Exploring Night Sky Photography

Pasture Arch, Walpole NH

Rye Beach, NH, July

I'm happy to admit that I am not an expert on astrophotography, but the improved low light capabilities of newer digital cameras have made the process of capturing the night sky so easy and the results so remarkable, that it is hard to avoid giving it a try. There are a number of great photographers who have concentrated on this special photographic niche. They have produced breath-taking star field images, and have generously published detailed descriptions of the special techniques required. I have included links to a couple of the best discussions, but I thought a more personal and less encyclopedic introduction might be helpful.

Milky Way over my Driveway

I remember how amazed I was when I looked at my first night sky photograph. It was just a random piece of unremarkable sky, but I was blown away by the ability of long exposures to see far deeper into the universe than is possible with the unaided eye. I had to do more.' I get out occasionally, but my explorations of the night sky are limited by a persistent laziness that makes it difficult to leave my warm bed for a cold and lonely pasture. I'm always happy when I come back from a night shoot, but it is just a matter of getting out of the door. I succeeded last week in capturing the Milky Way from a spot in Walpole that I had always thought would provide an interesting foreground and perhaps a description of the process from a aspiring amateur may be of value to those who are thinking of exploring this remarkable field of digital photography.




The Galactic Season

Alyson's Orchard Walpole, September

Of course when we talk about night sky photography, the major attraction is the dense band of stars in the Milky Way and for the best show, timing is crucial. Currently, we are in a great time of the year for capturing the Milky Way in the Northern Hemisphere. The Galactic Core season begins in the spring when it is located, at its highest point, in the southwest. The high point moves across until it is found in the southwest during the fall. In the spring, the Milky Way extends in an arc across the horizon, allowing the capture of dramatic panoramic views across a large portion of the sky. As we get into the summer and fall, the band of light moves into a more vertical orientation, making it difficult to capture the full Galactic disk as it arcs across the dome of the sky. Each season provides a variety of opportunities to use our Galaxy in your images, but, happily, the frigid months of winter are not the best time to look for the Milky Way.

Spofford Lake, Spring Arch

The Moon
 Star field observation starts with an understanding of the location of the moon. Each month I note on my calendar the few days around the new moon. Although a little peripheral moonlight can help illuminate foreground elements, the new moon is generally the best time to clearly capture the stars in their full glory. Around the time of the new moon, I start checking the weather for the best chances of clear sky's. It is exciting to find a crystal clear night on just the right day, but I'm embarrassed to admit that I am often equally thrilled to see clouds obscuring the sky, giving me a reasonable excuse to rush off to bed.



The Right Spot
I am always looking for good locations to capture the Milky Way. There are three basic requirements

South Facing View.
The Milky Way moves across the sky from Southeast to Southwest and a prime location must have a clear view to the horizon in that direction. I spend time scanning my favorite locations, looking for those with the proper orientation.

Avoiding Light Pollution.

Brattleboro Light Pollution

Light pollution is persistent problem. Even out in the country, it is amazing how much artificial light will show up when I am shooting with ISOs from 2500-3200 at f2.8 and 20-30 second exposures. 




 


 


Martha's Vineyard, Ocean Dark

A faint glow on the horizon,which is barely perceptible to the unaided eye, can look like a blazing sunrise when captured in a long exposure. I try to get away from major centers of civilization, but even a small village like Spofford can throw up a surprising amount of light. I envy my friends who are fortunate to live near the ocean, where views out to sea are relatively clear of artificial light. For those of us who are land-locked all we can do is get as far away from people as possible, minimize the glare in Photoshop and tell everyone that that orange patch is actually the first glow of sunrise.







Foreground

Jaffrey Silos

Finding something of interest in the foreground is key to achieving context and drama in a star field image. I'm always looking for trees, church spires, barns, or farm equipment that I can position before the great arch of stars. Of course the "sea coasters" have an endless array of lighthouses to use for drama, but we can catch the stars reflected in the calm waters of local rivers and lakes. The key to effective use of foreground elements is to get close enough.  Star fields are generally shot

Chesterfield Town Hall

atextreme wide angles. I almost always use my 16mm lens. and with that broad angle of view the foreground must be quite close to be seen to dramatic effect. The foreground elements can be striking in silhouette against the bright sky, but I often play with light painting using my trusty light LED flashlight. Light painting is all about experimentation and using a subtle touch. The foreground may also be captured in the natural light with a separate long exposure that can be blended with the star field image during post-processing.

My Walpole Apples
 For years I have been attracted to a couple of lone apple trees which sit out in the middle of a lovely pasture in Walpole New Hampshire. I have shot the trees in various seasons and conditions of light, but I have always felt that they might serve as interesting foreground subjects for a Milky Way photograph. The trees are isolated in the middle of a large pasture on the crest of a hill looking off to the south. I knew I would have freedom to move around the trees to find the best angle under the arch of the Milky Way. I had shot stars from edge of this location before, but I had never ventured out to get close enough to bring the trees into the foreground. About one week ago I finally got my chance.



The Right Day and Time

Photographer's Ephemeris, Walpole Apples

I used the Photographer's Ephemeris to find the nights in May when the Moon would not be an issue. TPE is THE essential piece of software for anyone wanting to predict the locations of the Sun and Moon from any location and on any day. My current favorite program for predicting the

PhotoPills

location of the Milky Way is Photopills. Although the program's user interface takes a bit of getting used to, it shows the position and elevation of the Milky Way throughout the night from any location. I was able to see that the Galactic Arch would be in the best position over my Walpole Apples between 1 and 3 AM on the days when the Moon would be new or below the horizon.








I knew the what, the where and the when, all that remained was the fourth "W", the weather. 


The forecast was for one clear night before a warm front was predicted to cloud the skies for several days. I took a nap in the

Dublin Lake & Too Distant Monadnock

early evening and then got out to my isolated spot at about 12:30 AM. After fumbling my way through the pasture's irregular ground I was where I wanted to be, next to my Apple tree. For once I prepared myself perfectly. I had clothing that was sufficiently warm, I used my Overshoe Boots to protect my feet from the damp and the ticks and I made sure that my flashlight had fresh batteries. I use a flashlight that is equipped with a red filter to preserve my night vision as I work the controls. Before I left home I had mounted my 16-35mm lens, set it to its max wide angle and adjusted the focus to where long experience has shown me that infinity lies. The stars are definitely at infinity but they come into sharpest focus slightly short of the lens' max position. It takes a bit of experimentation to find the right spot. An especially bright star, the lunar surface or even a distant light can be used to discover the best adjustment. Once set I used gaffer's tape to fix the adjustments in place.


In the Field

Walpole Apple, We'll Call It Sunrise

The night was lovely. With the exception of a few clouds on the southern horizon, the sky was crystal clear and peaceful, although, as always, it was a bit spooky standing alone in the inky dark with nothing but the hooting of owls and the howling of distant (hopefully) coyotes to keep me company. Fortunately I was too busy to spend much time thinking about being stalked by ravenous preditors, or shambling zombies. The Milky Way was beautiful and easily visible to the unaided eye allowing me to position the camera to capture the Apple tree nestled under the arch, but even when maximally dark adjusted my eyes could not remotely appreciate the intensity and depth revealed by the camera sensor. After a few experimental shots, I settled on ISO 2500, f2.8 and a 20

Cosmic Apple, Walpole, Light Painted

second exposure. I made sure that my camera was set for Mirror Lock-Up and Long Exposure Noise Reduction. With the extra time required for noise reduction, each exposure took close to one minute, a duration which seemed much longer when trying to stand perfectly still in the dark. I grabbed a few single shots near the tree, including experimenting a bit with light painting, and then settled into shooting several series of images across the sky for eventual reconstruction into panoramic studies. I shot 6-7 images for each panorama. Without clear references, the greatest challenge was in keeping the camera level through the series of images. It is at this time that keeping my eyes fully dark adjusted was critical to pick up on key landmarks. After expending so much effort to place myself in a special location at the perfect time, I felt reluctant to leave. I wanted to make sure that I had captured all the necessary shots, but the howling seemed to be getting closer, so I stumbled my way back to the car and headed for home and the welcoming arms of Photoshop.

Light Painted Apple, Walpole, NH

Connecticut River, Chesterfield, NH

I reached home at about 3AM and as always, instead of heading immediately to bed, I had to upload my images and apply some preliminary edits to get a sense of what rewards I had received for the my sleep deprivation. I'm still experimenting with post-processing techniques for star field images. My current approach includes preliminary adjustments in Lightroom and final localized tweaking in Photoshop, but it would be best to save that discussion for another blog. Besides, every time I come back from a night under the stars, I seem to take a different approach in the digital darkroom.

I hope this discussion provides a helpful overview of how a relative new-bee might approach star field photography. With just a little care, the technical aspects are actually quite simple. The biggest challenge is to haul yourself out of bed to get to the right place at the right time with the right weather.

And watch out for the Zombies!


Other Articles From My Blog:

Night Time Photography, Searching for the Milky Way 
April 2013

Look to the foreground in Milky Way Photography
June 2014 

Valuable References:
Night Sky Photography, Aaron Priest

Aim for the Stars, Mike Blanchette,
New England Photograhy Guild


Jeffrey Newcomer
Partridgebrookreflections.com

Reclaiming the Sky

Boiling Sky, Langdon, New Hampshire

Finding the Hidden Detail 

 

Overcast skies have always been a challenge for photography and this is especially true in the Autumn, when the weather becomes more changeable. As I mentioned in last weeks blog article, the best approach flat dull skies has often been to crop them from the image, but with new powerful editing software it is possible to find interesting detail in those grey clouds without creating muddy foregrounds.   It is time to reclaim the sky.

Cheating with the Sky

For years it had been a habit of mine to collect images of nice skies.  Whether it was puffy white confections floating in a deep blue orb

Sky Archive

or the lovely colors of a golden sunset, I would always pause during my shoots to capture a few shots of the sky with as little ground as possible.  I would save these treasures in my "skies" folder to be pulled out whenever I had a picture with a lovely foreground but a flat washed out, overcast sky.  Back then, the selection tools in Photoshop were not as sophisticated as now, but I would still spend

Cheating on the Sky

time trying to seamlessly composite one of my skies to save my image.  The trick was to find a sky that seemed to match the scene's light direction and color, while muting the stark contrast between a bright sky and the softer foreground.  My results were decidedly mixed and, of course, bathed with artistic dishonesty. What can I say, I've always been willing to compromise my morals in the service of the image. The picture here represents the first time in years that I have blended a different sky into an image. The effect is purposely exaggerated, but I'm still glad that I don't have to do this anymore. 

 

 

Black Mountain, Dummerston, Vt

Things have changed in the last few years.  Today, It is a struggle to even find my Sky Folder.  The sky hasn't changed, and my moral compass hasn't shifted.  The difference has to do with the improvement in image depth and quality and the remarkable advances in editing software.   I can now bring out the the detail and drama that I saw in those dark and brooding skies

 

Winter Clouds Over Mt. Monadnock, Marlborough, NH

Shooting in the RAW

The first key to salvaging flat skies is a properly exposed RAW image.  It seems strange now that there was a time when I actually struggled over the question of whether I should switch my shooting from jpg to RAW.  The enhanced image depth from an 8 bit jpg to a 14 bit RAW file means that I can work with 16,000 tonal gradations as opposed to just 256.  That difference is especially powerful at the upper end of the brightness spectrum where the increased depth allows wonderful detail to be drawn out, even from apparently featureless skies.  This was never possible with jpg files.  (see my article about exposing to the right).  Proper exposure is still important. It is critical to avoid over-exposure which can result in blown out the highlights.  Here again the histogram is invaluable.  A properly exposed RAW file is the essential prerequisite, providing the information necessary for the next step to a reclaim the sky and that  next step comes in the software.

Software Highlight Control
 

There have been substantial improvements in highlight management in recent versions of photo editing software.  Here I will be speaking of Photoshop and Lightroom (LR), but there may be similar tools in other programs.  Essentially what the software does is to expand the tonal range in the highlights of the sky to provide more contrast without unnaturally darkening the rest of the image.  Again, it is important to start with the increased tonal range found in the RAW file.   There are a number of tools that can be used to reach this goal.

Shadow/Highlight

Since its introduction in Photoshop CS, one of my favorite tools in Photoshop has been the Shadow/Highlight adjuster (S/H).  This is found in the adjustment section of the Image pull-down menu..  The tool almost magically allows individual adjustment of both the highlights and shadows in an image. For this discussion, I will be focusing on the highlights where the S/H tool draws out the contrast and detail in the skies.  The Tonal Depth slider controls

Shadow / Highlight Adjustment

the range of the effect restricting it to the desired areas of brightness.  Shadow/Highlight is often one of my first steps in managing highlights, but it must be used carefully.  Overuse can lead to unnatural appearing skies and the presence of bright halos around areas of high contrast. The halos can be controlled by adjusting the radius slider.   Even with the increased tonal depth of RAW images, attempting to draw out too much contrast can lead to the appearance of posturization, with sharp steps between tones.  The goal should be to adjust the sky to reveal the detail seen on site.  I must point out that the S/H tool is too complex to be available on an adjustment layer and has to be applied to the actual image.   To protect the background image I always work with S/H on a copy of the image layer.  Alternatively, the  S/H adjustments can be applied to a Smart Object Layer, allowing continuous adjustment as the editing process proceeds.  The S/H tool is remarkably powerful but in recently I save these adjustments for later in my editing work-flow and do much of my "sky work" in the RAW of Lightroom.

Lightroom and Camera Raw

Newer versions of Lightroom and Photoshop’s Camera Raw have added greater flexibility in dealing with lost details in the highlights and have eliminated or reduced my need to use S/H later in my workflow.  Recently I have shifted much of my RAW editing from Camera Raw to Lightroom 5.  I find the work flow to be much

Flat Raw Image / Good Histogram

easier and more intuitive, but newer versions of Camera RAW have similar capabilities. In my photograph of fall color across a field in Langdon, New Hampshire, the original RAW image appears flat with washed out colors and the sky has none of the color  and contrast that I remembered from the scene.  This is typical for unedited RAW images, but, as can be seen in Lightroom 5, the histogram reveals good tonal range.  The highlights are shifted to the right but are not blown out.  The picture does not look great, but I know that my vision is hidden within the pixels, straining to be released.

The Develop Module

In Lightroom's Develop Module, I slightly increased the exposure and then reduced the Highlights and Whites sliders to reveal the sky detail.  The Shadow and Blacks sliders controled the exposure and contrast in the shadow areas.  My basic approach is to use the

Lightroom 5 Development

Whites and Shadows sliders to make the major changes.  I then increase the Highlights slider to add contrast and avoid muddiness in the sky.   In the same way,  I decrease the Blacks slider to  provide contrast and definition to the shadows.  The result  should be softer contrast in the mid tones while preserving the "Pop" in the highlights and shadows.  These alterations could be done with careful manipulation of levels and curves in Photoshop, but they are easier and more naturally controlled in LR or Camera Raw.  And all changes are reversible and nondestructive. 

After my tonal adjustments I continue to work through the Develop Module.  I have come to like the workflow suggested by the stack of tools in this module.  I adjust vibrance and clarity.  I make some preliminary tweaks to sharpness and noise, although my final sharpening is always reserved for the end of my editing, when I have the image at its desired size.  The automatic Lens and Chromatic Aberration controls generally work well, but I always zoom in to the edges to to make any necessary custom adjustments. 

 

Photoshop Tweaking

Shadow/Highlight Adjustment

By the time I move my images over to Photoshop, the skies are generally looking pretty good.  I may still use the S/H tool but the

Selective Curve Adjustment in SKy

adjustments can be fairly subtle and much less likely to add artifacts and halos.   In this image I took the further step of isolating the sky in a carefully drawn selection and then added further contrast with a curves layer.  The end result was purposely over done for illustration, but the advantage of the selection is that I was able to invert it to apply a separate curve adjustment to the foreground.  Normally I would mute the effects shown here but in every step the strength of the manipulations are strictly a matter of taste.

 

 

That's it.   The result is a image that shows the brilliant fall color against the dramatic boiling sky that was visible on that cool autumn morning.   It only remains to add a couple of caveats.  

First I apologize for rushing through descriptions of editing that would require books to fully describe.  My purpose is only to illustrate what is possible in our amazing digital world.  Full understanding and control of these tools is really an exciting, life-time journey.   For those who don't have access to programs such as Lightroom and Photoshop, I can only say that amazing capabilities are within the range of most budgets.  Lightroom 5 is available for only $149 - save your pennies.

 

Steel Sky, Chesterfield, NH

 

Some will say that the same results could be obtained with a multi-image HDR.  Certainly true, but for me the adjustment of the single image is easier to control, more natural, and less subject to artifacts and noise.  

As always it is a matter of taste, but regardless of your approach, get out there and reclaim the sky!

Jeffrey Newcomer

Partridgebrookreflections.com