Macc Astro header

Above: Society members prepare for the Hardraw “Silly Walk” competition. Below: Outright winners, Andrew G and Andrew H, exhibit class leading style as they demonstrate their consummate skill to the astonished audience of Tripodia, during the Hardraw trip on September 16th - 18th, 2005
Photos by Megan Argo

Hubble at 15

As well as being our Society’s 15th birthday, this year is also the 15th anniversary of the Hubble Space Telescope (HST), launched on the 24th April 1990 in the cargo bay of the shuttle Discovery. Over its lifetime, astronomers all over the world have used it to take spectacular images of an enormous variety of objects: from planets in our own solar system, to nearby star forming regions, to galaxies in the distant universe. Despite its track record, however, the future of this great instrument hangs in the balance.

Hubble’s history has not been a smooth one, but when you consider the massive technical obstacles involved in building, launching and maintaining an instrument of this sort, you cannot fail to be impressed. No one can forget the initial difficulties when, on first light, the spherical aberration in the primary mirror was discovered. At the time, many people took the opportunity to criticise the project (and NASA as a whole), and it’s future looked murky for a time. The first servicing mission, SM1, fixed this problem and full operations finally began. Now, safety concerns, budget cuts and changed priorities at NASA have meant that that the future operation of the HST is being threatened once again.

Servicing missions

The first servicing mission, SM1 (STS-61, Endeavour), was launched in December 1993. The goals of the mission were not just to fix the optics, but to install new equipment, and prove the in-orbit servicing concept was workable. Hubble was designed from the start to be easily serviced by astronauts. The body of the telescope has many handrails, and the instruments are modular in design: they can be pulled out and replaced with relative ease. As well as installing the COSTAR module (Corrective Optics Space Telescope Axial Replacement) to fix Hubble’s defective vision, the astronauts on SM1 installed several new components, including WFPC2, an upgraded version of the original Wide Field and Planetary Camera which contained improved detectors and gave better performance in the ultraviolet part of the spectrum. They also replaced several other critical components such as solar panels, gyroscope control units and flight computer coprocessors.

The second servicing mission, SM2 (STS-82, Discovery), flew in February 1997. The astronauts on this mission installed two new instruments: the Space Telescope Imaging Spectrograph (STIS) and the Near Infrared Camera and Multi-Object Spectrometer (NICMOS). STIS provided a great improvement in Hubble’s spectral capabilities, its two dimensional detectors provided 30 times more spectral data and 500 times more spatial data than the previous instruments. They also replaced several pieces of electronic and mechanical hardware such as the Fine Guidance Sensors, part of the vital electronics which keeps the telescope pointing in the right direction accurately during an observation.

The third servicing mission was split into two parts, SM3A and SM3B. The first of these, SM3A (STS-103, Discovery) was launched in December 1999. This mission was made more urgent when another of the telescope’s gyroscopes failed, leaving only two of the six operational. The gyroscopes provide vital data on the orientation of the satellite, and three are required to provide sufficient information to keep it pointing in the right direction for each observation. Hubble was designed to operate with a minimum of three functional gyroscopes, so when the fourth one failed, a mission had to be put together quickly (which, for the space program, means seven months). As well as replacing all six gyroscopes, the crew installed new insulation and guidance sensors, and upgraded the flight computer and transmitter.

The second half of the third servicing mission, SM3B (STS-109, Columbia), flew in March 2002. This mission installed the new Advanced Camera for Surveys (ACS), a highly sensitive new camera working in the visible through to far ultraviolet parts of the spectrum. It also replaced the solar panels with two smaller, but more efficient, units, and installed a new cooling system to revive NICMOS which had depleted the supply of solid nitrogen ice keeping it cooled since being installed in 1997.

SM4 - Cancelled?

Since the shuttle accident of 2003, when Columbia suffered a catastrophic failure on re-entry, NASA’s remaining shuttle fleet has been grounded. It was at this time that the fourth Hubble servicing mission, due to be launched in 2005/6, was cancelled by the then administrator, Sean O’Keefe. This decision, based largely on safety concerns, potentially shortened the lifetime of the instrument by several years. Since then there has been a huge response from astronomers around the planet in support of the continued operation of the observatory, and NASA agreed to re-examine options for a final servicing mission.

It was suggested that the safest way to perform the tasks due to be carried out on SM4 would be to fly a completely automated mission, with no human astronauts required. When this idea was initially proposed, many people were sceptical. The technology required to perform such a complicated operation is by no means trivial.

So what were the goals of SM4? Aside from the standard orbit boost, the crew would have replaced one of the fine guidance sensors, fixed damaged insulation and installed some new science instrumentation. One of these new instruments, the Wide Field Camera 3 (WF3), was to replace WFPC2, while the Cosmic Origins Spectrograph (COS) would have replaced COSTAR. Why replace the corrective optics? With the replacement of WFPC2, all the instruments on the observatory would have their own built-in corrections to compensate for the spherical aberration of the primary mirror, making COSTAR.


Hubble is currently still in operation, but how long for depends on many factors. Some of the instruments are still functioning normally, although STIS ceased operations in August 2004 due to a power supply failure. STIS is currently in safe mode and is powered down. Although engineers have been working on possible work-arounds, it is looking likely that the only way this instrument would be put back into operation is with some kind of servicing mission. More seriously, from a general operations point of view, two of the six gyroscopes on board have failed, leaving Hubble operating on three with one as backup.

The gyroscopes provide the data required to keep the telescope pointing in the right direction during an observation. Currently, three are required in order to accurately point the telescope so if another were to fail, there would be no backup. After the initial decision to cancel the fourth servicing mission, scientists and engineers started working on ways to enable Hubble to function using just two gyroscopes in order to prolong the life of the remaining components. They realised that data from the fine guidance sensors can provide the same information that would be provided by a third gyroscope. Simulations and tests have been carried out using mock-ups of the telescope on the ground and, once the new system has been approved, one of the gyroscopes will be switched off, leaving Hubble functioning on just two.

NASA’s reasoning

A shuttle servicing mission to Hubble was looked at in depth by the Columbia accident investigation board. Although several successful servicing missions have been carried out before, it is now thought too risky to send people to the orbit of Hubble. If the shuttle has a problem while in orbit with the ISS then there is the possibility of at least having somewhere relatively safe for the astronauts to go until another craft can be sent up to bring them down. Hubble orbits at a higher altitude and, should there be a problem, there is no where to go. A rescue would be virtually impossible in that scenario.

One proposed solution to this dilemma is to send a robotic mission to service the telescope. This, although the safest from a human life point of view, is not the most practical method of servicing the telescope. The mission would have to be designed, built, tested and flown within two years in order to stand a reasonable chance of saving the HST. Of course, this has to be done on a budget too.

Although this sounds like an incredible amount of work on a very short timescale, the reality is that the basic technology already exists. Using the robotic arm model of the Remote Manipulator System (RMS) on the shuttle, the same company (MD Robotics) came up with the Special Purpose Dextrous Manipulator, Dextre for short, a robotic arm designed for operation on the ISS. After the suggestion that a robotic mission to Hubble was the only way to service it, a mock-up of the Hubble was taken up to the test facility at MD Robotics in Ontario and engineers were able to demonstrate that Dextre would be capable of removing WFPC2, installing WFPC3 and COS and connecting up new batteries.

NASA’s priorities have often been dictated by politics. Currently, a large proportion of their budget (both monetary and time) is going into President Bush’s ‘Moon and Mars’ program. His speech to NASA in January 2004 laid out the three goals for NASA over the coming years: completion of the ISS (including returning the shuttle to flight, and then retiring the fleet by 2010), developing the new Crew Exploration Vehicle (CEV) as a replacement for the shuttle (with the first manned mission no later than 2014), and a return to the Moon by 2020.

Cynics among you may notice that there is not much mention of science in there. Much of the estimated cost of sending manned missions back to the Moon will come from budget reallocations within NASA itself. This could mean cuts in some of the science programs, and it is possible that some missions currently in the design phase may be scrapped. This assumes it will actually happen of course. Bush Senior also proposed sending humans to Mars when he was in office in 1989, but the project was estimated at 500 billion dollars and was eventually abandoned.

JWST: Hubble’s replacement?

Often referred to as Hubble’s successor, the James Webb Space Telescope is due for launch in 2011. Named in honour of NASA’s second administrator, the JWST is designed to answer specific scientific questions: how do galaxies form, what triggers star formation, and what are the characteristics of extra-solar planets? It is designed to study the optical and ultraviolet light from the early universe which has been redshifted to the infrared part of the spectrum, hence the JWST is essentially an infrared telescope. This differs from the HST which works from the infrared, through optical and into the ultraviolet and is far more “general purpose”.

JWST will have an impressive array of scientific instruments to help it achieve its goals: a near infrared camera (NIRCam), a near infrared spectrograph (NIRSpec) capable of taking the spectrum of up to 100 objects simultaneously, a mid infrared camera and spectrograph (MIRI) and a tuneable filter camera (FGS-TF) which will be able to image in a narrow wavelength range.

It is not just the instrumentation that will be cutting edge. The segmented mirror design is making use of the most recent developments in materials science so as to be light and robust. The deployment of the mirror poses a technical challenge as the whole satellite will be launched on a standard rocket, possibly a European Ariane, so the mirror will have to be deployed in space. The mirror will be made up of 16 hexagonal panels and will be over six metres in diameter with a total area of 25 m2.

Unlike Hubble, the JWST will be situated at L2, a point 1.5 million km from Earth. If there happens to be a problem with any of its components after launch there will be no possibility of a servicing mission, so let’s hope the mirror is the right shape!

That is the current plan. In 2003 it was reported that the budget for the JWST was already in danger of seriously overrunning the original projections, it now appears that this has become the reality. The mirror has already been scaled back from the original 8-m design, and the current suggestions to reduce the cost could result in either a further reduction in collecting area down to 4-m, or scrapping one of the three science instruments. Neither of these solutions is attractive to the astronomers who will ultimately use the instrument.

There is hope for optical astronomy in space, however. A group of astronomers from Johns Hopkins University, Rochester Institute of Technology and the National Astronomical Observatory, Japan have proposed the Hubble Origins Probe (HOP). The early design is similar to Hubble with a 2.4 metre mirror, and able to make use of both WF3 and the COS, should they not end up on Hubble itself, as well as a new instrument known as the Wide Field Imager.

So, while HOP tries to get off the drawing board, and JWST tries to decrease its costs, Hubble continues to orbit at a height of roughly 600 km, taking 97 minutes to complete one orbit of the Earth. In the 15 years during which it has been in operation so far, the HST has completed more than 80,000 orbits, travelling a total of 3.5 billion km or 25 times the distance from the Earth to the Sun, and captured over 500,000 images and spectra. Here’s hoping for many more.

Related Info

Hubble's future:
Sean O'Keefe's comments:
Bush's vision (BBC):
Bush's vision (Whitehouse):
Servicing missions:

Megan Argo

More Experiments in Receiving Weather Images from NOAA Satellites

This image was received on Tuesday 13th September at approximately noon local time. The fog has cleared and we have a lovely sunny day. I probably need to place an aerial in the loft for better reception.

This image was transmitted by NOAA 15 heading south on 12 09 2005 @ 10.57 UTC. The basic image has a map overlay and false colour added by software. The yellow cross is Macclesfield!

Alan Banks

Astronomy Software Review. CyberSky Version 3.3.1

This software CD was included with a 3-inch spherical mirror Newtonian telescope on an alt/az mount plus tripod all fitted neatly in a convenient plastic suitcase and retailed for only £25 by our local ALDI supermarket last year. The packages sold like the proverbial hot cakes. I freely admit that I was not expecting much from the software as it must have been thrown in for “free” at that price. I suppose some readers will groan at me for buying a Newtonian telescope with a spherical mirror but don’t worry, it was purchased for a specific purpose. One day and time permitting, the spherical Newt will hopefully be converted into a Schmidt camera by the addition of an extension tube and an entrance aperture at the centre of radius of the mirror.

CyberSky consists of only about 4.5 megabytes and is very easy to install, a process which takes only about 10 seconds! When running, it does not require the disc to be inserted into the computer like some of the older types of astronomy software. Furthermore, it boots up immediately and has NEVER made my PC or laptop crash. CyberSky runs on Windows 95 through to XP. Nothing disappears from the screen; the software behaves itself admirably and is very simple to use (its biggest attribute in my opinion). Even some of the more elaborate and rather expensive types of software have caused my laptop and PC to crash. You can set your own viewing location by punching in your local latitude and longitude although there is a long list of preset viewing locations provided alphabetically by country under “options”. Manchester is the nearest place to here on the list.

There are only two drawbacks that I can find with CyberSky. The time span it covers is restricted from 4000BC to 4000AD and it will not “make a movie”. However, it will “save Bitmaps” which is a useful tool for doing presentations or saving a particular map of the sky. The “animation real time” is excellent with objects slowly creeping across the screen whereas with some brands of software the stars “jump” at one minute intervals. I have set the star limit at about magnitude 5.5 otherwise there is too much information on the screen. In Congleton we are lucky to see stars dimmer than magnitude 4 due to local light pollution.

I would thoroughly recommend this particular astronomy software to anyone interested in astronomy just on the basis of its simplicity and ease of use and in my opinion CyberSky is a “must” for all schools. Teachers please note.

By the way, I suggest that anyone using astronomy software should set the computer’s time to GMT even during the summer months. I have had some software and the Skysensor 2000PC telescope controller lock on to BST when I control the Skysensor from a PC!

Ian D. Longshaw

Solar prominences

Here a some pics of the sun done in h-alpha, I used the solarview 50 with a canon eos 300 digital camera attached. On some I have removed the colour and reversed black and white.

Ian D. Longshaw

“Big Baby” Galaxy discovered by NASA

Two of NASA’s Great Observatories, the Spitzer and Hubble Space Telescopes, have teamed up to “weigh” the stars in several distant galaxies. One of these galaxies, among the most distant ever seen, appears to be unusually massive and mature for its place in the young universe.

This came as a surprise to astronomers. The earliest galaxies in the universe are commonly thought to have been much smaller associations of stars that gradually merged to build large galaxies like our Milky Way.

“This galaxy, named HUDF-JD2, appears to have ‘bulked up’ amazingly quickly, within the first few hundred million years after the big bang. It made about eight times more mass in stars than are found in our own Milky Way today, and then, just as suddenly, it stopped forming new stars,” said Dr. Bahram Mobasher of the Space Telescope Science Institute, Baltimore, and the European Space Agency, Paris.

The galaxy was pinpointed among approximately 10,000 others in a small patch of sky called the Hubble Ultra Deep Field. The galaxy is believed to be about as far away as the most distant known galaxies. It represents an era when the universe was only 800 million years old. That is about five percent of the universe’s age of 14 billion years. Scientists studying the Ultra Deep Field found this galaxy in Hubble’s infrared images. They expected it to be young and small, like other known galaxies at similar distances. Instead, they found evidence the galaxy is remarkably mature and much more massive. Its stars appear to have been in place for a long time.

Hubble’s optical-light Ultra Deep Field image is the deepest image ever taken, yet this galaxy was not evident. This indicates much of the galaxy’s optical light has been absorbed by travelling billions of light-years through intervening hydrogen gas. The galaxy was detected using Hubble’s near-infrared camera and multi-object spectrometer. It was also detected by an infrared camera on the Very Large Telescope at the European Southern Observatory. At those longer infrared wavelengths, it is very faint and red.

The big surprise is how much brighter the galaxy is in longer-wavelength infrared images from the Spitzer Space Telescope. Spitzer is sensitive to the light from older, redder stars, which should make up most of the mass in a galaxy. The infrared brightness of the galaxy suggests it is massive. “This would be quite a big galaxy even today,” said Dr. Mark Dickinson of the National Optical Astronomy Observatory, Tucson, Ariz. “At a time when the universe was only 800 million years old, it’s positively gigantic.”

Spitzer observations were also independently reported by Dr. Laurence Eyles from the University of Exeter in the United Kingdom and Dr. Haojing Yan of the Spitzer Science Centre, Pasadena, Calif. They also revealed evidence for mature stars in more ordinary, less massive galaxies at similar distances, when the universe was less than one billion years old.

The new observations reported by Mobasher extend this notion of surprisingly mature “baby galaxies” to an object which is perhaps 10 times more massive, and which seemed to form its stars even earlier in the history of the universe.

Mobasher’s team estimated the distance to this galaxy by combining information provided by the Hubble, Spitzer, and Very Large Telescope observations. The relative brightness of the galaxy at different wavelengths is influenced by the expanding universe and allows astronomers to estimate its distance. They can also get an idea of the make-up of the galaxy in terms of the mass and age of its stars.

While astronomers generally believe most galaxies were built piecewise by mergers of smaller galaxies, the discovery of this object suggests at least a few galaxies formed quickly long ago. For such a large galaxy, this would have been a tremendously explosive event of star birth.

JPL manages the Spitzer Space Telescope mission for NASA. Science operations are conducted at the Spitzer Science Centre at the California Institute of Technology in Pasadena. The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. The Very Large Telescope is a project of the European Southern Observatory at the Paranal Observatory in Atacama, Chile. For more information and additional images visit: and

Gay Yee Hill Jet Propulsion Laboratory,
Pasadena, California


Astronomers are hoping to obtain funds to allow the Deep Impact parent spacecraft to visit Comet 85P/Boethin in late 2008. That comet made two close approaches to Jupiter during the 20th century and will make two close approaches to Earth and two to Jupiter during the first half of this century. There seem to be major differences between the nuclei of the comets that have been observed from close quarters by spacecraft (Halley, Borrelly, Wild 2 and Tempel 1). Tempel 1 does not conform to the ‘fresh surface --no impact craters --crusted-over dirty iceball model that was popular previously, so the more cometary nuclei that can be studied at high resolution the better. Comet Boethin is one of the most accessible periodic comets for the Deep Impact spacecraft and would require the shortest flight time. A concern about Boethin is that it has been seen only in 1975 and 1986. It was missed at its 1997 return to the Sun because it was on the far side of the Sun from the Earth. The spacecraft team would be reassured if a large telescope could recover the comet this year or next, in good time before its return to perihelion in 2008.


Astronomers using the XMM-Newton space observatory have found that a star called SN 1979C that exploded in 1979 is as bright today in X-rays as it was when it was discovered years ago, a surprise because such objects usually fade rapidly. The scientists can document a unique history of the star, both before and after the explosion, by studying rings of light spreading from the blast, similar to counting rings in a tree trunk. Among the interesting finds is the history of the star’s stellar wind dating back 16000 years before the explosion. Such a history is not even known about our Sun. Also, the scientists could measure the density of the material around the star. The lingering mystery, though, is how this star could fade away in visible light yet remaining so radiant in X-rays. Supernovae are typically half as bright after about ten days and fade steadily after that, regardless of the wavelength. SN 1979C has in fact faded in optical light by a factor of 250, becoming barely visible with a good amateur telescope. In X-rays, however, it is still the brightest object in its host galaxy, M100, in the constellation Coma Berenices. SN 1979C appears to have originated from a star of about 18 solar masses that produced fierce stellar winds that blew into space for millions of years, creating concentric rings. The X-rays -produced after the explosion when the supernova shock caught up with the stellar wind and heated it to a temperature of several million degrees – illuminated 16000 years’ worth of stellar activity.

New Scientist

Astronomers using the Keck II telescope in Hawaii to make new observations of the motions of stars in the most distant outskirts of the spiral galaxy M31 have discovered that it is much bigger than was previously thought. They found that the movement of the sparse smattering of far-flung stars is actually synchronized with the rest of the galaxy’s stars, rotating in an orderly way around its centre. The stars had been seen before, but astronomers had assumed they were captured fragments of other galaxies that would retain their own, essentially random, stellar motions. It is now estimated that the disc of the galaxy is 220,000 light-years across.

New Scientist

Astronomers mapping the distribution of hydrogen gas within the Milky Way, a project known as the Southern Galactic Plane Survey, recently discovered another arm of our own Milky Way galaxy. The structure consists of an arc of hydrogen gas 77,000 light-years long and a few thousand light-years thick running along the galaxy’s outermost edge.

BBC Online

Astronomers say that the Kuiper Belt Object 2003 EL61 rotates once every 3.9 hours, which makes it the fastest-rotating object of its size in the Solar System. Rather than being spherical like Pluto, the object has a shape much like a squashed rugby ball, its discoverers say. By knowing its shape, astronomers have been able to determine that the object is about two-and-a-half times denser than ice; they have also found that its reflectivity is almost that of pure snow. 2003 EL61 is big enough for gravity to be the dominant force governing it rather than its internal structure.

The Register

European astronomers have discovered a quasar without a detectable home galaxy. The team studied 20 relatively close quasars (a mere five billion light years away), drawing on data from both the Hubble telescope and the VLT. In 19 of the 20 cases, they found that the quasar was, as expected, sited at the centre of a massive galaxy, but in the twentieth case no host could be seen. Instead, the astronomers observed that nearby there was a star-forming galaxy showing signs of a recent collision, and there was a cloud of gas about 2,500 light-years across just next to the quasar. However, the researchers note that observing the host galaxy of a quasar is often challenging work because the quasar completely outshines the host, so all that they can really say about the twentieth quasar is that any host galaxy must be a good deal fainter than normal.


The Cassini spacecraft has captured a series of images showing a marking that is darker than anything else around it. It is remarkably lake-like, with smooth, shore-like boundaries unlike any seen previously on Titan. Scientists say that it is definitely the best candidate they have seen so far for a liquid hydrocarbon lake on Titan. The suspected lake measures 234 by 73 kilometres. Its perimeter is intriguingly reminiscent of terrestrial lakes’ shorelines that are smoothed by water erosion and deposition. The feature lies in Titan’s cloudiest region, which is presumably the most likely site of recent methane rainfall. Other possibilities are that the feature was once a lake but has dried up, leaving behind dark deposits, or that the ‘lake’ is simply a broad depression filled by dark, solid hydrocarbons that have fallen from the atmosphere onto Titan’s surface. In that case, the smooth outline might be the result of a process unrelated to rainfall. Another 39 Titan fly-bys are planned for Cassini’s prime mission, and the scientific teams will have opportunities to observe the lake feature again and to look for mirror-like reflections, that would strongly suggest the presence of liquids, from smooth surfaces elsewhere on Titan.

BBC Online

Saturn’s ring system has its own (extremely tenuous) atmosphere --separate from that of the planet itself -according to data from the Cassini spacecraft. By making close fly-bys of the ring system, Cassini has been able to determine that the atmosphere around the Rings is composed principally of molecular oxygen. The finding was made by two experiments on Cassini --the mass spectrometer and plasma-science instrument --which show the atmosphere to be very similar to those of Jupiter’s moons Europa and Ganymede.


NASA has published plans for the next generation of spacecraft to take people back to the Moon and on to Mars and other destinations. The study makes specific design recommendations for a vehicle to carry crews into space, a family of launch vehicles to take them to the Moon and beyond, and a ‘lunar mission architecture’ for landing on the Moon. It also recommends the technologies that NASA should pursue in the near term. The study will assist NASA in achieving President Bush’s ‘vision for space exploration’, which calls for the agency to return the space shuttle to safe flight, complete the International Space Station, return to the Moon, and continue exploration to Mars and beyond. America’s next-generation spacecraft will use an improved, blunt-body crew capsule, and will accommodate up to six people. The spacecraft will be built upon the foundation of the proven designs and technologies used in the Apollo and space shuttle programmes, while having far greater capability. It will be able to carry larger and heavier cargoes into space and allow more people to stay on the Moon for longer periods of time. The new spacecraft will be able to be configured either to support human explorers or fly unpiloted to carry cargo. Its design allows the flexibility to ferry crews of three astronauts, plus additional supplies, to and from the International Space Station, take four crew members to lunar orbit, and eventually maintain up to six astronauts on a mission to Mars. Crews and cargo will be carried into orbit by a launcher consisting of a solid-propellant booster and an upper stage powered by a Shuttle main engine that can lift 25 metric tons. The spacecraft is intended to be safer than the space shuttle because of its in-line design and launch-abort system.


Thanks to all who contributed to this edition.
Dave Ogden

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