Creating a Panoramic Horizon

TheSky6 showing a panoramic horizon of Texas A&M Astronomical Observatory

TheSky6 can load and display panoramic horizons using the Real Mode Options command. Several different horizons are supplied. By default, these files are located in the following folder on your hard drive:

C:\Program Files\Software Bisque\TheSky6\Data\Pictures\Horizons\More

Click here to download Software Bisque additional panoramic horizons.

You can even construct a panoramic horizon of your backyard!

Sample TIF file showing 360 degree horizon

The panoramic horizon is a standard TIF file. This file must also include a "masked" area called an "alpha channel" that defines the transparent portions of the horizon (the black region in the above image is the alpha channel). Most advanced image processing software (such as PhotoShop®) has tools that allow you to define an alpha channel for a TIF image.

Collecting the Pictures

If you wish to create a panoramic horizon, the following hardware and software is required:

• A digital camera

• A tripod

• "Image stitching" software that supports the 24-bit TIF file format

• Image processing software (such as PhotoShop®) that supports the 24-bit TIF file format and alpha channels (for transparency).

Picture Taking Tips

• A cloudy day is best for even light distribution.

• Use the default zoom settings for your camera. Don't use the zoom feature.

• Typically 8-10 images cover the entire 360 degree horizon.

• Make sure that the tripod is level so that the "ends" of the panorama match.

• The "experts" recommend using up to a fifty percent overlap between images for best result using image stitching software.

Creating the Panoramic Image Tips

• The TIF image must have an "alpha" channel. The alpha channel defines the areas that are transparent and visible. Use your favorite image processing software to create an alpha channel layer to define a mask of the transparent regions, and then save this TIF image. Your image processing software should have detailed information about how to accomplish this.

• The width of the image should be 5000 pixels or less.

• The height of the image should be 500 pixels or less.

• Use your favorite stitching software to combine the individual images. Search the web for a list of software that can perform this operation.

There are many web sites dedicated to creating photographic panoramas. Use your favorite search engine to search for "panorama" and "panorama tools" or "image stitching".

Using Your Panoramic Horizon TIF

After you have created your panoramic horizon TIF image, you'll need to configure TheSky6 to use it. In this example, the TIF file is named "MyPanoramicHorizon.tif."

1. Copy the file MyPanoramicHorizon.tif into the <My Documents>\Software Bisque\Horizons folder.

2. TheSky6 uses a text file to define how the photograph is displayed on the virtual sky. This text file the extension ".horizon." You must create a ".horizon" file with the same name as your TIF file (MyPanoramicHorizon.tif) and save this file in the same folder as the TIF image. There is a file named "Default.horizon" in the "Horizons" folder. Right-click on this file, and then click the Copy command. Next, click Edit | Paste. Rename the file Copy of Default.horizon to MyPanoramicHorizon.horizon.

3. Launch TheSky6.

4. Click View | Real Mode Options.

5. Select the Horizon Picture option, and then click Browse.

6. Select MyPanoramicHorizon.tif and then click Open.

7. Click Apply and Save.

Sample .Horizon Text File

// TheSky6 horizon definition file. Copyright (c) 2005 Software Bisque

// The TIF file must reside in the same folder as this definition file.

// Keywords (ALT TOP, ALT BOT, AZIM) must be uppercase followed by

// the equal sign (=).

ALT TOP =    7.0

ALT BOT =  -18.0

AZIM    =   90.0

TYPE    = PANORAMA

TYPE    = SHAPE=FALSE

See the Real Mode Options dialog box for additional information.