This Sunrise/Sunset Computer is provided as a public service by

Horizon Network Security
We are the experts in inexpensive but highly effective Network Security, providing Open Source Linux Adaptive Firewalls with VPN, automatic failover, caching, and traffic shaping options, network security audits, and Linux and Unix system hardening, installation, and system administration. Managed 24x7 monitoring, service, and security patch installation is available at reasonable rates.

Our Firewalls work very well with otherwise all-Microsoft Windows, NT, or all-Unix networks. We take care of commercial, non-profit, educational, and government clients worldwide. You will be working directly with our experts who can explain in English why UDP services and Active FTP are less secure than most TCP services or why random TCP sequence numbers are so important for good security and if your systems offer it.

You can pay more for a big name but probably you will not get better results, just a junior engineer who knows which buttons he usually clicks on a GUI or what same rules he used for the last 10 clients. Contact us at or +1 770-662-8321 (10 am - 6 pm US Eastern Time) for a solution to your needs before a cracker contacts you!

We also wrote the 5 star Prentice Hall book "Real World Linux Security"!

Compute Sunrise, Sunset & Twilight For Cities & Airports (for the experienced)
Type: Airport ID Airport name City, State* County, State* State+ Lat/Lon Lat/Lon S.P.
* Select City (optionally County for U.S. airports) optionally followed by U.S. state (using postal abbreviation) or Country with a separating comma.
+ Select State to to list all airport IDs in that state or country.
Location: (Blank for PDK: Atlanta, Georgia.)
Date (usually Month Day Year):
(Knows "today", "tomorrow", "yesterday". Blank means "today".)
Order a book on Linux today.
Moon Phases U.S. Tide tables World Tide tables

Scroll down for more options to tailor the request

Time zone: Automatic Eastern Central Mountain/Other Pacific/West GMT
Custom time zone: Aviation Data Astronomical Data
Data Entry Tips City Lat/Lon Definitions Form for new users
Text color: White Black Background keyed to time of day (hard to see on some systems)

How many days: One day 1 month 2 months 3 months 6 months 1 year table (sometimes times out)
Tables include: Midday Sunlight each day Sunlight summed for month Sunlight summed
Tables start on first of the month
Date format: April 25, 1996 25 April 1996 (Europe) 04/25/96 25/04/96 (Europe)

Note: if one of the European formats are selected then when entering the date a day number is assumed to precede a month number.
Do Not Press This Button!
It is only for internal debugging and it will not help you.

This Sunrise/Sunset Computer is provided as a public service by
Horizon Network Security

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Last updated on 09 September 2020.
TERMS OF USE: You may use this Sunset Computer up to 100 times on up to 20 different locations unless you ask for and receive permission for greater use. Exceeding these TERMS OF USE constitutes criminal activity and also will get your site or your network blocked and the FBI notified. We apologize to the hundreds of thousands of users who respect our service for the few who do not.

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