Memorandum from the Mexborough and Swinton
Astronomical Society submitted by Tony Morris
We are a group of amateur astronomers based
in South Yorkshire with our own observatory located in the countryside
to the north of Rotherham.
Members of the Committee
You could try a little experiment yourselves
the next time you leave the "house" during the winter
evenings. Take a few seconds to look up at the night sky. Is it
clear of clouds, yes? Can you see any stars or planets; can you
make out any of the constellations?
To answer the Committees questions based on
our local perspective.
1. What has been the impact of light pollution
on UK astronomy?
Our southern observing horizon is over the Rotherham
and Sheffield urban conurbation. Light pollution dominates approximately
the first 20 degrees from the horizon on most nights. The orange
sky pollution we see is mostly from poorly directed street lighting.
Further sources of pollution come in the form of high intensity
floodlights which allow light to spill out away from the intended
area. To our northern horizon recent developments have added yet
more light pollution to the sky.
One of the most disappointing aspects of the
burgeoning light pollution is usually demonstrated during our
public outreach evenings or when we run special events for school
children; this is the increasing difficulty showing the main constellations
to our visitors. It is now only the brightest stars that can easily
be seen with the naked eye. The younger generations are losing
the splendour and the inspiration of the night sky.
As a society we try to escape our local light
pollution once a year by travelling to a dark sky site. We usually
travel to and stay in rural Aberystwyth as a group. Our observing
is usually done from the hills a few miles inland from the town
itself. The difference in the darkness of the night sky is absolutely
stunning. It throws into stark contrast the light pollution over
a typical urban area to the potential night sky we could all enjoy
if the light sources were efficiently directed to where they were
needed.
For members trying to pursue special interests
within our society we have recently purchased a "light pollution
filter" to use with our telescopes. Unfortunately it is not
really effective. As stated by the manufacturer it is not an alternative
to a really dark sky.
We seem to be living in a time where there are
now more telescopes, equipment and books available than ever before
but our skies are becoming more light polluted. It is difficult
to understand the underlying reasons behind this conundrum, but
possibly the commercialised production of astronomical equipment
at affordable prices with the availability of more disposable
income has led to the equipment boom. People may be buying equipment
only to be put off by the poor skies, thus the equipment lies
dormant at no great financial loss to the owner. Maybe the advancing
age profile of many astronomy societies is a by-product of our
poor skies, as the younger generations cannot see them as their
parents did
Due to the combination of our famous British
weather and light pollution a good dark sky is a rare event indeed.
Arm chair internet astronomy is flourishing with visits to our
American and Australian colleagues web sites a must, where they
can still enjoy really dark skies due to the remoteness of some
of their observing sites.
2. Are current planning guidelines strong
enough to protect against light pollution?
Although our observatory is located in a countryside
area with no local street lights we are now finding that local
buildings have been flood lit for various reasons. We have two
examples:
(a) A local monument on the Wentworth estate,
approximately 250 meters west of our observatory, has been restored
and re-opened to the public for limited daytime use. Unfortunately
for us part of the restoration project allowed floodlights to
be installed. None had been fitted in the past. To the lay person
it appeared that the upper floodlights had been attached to the
monument by unsightly scaffolding poles. They looked completely
out of character during the daytime. Although the flood lights
were to be operated between certain times and dates; within the
first few weeks of operation enough chaos was produced by members
of the public travelling on unlit narrow lanes looking for the
illuminated monument that questions were asked about the reason
for flood lighting. A site meeting was attended by a Wentworth
estate representative who thought that the floodlights detracted
significantly from the monument. He "suggested" that
they should be removed; they were! If this source of pollution
had been allowed to continue it would have severely limited our
enjoyment of the night sky towards our western horizon.
(b) A small public house within 1km of our
observatory has been renovated and enlarged by its new owners
after a fire. It is now a multicoloured light pollution source.
The roof tiles are flood lit with green light, the roof eves have
bright blue neon tubes under them and the walls have white floodlights
pointing upwards. To add further light pollution the signs are
upwardly illuminated!
These examples highlight the difficulties for
us as amateur astronomers in understanding the effectiveness of
the planning rules as outsiders in this area. Whereas the local
council has been replacing defective street lamps with the new
types that direct the light downward, illumination schemes like
the examples above are allowed to take place.
It would appear that current planning guidelines
are not strong enough to protect against light pollution.
3. Are planning guidelines being applied and
enforced effectively?
Taking the two examples above it is difficult
to determine if the guidelines or enforcement are at fault. It
may be the case that once a scheme that produces light pollution
is committed then retrospective enforcement is difficult to carry
out unless sufficent complaints are received.
4. Is light measurable in such a way as to
make legally enforceable controls feasible?
There are guidance notes already issued by the
Institute of Lighting Engineers for reduction of light pollution.
These guidance notes give the maximum light levels to be allowed
under certain conditions. These guidance notes should have been
based on measurements to be of any worth. There are quite accurate
light meters available to amateur photographers, calibrated versions
of this type of instrument complemented with operator training
and light pollution centric operational instructions give a basis
for legally enforceable controls.
Even before the controls were applied many lighting
applications should come under further scrutiny by carrying out
a simple walk through test.
This test should address the following issues:
— Is the lighting really needed?
— What does the light do?
— Does it do it cost effectively?
— Could it be more environmentally
friendly?
— Could it be achieved in an environmentally
sustainable way?
Often we can readily test for lighting effectiveness
without the need for special equipment, for example:
— How many commercial and road signs
are flood lit from below where a substantial portion of the light
misses the target area? This is particularly noticeable during
foggy conditions as the beams of wasted light can be seen easily.
— How many times can you see the bulb
of an illuminating device when you are not within its target area?
Sports grounds and flood lit car sales lots are typical examples
of wasteful illumination.
— Pavement ground lights that illuminate
the soles of your shoes as you walk through our towns and cities;
how are these fittings supposed to be contributing to the enhancement
of our environment?
5. Are further controls on the design of lighting
necessary?
The area of lighting seems to be riddled with
inconsistencies; for example at the domestic level when you visit
your local DIY store you are presented with a wide choice of light
fittings. Many displays encourage you to buy well designed light
fittings with energy efficient bulbs for indoor use, but the next
display may offer poorly designed 500 watt outdoor security lights
with no real guidance as to the impact of these devices on your
neighbours or the environment. Your local council may be fitting
well designed full cut off streetlights on the same street as
premises wastefully illuminated with upward pointing floodlights.
With the environmental and financial impact
of energy generation, and the growing awareness of the disappearing
night skies we must all be concerned about the design and implementation
of all lighting schemes from individual bulbs to national projects.
April 2003
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