Astronomy at Dwejra

Astronomy

In this section you will learn about the amazing vistas you can have of our home galaxy, the Milky Way - and why Dwejra is designated as a dark sky heritage area. If you want to find out why Dwejra is a good place to observe the night sky, what are the problems that threaten the night sky of Dwejra, and what you can do to help make it better, then this is the page for you!

WHY DWEJRA?

Why is Dwejra a good place from where to do astronomy? Modern times have seen the proliferation of artificial light sources, many of which are not well-designed and send a lot of their light where it is not needed, i.e. up in the sky. (You will learn more about this in the feature below on light pollution.)

Dwejra being one of the most remote locations from mainland Malta and central Gozo, it is the best remaining site for carrying out observations of the night sky, particularly when looking towards the South-Western horizon. This does not mean that Dwejra is free from light pollution; indeed encroaching light pollution from the rest of Gozo is a big threat to the future of Dwejra's night sky. Read on to learn more about some of our universe's marvels you can observe from Dwejra.

The Milky Way from Dwejra (Image: J. Caruana)

WHAT CAN I SEE FROM DWEJRA?

On a clear night, looking up at the sky from Dwejra you will be rewarded with breathtaking views of the universe. In Summer, the Milky Way rises from over the horizon stretching upwards in its majestic glory. Stellar nurseries (called nebulae), faint stars and distant galaxies all appear brighter than from other places around the Maltese islands. Need help to get started? You're in the right place.

DO I NEED A TELESCOPE?
You do not need a telescope to enjoy the night sky of Dwejra. Looking up at the sky with your own naked eye, the Milky Way is clearly visible.

WHEN IS THE BEST TIME TO VIEW THE MILKY WAY FROM DWEJRA?
The bright core of the Milky Way is visible in summer. However, especially during summer months, the Maltese islands tend to be very hot and humid, with Southern winds bringing dust and adversely affecting what astronomers call transparency. For this reason, ideally you should make your trip when the wind is from the North. Early September, when temperatures have also started to cool down a bit, is a good time to venture to Dwejra for a good view of the Milky Way. Don't leave it for much later though, as the core of the Milky Way will then dip below the horizon.

HOW CAN I TAKE A PICTURE OF THE MILKY WAY?
For this, you need to be able to keep the shutter of your camera open for a few seconds. Three steps to follow are:

Choose manual mode (if your camera has one).
Pick a high ISO setting (which means you are pushing up the sensitivity of the sensor).
Use the widest angle lens you have available (if you're using a zoom lens, zoom out to the widest setting).
Select a long exposure time of between 20 and 30 seconds.

Of course you'll have to keep your camera still while it is recording the picture, so a small tripod will come in handy.

Below you can view some pictures of the night sky at Dwejra taken with just a camera mounted on a tripod.

WHAT, EXACTLY, IS LIGHT POLLUTION?

Put simply, light pollution is any light that is brighter than required, misdirected such that it spills onto areas which are not intended to be illuminated, and intrusive. Very often it is the result of poorly designed lighting fixtures or ill-thought lighting plans.

Looking at the diagram to the right serves to highlight some of the main problems we often encounter. In this illustration, the region on the ground intended to be illuminated is marked. However note how some light is leaking upwards to the sky, some finds its way into the eyes of passersby causing glare, and some even trespasses into someone's home.

For purposes of astronomy, any light that finds its way to the sky is problematic. Whether the light is leaked directly towards the sky or whether it reflects off the ground and sent skywards, it creates skyglow that hampers our views of our beautiful universe.

(Image: J. Caruana)

IS DWEJRA'S DARK SKY HERITAGE PROTECTED?

In principle, yes. The 2002 MEPA Gozo & Comino Local plan designates a number of dark sky heritage area around Gozo and Comino. For such areas, the plan states that:

where relevant, reflective signs shall be employed to guide driving at night, whilst the installation of lighting which is not related to aerial or maritime navigation, shall be strongly discouraged.

This goes some way towards preserving the darkness of Dwejra's night sky. However, despite these efforts, threats to Dwejra's night sky heritage still abound; the next section takes a look at these threats, and further down you will learn what you can do to help keep the night sky of Dwejra as dark as possible.

This image, reproduced from the Gozo & Comino Local Plan (MEPA) depicts in purple all designated dark sky heritage areas around Gozo and Comino. (Image: formerly MEPA; now ERA & PA)

WHAT ARE THE THREATS TO THE NIGHT SKY OF DWEJRA?

The factors affecting the pristine views of the night sky at Dwejra are various. The three major threats are:

ENCROACHING LIGHT POLLUTION FROM THE REST OF GOZO, particularly with the recent introduction of bright, white LED lights in street-lighting fixtures.
CHURCHES AND OTHER MONUMENTS which are often over-illuminated by floodlighting or other unnecessarily bright lights, which lights oftentimes are setup up such that they uplight the structures (i.e. the lights aim upwards)
INFRINGEMENT OF REGULATIONS on the site itself, where there should be no artificial lighting whatsoever.

The recent installation of bright, white LED bulbs in street lights has had a terrible impact on the night sky of Dwejra, as well as other places all over the islands. Not only are these lights very bright, they also emit light across a wide wavelength range (including in the bluer parts of the spectrum) compared to more traditional, warm sodium lights whose light could be filtered out by special filters that block Sodium emission. Whilst more energy efficient, unless they are filtered to limit their spectral output, they are very detrimental to astronomy. Moreover, more studies are suggesting that blue light is detrimental to our health by suppressing Melatonin and shifting our Circadian rhythm.

A photo from Space showing the Maltese islands at night. Light pollution is visible all over the islands, concentrated towards the South East.

Skyglow from Gozo encroaches upon Dwejra as it illuminates the North Eastern sky. (Image: J. Caruana)

The effect of skyglow is also seen in this picture taken during an overcast night. It shows clouds being illuminated by skyglow. In turn, the clouds reflect the light upon the ground which becomes clearly visible in this picture. (Image: J. Caruana)

WHAT CAN I DO TO HELP?

AVOID USE OF UNNECESSARY LIGHTING

Wherever possible, avoid installing lighting fixtures outside. If lighting is required, ensure it is of the full cutoff type, i.e. the light has a properly shielded bulb and sends all its light downwards where illumination is actually required. Make sure you do not use more light than is required (e.g. use lower wattage and avoid bright, white LED lights).

SPREAD THE WORD

Awareness and education are hugely important. Spread the word about the adverse effects of light pollution, but don't limit the conversation only to negative aspects. Inform people about the beauty of the night sky - a beauty which we stand to lose if we do not act! For thousands of years, humanity looked up at the night sky and wondered. We should ensure that the beauty of our home in the cosmos, our Milky Way, is still visible to the generations that come after us.

SPEAK UP

When you spot disregard for regulations, particularly with regards to the ban of lighting at Dwejra itself (but not just), do speak up and inform the authorities. Reports of illegal development can be sent to the Planning authority here, whereas the Environment and Resources Authority can be reached via email. Moreover, make pressure on your local council to take action with regards to unnecessary lighting of public monuments and church facades, especially in late hours.

Astronomy

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