Comet Halley's nucleus - Images obtained by the Halley Multicolour Camera (HMC) on board the Giotto spacecraft

This page shows images used to construct the HMC image catalogue (ESA SP-1127 Volume 1).
Follow the link at the captions in the list below to view the corresponding image.

	Artificial colouring of images (left) was used to enhance small contrast steps. However, interpretation is easier when looking at the black and white representation (right).
	Image 3056 of comet Halley (a), its energy spectrum (b), and a coherent noise component (c).
	HMC image 1822 (a), cleaned of known defects (b), its coherent noise component (c), and with noise removed (d).
	Five images (left) scaled, co-aligned and averaged to one mean image taken as reference to separate noise contributions from a single image.
	Calibrated and cleaned versions of three HMC images and separated random and coherent noise. Unsharp masking has been used to emphasize the noise for the third image.
	Demonstration of the effectiveness of the responsivity correction. Examples of the results before (centre) and after (right) correction are presented for this image (top) and the unsharp masked version (bottom).
	HMC image of the Earth at a distance of 20.9 million km, unprocessed (left) and PSF corrected (rigth).
	HMC image 3056 of comet Halley at 124000 km: the first detection of a cometary nucleus.
	Calibrated (left) and PSF processed version (right) of HMC image 3491 taken at a distance of 4900 km.
	The rectification procedure converts a rectangular image (left) to a 'pie-shaped' image (right).
	'Filaments' seen in the dust emission, far too faint to be seen by ground-based observers.
	The variation of the dust emission strength with the projected angle.
	The intensity variation on crossing the nightside limb. The increase by only about a factor of 2 indicates approximately equal dust column densities beyond the nucleus and between Giotto and the nucleus.
	Evidence of non-radial dust flow: an intensity profile taken along the line of the x-axis of the graph.
	The azimuthal average decreases stronlgy with decreasing impact parameter.
	The change in the direction of the maximum emission can be seen in this polar transform of HMC image 1586 (left). The main jet appears curved in this plot. The original image with the position of the reference line in on the right.
	False colour representations of ground-based images taken using HMC filters.
	The ground-based observations in the previous image have been ring masking processed to enhance the appearance of dust jets evident in the data.
	The orientation of 13 spin axes. Red lines indicate into the plane, green lines out of the plane. The projection of the Sun-comet line is to the left. The view in the HMC image plane is shown as well as the view in the plane of ground-based observations.
	Two clear filter images of the nucleus with intensity contours.
	A tableau of features on the surface of Halley's nucleus. Non-linear contrast enhancement has been applied.
	A composite image showing the rotation axis derived by Wilhelm et al. (1986) projected in the HMC image plane.
	Azimuthal averages seen through each of the four broad-band filters.