Tutorial

Learn how to use the AstroPhotography Camera app

1-Take photos

Take the best images

The quality of the photo you take at first is 90% of the final result. Here are some advices to work in the best conditions:

  • Avoid light pollution.
  • Use a tripod
  • Set a timer

ISO

Screenshot ISO

ISO is the sensibility of your sensor. Higher values lead to brighter, but also noisiest images.

Possible values: devices dependant.

Exposure time

Screenshot Time Exposure

This is the amount of time the sensor will be exposed to light.

Possible values: 5'' max in lite version, limited by device with pro version. Not all device have the same maximum for this settings, it could be 10'', a minute etc... (for instance the LG G4 has a 30'' maximum in manual mode.)

Number of shots

Screenshot Number of shots

The number of images the camera will takes in a row.

Possible values: 5 max in the lite version, unlimited in pro. (note that if you set insanely high numbers, there's a good chance you fill your memory or empty the battery of your device before the capture session ends.)

Aperture

Screenshot aperture

The aperture of the lens. Fix on a vast majority of portable devices for now.

Possible values: device dependant.

Focus

Screenshot focus

Set the focus. Default value is infinity.

Possible values: device dependant.

Timer

Screenshot timer

Time before the capture starts.

Possible values: 0, 2, or 10''.

2- Align and stack images

Why stacking?

Basically to get a better noise/ ratio and avoid star trails. For instance, a single shot of 30s at ISO 800 will have more noise than 6x5 shots stacked with same ISO.

Alignment method

Step one: point 3 isolated stars in the first shot of your session. Once it is done, you should see three green circles around the stars you selected.

Step two: press the arrow to get to the last shot of your session. You should see the three circles at the same location as in the first picture, but there's a good chance that the stars have moved because of the earth rotation. Move the 3 circles to point the same stars you selected in the first picture and press the validate icon. The alignment and stacking process should begin. Note that it could take some time, depending the size and numbers of images to process.

Star detection threshold

Usefull if you have issue pointing the stars. Lower values means the application will be able to detect darker stars, but can lead to imprecise alignment.

Default value: 70.

Preview brightness

Brightness of the align activity. Note that this setting doesn't have any effect on the alignment process, only for visual comfort.

Troubleshouting

When aligning images, I've got a "Couldn't align any images" message

Try to lower the threshold setting.

The images aren't well aligned after stacking.

It could be because you threshold is, this time, too low. Try higher values.

3- Post processing

Brightness

Screenshot brightness

Set the brightness of the image.

Contrast

Screenshot contrast

Set the contrast of the image.

Blur mask

Screenshot blur_mask

Apply a blur mask to the image. This setting is very usefull to flatten the background of the sky, to get rid of light pollution for instance.

Settings:
Iterations
Radius
Strengh

Automatic black balance

Screenshot black balance

Usefull to blacken the background of the sky. Zoom and release on a sky portion without or with the less stars possible.

Automatic white balance

Screenshot white balance

Zoom and release on a unsatured white star.

RGB

Screenshot brightness

Adjust the red/green/blue values of your image.

Black and white

Turn the image into black and white.

Crop

Screenshot brightness

Crop the image.

Saving your result

When hitting the save button, the saving process should begin. It could take some time, as it's processed on the real image file. (what is on the screen is a smaller version for performance purposes)