Introduction

OPUS (Outer Planets Unified Search) makes available more than 1,500,000 images and spectra of the outer planets (Jupiter, Saturn, Uranus, Neptune, and the Kuiper Belt) from Voyagers 1 and 2, Galileo, Cassini, New Horizons, and the Hubble Space Telescope. (More details about these missions and what OPUS provides can be found in the About section of the Help menu.)

OPUS makes it easy to perform four main tasks:

  1. Search for observations (e.g. images and spectra) using a variety of simple and complex search terms.
  2. Browse the results of the search using intuitive, colored thumbnails.
  3. Get Details on individual observations.
  4. Download PDS products (e.g. raw or calibrated data, preview images, geometry metadata) for off-line use.

These four tasks correspond to the four navigation tabs at the top of the OPUS screen. You can switch among these tabs in any order as you explore the data OPUS has to offer.

Searching

The Search tab consists of:

  1. A series of search terms on the left side organized by category. By default, there are six categories:
    1. General Constraints includes high-level information such as the mission, instrument, and target name.
    2. PDS Constraints includes search fields more internal to the PDS, such as the Bundle/Volume ID and PDS3 Data Set ID. These fields are less likely to be useful to the casual user.
    3. Image Constraints permits easy searching across missions and instruments by abstracting away details about the physical details of the observation, such as image size and exposure time.
    4. Wavelength Constraints permits easy searching across missions and instruments by abstracting away details about what portion of the electromagnetic spectrum the observation encodes, such as wavelength range and polarization.
    5. Occultation/Reflectance Profiles Constraints permits easy searching on the common attributes of both spacecraft-based and ground-based occultation profiles.
    6. Surface Geometry Constraints allows searching on the details of any body in the field of view, such as latitude and longitude or lighting geometry.
    7. Ring Geometry Constraints allows searching on the details of any planetary rings in the field of view, such as radius and longitude or lighting geometry.
    In addition, new categories will appear when the search is sufficiently restricted. For example, when all observations in the current search are from Cassini, a Cassini Constraints category will appear with Cassini-specific search fields.
  2. A series of search fields on the right side. When OPUS starts, Planet and Intended Target Name are provided. Additional fields can be created by clicking on one of the search terms on the left. Search fields can be minimized by clicking on the icon, closed by clicking on the icon, or reordered by dragging and dropping the entire search field box.

There are four basic types of search fields:

  1. Multiple-Choice Fields (such as Planet and Mission) allow you to select one or more items by clicking on a checkbox. If you select more than one item, your search will return results applicable to any of those items.
  2. String Fields (such as Bundle/Volume ID) allow you to search on strings. You can provide strings that match the beginning or end, match exactly, are (not) contained anywhere within, or match a regular expression. As you type your search string you will be presented with suggestions; click on one of the suggestions to have it placed in the search field.
  3. Numeric Fields (such as Observation Duration or Observed Ring Radius) allow you to search on a range of numbers by specifying either a minimum or a maximum value, or both. The Observed Ring Radius and Wavelength fields also allow you to type a ring or satellite name, or a color, respectively, into the minimum field. A dropdown box will give you a list of preprogrammed ranges for your convenience. Many numeric fields support selection of units. The default unit will be displayed in the search box title, but other units may be selected. Any values that have already been entered will automatically be converted to the newly select units. The Any/All/Only dropdown allows selection of how overlapping ranges are handled; a full explanation is available in the FAQ.
  4. Date/Time Fields (such as Observation Time) allow you to search on a range of dates and times by specifying a minimum or maximum date/time, or both. You can enter dates and times in a wide variety of formats, although the standard is YYYY-MM-DD[Thh:mm:ss.sss]. Once you finish entering a date/time, it will be reformatted into the standard format for you.

For the latter three types of fields, as you type your search value you will receive feedback indicating if the value is legal. A green box means it is fine as-is. A yellow box means the value is illegal and you should change something before leaving the search field (by clicking elsewhere or hitting the Enter key). If you leave the field with an invalid value, it will turn red and no search will be performed until you fix the value.

For string, numeric, and date/time fields, you have the option of searching on multiple sets of values. You do this by clicking on the "+(OR)" button, which will add an additional set of input fields. The multiple input ranges are "OR"ed together. For example, if you search on emission angles between 10 and 80 and also between 100 and 170, your results will contain observations that match either set of criteria. You can have up to 10 such ranges for each search field. All values must have the same units.

As you enter search values, the number of results that are selected will constantly update in the Browse Results tab. In addition, you will be provided (in green) in each search field with the minimum/maximum values or date/times, or the number of results for each multiple-choice item, based on your current search criteria.

The Surface Geometry Target Selector search field is special. Only one surface geometry target can be selected at a time. When you select a surface geometry target, a new [Target] Surface Geometry Constraints category will become available providing search fields for that single target. If you later change the surface geometry target, all of the existing target-specific fields you selected will automatically switch to the new target but keep their existing search values. This is useful for cases such as searching for similar lighting geometry for different targets. In addition, any metadata fields you selected for the previous target will be duplicated for the new target. If you close the Surface Geometry Target Selector, all target-specific search fields will also be closed.

Once you have entered some search constraints, it's time to browse the results.

Browsing

The Browse Results tab shows the observations selected by your search in one of two ways:

  1. The Gallery View shows a grid of colored thumbnails. The meaning of the thumbnail contents differs depending on the instrument, but in general it attempts to capture the image including filter color or wavelength range (for imaging cameras or spectrographs) or footprint (for non-imaging spectrographic instruments).
  2. The Table View shows a series of rows, one per observation, containing the currently selected metadata fields. The small thumbnail in each row can be expanded by hovering the mouse over it.

You can switch between the two views by clicking on View Table or View Gallery.

You can navigate through the result set using the scrollbar on the right, which may be moved either up or down. As the scrollbar approaches one of its extremes, additional data will be loaded, giving the appearance of a continuous data set in either direction. You may also use the mouse wheel, up/down arrow keys, or page up/down keys. To move a larger distance through the result set, you may use the slider at the top of the screen. The observation number you select will appear in the top-left thumbnail (gallery) or top row (table).

Each observation has a menu () that allows you to perform a variety of operations, including adding or removing the observation from the cart, starting or ending a range of observations to be added or removed from the cart, adding all of the observations in the current search result set to the cart, showing the details of the observation, or downloading observation data. A single observation may also be added to or removed from the cart by using Ctrl+Click, clicking on the or icons in the gallery view, or clicking on the checkbox in the table view. A range of observations may also be added to or removed from the cart by using Shift+Click to start and end the range. If the starting observation is not currently in the cart, all observations in the range will be added; if the starting observation is already in the cart, all observations in the range will be removed. In the table view, the icon in the table header can also be used to add all observations in the current result set to the cart. See the section on the Cart tab below for more information on downloading the contents of the cart.

Results may be sorted in either ascending or descending order by one or more metadata fields. The current sort fields and their associated sort directions are always displayed at the top after the icon (the sort order must always include OPUS ID as the final field to ensure a deterministic ordering). The sort fields may be reordered by dragging the field name and the sort direction for a field may be changed by clicking on the field name. Sort fields may be added from the currently selected metadata fields by clicking ; to change the list of available fields use Select Metadata. A sort field may be removed by clicking its icon. In the table view, if a column is being used to sort it will display the sort direction ( or ) and a number in a circle showing its position in the sort order. Clicking on the header of a column that is used in the current sort will change the direction for that field. Clicking on the header of a column that is not currently being used will replace the current sort if there is only one field there (other than OPUS ID), or ask if you want to overwrite or append to the end of the current sort otherwise. Ctrl+clicking on a table header will always append that field to the end of the sort (but before OPUS ID). The same sort order applies to the Browse tab and the Cart tab.

Clicking on a gallery thumbnail or table row will display a larger version of the thumbnail along with the metadata for the currently selected metadata fields; this is called the slideshow view. You may navigate by clicking on the or icons or using the right/left arrow keys. You may also add or remove observations from the cart or perform the operations permitted by the menu.

Which metadata fields are displayed in the table view and slideshow view can be changed by clicking on Select Metadata at the top. Fields may be added or removed by clicking on them on the left or removed by clicking on the on the right, and may be reordered by dragging. When available, the display units for the metadata field can be changed by clicking on the current units name shown in parentheses. Fields can be added or removed in the table view by hovering over the column header; click on the to remove a field or the to add a new field before or after the column. Finally, fields can also be added, removed, or reordered in the slideshow view by clicking on Edit. The fields and units selected here also affect what is included in a CSV file when using Download CSV (all results) at the top or the Download CSV of selected metadata menu option, as well as what is included in downloaded CSV, data, and URL archive zip/tar/tgz files available on the Cart tab. A button is available to conveniently create a CSV file directly from the Select Metadata dialog without having to save the selected fields first.

The Cart

The cart contains observations for future downloading. As described above, you can add or remove individual observations or ranges of observations from the Browse Results tab. The number of observations in the cart is displayed next to the Cart tab.

The Cart tab allows you to view and navigate through the cart in the same way the Browse tab allows you to view and navigate through the total result set. In addition, the Download Data pane on the left shows the estimated total download size of the cart as well as which data products will be included in a download. The individual products can be selected or removed to reduce the file size. If your browser is too narrow, the Download Data pane will not be visible until you press the Download Data button.

While on the Cart tab, you move observations to the recycle bin rather than removing them from the cart entirely. These observations will be marked with . You can then restore observations from the recycle bin to the cart. Observations may be moved to the recycle bin or restored to the cart as individual observations or as ranges of observations. In addition, all observations in the recycle bin can be moved to the cart at once by clicking on Restore Recycle Bin to Cart. All observations can be removed from the recycle bin by clicking on Empty Recycle Bin.

Observations in the recycle bin are not counted as part of the number displayed next to the Cart tab, nor will they be included in the downloaded data. The total number of observations currently in the recycle bin will be displayed next to the Restore Recycle Bin to Cart option.

Three basic methods of download are provided:

  1. A Data Archive includes all of the selected data products in a single zip, tar, or tgz file. The data products can be laid out in a flat directory structure with all files in the root directory of the archive file, or in a hierarchy that echoes the directory structure in the main Ring-Moon Systems Node holdings. Also included in the archive file are a metadata CSV file (data.csv), a manifest file (manifest.csv) showing which files are included along with their details (including checksums and sizes), and a file containing the URLs for each data product (urls.txt). On the Cart tab, the Data Archive button will produce a zip file containing all observations in the cart. You may also download a zipped data archive of all relevant products for a single observation using the menu anywhere it is available.
  2. A URL Archive is similar to a data archive, but includes only the non-product files (metadata, manifest, and URLs) in a single zip, tar, or tgz file. This results in a very small download. The actual data products can then be retrieved using a command-line utility such as wget: 
        wget -i urls.txt
  3. A Metadata CSV is a comma-separated value (CSV) text file containing one row per observation. The rows contain all of the metadata fields selected using the Select Metadata option (or other technique, as described earlier). On the Cart tab, the Metadata CSV button will include all of the observations in the cart. On the Browse tab, the Download CSV (all results) option will include all of the observations in the result set (which may be a lot!). The menu may also be used to create a metadata CSV file for a single observation anywhere it is available.

Observation Details

Finally, it is possible to view all of the available product files and all of the available metadata for an observation by using the Detail tab.

To view an observation's details, you may click on a thumbnail's icon or select Show detail in the menu.

The Detail tab includes a larger version of the thumbnail on the right. On the left is:

  1. The OPUS ID you are viewing.
  2. A button to add or remove this observation from the cart.
  3. A SHARE button that copies the short URL of this Detail tab (without any search details) to the clipboard.
  4. Links to download a data archive or URL archive for the observation.
  5. A list of all available PDS product types for the observation, along with all files that are available for each. Multiple versions are offered if available. If an Index file has an active link, clicking on it will provide the full detail of the observation in the given index file.
  6. Metadata for the currently selected metadata fields, including the option to download a metadata CSV file for the observation.
  7. All available metadata for the observation, including the option to download it all in JSON format. Each string or multiple-choice field has a icon after the value. If you click on this icon, a new browser tab will open with a new OPUS that searches only for that value for that search field. This is useful, for example, for easily finding other observations with the same Cassini Observation Name as the one you are currently looking at.

Getting Help

Selecting Help will provide you with various options to get additional assistance:

Thank you for your interest in OPUS! We hope you enjoy your experience and find your data easily, and we look forward to hearing your feedback.