HDSR
Hanle Dark Sky Reserve
HDSR LIGHT MANAGEMENT PLAN

Download the Light Management Plan document here

Causes of Light pollution

The causes of light pollution are usually classified as Sky glow (brighter night sky near the horizon from man made lights from villages and towns), Glare (uncomfortable bright lights, e.g. from commercial sign boards etc), Light intrusion (light escaping upwards or sideways from lit up windows, etc), and Headlights (light from vehicles, especially high beam).

How we tackle this at HDSR

Funded by UT Ladakh, IIA has provided warm color bulbs, outdoor lamp shades, and black curtains to every single house within HDSR. Light pollution is being monitored regularly as well. All roads have been equipped with retro-reflectors. Once completed, high beam headlights will be prohibited inside the HDSR region.

The Hanle Dark Sky Reserve implements a Light Management Plan to control light pollution inside its area, and hence preserve the darkness of the night sky.

Causes of Light pollution

The causes of light pollution are usually classified as Sky glow (brighter night sky near the horizon from man made lights from villages and towns), Glare (uncomfortable bright lights, eg from commercial sign boards etc), Light intrusion (light escaping upwards or sideways from lit up windows, etc), and Headlights (light from vehicles, especially high beam).

The most egregious light pollution in HDSR arises from

1. Spillover light from the villages and the Gompa inside HDSR (from windows, external lamps in houses, etc). The horizon is brighter near the horizon towards these villages, and the light thrown upwards from these lamps can affect the telescope observations in the Observatory on top of the hill.
2. Headlights of vehicles on the road are particularly bad for astronomers. The light from high beams can light up the sky, and affect long exposures of the optical telescopes (HCT and GIT). They are even more damaging for the Cerenkov Gamma-ray telescopes MACE and HAGAR. Their optics are open to the sky without a protective dome and the headlights can easily damage their electronics, and have to be reset after every such event.
3. Floodlights etc from the army camps nearby. The senior army staff are working with the UT Ladakh to reduce the light pollution from the camps inside HDSR.
4. Flashlights used by visiting tourists.