astronomical observation:
```
cd /var/www/html/interview-nrao
python scanner.py given/input.txt
```
**Note:** `scanner.py` requires a valid input text file to proceed with calculations.
A successful execution of the above script, produces a log-file, containing the overall *simulated* observation time:
```
cd /var/www/html/interview-nrao/log
pico observation.log
```
**Note:** each line within both the `given/input.txt`, and `log/observation.log` represents an observation scan. The last line represents the sum of all observation.