LUMANDAR AS4, the new astronomical clock


Horloge Astronomique Lumandar AS4

The astronomical clock LUMANDAR AS4 is designed by COMETA, French leader of GPS astronomical clocks.

Our will: increased reliability of simplification of installation, maintenance, management and use, to allow its use to all municipalities and communities.

LUMANDAR AS4, what’s new?

This device has been designed around our experience since the 2000s in the design of astronomical clocks (STELLA and HELIAN) and the constancy of AS1, AS2 and AS3 clocks. All using the same ephemeris calculation algorithm. This makes it possible to continue installing Lumandar AS4 in municipalities equipped with AS1, AS2 and AS3 clocks.

Our device consists of a modular housing, containing tropicalized electronic boards, which is installed on a DIN rail support. It has two potential free relay outputs, allowing independent management of lighting solution, namely the different programming settings of outgoing lines from the cabinet or illuminations if a dedicated network is available.

The second element is a GPS antenna that is installed inside the cabinet (fiber type) or through the wall (for metal cabinets). This element makes it possible to simplify the programming of this device. It is no longer necessary to program the location in each municipality. Indeed, the GPS antenna automatically takes the location and puts the device on time.

LUMANDAR AS4: the functioning

Thanks to its GPS antenna, AS4 receives, every second, the UTC signal (GMT time). It provides in parallel the local time with the change of summer / winter time. The time setting is completely automatic regardless of the zone, unlike terrestrial radio transmitters.

The GPS location is more precise (3.4 km² area against 560 km² IGN) and allows a Plug & Play installation.

It is preferable that each street (or neighborhood) turns on one after another from EAST to WEST (distance of 1 min maximum) following the curve of the sun. In France, we do not light Strasbourg at the same time as Brest. In addition, a synchronization of an entire city necessarily generates a significant current demand that can be harmful for the power grid.

GPS synchronization is the most accurate and sustainable solution.

LUMANDAR AS4 retains, however, the possibility to be located via an IGN code.

By default, LUMANDAR AS4 will automatically follow the ephemeris (at 4 Lux on a clear day) from its place of installation. Thus, it is possible to customize the functioning mode of the clock via an Android Smartphone / tablet, thanks to the intuitive software ILIEC (Intuitive Software Interface for Connected Lighting).

LUMANDAR AS4 operates mainly in autonomous mode synchronized by the GPS probe. It therefore remains eligible for the Energy Savings Certificate.

It can also be used for orders issued by the city’s supervision center via the LoRa COMETA network.