UV/optical telescope aboard the Nasa Swift Explorer satellite has revealed new information about Pinwheel Galaxy
Using high precision mirrors supplied by Optical Surfaces the UV/optical telescope aboard the Nasa Swift Explorer satellite has revealed new information about Pinwheel Galaxy [M101] - a bright, face-on, spiral galaxy located in the constellation Ursa Major, about 15 million light years from Earth.
The satellite was designed to observe gamma rays bursts, the most energetic phenomena in the universe.
As a result of their high-energy output, they can be seen at greater distances and therefore yield data from close to the origins of the universe.
The UV/optical telescope (UVOT) on the Nasa mission was launched in November 2004 to provide ultraviolet and optical data on these gamma-ray bursts.
Based upon a Ritchey-Chretien cassegrain design, the UVOT offers a wide field of view and high spatial resolution, which placed high demands on the precision and mounting requirements of the telescope optics.
Optical Surfaces says it was chosen for its international reputation in large and demanding high precision optics, to produce the primary and secondary hyperbolic focusing mirrors and filter mounts for the UVOT.
Based on a lightweight conical back design the F2 primary of 310mm diameter was matched to a hyperbolic secondary to give a uniform lambda/25 RMS surface finish to nurse every photon into the correct place.
The challenging process of mounting and testing the optics to ensure they met specification was achieved using the company's own in-house test and calibration facilities.
The UVOT consists of a Ritchey-Chretien telescope feeding a compact image intensified photon-counting detector operating over the wavelength range 170nm to 550nm.
UVOT images are taken through a number of filters each sensitive to light of a different colour, ranging from ultraviolet light through the blue to yellow portion of the visible spectrum.
The resultant false-colour images show the shortest wavelength ultraviolet rays as blue, and the longest wavelengths as red.
The first images from the UVOT have shown that hot young stars are being formed in abundance in M101, especially in the spiral arms of the galaxy, where they show up in ultraviolet light.
The central regions of the galaxy have cooler, old stars, which appear red in the picture.
A number of foreground stars, located in our own galaxy, also reveal themselves by their red colour.
