CHDK AstroKam


CHDK AstroKam is a Windows application that lets you control your Canon CHDK camera via USB remote control.

M31 using Canon SX530HS processed in StarTools

It is designed to take long exposures of the night sky. It has LiveView and copies of your camera buttons which allows you to set all the camera parameters remotely as well as RAW shooting. It also allows you to set multi-second duration exposures for deep sky work with the following options:

  1. Single exposure.
  2. Sequence of exposures for stacking.
  3. Sky survey plans of different targets using ASCOM controlled telescope mounts.
  4. Automatic dark and bias frames.
  5. Flat and dark flat frames routine.
  6. Automatic generation of Deep Sky Stacker project files.
  7. Sort module for removing duff images prior to stacking.
  8. Integration with PHD2 autoguider.
  9. Integration with All Sky Plate Solver for accurate target centering.
  10. Integration with Cartes du Ciel observing lists.
  11. CHDK script version (right-click to download) which will run in camera without PC.


You must install the following items before AstroKam:

You should also do the following on your camera’s CHDK menu.

  • Check Enable Lua Native Calls under Miscellaneous Stuff.
  • Uncheck Enable Remote under CHDK Settings>Remote Parameters.
  • Set raw prefix to “CRW_”, raw file extension to “.DNG” and save raws with JPEGs (in the CHDK RAW + DNG menus).

The latest version of AstroKam is available from my software support group.

If you have problems running AstroKam then try running chdkptp on which AstroKam is based. It has an excellent troubleshooting guide to get you started.

Note that you can run AstroKam without a real telescope by selecting the virtual telescope for .NET under the Scope button.

Quick Start Guide

  1. Connect your camera to your PC using a USB cable.
  2. Turn on your camera and run AstroKam.
  3. Choose your top working folder.
  4. Choose your ASCOM telescope.
  5. Click the OSD button to see the camera on screen display.
  6. Click the Record button to put your camera in shooting mode.
  7. The default exposure Tv is shown at bottom left. Adjust this using the Tv+ and Tv- buttons.
  8. Click Test to take a long exposure shot. The title bar will show “Taking shot”.
  9. The title bar will show “Ready for next shot” when the shot is finished.
  10. The rest of the buttons have detailed tool tips which show how to use the other features.

Main Window

The main window has 2 rows of buttons at top and these all have drop down tool tips to explain what they do.

There are various status messages at bottom which are mostly self explanatory. Clicking the Screenshot message will save the AstroKam window to disk. The FL message displays the current exif focal length in mm. with the 35mm equivalent in brackets.

Sort Window

The sort window lets you review your captures and send any duffers to a trash sub folder. You can also send any meteors, satellites, etc to a UFO sub folder.

After sorting, click the DSS button to save a cleaned up DSS file to disk.

AstroKam Settings

Click the Settings button on the main window to display the Settings window. This has several pages which are mostly self explanatory as shown below.

Settings – General

Settings – Camera

Wheel control is sketchy so there are 2 options to try. If neither work then adjust the wheel manually or use CHDKPTP.

The ISO factor converts the AstroKam ISO into Canon units. For my SX230 and SX530 this is 0.625.

Settings – LCD

Don’t use invert and black and white together.

Settings – Scope

Settings – PHD2 Autoguider

PHD2 should be running with all equipment connected.

Settings – All Sky Plate Solver

ASPS will take an image after slewing to each target and work out exactly where the scope is pointed. AstroKam will then nudge the scope to exactly centre the target.

ASPS should not be running. Use delta will calculate the offsets between the target and actual scope position and nudge by that amount. The default will sync the scope and them move to target.

Settings – Target

Use this to set up individual targets which you can shoot immediately or add to a plan.

Settings – Plan

The easiest way to generate a plan is to create and save an observing list in Cartes du Ciel and then import it here.

Settings – Tools

Settings – Log

This displays a log of the current session which is also saved to file.

AstroKam Script

This script allows you to shoot a series of lights, darks and biases without being connected to a PC. You must enable lua native calls in your camera’s CHDK settings for it to work.

To use it, set your camera’s ISO and aperture and set your focus to manual- infinity. In the script, you can set the exposure time for lights (darks are the same) and biases. You can also set the number of lights to shoot for each dark/bias pair.

Right-click to download it here.


AstroKam is a wrapper around the excellent CHDKPTPRemote.NET by mweerden and chakphanu’s LiveView branch of it. Many thanks to them for permission to use their code in AstroKam.

 Posted by at 3:17 pm