(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.

One thought on “(Mostly) Free Tools for Star Trails and Star Circles

  1. Pingback: Damnable Dew! | Star Circle Academy

What do you think about this?