WAITING FOR THE SHADOW

SOLAR AND LUNAR ECLIPSE OBSERVING

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"Eclipse on Top of the World"
The March 20, 2015, Total Solar Eclipse



Power Considerations

Electrical Plugs

Norway uses the Europlug (Type C & F), which has two round prongs with 220 volts coming out of the outlets.
Most laptops, chargers and appliances will automatically work with 220 volts (check the back of your laptop for power input markings.) That means, you'll only need an adapter to change the shape of your power plug to fit into an outlet in Norway. These power adapters are relatively cheap.

If you bring small appliances, be careful. The shape adapter may not be enough. While basically all personal electronics in recent years will accept both voltages, some older, smaller appliances don't work with the hefty 220v in Europe. Check if the label near the appliance's power cord shows 100-240 v and 50-60 Hz. If it does not, you will need a "step-down transformer" (also called a converter).  The converter will reduce the 220 volts from the outlet to provide just 110 volts for the appliance. These converters cost a little more than simple adapters.  

Tip: Don't bring any type of hair dryer to Norway - they can be hard to match up with a suitable converter due to their high power consumption. Instead, just check if your accommodation in Norway has one in the room, or buy a cheap one locally.

Source : http://goscandinavia.about.com/od/norwa1/f/eleoutletnorway.htm



Using Cameras, Batteries in the cold

In addition to a potential temperature drop during the eclipse, travellers to Svalbard may expose cameras to extreme cold taking snowmobile tours, and attempting to photograph the Aurora Borealis at night.

Cameras and the cold
Mechanical operation  : - Modern cameras work on minimal lubricants, relying instead on low friction materials such as Teflon for lubrication. Provided power can continue to be supplied to the camera, most modern cameras will continue to work in the cold.  Older mechanical cameras used 20-30 years ago needed an overhaul and special low temperature lubricants applied to avoid moving parts seizing up in the cold.

Condensation       Never bring a cold camera directly indoors or into the inner area of a tent.  These environments always have high humidity levels.  Water will immediately condense all over the exterior of the camera and can even condense on interior components and the film.   While still outdoors in the cold, seal the camera and lenses in a plastic bag.  This traps dry air around the camera.  Place the camera inside a camera bag for insulation and bring it inside to allow it to warm slowly.  In a tent, leave the camera in the vestibule area rather than taking it into the inner tent providing that the camera is not at risk of water damage from rain or being gnawed by animals  (Don’t laugh,  some of my camera gear has the teeth marks to prove this!)   Condensation on an internal element is very difficult to remove.  It is also inadvisable to change film in a warm and humid environment, then go straight into the cold.  

Batteries
Modern DSLR camera employ Lithium ion batteries which are reasonably resistant to cold but have some special requirements.

"Charging temperature limits for Li-ion are stricter than the operating limits. Lithium-ion chemistry performs well at elevated temperatures but prolonged exposure to heat reduces battery life.

Li‑ion batteries offer good charging performance at cooler temperatures and may even allow 'fast-charging' within a temperature range of 5 to 45 °C (41 to 113 °F).[54] Charging should be performed within this temperature range. At temperatures from 0 to 5 °C charging is possible, but the charge current should be reduced. During a low-temperature charge the slight temperature rise above ambient due to the internal cell resistance is beneficial. High temperatures during charging may lead to battery degradation and charging at temperatures above 45 °C will degrade battery performance, whereas at lower temperatures the internal resistance of the battery may increase, resulting in slower charging and thus longer charging times.[54]

Consumer-grade lithium-ion batteries should not be charged at temperatures below 0 °C (32 °F). Although a battery pack may appear to be charging normally, electroplating of metallic lithium can occur at the negative electrode during a subfreezing charge, and may not be removable even by repeated cycling. Most devices equipped with Li-ion batteries do not allow charging outside of 0-45 °C for safety reasons, except for mobile phones that may allow some degree of charging when they detect an emergency call in progress." [Wikipedia]

Friends who have used  DSLR's in Antartica tell me that they just kept the battery in their inside pockets unti they needed to use it. Then the heat generated by the camera and battery during use, kept it warm enough.


Eveready Energizer Ultimate Lithium are a non-rechargeable Lithium Iron Sulphide battery that have no liquid to freeze and can be used, with some slight output reduction down to -40C. They are available in AA size (L91) and AAA size (L92). Many  battery grips for DSLR’s can take AA sized batteries along with most accessories - flash, flashlights, time-lapse controllers, Vixen Polarie etc etc.  The grip can be kept inside your jacket until ready for use thus minimizing temperature drops.  

The Discharge profile and Temperature effect on capacity diagrams are shown below for AA and AAA sizes.
 


Umbilical Power Pack

A battery pack can be worn inside your jacket with an umbilical line running to the DC input of your DSLR camera or other accessories. If it is the wrong voltage, DC – DC converters with variable voltage output can provide the correct output.

These are often based on an LM2593/2596 chip  http://www.ti.com/product/lm2593hv in a buck converter circuit.  These can be purchased on ebay for a few dollars have 90+% conversion efficiency.

This is my LM2596 circuit ready to be installed in a box. It has an adjustable 3 amp output and a 5v USB connection.  Once in the box, the display is easier to read.  The voltmeter chip on this card consistently reads 0.2v low.  

  


Operation   The biggest problem in extreme cold can be avoiding frost-bite of your own hands.  To avoid this problem a tube of polar fleece can be jacketed around the camera with a hole for the lens. Place your hands in each side to operate the camera so the fleece tube acts like a big mitt to give your ungloved hands protection while operating the camera. (Geoff Sims)

An old polar fleece jacket can have it's sleeve cut off and donated to the cause.  



Introduction Sun/ Moon
Rise/ Set & Twilight 		 Solar Altitude
and Azimuth
on Eclipse Day		 Orientation- corona
Sun's axis
EQ mount alignment		 Sky at totality  Photographic Information Power & Batteries Further reading