The Extreme Ultraviolet Imager (EUVI) is part of the Sun Earth Connection Coronal and Heliospheric Investigations (SECCHI) instrument suite on the NASA STEREO mission. The SECCHI on the two STEREO spacecraft are identical suites of remote sensing instruments designed to observe coronal mass ejections (CMEs) at the Sun and in transit outwards to 1 AU.EUVI measured emission lines at 30.4 nm (He II), 17.1 nm (Fe IX), 19.5 nm (Fe XII), and 21.1 nm (Fe XIV). The EUVI's 2048 x 2048 pixel detectors have a field of view out to 1.7 solar radii, and observe in four spectral channels that span the 0.1 to 20 MK temperature range. In addition to its view from two vantage points, the EUVI will provide a substantial improvement in image resolution and image cadence over its predecessor SOHO-EIT, while complying with the more restricted mass, power, and volume allocations on the STEREO mission.

The Heliospheric Imager-2 (HI-2) telescope is part of the Sun Earth Connection Coronal and Heliospheric Investigations (SECCHI) instrument suite on the NASA STEREO mission. The SECCHI on the two STEREO spacecraft are identical suites of remote sensing instruments designed to observe coronal mass ejections (CMEs) at the Sun and in transit outwards to 1 AU. The HI-2 telescope observes the inner heliosphere from 66 to 318 solar radii with the band-pass wavelength of 450-750 nm.

The Heliospheric Imager-1 (HI-1) telescope is part of the Sun Earth Connection Coronal and Heliospheric Investigations (SECCHI) instrument suite on the NASA STEREO mission. The SECCHI on the two STEREO spacecraft are identical suites of remote sensing instruments designed to observe coronal mass ejections (CMEs) at the Sun and in transit outwards to 1 AU. The HI-1 telescope observes the inner heliosphere from 12 to 84 solar radii with the band-pass wavelength of 450-750 nm.

The Heliospheric Imager-2 (HI-2) telescope is part of the Sun Earth Connection Coronal and Heliospheric Investigations (SECCHI) instrument suite on the NASA STEREO mission. The SECCHI on the two STEREO spacecraft are identical suites of remote sensing instruments designed to observe coronal mass ejections (CMEs) at the Sun and in transit outwards to 1 AU. The HI-2 telescope observes the inner heliosphere from 66 to 318 solar radii with the band-pass wavelength of 450-750 nm.

The Heliospheric Imager-1 (HI-1) telescope is part of the Sun Earth Connection Coronal and Heliospheric Investigations (SECCHI) instrument suite on the NASA STEREO mission. The SECCHI on the two STEREO spacecraft are identical suites of remote sensing instruments designed to observe coronal mass ejections (CMEs) at the Sun and in transit outwards to 1 AU. The HI-1 telescope observes the inner heliosphere from 12 to 84 solar radii with the band-pass wavelength of 450-750 nm.

The COR1 telescope is the inner coronagraph of the Sun Earth Connection Coronal and Heliospheric Investigation (SECCHI) instrument suite aboard the twin Solar Terrestrial Relations Observatory (STEREO) spacecraft. Like all coronagraphs, COR1 is designed to measure the weak light from the solar corona in the presence of scattered light from the much brighter solar photosphere. It designed to observe the white light corona from 1.4 to 4 solar radii.

The COR1 telescope is the inner coronagraph of the Sun Earth Connection Coronal and Heliospheric Investigation (SECCHI) instrument suite aboard the twin Solar Terrestrial Relations Observatory (STEREO) spacecraft. Like all coronagraphs, COR1 is designed to measure the weak light from the solar corona in the presence of scattered light from the much brighter solar photosphere. It designed to observe the white light corona from 1.4 to 4 solar radii.

Cor2 is one of the coronagraphs aboard the STEREO-B spacecraft. It is part of the SECCHI instrument suite. It observes the off-limb corona between 2.5-15 solar radii in visible light. It acquires both total and polarized brightness images.

Cor2 is one of the coronagraphs aboard the STEREO-A spacecraft. It is part of the SECCHI instrument suite. It observes the off-limb corona between 2.5-15 solar radii in visible light. It acquires both total and polarized brightness images.

The IMAGE extreme ultraviolet (EUV) imager detects resonantly scattered solar EUV photons with a wavelength of 30.4 nm that have been resonantly scattered by singly ionized helium (Sandel et al., 2000). The sizeable database of IMAGE global snapshots from the extreme ultraviolet (EUV) imager provides revolutionary observations of spatial and temporal plasma distributions throughout the plasmasphere. In this study, the IMAGE EUV data have been mapped to the equator using the approach detailed in Gallagher et al. (2005). IMAGE EUV data have been used to create an automated method that locates and extracts the plasmapause. The plasmapause extraction technique searches a set range of possible plasmasphere densities for a maximum gradient in order to identify the magnetic local time, MLT, dependent plasmapause position as a function of time. This description has been adapted from text appearing in Katus et al. (2015).