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And welcome. Welcome to 'UnderSouthWest Skies'. Thanks for stopping by. I hope you find the experience worthwhile. This blog post has been written from my own 'beginner perspective' after doing lots of reading on the topic below. In getting my head around it all, I may have got odd bits slightly wrong; but, like you, I am on a leaning journey, so please forgive any unintentional errors. Meanwhile, clear skies to you. Take care and thanks for visiting Steve aka PlymouthAstroBoy
Someone sent me a comment via YouTube recently, having watched one of my recent stargazing timelapses taken at Wembury Point, just outside Plymouth. You can see it below.
He commented
“You look freezing cold and clearly don’t know how to
prepare for and stay warm on cold nights”
Yep, I was very cold! But, contrary to his observation, I
was doing something about it!
But in hindsight, the video does raise legitimate questions
‘Why did I get so cold?’ ‘How did I know I was getting low level
hypothermia?’ and “What did I do to get over it?”
Many, man years ago I was a keen mountain walker, completing
both Summer and Winter Mountain Walking Leader courses along with some on ‘Running
fieldwork and expeditions in challenging environments’. Whilst I confess, I
have forgotten much of what I learned, some of it did stick!
So, “Why did I get so cold?” Too long setting up in an exposed
location, where I spent lots of time standing around waiting for things to
happen!
“How did I know I was getting low level hypothermia?" Lost
contact with my feet and hands; and it was taking an age to do some basic
calculations on image acquisition.
“What did I do about it?” Hot drink, warm soup,
blanket wrap and lots of moving! Oh, and I cut short the planned imaging
session to go home!
So, in this post, a beginner’s guide to keeping warm
on those really cold winter nights – I share my tips – gleaned from lots
of winter walking, alpine climbing and camping all those years ago.
Before that though, , let’s quickly with some basics. Hypothermia,
our main enemy on a cold night dangerous and serious; it sneaks up on you and
you don’t always know you are suffering it until it becomes too late!
So, firstly “Why are we at possible risk of getting
it?”
Well, think how long we spend outside doing astronomy or
astrophotography. My Wembury Point session mentioned above lasted seven hours! It
took me twenty minutes to set up the equipment, fifteen minutes to sort out
polar alignment, most of which was spent on my knees looking up through the
polar scope and then another twenty minutes or so trying to star hop, locate
and then move the telescope to the right area of space I wanted to image that
night! Not a huge amount of movement in that hour and lots of contact with cold
ground and standing around. Barely any movement! Typical session then!
Secondly, “What is hypothermia and what causes it?”
Hypothermia is a dangerous drop in body temperature below
35C (normal body temperature is around 37C). It's a medical emergency that
needs to be treated in hospital. As the body becomes colder, blood vessels
constrict. Blood flow to the extremities reduces leading to loss of feeling in
hands and feet.
Causes of hypothermia – in our particular context, a
very cold stargazing night – not wearing appropriate clothing i.e. a layering
system or clothing that has become wet or damp due to water or perspiration. Staying
out too long in the cold and/or not wearing an outer windproof layer on windy
nights. Inadequate clothing, insufficient movement to generate enough body heat
and not eating or drinking enough warm food/fluids to maintain core body warmth.
A lack of shelter or exposed observation location – well there are plenty of basic
causes here! Oh, and if you trip and injure yourself – then an increased risk
of getting hypothermia, almost certainly!
Thirdly then, “What are the symptoms of hypothermia?”
Starting with the obvious ones -
- Shivering: Uncontrollable
shivering that may stop at very low body temperatures
- Slowed
movement: Poor coordination or slow reactions
- Stiffness: Stiffness
in the arms and legs; loss of feeling in feet and hands
- Confusion: Memory
loss or confusion that may worsen as hypothermia progresses
Then there is
- Cold
skin: Pale, cool, or bright red skin
- Slowed
breathing: Shallow or slow breathing
- Slowed
heart rate: Weak pulse or low blood pressure
- Drowsiness: Lethargy
or sleepiness
- Slurred
speech: Slow or mumbling speech
- Loss
of consciousness: Coma or cardiac arrest if left untreated
Remember, we are all different so there is no particular order
to these symptoms appearing!
Fourthly then, “How do we prevent ourselves getting hypothermia
in the first place?”
My practical tips:
1.
Dress in layers of appropriate clothing. Most
important as far as I am concerned – Adopt a proper layering system that allows you to
adjust your clothing layers based on how warm or cold you are feeling at any
point in time. Absolutely critical.
a.
Base layer next to skin should be
moisture wicking which will keep sweat away from your skin. (And that is not
cotton! Never, never cotton! It soaks up moisture and will make you feel colder
and clammy.) Merino wool or synthetic fabrics – a good outdoor retailer will
have plenty to select from.
b.
Then, on top of the base layer, an insulating
layer - be it fleece top, fleece jacket or down coat. Its aim? To trap heat
and provide warmth.
c.
Finally, a windproof/waterproof outer layer
– to protect you against wind and rain. It’s important that the small of your
back isn’t exposed if you bend over at the eyepiece. My sleeves are slightly
over long so they overlap my gloved hands
d.
Let’s not forget other essential clothing
items – a good hat (an insulated one which comes down over your ears), a
scarf, and a good glove system – for me this is an essential one – I get really
cold hands very quickly. I have always
used a layering system for my hands – very thin fingerless inner gloves which
stay on permanently – then a thicker pair of outer gloves and finally an outer
thin mitt. The latter two get removed as and when. Those inner gloves? Never! I
always carry two hats as well – overkill given I have a hood on my down and
outer jackets as well.
e.
Footwear wise – many people wear
insulated boots and thermal socks – great combination. I don’t have those boots
– I use my walking boots and a two-sock system – a very thin pair and then a
thermal pair over the top. Thick cozy
socks are essential. My other sock system are thermal socks which have a very
thick sole but thinner uppers and are knee height! They work well. Some people
put thermal insoles in their boots – brilliant - done that before. Boots need
to be waterproof – remember water is the enemy – wet = cold = hypothermia
causing.
f. Further tips about layering – don’t wear unnecessary layers of clothing; they will restrict blood flow to your extremities. Aim to keep as much heat as possible trapped within your layer system – each layer should be loose fitting and overlapping the edges of layers below so that heat will rise up through the layer above. So, my socks go on first, then my long-johns so that the leg overlaps the sock. My thermal top next so it loosely overlaps my thermal bottoms. You are getting the picture! Make sure your trousers over lap your boots so warm air from your feet rise into your trousers. It all makes sense doesn’t it.
2.
Ground insulation – no seriously, give it
some thought! When polar aligning, I knee on two small but thick folding
camping seat mats. Sat on the car boot bumper area, the same mats go beneath my
bum! Camping mat under my chair so my feet are off the cold ground. Makes sense
– it works!
3.
Bring a Blanket or two – I use three
blankets of different thicknesses to wrap myself in when sat down in the boot
space of the car or on my collapsible camping chair. Again, three blankets act
as a layering system. From very thin to quite thick and heavy. I can use the
thicker blanket as an additional layer over the top of my clothing as well – as you
saw in the time lapse above.
4.
Generally, I try to keep active during the
night with a routine – around every thirty minutes or so I will walk about
a bit. I’ve been known to put on some good dance music via my earbuds and bop a
wee while – but never when others are around. I give ‘Dad’ dancing a real bad
name! Just not for public observation! Don’t overexert yourself though;
remember sweat is the enemy and one of the starting causes of chilling when you
stop moving!
5.
Warm food and drink – An insulated bag
with thermos flasks in it - hot water in the flasks to make cups of tea or
chocolate – I bring sachets/teabags. I find hot water on its own retains heat
longer than actual tea. A small metal drink bottle of milk. A food flask
containing hot soup. Mood boosting when you suddenly flag. A stargazing night
is just not complete without some good food and drink, whilst gazing
heavenwards. And chocolate, along with cheese and marmite sandwiches - goes
without saying!
6.
A well-chosen location for stargazing –
key points here – shelter from the wind, some form of low-level barriers –
hedges, walls, enclosure of some form. No exposed open hill tops or flat
extensive fields.
7.
Consider what time you start stargazing –
as the night progresses, the temperatures fall; those wee hours after midnight
often cold. Go early, try to finish around midnight. Be very aware that after
midnight there is an increased risk of cold exposure and hypothermia as
temperatures fall further, so adjust clothing as necessary.
8.
Whoever invented hand warmers – thank
you! I got a pair given to me this Christmas (thank you No1 daughter (and
son-in-law)) – mine are USB rechargeable ones. They last for around six hours
on the low setting. They sit between my thin inner and first pair outer gloves.
I LOVE them!
9.
Comfort planning – a deck chair, or in my
case a Kentucky stick chair I made. Pop a blanket on it and then wrap other
blankets around myself. I operate out of the boot of the car. The advantage of
a Skoda Yeti – flat boot space – I can perch on the outer bit, sit fully inside
it in shelter, have all my bits and pieces laid out in it, easy to hand! The
boot stays high up out of the way. I can orientate the car to be out of the
wind.
10.
Take a friend with you – everyone comes
equipped with blankets, chairs, food etc. Convivial chatter, high spirits,
people to watch over each other, shared learning about the night sky.
11.
Keep an eye on the weather – especially any
rising wind – in this instance put back on any outer windproof layers you may
have removed earlier in the night
12.
Know when it’s time to leave – key
mountaineering skill – know when to turn back or not go out onto the hill at
all! Shivering? Lost contact with fingers? Stumbling and kicked the tripod?
Time to pack up and go home and get warm. There will always be another night of
imaging.
So finally, let us address the issue of what happens if you or
the friend with you starts to get hypothermia. “How do you treat hypothermia?”
1.
Get the casualty out of the wind and cold –
into the car promptly. Can’t do that – find a sheltered spot – get out of
the wind!
2.
Put a windproof over their clothing layer
3.
Insulate them from the cold ground – remember
those thermal mats I mentioned? Remember the blankets? Have them sitting and
resting immediately.
4.
Remove any wet clothing – wrap them
in a space thermal foil rescue blanket (always carry one with your first aid
kit); cover their head
5.
Can’t get them to the car – It’s a 999
jobbie – and promptly! Stay with your casualty at all times whilst waiting for
the ambulance to arrive. UK based? Got the ‘whatthreewords’ app downloaded
on your phone?
6.
Monitor breathing and level of
responsiveness and if the casualty is alert give some warm drinks and that
high energy food – remember the chocolate I mentioned?? High energy intake
allows them to keep shivering which generates warmth.
7.
Heat pads – if you have some – use them
– but not directly on the skin! And not on the chest, back or arm pit!
If you think they have moderate hypothermia then note the
following:
1.
Don’t give food or drink
2.
Handle very gently.
3.
Lie casualty down and really insulate them from
the ground – keep them horizontal
4.
Wrap them in insulating layers – survival blankets,
ordinary wool/fleece blankets, plastic orange bivvy bag
5.
Insulate head, neck area and DO NOT warm up extremities
with heat pads
I hope this overview of how to stay warm on those cold winter nights helps. As always, if you have any tips to add, then drop the into the comment box below. Always good to hear from others. In the meantime, clear skies and safe stargazing to you all
Steve (PlymouthAstroBoy)
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