Category Archives: Class

The Six Month Sabbatical

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It is amazing how a planned six month sabbatical turned into 14 months. We decided to retreat from our teaching and photography schedule for the first six months of 2015. Family and work issues lengthened that to 11 months… and well, it has taken another several months to get back on our feet.

And we are re-starting with a Free “Exploring Night Photography” class that extends from April 6th, to May 25th, 2016.  However before I even started writing this column the class was full. The class would not help many of you since it is being taught in Los Gatos, California, with thanks to Venture Christian Church for providing the venue.

But there is good news: in the coming weeks we will be publishing the material we use in the class HERE on the website.  The class is aimed at DSLR photographers who have gotten out of “Automatic” mode at least once, but that is the only real requirement.

Here is the course description:

EXPLORING NIGHT PHOTOGRAPHY:

You’ve got a Digital, Single Lens Reflex (DSLR) camera, and you are getting fairly good at it. Now it is time to try something new and creative: photos taken at night. Night photos can reveal the amazing majesty of the night sky (Isaiah 40:26). You will learn how to photograph in low-light using your DSLR. Along the way you will learn a little about the night sky and several photography techniques that will aid all of your photography efforts. Most of all you’ll be amazed at how much there is in the dark that remains unseen without the aid of a camera. You just might unleash a creative direction you may have never considered. This is a hands-on course. You will be taking photos on the very first session of the course, so bring all the equipment listed in the prerequisites.

Prerequisites:

  • Must have a DSLR camera (smart phones are not acceptable)
  • Must understand the basics of exposures – i.e. the relationship between f-stop (aperture), sensitivity and exposure length, and have shot photographs in some mode other than “Automatic”.
  • Your camera’s operators manual

Also recommended are:

  • A tripod- strongly recommended!
  • A remote release (cable)
  • An Intervalometer (Steven will have some to loan)
  • Extra batteries
  • Memory card(s)

5418793950_1bb7084134_z

Teacher Bio

Steven Christenson is the founder and teacher of StarCircleAcademy.com, and winner of the 2010 Greenwich Observatory “Astronomy Photographer of the Year”, and a runner up in 2012. His work has been published as album covers, in the Economist and Backpacker Magazine and even featured on local TV stations. Steven specializes in “Landscape Astrophotography” a field that is easily approachable by anyone with a DSLR camera and a tripod.  You can read his instructive columns on his website (StarCircleAcademy.com).

What you will miss is the hands-on portion, of course, and the relentlessly punny style of Steven’s teaching, but the good news is that the discussion, resource list and class exercises will be right here for you to follow along.

And, it is not too late to influence what we cover… So feel free to ask any beginnerish questions here and we will either respond directly or include that material in what we publish here on the web.

Hope your skies are dark and clear, and the stars smile for you!

Stratospheric Exercise for Moonatics

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The moon setting behind the US Capitol Building, Washington, DC

If you’re going to chase the moon (or the sun), there are problems that you need to solve.  Here are some exercises to hone your sun and moon chasing skills so you can turn the chasing into catching.  The questions get progressively harder.  Those who have taken our Catching the Moon Webinar will find the answers and much more detail on the private course materials page.  The tools you will need to solve the problems include

You might also want to read some of our past articles on the topic, especially part 1 and part 2.

The Stratosphere Tower, Las Vegas, Nevada

I’ve picked a place that I hope few people are intimately familiar with.  Many of use have been to Las Vegas, Nevada and know that there is one of the worlds tallest towers there. I’ve even had the thrill of hopping on the “Big Shot” ride – the tallest ride in the world.  The Stratosphere Tower is second in the Americas in height only to the CN Tower in Toronto.  The Stratophere’s height above relatively flat surroundings makes it an easier target for catching a sun or moon set or rise from a distance far enough to make the tower seem small.  Even though the Stratosphere is tall, there are complications – including surrounding buildings and surrounding mountains. The farther you move away from the tower, the more significant those obstructions and potential obstructions become.

If you have never seen the tower, above is a relatively close up shot captured from Google Street View. Take note of the height of the mast above the “bulge” in the tower – that’s where you find the ride “Big Shot.” To my thinking it would not be terribly interesting to get an alignment with the sun or moon behind the mast of the tower. On the other hand, if the moon/sun diameter is not as large or larger than the bulge, the shot may not be all that interesting either.

On to the questions, starting from the basic data you need to collect, and on through to solving a “real life” alignment problem.

  1. What is is the correct GPS location for the Stratosphere Tower in Las Vegas, Nevada?
  2. The base of the Stratosphere Tower is at what elevation?
  3. Looking west from the base of the Stratosphere Tower, what is the azimuth and altitude of the tallest natural obstruction in the range of West, south west, to west north west (235 to 295 degrees)?
  4. From the tower at ground level: sunset on Tuesday, August 28, 2012 occurs in line with which of these natural features:
    1. La Madre Mountain
    2. Griffith Peak
    3. Lone Mountain
    4. Frenchman Mountain
    5. Mt Charleston
  5. On what day in August, 2012 will the sun appear to set on (not behind) La Madre Mountain peak?
  6. How far is the summit of La Madre Mountain from the base of the Stratosphere Tower?
  7. Can the Stratosphere Tower be seen from the intersection of Boulder Hwy (Nevada Route 582,aka Fremont Street) and East Sahara Avenue?
  8. If the tower is visible from the above intersection, which part of the intersection provides the least obstructed view?
    1. East
    2. North
    3. South
    4. West
  9. How tall is the Stratosphere Tower (excluding the antenna/mast on top)?
  10. How far is the Stratosphere Tower from the Fremont Street/East Sahara avenue intersection?
  11. What is the difference in altitude between ground level at the Stratosphere, and the ground level at the intersection?
    1. The intersection is 279 feet lower
    2. The Stratosphere is 279 feet lower
    3. No change
    4. The Stratosphere is 1,402 feet higher
  12. What is the altitude (angle above ground) from the intersection to the tip of the mast of the Stratosphere?
  13. On Wednesday, December 19, 2012 from the intersection, the moon will pass closest to the Stratosphere tower at what time:
  14. From the intersection the apparent moon size is about:
    1. Equal to the tower height, excluding the mast
    2. Half the height of the tower, excluding the mast
    3. 1/6 the height of the tower, excluding the mast
    4. Twice the height of the tower, including the mast
  15. On Wednesday, December 19, 2012 at the time calculated in question 13 the moon will:
    1. Pass just under the bulge in the tower
    2. Pass just over the bulge in the tower
    3. Pass behind the bulge of the tower
    4. Pass through the mast of the tower
  16. As seen from the intersection: what is the first day after June 13, 2012 when a nearly full moon (at least 95% illuminated) will appear to set behind the Stratosphere Tower?
  17. What is the NEXT day after the date found in the previous calculation that a nearly full moon will appear to set behind the Stratosphere Tower? (Hint: it’s more than a year later than the previous event).
  18. You want to catch Venus crossing the face of the sun as the sun sets behind the Stratosphere tower on June 5, 2012. In what publicly accessible location would you stand, and at what time so that:
    1. The sun is as large as possible relative to the tower (i.e. you’re standing as far away as practical).
    2. You are confident there is a visible line of sight to the tower.
    3. There are as few obstructions as possible in your line of sight.
    4. There is no mountain, hill or other building behind the tower along the sightline.
    5. You have at least a little bit of room to move to correct for misalignments in your calculations (e.g. standing on a manhole cover in the middle of the freeway is not advisable!)

Good luck!

PS If you’re stumped, I recommend our Catching the Moon (and Sun) Webinar.

NOTE: You are free to ask or answer any of the questions in comments, but those comments will remain private so that those who come along later won’t be tempted to cheat!

Easy (HDR) Blending with Stacking Software

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I’ve been teaching a “Catching the Moon” webinar approximately monthly. The focus of that course is to teach how to properly expose for the moon, how to catch the moon aligned with your favorite landmark, and how to determine the optimum light scenarios.  The webinar is based on my Alignment 1 and Alignment 2 articles with a healthy dose of additional material including some private material for students only.

One of the most difficult aspects of getting a moon alignment is that there is a pretty small optimum time window for getting an exposure.  Shooting earlier or later makes the foreground illumination and the moon illumination all but impossible to get both exposed properly in a single shot.

Here is an example of a single shot where the lighting was pretty close to perfect (though you can see the moon is a bit over exposed).

A Perfect 10 [5_057646]

However later that evening the sunset occurred quite a while before moon rise, so the sky and foreground were much darker.  The photographer faces a conundrum. Expose for the foreground or expose to preserve moon features.

On the left is a 30 second exposure prior to moon rise (though a tiny bit of the moon is in fact visible). On the right a 1/25th of a second exposure. Both taken on a tripod at f/9, ISO 250, 444mm effective focal length.  The problem is that a longer exposure renders the moon as a white featureless blob or streak (see below for an example). However exposing for the moon as on the right renders the foreground all but invisible.

What to Do?

There are a couple of simple alternatives. One is to bring both images into Photoshop. Make both images layers, the moon on top of the background and combine the two images using “Lighten” blending mode.  That will work very well and it’s essentially what happens when using the StarCircleAcademy Stacking Action. But that action, and even Photoshop are overkill for this situation.

Free Solution!

Fortunately Markus Enzweiler offers a free solution called StarStax that runs on Windows, Linux and Mac that makes it trivially simple to combine these two exposures – assuming they were taken on a tripod and the zoom, focus and direction does not change between shots.  StarStax is tailored to stacking star trails, but it does the same operation that Photoshop (and Image Stacker and StarTrails.de do).

And fortunately you can make it do a little more with almost no extra effort… as in this example. When the first image was taken it was quite dark and required a long exposure to capture foreground details.  Then all the moon images were taken with identical settings using an intervalometer.  It’s interesting to note how the moon darkens and deepens in color as it sinks in the atmosphere.

Project Impact [5_057573-615br]

So how do you create the simple or “stacked” motion images?  Easy.

 And here is the result.

Obviously to create a descending or ascending moon sequence you merely need to combine exposures taken at the appropriate interval. What is that interval? The moon travels roughly its diameter in two minutes. About 2 minutes, 14 seconds to be more precise.  I recommend taking exposures twice or four times as often as that, however and just use every-other or every fourth shot.

Since I took a simple approach to blend the images I also elected to go simple in presentation. Rather than fight the many different colors inherent in urban night scenes, I used Picasa3 to convert to monochrome, crop and frame the combined image – here using an earlier shot than the “Golf Ball on a Tee” shot above.

In the Evening [5_057775+92]

Here is one last example of a descending crescent moon combined using Photoshop. Here I didn’t wait a full moon diameter time between images because it was a crescent moon:

Mamma Glows, Baby Shines

 This also illustrates why taking more frequent exposures gives more creative latitude.

 

Learn from the HDR Pro

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I’ve said it before, but it bears repeating.  Were it not for what I learned from my friend and mentor, Harold Davis, my Astronomy Photographer of the Year, 2010 win would not have happened.

Photon Worshippers **Winner Astronomy Photographer of the Year, 2010 - People and Space **

It is really just not possible to capture the wide range of exposure latitudes without post processing. Moreover processing with traditional tools does not result in as pleasing a result. It took application of the Hand HDR blending technique I learned at one of Harold’s workshops (and from his book) to make the image possible.  I hope you’ve also noticed that the image above bears none of the hallmarks of “typical HDR” imagery.

Harold is teaching an HDR workshop on March 24, 2012 in Berkeley, California. For details please see “Photography with Harold Davis”  Harold has a book on the subject scheduled to publish in July, 2012. You can pre-order it now for a quite modest price.  The Hand HDR techique is also covered along with several other powerful tips in his book The Photoshop Darkroom: Creative Digital Post Processing.

A Line in the Sand [C_035604-8PSb]

Here is the same subject using automated HDR processing:

In Another Universe [5_019718-23hdr]

And another example that “screams” HDR with its “gritty” texture and surreal look.

That Sinking Feeling [C_035617-21de]

But you do NOT have to make images like that. You can if you wish. Harold will show you both!

If you’d like to see all of my images of and around the marvelous location, take a look here.