Archive for the ‘Aviation’ Category

Using “Golden Hour” in photography

13 Jan 2013

Of all my photos of Taiwan, this photo of Taipei 101 taken from my apartment there has generated the most questions on photography:

1024-IMG_7047_6_8_Localtone

For those that recognize it, this is obviously using HDR, but even the unbracketed version of this photo is pretty special, thanks to capturing it during Golden Hour.

Not really an hour, but often thought of that way, Golden Hour is the time after sunrise or before sunset when the sun is less than 10° above the horizon. For mid-latitudes, this often maps to an hour. Ottawa in winter has a 90 minute golden hour, but in the Philippines, golden hour lasts only about 45 minutes. (in Achorage, Alaska in January, golden hour can last all day!)

If you are trying to plan your shooting to take advantage of golden hour, particularly when travelling, a great resource is http://www.golden-hour.com/. It will do its best to determine your location based upon your IP address, but you can also just center the map on your location by selecting the last entry (Map Centre) in the Location drop-down list.

The other key element is weather – who wants to get up for sunrise and find that you’re looking at a wall of gray clouds that gives only minimal flat light.  The best resource is to use is something called a Terminal Area Forecast. There is a Canadian version of the same page offered by NavCanada, but the US version covers both Canada and the US, and is a little easier to read.

Using this site is probably a post in itself, but here are a few hints if you consider yourself  tech savvy:

  • To use it, you will need to know the airport code for the nearest city with a weather office, use http://www.world-airport-codes.com if you don’t know your local code (Ottawa is YOW)
  • On the Terminal Area Forecast page, you need to enter that code in the box at the top right of the page in the “Area Forecast Product” section, but there is a twist. You need to add a “C” in front for Canadian sites, or a “K” for US sites.  (so you would use CYOW for Ottawa, KSFO for San Francisco)
  • Select the “Translated” radio button, then click “Get TAFs”

Here are the sample results for Ottawa, and for San Francisco for tomorrow morning. As you can see, Ottawa will be covered in fog, so there is no value in getting up. However, San Francisco is forecast for a remarkably clear day – but likely no clouds for interest in the sky. Possibly an ideal day for shooting, but not if you want to catch the Golden Gate bridge shrouded in fog.

Have fun!

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San Francisco (KSFO) Sample Terminal Area Forecast

13 Jan 2013

Sunrise in San Francisco tomorrow is at 7:25, which is 15:25 UTC, so the relevant section is this one:

Text: FM130500 03003KT P6SM SKC
Forecast period: 0500 to 2200 UTC 13 January 2013
Forecast type: FROM: standard forecast or significant change
Winds: from the NNE (30 degrees) at 3 MPH (3 knots; 1.6 m/s)
Visibility: 6 or more miles (10+ km)
Clouds: clear skies
Weather: no significant weather forecast for this period

 

Here’s the full report:

Aviation Digital Data Service (ADDS)

Output produced by TAFs form (2010 UTC 12 January 2013)
found at http://aviationweather.gov/adds/tafs/

Forecast for: KSFO (SAN FRANCISCO , CA, US)
Text: KSFO 121734Z 1218/1324 12004KT P6SM FEW025
Forecast period: 1800 to 2000 UTC 12 January 2013
Forecast type: FROM: standard forecast or significant change
Winds: from the ESE (120 degrees) at 5 MPH (4 knots; 2.1 m/s)
Visibility: 6 or more miles (10+ km)
Clouds: few clouds at 2500 feet AGL
Weather: no significant weather forecast for this period
Text: FM122000 32008KT P6SM FEW025
Forecast period: 2000 UTC 12 January 2013 to 0500 UTC 13 January 2013
Forecast type: FROM: standard forecast or significant change
Winds: from the NW (320 degrees) at 9 MPH (8 knots; 4.2 m/s)
Visibility: 6 or more miles (10+ km)
Clouds: few clouds at 2500 feet AGL
Weather: no significant weather forecast for this period
Text: FM130500 03003KT P6SM SKC
Forecast period: 0500 to 2200 UTC 13 January 2013
Forecast type: FROM: standard forecast or significant change
Winds: from the NNE (30 degrees) at 3 MPH (3 knots; 1.6 m/s)
Visibility: 6 or more miles (10+ km)
Clouds: clear skies
Weather: no significant weather forecast for this period
Text: FM132200 32005KT P6SM FEW025
Forecast period: 2200 UTC 13 January 2013 to 0000 UTC 14 January 2013
Forecast type: FROM: standard forecast or significant change
Winds: from the NW (320 degrees) at 6 MPH (5 knots; 2.6 m/s)
Visibility: 6 or more miles (10+ km)
Clouds: few clouds at 2500 feet AGL
Weather: no significant weather forecast for this period

Ottawa (CYOW) Sample Terminal Area Forecast

13 Jan 2013

Sunrise in Ottawa tomorrow is at 7:40, or 12:40 UTC, so the relevant section is this one:

Text: FM131200 09003KT 1/8SM -DZ FG VV001
Forecast period: 1200 to 1500 UTC 13 January 2013
Forecast type: FROM: standard forecast or significant change
Winds: from the E (90 degrees) at 3 MPH (3 knots; 1.6 m/s)
Visibility: 0.13 miles (0.21 km)
Ceiling: indefinite ceiling with vertical visibility of 100 feet AGL
Clouds: obscured sky
Weather: -DZ FG (light drizzle, fog)

Here’s the full Terminal Area Forecast:

Aviation Digital Data Service (ADDS)

Output produced by TAFs form (2024 UTC 12 January 2013)
found at http://aviationweather.gov/adds/tafs/

Forecast for: CYOW (OTTAWA INTL , ON, CA)
Text: TAF CYOW 121738Z 1218/1318 19005KT P6SM OVC030
Forecast period: 1800 to 1900 UTC 12 January 2013
Forecast type: FROM: standard forecast or significant change
Winds: from the S (190 degrees) at 6 MPH (5 knots; 2.6 m/s)
Visibility: 6 or more miles (10+ km)
Ceiling: 3000 feet AGL
Clouds: overcast cloud deck at 3000 feet AGL
Weather: no significant weather forecast for this period
Text: TEMPO 1218/1219 6SM BR OVC015
Forecast period: 1800 to 1900 UTC 12 January 2013
Forecast type: TEMPORARY: The following changes expected for less than half the time period
Visibility: 6 miles (10 km)
Ceiling: 1500 feet AGL
Clouds: overcast cloud deck at 1500 feet AGL
Weather: BR (mist)
Text: FM121900 19010KT P6SM BKN030
Forecast period: 1900 UTC 12 January 2013 to 0500 UTC 13 January 2013
Forecast type: FROM: standard forecast or significant change
Winds: from the S (190 degrees) at 12 MPH (10 knots; 5.2 m/s)
Visibility: 6 or more miles (10+ km)
Ceiling: 3000 feet AGL
Clouds: broken clouds at 3000 feet AGL
Weather: no significant weather forecast for this period
Text: TEMPO 1219/1305 OVC020
Forecast period: 1900 UTC 12 January 2013 to 0500 UTC 13 January 2013
Forecast type: TEMPORARY: The following changes expected for less than half the time period
Ceiling: 2000 feet AGL
Clouds: overcast cloud deck at 2000 feet AGL
Weather: no significant weather forecast for this period
Text: FM130500 19007KT 6SM BR SCT004 OVC010
Forecast period: 0500 to 1100 UTC 13 January 2013
Forecast type: FROM: standard forecast or significant change
Winds: from the S (190 degrees) at 8 MPH (7 knots; 3.6 m/s)
Visibility: 6 miles (10 km)
Ceiling: 1000 feet AGL
Clouds: scattered clouds at 400 feet AGL
overcast cloud deck at 1000 feet AGL
Weather: BR (mist)
Text: FM131100 VRB03KT 1SM -RA BR OVC004
Forecast period: 1100 to 1200 UTC 13 January 2013
Forecast type: FROM: standard forecast or significant change
Winds: variable direction winds at 3 MPH (3 knots; 1.6 m/s)
Visibility: 1.00 miles (1.61 km)
Ceiling: 400 feet AGL
Clouds: overcast cloud deck at 400 feet AGL
Weather: -RA BR (light rain, mist)
Text: FM131200 09003KT 1/8SM -DZ FG VV001
Forecast period: 1200 to 1500 UTC 13 January 2013
Forecast type: FROM: standard forecast or significant change
Winds: from the E (90 degrees) at 3 MPH (3 knots; 1.6 m/s)
Visibility: 0.13 miles (0.21 km)
Ceiling: indefinite ceiling with vertical visibility of 100 feet AGL
Clouds: obscured sky
Weather: -DZ FG (light drizzle, fog)
Text: FM131500 12008KT WS015/17035KT 1SM -RA BR BKN004 BKN150
Forecast period: 1500 to 1800 UTC 13 January 2013
Forecast type: FROM: standard forecast or significant change
Winds: from the ESE (120 degrees) at 9 MPH (8 knots; 4.2 m/s)
Visibility: 1.00 miles (1.61 km)
Ceiling: 400 feet AGL
Clouds: broken clouds at 400 feet AGL
broken clouds at 15000 feet AGL
Wind shear: at 1500 feet ( 457 m) AGL, from the S (170 degrees) at 40 MPH (35 knots; 18.2 m/s)
Weather: -RA BR (light rain, mist)
Text: PROB30 1315/1318 1/2SM FG VV002 RMK NXT FCST BY 122100Z
Forecast period: 1500 to 1800 UTC 13 January 2013
Forecast type: PROBABLE: 30 percent likelihood of the following during this time
Visibility: 0.50 miles (0.80 km)
Ceiling: indefinite ceiling with vertical visibility of 200 feet AGL
Clouds: obscured sky
Weather: FG (fog)

 

HP-24 Project

31 Aug 2011

I have mentioned this to most of my flying friends, but for those of you who are “makers” not “aviators”, you may want to check out this facebook page and site which documents the creation of a high-performance homebuilt carbon fibre sailplane.

Older updates can be found at: http://www.hpaircraft.com/hp-24/

More recent updates are available on Facebook, at https://www.facebook.com/pages/HP-24-Sailplane-Project/200931354951

The amount of design work (both low and high-tech) is mind-boggling.  As a bonus, the guy that is creating the design is a genuinely nice guy who has been of assistance to countless owners of previous “HP” aircraft, including my RHJ-8. Have fun!

McCready and Speed-to-fly resources (Aviation)

28 Jun 2011

Gliding is all about flying efficiently, and one of the main things we try to do is minimze the amount of time we are spending in sinking air.  These links are probalby not worth reading unless you’re into aviation in general, and have at least some interest in how we glider pilots maximize our time aloft. 

These articles both give much more clear explanations of speed-to-fly than I’ve ever managed to do, so I thought it worth bookmarking them for future consideration.

http://www.5c1.net/Glider%20Performance%20Airspeeds.htm

http://www.dartmoorgliding.co.uk/Cross_Country_Training_Module_5.pdf  (part of a series of 7 articles at http://www.dartmoorgliding.co.uk/html/cross_country.html)