GUIDE TO OBSERVING COMETS (updated 2018)
1. AVOID LIGHT POLLUTION
In Australia, the majority of people live in urban areas. The urban sprawl
combined with inefficient lighting practices or "light pollution"
has resulted in the night sky being lost to our current and future generations. This is the main reason why comet Halley in 1986 was labelled
by the general public as a poor performer when in fact, given dark country sky locations, was an impressive object.
Ensure that the direction in which you wish to observe the comet does not overlook populated areas.
For many, this means travelling to a dark observing site. Before this is suggested, refer to tips 2 and 3.
2. AVOID MOONLIGHT
The Moon is the brightest object in the night sky and acts as a natural light
Therefore it is important to observe comets in periods free from moonlight interference.
There are many free mobile apps or websites that provide you with local times for moonrise & moonset.
The exception to this rule is of course the appearance of a bright comet where every opportunity to observe it should never be missed.
3. AVOID CLOUD
It's of no use to travel many kilometers to your dark observing location only
to find that cloud interrupts the view.
One of the best weather prediction websites for Australian observers is the Bureau of Meteorology http://www.bom.gov.au/
It has high resolution satellite animation at http://satview.bom.gov.au
In Layers, select coastal, boundaries, roads, cities. Infrared greyscale for night-time animation.
You can see in real time where the clouds are at with this animation.
Also highly recommended is the Skippy sky website at https://www.skippysky.com.au/Australia/
If your location is dark blue for the forecast period, you have a great chance of clear skies.
4. DARK ADAPTATION
An essential requirement for observing astronomical objects.
Dark Adaptation requires the observer to avoid direct light for at least 15 minutes prior to observing.
The eye in total darkness will progressively develop a light sensitive pigment called Rhodopsin (a derivative of Vitamin A)
which enables greater peripheral vision at night. Persons lacking in Vitamin A will suffer from "night blindness".
To maintain dark adaptation during the night, avoid light eg. wear an eyepatch and use a low light RED torch.
5. USE AVERTED VISION
A trick of the trade is to use the side of the eye rather than look directly
at the astronomical object
since your peripheral vision is much more sensitive to faint light.
The most effective method for observing faint astronomical objects is when you combine Dark adaptation and Averted vision with Movement.
i.e. wiggle a pair of binoculars or telescope.
6. OBSERVE AT THE END OF ASTRONOMICAL TWILIGHT
Your evening sky is not completely dark until it enters "astronomical
twilight". This is when the Sun reaches 18 degrees below your horizon.
The reverse is true for sunrise. Depending on your location, this is usually at least 1 hour (more likely 1:20) after Sunset or before Sunrise.
7. USE OPTICAL AID
A bright comet will appear far more spectacular with optical aid. The best
instrument to use is a pair of 7x50mm binoculars.
This usually gives a field of view of around 8 degrees, perfect for close inspection of the coma and tail.
10x50mm binoculars are preferable for elderly observers.
Through a telescope at high power, you may witness dust jets or nuclear fragmentation.
8. KNOW EXACTLY WHERE AND WHEN TO LOOK
Predicting the brightness of a particular comet is educated guesswork at
best, but we do know where a comet will be located in the sky at a particular
You should learn to recognize the stars and constellations in which a comet will travel through, well before the event.
A torch wrapped in thick red cellophane is an essential observers tool for reading maps at night.
Or use my night mode charts.
9. WEAR APPROPRIATE CLOTHING
Spending an evening under the stars requires common sense. Wear appropriate clothing to protect you from cold and wind.