Shoot the Stars with your iPhone

I've recently discovered an app called NightCap Pro that allows you to take night sky (and other low light) images with an iPhone.

I haven't had much in the way of clear skies lately, but I have had a chance to try to app out a bit to see what you can do with it, and I must say, that I'm impressed.

The app has several modes that will appeal to those wanting to capture shots of the night sky. The shot above was my first photo with the app. It was taken in Star Mode and shows the constellation Orion. One of the great features of the app is that you can basically set the focus on your phone's camera to infinity, so you don't have to worry if your stars will be pin points or not. I wish that my DSLR had that ability, as getting a good focus at night can be challenging.

Of course, to take any night sky photos (with an iPhone or DSLR) a tripod of some kind is an absolute must. I've got a Joby for my iPhone and it is great. You can attach it to just about anything. For ease of use, I've been gripping mine to my my regular camera tripod, but my backyard fence would also do nicely.

What I especially like about the app is that you can set it to Star Trails Mode to capture long exposure photographs of the night sky. The shot above shows Orion again (with an airplane flying past Betelgeuse).

Here's a longer shot, with numerous airplane trails, pointed at Polaris, the North Star.

And another photo with Polaris at left and the stars of the Big Dipper ascending just right of middle. The Night Cap Pro app also has a mode for photographing satellites and meteors, which I have yet to try out.

Of course you'll always get better night sky pics with a DSLR camera than you will with the teeny tiny aperture that an iPhone has, but that's the point. It is impressive that you can get any star photos at all with an iPhone. That's the great thing about this app, it allows your tiny iPhone camera to do much more than it was designed to do.

I took this shot of star trails (and a meteor) over Halemaʻumaʻu Crater in Hawai'i Volcanoes National Park in the summer of 2014 with a DSLR. Next time I'm there I'll try it with my phone too.

The Window Seat

When flying it sure it nice to have lots of leg room. That makes the aisle seat a very attractive choice, but the window seat can offer some pretty amazing views that are tough to pass up. I just took a whirlwind trip to Portland Oregon and back and very much enjoyed looking out the window.

On the way up I unfortunately sat at a really scratched up window that also had a fair amount of condensation, which later became ice, between the window's layers. It didn't offer the best of views, although I did manage to see Crater Lake National Park and snap this shot of it with my phone:

If you look closely, near the bottom of the photo you can see the big, round caldera of Crater Lake and also Wizard Island within it. I was fortunate enough to be able to visit CLNP in person in the summer of 2008. Here's how it looked back then:

It certainly is a beautiful place.

For this morning's flight back home I had the window seat again and a better window. I tried some more photography with my phone. I took some still shots like this one of some snow-covered mountains:

I also tried out the free Motion Pictures app for my iPhone, allowing me to make some time-lapse movies of the views.

This was shot with one frame every second and 30 frames are in each second of the resulting video. The app is very easy to use. I'll have to find some other interesting ways to make use of it. Here's another short video shot looking out the air plane window with the same settings:
You'll notice that I didn't do the best of jobs holding the phone very steady. When we flew over the Grand Canyon I was even worse at holding the phone steady. So instead of subjecting you to that bumpy video, I'll just post a still:

 I've got a some more trips coming up soon. If I get any interesting videos, I'll be sure to post them here.

Measure the Night Sky with your Phone

People with an interest in light pollution can now use their smartphones to measure the brightness of the night sky. There are new apps out for both iPhone and Androids that are easy, accurate and inexpensive.

The iPhone app is called Dark Sky Meter. It works very much like the much more expensive Sky Quality Meter and its results compare very favorably to it. It is available in both free (also called Lite) and Pro versions. The Pro version currently costs just $3.99.

It uses the iPhone's camera to first take a dark frame (done by placing your finger over it) and then measures the night sky. The app knows date, time, location, moon phase, weather and the phone's tilt so it can generally tell what data is good or not.

Here's a sample of what the readout looks like with the Pro version. 

That's a measurement made from my yard. 20.25 is the night sky brightness as measured in magnitudes per square arc second. While that may be arcane to some, it is a useful number to know. I wont go into the details here, but higher numbers are darker. There's also a description to go with it. Also reported is the naked eye limiting magnitude, which happened to 6.18 at the zenith for me.

The Pro version also lets you see your own data:

That's a nice feature as it lets you track what is going on from your observing site and, if you want, to send your numbers off to programs like GLOBE at Night. Yes, I need to make more measurements. The user also has the option of uploading the data to the app's database. You can view all the data on their interactive map, here. It is good stuff, but more people need to be contributing. The International Dark-Sky Association has worked directly with the app developers and is hoping that crowdsourcing will lead to many useful measurements.

The app is currently most accurate using the iPhone 4S or 5. It works for the 4, but the camera is not as good, so the quality of the data suffers.

Android users should not feel left out as there is an app for them too. The free app Loss of the Night allows Android users to measure night sky brightness by observing stars. The data from that program is also used to help track and study light pollution. As you may have guessed, I do not have an Android phone. So, while I have not personally tried it out I hear very good things about the app and how it works.

It has never been easier to measure the impact of light pollution on the night sky. So why not download one of the apps and help contribute to science?

App Review: Sky Week

One of the nice things about many astronomy apps for the iPhone & iPad is the ability to tie the built-in GPS, compass & motion sensors to allow a novice user to go out under the sky and identify what is up right then and there.  I will be talking about some of those apps in the near future, but I am going to start off with a simpler, but useful app called Sky Week.

The Sky Week app comes from the folks at Sky & Telescope magazine.  Its function is to give novice & expert stargazers a look at what is of interest in the night sky for the coming week. 

The app loads and if necessary updates quickly, giving the user a display like the one shown here:

What you see is a description of event or two for each of the days in a nine day period.  Further down (below this screen grab) is visibility information on our solar system's eight planets. The app is updated weekly and does not allow you to scroll forward or backward in time to get lists for other weeks.  You can easily set the view to display red text on a black background - a handy feature that allows you to use the app while keeping your eyes adapted to seeing in the dark.

Each of the events listed contains a red VIEW link on the right that opens a simple interactive star chart that is tied the date & time for the event.  Here is a screen grab for the star chart for the event for Friday, March 4, 2011:

It brings up a star chart showing where in the sky to find the star Sirius.  You can pinch to zoom, scroll around the sky with your fingers and use the interface at the bottom to adjust the time you are viewing the chart.  Most often the star chart that pops up is for your current location, but the descriptions are generally written for observers located in the middle of North America.

While finding Sirius is pretty basic (after all it is the brightest star in the night sky), the app contains more detailed information that will please more seasoned amateur astronomers such as when and where to spot an asteroid occultation (when an asteroid can be seen to pass in front of a star) or when the eclipsing binary star Algol hits maximum or minimum brightness.

Sky Week runs smoothly on the iPhone and the iPad where runs in the iPad's native resolution and  is one of the few astronomy apps that I actually use every week. It is available from the iTunes App Store for just $0.99.

Note the version that I reviewed is 1.0.2.

App Review: Exoplanet

These days the branch of astronomy devoted to the discovery and study of exoplanets (planets that orbit stars beyond our sun) is undergoing an explosion of sorts as new worlds are being discovered at a prodigious rate.

Just a couple of weeks ago the team of astronomers using the Kepler space telescope announced the discovery of a solar system with six worlds and that they had over 1,200 more exoplanet candidates awaiting confirmation. Many more exoplanets have yet to be discovered by the Kepler and other teams, but if their early exoplanets are confirmed it implies that their may be well over a million Earth-like worlds in our galaxy alone.

Keeping current with this field is now officially a difficult task.  Fortunately there is a handy, free app called Exoplanet available for the iPhone & iPad that conveniently summarizes just about everything that is known about the exoplanets that have been discovered so far. 

Upon opening the app, you'll be prompted if there is new data waiting to come over to your device. As of the last update to the database there are 528 known exoplanets.The app allows you to see data on the exoplanets and sort this data by any number of characteristics such as orbital period, mass, radius, discovery year and much more.  You can even filter the data and combine search features.  So if you want to sort the list by mass and only see exoplanets around G-class stars (like our own sun), you'll find that the smallest exoplanet discovered so far that orbits around a sun-like star is Kepler-11 f  (one of the member of the six-world system illustrated near the top of this posting).

You can choose the exoplanet with a simple touch and a graphic like the one below (this time for Kepler-10 b) pops up that graphically displays the method of discovery (transit), the size of the world (relative to Earth, Jupiter, Uranus or Neptune), a star chart showing the location of the host star, and an orbital diagram that relates the orbit of the exoplanet to our own solar system.  Touch any one of these and an expanded view slides into view. There is also actual data on the world and links to published scientific papers related to the world you are looking at.

From the main menu you can also find recent exoplanet news, basic information on exoplanets and how they are discovered.  The app also has the ability to generate plots of data which you can then export to a PDF file.  The Milky Way section plots the locations of exoplanets in our galaxy.  You can zoom and tilt the view of the galaxy.  I found the Milky Way plot to be the least useful tool within the app.

If you are interested in exoplanets or possibly looking for data to help draft a science fiction story this app is a worthy tool.  Exoplanet provides current and accurate information on exoplanets. I have been running it for some time on an iPhone 3GS and an iPad. The app is very easy to use and free.  There is some hint in the app that a future update may make it ad supported.  Currently there is a provision to "Remove ads for $0.99" even though there are no ads in the app yet.  $0.99 isn't much of an investment to help support future releases.  Check out the developer's website for more information and a video of the app in use.

I plan on doing more reviews of astronomy apps. As you may have guessed, I am an IOS user so the reviews will be skewed to apps that are available for the iPhone and iPad.