IRNSS 1C satellite successfully launched by ISRO which is 3rd in its constellation of 7 satellites

               IRNSS is an independent regional navigation satellite system being developed by India. It is designed to provide accurate position information service to users in India as well as the region extending up to 1500 km from its boundary, which is its primary service area. The Extended Service Area lies between primary service area and area enclosed by the rectangle from Latitude 30 deg South to 50 deg North, Longitude 30 deg East to 130 deg East. 

               

                IRNSS will provide two types of services, namely, Standard Positioning Service (SPS) which is provided to all the users and Restricted Service (RS), which is an encrypted service provided only to the authorised users. The IRNSS System is expected to provide a position accuracy of better than 20 m in the primary service area. 

                IRNSS comprises of a space segment and a ground segment. The IRNSS space segment consists of seven satellites, with three satellites in geostationary orbit and four satellites in inclined geosynchronous orbit. IRNSS-1A, the first satellite of the IRNSS constellation, has already started functioning from its designated orbital slot after extensive on orbit test and evaluation to confirm its satisfactory performance. 

                IRNSS ground segment is responsible for navigation parameter generation and transmission, satellite control, ranging and integrity monitoring and time keeping. 

Applications of IRNSS:

• Terrestrial, Aerial and Marine Navigation
• Disaster Management
• Vehicle tracking and fleet management
• Integration with mobile phones
• Precise Timing
• Mapping and Geodetic data capture
• Terrestrial navigation aid for hikers and travellers
• Visual and voice navigation for drivers

                                                                      --Sources:

                                                                  http://www.isro.org/satellites/irnss.aspx
                                                                  https://www.youtube.com/watch?v=VpcxKE2IXmQ

Getting to know the BINNACLE !

This is what a Binnacle looks like !

Binnacle:

A binnacle is a waist-high case or stand on the deck of a ship, generally mounted in front of the helmsman, in which navigational instruments are placed for easy and quick reference as well as to protect the delicate instruments.

Parts of a Binnacle

Binnacles have formed a mainstay of maritime operations worldwide. Vessel operators and skippers, across the world, are assured of a safer and surer voyage on account of this simplistic aiding navigation equipment.

About Binnacles:

• Flinders tubing was yet another methodology utilised to counteract the magnetic disruptions. The tubing consists of a couple of rods placed on each side of the instrument.

• The Flinders tubing are named after noted British adventurer Sir Matthew Flinders, who mapped out the Australian coast.

• In the mid-19th century, inventor John Gray came up with the idea to place auto-adjusting magnets to balance the magnetic disruptions, caused by the nautical compass.

• Magnetic balls were invented by Englishman Lord Kelvin in the late-1800s. The basic principle of their adoption was to place two magnetic balls on either side of the marine binnacle. The magnetic disruptions caused would be balanced by these two magnetic spheres.

Getting to know the Sundial !

This is what a Sundial looks like !

Sundial:

It is an instrument showing the time by the shadow of a pointer cast by the sun on to a plate marked with the hours of the day.

1. You can tell the time by looking at the shadow cast by the Sun as it shines on the pointer of a sundial. The proper name for the pointer is a gnomon (said 'nom-on') Sundials. A sundial works by casting a shadow in different positions, at different times of the day.

Problems using Sundial:

Irregularity of the motion of the sun from year to year. 

During one leap year cycle of 4 years, the key solar parameters of Equation of Time and Declination vary significantly!  This is shown in the following graph.

Getting to know the ASTROLABE !

This is how an astrolabe looks like !

 An astrolabe is a very ancient astronomical computer for solving problems relating to time (what time is it ?) and the position of the Sun and stars in the sky.  

Astrolabes are used to show how the sky looks at a specific place at a given time. 

Parts of an Astrolabe

The Mater

The Mater is the main part of the astrolabe; all the other parts connect to it. 

The Plates or Climates

An astrolabe is a very precise instrument, but its accuracy is tied to a specific latitude 

because the projection of the visible sky changes with the viewer’s latitude.

The Rete

The Rete is a cutout overlay that rests on top of the plates. It shows the projection of the 

celestial sphere. Unlike the plates, the rete is designed to turn freely.

The Rule

The Rule rests on top of the rete, and is designed to turn freely. It is used as a pointer during 

calculations and, depending on the origin of the astrolabe and the preference of the maker or 

owner, might be double or single ended; or not be present at all.

The Alidade

On the opposite side of the astrolabe from the rule is the alidade. This is a double-ended 

rotating pointer arm with a set of attached sights for taking accurate angle measurements.

Pin 

Tying together the rest of the parts and providing a pivot point for the rotating parts, the pin 

is placed through the center of the mater.

Mariner's Astrolabe

How to Use an Astrolabe?

Uses:

-- Finding the time during the day or night

-- Finding the time of a celestial event such as sunrise or sunset

-- Finding Latitude of user's location

-- As a handy reference of celestial positions

-- Mariner's astrolabe was widely used as a navigational device

-- Islamic prayer times are astronomically determined

-- Casting Horoscopes

--And many others

In the 10th century, Abd al-Rahmân b. Umar al-Sufī (d. A.H. 376/A.D. 986-7) wrote a detailed treatise on the astrolabe consisting of 386 chapters in which he described 1000 uses for the astrolabe. al-Sufī perhaps overstated the flexibility of the astrolabe, but astrolabes can be used to solve many astronomical problems that would otherwise require rather sophisticated mathematics.