New MOC Stamp Layer

The MOC Stamp Layer will display stamps for all of the images taken by the Mars Orbital Camera (MOC) aboard Mars Global Surveyor. While the search interface is similar to the THEMIS Stamp Layer, there are changes that allow users to search for images by the many parameters associated with MOC images.

Open the MOC Stamp Layer

1. Open the Stamp Layer: Chose "Add New Layer" -> "Stamps" -> "MOC Stamps".
2. Enter Search Parameters: An input box will appear with all of the available search parameters. It is not necessary to enter values for each parameter, but the more specific your search the faster it will be. The allowable values for each field are given in the quick reference table below followed by more detailed descriptions of each search parameter.
3. Perform Image Search: Clicking OK will make the Stamp Layer perform the search and display the results. Depending on how specific the search parameters are, it may take the Stamp Layer a few minutes to find and create stamps for all of the images. Once the stamps are displayed in the Viewing Window, users can right-click on an outline to either render the image (display the image data in JMARS) or view the image in a web browser.

Search Field Descriptions

Image ID

A unique identifier for each image commanded; follows the pattern XXX-ooooo, where:

a) XXX is a 3-digit mission phase identifier

b) ooooo is the zero padded, 5 digit image number

Instrument

The MOC had two cameras: a narrow-angle and wide-angle. This identifies which camera was used to collect the observations.

Filter

The MOC wide angle camera had both blue and red filters. The MOC narrow angle camera only took unfiltered (N/A) grayscale images.

Mission Phase

The MOC imaging mission is divided into the following phases:

AB1 Aerobraking Phase

SPO-1 First Science Phasing Orbits

SPO-2 Second Science Phasing Orbits

Mapping Mapping Phase (First Martian Year)

Extended Extended Mission Phase (Second Martian Year)

Relay Relay Mission Phase (Third Martian Year)

Support Support Mission Phase (Fourth Martian Year)

Longitude

This is the approximate longitude on the planet Mars of the image center. All values are based on the IAU 2000 aerocentric model of Mars with east positive longitude. (gives in degrees of East Longitude)

Latitude

This is the approximate latitude on the planet Mars of the image center. All values are based on the IAU 2000 aerocentric model of Mars with east positive longitude.

Orbit

Spacecraft orbit during which this image was observed. By definition, orbits begin at the ascending equator crossing of Global Surveyor's polar orbit.

Downtrack Summing

Spatial average of NxN pixels of data before downlink; summing=1 implies that no spatial averaging has been applied. In all but a few unusual images, the crosstrack summing was set at the same value as the downtrack summing.

Scaled Pixel Width

This is the image resolution in meters per pixel at the center of the image. For most narrow angle images, this value will be approximately the same over the entire picture. For wide angle images, the pixel scale will vary over the image.

Lines

Line Samples

Solar Longitude

This is the position of Mars relative to the Sun measured in degrees from the vernal equinox (start of northern Spring). This number is used as a measure of Martian seasons. (Also known as heliocentric longitude and abbreviated Ls.)

a) Northern Spring/Southern Autumn start at 0°

b) Northern Summer/Southern Winter start at 90°

c) Northern Autumn/Southern Spring start at 180°

d) Northern Winter/Southern Summer begin at 270°

Local Time'

This is the local time on Mars at the center of the image relative to a division of the martian day into 24 equal parts. A martian day is slightly longer than 24 hours and 37 minutes long.

Incidence Angle

Derived for the center of the image, this is the angle between the Sun and a "normal" drawn perpendicular to the planet's surface at the time the image was acquired. A higher incidence angle means that a person standing on the ground would see the sun lower toward the horizon.

Emission Angle

Measured from the center of the image, this is the angle between the MOC and a "normal" drawn perpendicular to the planet's surface. In most cases, the MOC is looking "straight down" and the emission angle is thus close to 0°.

Phase Angle

This is the angle between the sun, the surface, and the MOC at the time the picture was obtained.

Slant Distance

This number is similar to the spacecraft altitude, but also takes into account the emission angle. If the emission angle is 0 then this number is the same as the spacecraft altitude. If the emission angle is much greater than 0, then the "slant distance" to the surface at the center of the image is also greater than the spacecraft altitude.

Rationale Description

A short description of why the image was targeted.

Stamp Layer Functions

The MOC Stamp Layer's functions are identical to the functions of the Thermal Emission Image System (THEMIS) Stamp Layer and are explained in detail on its wiki page.