Observatory Preferences

To open Observatory’s preference window, choose Observatory ▸ Preferences, or use the keyboard shortcut (⌘,). There are four preference panes that you can use to further customize Observatory to suit your needs.

General Preferences

General Preferences
General Preferences

The General tab of the Preferences window includes settings for common interactions you’ll have with Observatory. It contains the following preferences:

Stacking, calibration and the star detector, used internally by the plate solver and the align adjustment, all optionally use a GPU for their computations. It may not always lead to a performance improvement, so use this option with caution.

Accounts Preferences

The Accounts tab of the Preferences window includes settings for the Virtual Observatory.

The Virtual Observatory is used to search for and download images from several professional astronomical image archives. To download images from the ESO archive a user account is required. Creating it is free, and can be done at http://www.eso.org/userportal/. On that page, select I would like to create a new account, and follow the instructions.

After you have created the account, enter your ESO User Portal username and password here. The account information is securely stored in your computer’s keychain and only transmitted to eso.org over a secure connection. It is never transmitted to us or anyone else.

Accounts Preferences
Accounts Preferences

Catalogs Preferences

The Catalogs tab of the Preferences window includes settings for optional astronomical catalogs that enhance the astrometrical matching capabilities of Observatory.

Although Observatory comes with the highly accurate Tycho–2 catalog of more than 2.5 million of the brightest stars up to magnitudes V~11, for many astronomical images this is not enough for finding an astrometrical match. Hence Observatory can be augmented with the UCAC4 and USNO-A2.0 catalogs.

Catalogs Preferences
Catalogs Preferences

UCAC4 is a catalog of 113,780,093 stars covering the entire sky, mainly in the 8 to 16 magnitude range in a single bandpass between V and R with positional errors of about 15 to 20 milliarcseconds. It is more accurate than the USNO-A2.0 catalog, and is preferred over it for astrometric matching. Observatory does not automatically download this 9GB catalog for you. Instead, you will need to do this manually from http://cdsarc.u-strasbg.fr/viz-bin/Cat?I/322A into a folder anywhere in your file system. After completing the download, this folder should then contain a UCAC4 folder that looks like this:

Finder - UCAC4
Finder - UCAC4

Now click the Select Folder… button of the UCAC4 Catalog section in the preferences, and select this UCAC4 folder.

The easiest way to download the data is to use an FTP client. Cyberduck (http://cyberduck.io/) for example, which is Open Source and can be downloaded for free by clicking the “Download for Mac” button on their website.

After installing the FTP client, open the UCAC4 catalog page in Safari and click the “FTP” tab. It will then automatically open the FTP connection using Cyberduck at the correct path (/pub/cats/I/322A) on the FTP server. Select all the files listed, including the UCAC4 folder, and click “Download To…” of Cyberduck’s menu. It’s 9GB of data, so the download will take a while.

Note that although Safari has some support for FTP, it will not work in this case because it is unable to resolve the UCAC4 link on this FTP server.

USNO-A2.0 is a catalog of 526,280,881 stars covering the entire sky, down to magnitude 19. The catalog can be downloaded from ftp://ftp.nofs.navy.mil/pub/outgoing/usnoa/ and requires approximately 7GB of disk space. Assuming you have downloaded it into a folder named USNO-A2.0, it will look like this afterwards:

Finder - USNO-A2.0
Finder - USNO-A2.0

Now click the Select Folder… button of the USNO-A2.0 Catalog section in the preferences, and select this USNO-A2.0 folder.

In the end, your Catalogs Preferences will look something like this:

Catalogs Preferences Example
Catalogs Preferences Example

You can now use both catalogs for astrometric matching, and overlay them onto your images.

Export Preferences

The Export tab of the Preferences controls how images are exported.

When you export images, you are presented with a number of presets for the output image format, the naming of the exported files as well as the generated folder structure. You configure these presets here. You can modify the default ones, or add and remove presets according to your needs.

Export Preferences
Export Preferences