Tag Archives: ephemeris

(Mostly) Free Tools for Star Trails and Star Circles

Planning Tools


  • There are lots of resources for weather, but I prefer ones that predict a few days in advance and provide an hour-by-hour forecast. In that category, I find Wunderground.com to be the best for multi-day forecasts. Wunderground’s forecasts include the temperature, wind speed and direction, percentage of cloud cover, probability of precipitation and the dew point throughout the day. And the “wundermap” of IR and visible radar is a great help, too – it even includes nearby weather stations, and webcams where available.
  • It is hard to beat ClearSkyChart – if there is a nearby astronomy observing area, that is – for predictions for the next 36 hours.  It is a little “busy” to see a Clear Sky chart, but once it is understood it is a great tool. Hint: Darker everything is good.

Location & Celestial Alignments

There are many online communities for finding and discussing photo locations.  I explain one method I use for finding photogenic locations in the video below.

  • The Photographer’s Ephemeris – free (and priceless!). Knowing the moon phase as well as the rise and set times of the sun, and moon is very helpful. I use a variety of tools for this, but TPE is the most useful by far- and there is an iPhone version as well (which is more difficult to use than the desktop version,  unfortunately). Below is a video demonstrating how I use TPE.
  • Sun and Moon Data (Monthly Calendar) – free (web resource). Knowing when the brightest lights in the sky will rise and set, and when twilight occurs is very important. Even better still, is this resource for printing out the vital data for an entire month.

Image Tools

Photo Management

  • Picasa3

It is hard to beat Picasa3 for a quality tool that works on Windows and Mac. The tool includes keyword searches, galleries, organization in albums and/or by folders and much more. Picasa3 is JPEG centric but it does recognize almost all formats – including RAW, and keeps the original files so that destructive edits are not so destructive.  I use it mostly for displaying and selecting photos, exporting them and uploading them to Flickr with the Flickr upload plugin. To use the Flickr Uploader plugin, the Flickr Uploadr tool is needed.  Other features of Picasa3 that I find very useful are the “CD Burn”, the Movie Creator, and the Text tool.  The image straightener tool is the simplest, cleanest method for fixing tilted horizons. I also use the export feature to add my copyright onto downsized images for export to Flickr or other sites.  Picasa3 does SO much more as well. And it is free! Free, I tell ‘ya!

  • Lightroom

I have no experience with Lightroom. I can’t bring myself to pay $200 for something Picasa3 already does very well and for free – and especially after shelling out mucho dinero for Photoshop.

Stacking (Combining) Images

For Windows based machines:

  • Image Stacker by Tawbaware – at $17 this is easily my favorite because of its versatility and speed. It is also well supported by Max Lyons. I highly recommend it.  Look below for a tutorial.
  • Startrails.exe – free. English and German versions. No updates in many years and it has a few “issues”. Hard to beat the price, though! It does handle dark frames better than Image Stacker. The tutorial below also shows startrails.exe.

For multiple computer types – including PC and Macintosh

  • DeepSkyStacker – free. Hard core tool for astrophotography and not particularly useful for star trails.
  • PixInsight – 171 euros. No experience. Looks daunting and again, geared toward astrophotography rather than star trails.
  • Adobe Photoshop – ($varies). The Extended version Statistic script is handy for stacking. Otherwise it is a tedious and slow tool (IMHO) for stacking.
  • GIMP – free. An open, free alternative to Photoshop. Trying to assemble all of the plugins and prerequisites to get the tool to do stacking is not worth the effort. GIMP under the covers is also an 8-bit per color editor so loses some fidelity. On the other hand, I find GIMP much, much easier to use for typical masking and combining of images.
  • Picasa3 – free. Yes, even Picasa3 can stack images using a “collage” in “Multi-exposure” mode. But the results are not all that spectacular. A plugin for Picasa3 could make nearly all the other tools unnecessary.

For a tutorial on using Image Stacker and/or StarTrails.exe please see here:




I can usually load Picasa3 make my simple adjustment and save the file before Photoshop has finished loading itself and an image.

  • Picasa3 – free. Very easy and fast to do simple spot touch ups, color balance, horizon corrections and tonal adjustments.
  • Photoshop – ($varies). More complicated adjustments like removing aircraft trails, combining images (hand HDR) are better left to Photoshop.

Image Manipulation

  • Photoshop – ($varies). The swiss army knife, atomic weapon, and grapefruit spoon of photo manipulation.
  • GIMP – free. In many ways easier to use then PS.
  • FSResizer – resize, frame, add copyright information.  A specialty tool, but a quick and handy one.

Star Circle Planning Tools in The Field

In early September, I discussed the four essential tools for planning a star circle or star trail shot. Briefly recapping, those are:

  1. Google Maps (or other mapping software preferably with roads and terrain maps).
  2. An ephemeris
  3. An Inclinometer
  4. A GPS Unit – very useful for finding a location as well as finding north (if your unit has a compass built in, that is).

In this article I am expanding on those basic items and I am about to tell you where most of these tools reside… wait for it… my iPhone. Trust me I am no great gusher of “all things Apple”. My co-workers have been defecting to the Mac platform while I have been cursing myself for sticking it out with Windows 7 and all of the bizarre behaviors that came with it.

But my iPhone is an indispensable tool for me. I use it much more onsite than for pre-planning, but the apps are very useful nonetheless. Can you do this stuff with a netbook? Probably. Android phone? Most likely. But I do not have those and I have come to love my *first generation* iPhone. Yep. Still first generation.  Sure I could grab my wife’s former G3 model since she’s moved on to an iPhone 4… but my iPhone feels quite comfortable to me because it is set up just how I like it.

My indispensable apps in approximate order of their value to me are as follows:

  1. Words With Friends $3 – or get the free version  (App Store, website)
    I have to do something to pass the time while the camera is clicking away. This is for playing scrabble with folks. Requires a data connection through wifi or carrier. Was VERY buggy, but stability has improved. I am usually playing 10 to 15 games at a time.
  2. Clinometer (for iPhone / iPod or iPad) $1  (App Store, website)
    Probably my most useful application. I use this onsite to measure angles from the horizon. I can determine if the North Star will be visible, and how close or far to get from a foreground object to have the north star where I want it. I start the app, sight along the long edge of the iPhone and read the angle on the display.   I can scout during the day and get just what I expect when it gets dark. I will cover this very useful tool in more detail in an an upcoming column as well as the next workshop.
  3. Starmap $12 or Starmap Pro $19  (App Store – regular, pro).
    I bought the regular version even though I knew the pro version was coming out. Great planetarium app with dates and locations for meteor showers of every description, sun, moon and planetary data, constellations and the ability to customize the display to match your viewing conditions. My main gripe is that it uses only “common” names for the constellations. I know the latin names (I much prefer Orion to “The Hunter”). Has a good “find it” feature and you can set it for different dates and times and locations. Very handy for navigating the night sky.
  4. Photo Buddy $2 (App Store, website)
    It is overkill for what I use it for which is primarily: calculating the hyperfocal distance, and calculating the angle of view. It will also calculate depth of field and has a sunrise and sunset function. There is a very wide selection of cameras and models which makes configuring it pretty easy even if the interface is just a bit clunky.
  5. Focalware $5 (App Store)
    I do not use this as much, but it will calculate sunrise, moon rise, sunset, moonset and altitude and azimuth for each. It needs a signal to determine your location or you can enter GPS coordinates.  There is a very advanced version of a similar app called Helios which sells for $30 – if they had it for the moon it would probably be worth the price.
  6. iCSC free. International Clear Sky Chart –
    Predicts visibility on an hour by hour basis for the next 24 hour period. Widely used by astronomers and usually very accurate. Covers most of the continental US and Canada.
  7. Safari (builtin) Sometimes you have to look something up on the internet… if the internet is available, that is.
  8. Flashlight (free). (App Store)
    This app is a bit clunky, but you can use it for light painting and once when my headlamp broke it was very adequate as a “flashlight” substitute since it can be set to any color or luminosity.
  9. Built in Camera (free)
    The old iPhone has no zoom so it is possible to measure angular dimension with just the camera display. It also comes in handy for grabbing quick shots of possible shooting locations. Admittedly the G3 version with built in location info would be better for this.
  10. TPE [The Photographer’s Ephemeris]  $9 (App Store, website)
    Sadly, since this app requires a data or wifi connection to be useful, and since the screen real estate is so tiny, I find this a less useful substitute for the free version which you can use on your laptop or desktop machine (Mac or PC). An iPad version is available which provides much more real-estate to work with. Haven’t tried that version yet, however. A new feature has been added which seems very interesting (finding WHEN the moon or sun will be in the direction you want)… but I haven’t used it yet.
    If you’d like to learn how to use TPE, there are many resources available, including a tutorial I did:  Using The Photographer’s Ephemeris
  11. TideApp (free)  (App store)
    When photographing along the coast it is very helpful to know when and how high the tides will be.  There are not many tidal stations and finding the closest and most accurate one is not easy… but it sure is handy when you need it.  Hint: if you want tides along the Pacific Coast do not pick stations that are inside of bays, rivers or estuaries.

Essential Tools for Planning a Star Circle Shot

Consider this image:

Bristlecone Pine Star Trail

Bristlecone Pine Star Circle

This shot was set up in the daytime. All the shooting happened while I was not there: I was sleeping in my tent! But that does not mean it was easy. I used several tools plus on-site scouting to conceive and execute this shot. The tools were:

  1. Google Maps (and Google Earth) – to locate potential subjects before scouting
  2. An ephemeris for the moon phase, rise time and set time to determine when the best possible times are to work with rather than against the moon;
  3. An inclinometer to measure the angular height of an object and the angle above the horizon.
  4. And a GPS unit (on site) to find and mark the shooting location AND to determine where true north is.

I’ll address them briefly here and then talk in greater detail about each in subsequent posts.

Google maps is very useful for identifying possible shooting locations, topography, roads and trails.

An ephemeris (meaning a schedule of events) is very handy for determining the best dates and times for night photography. You will need to know the phase of the moon, the moonrise and moonset times and sunrise and sunset times. There are many sources for this data but it is important that your data be for the location where you plan to shoot.

I did not actually use one for this shot, but an inclinometer used on site is very handy. An inclinometer measures the angular height of something relative to the horizon. Polaris sits above the horizon at an angle equal to the latitude of the observer. In Hawaii, the southernmost state, Polaris is about 19 degrees above the north horizon. But the Bristlecone pines in the White Mountains of California are farther north. At the latitude of the Bristlecone pines Polaris is 38 degrees above the horizon.

To make your shot set up much simpler you will need a way to determine where true north is (not magnetic north!). Although a student of the sky will be able to find the North Star at night, it is best to make sure you have north nailed before it gets dark. I find the best tool for this is a handheld GPS unit. I use the GPSMAP® 60CSx – newer devices are available.

In truth you can pare down this list to three tools. Your camera can be used to measure angles if you know the trick. More on each of these tools in subsequent articles.

If you would like some hands on experience learning and using these tools, please join us for our November 5-7th Star Circle Academy Workshop in Alabama Hills, California.