SPACEGUARD NEO ASTROMETRY PROJECT (SNAP)    

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• Objective

The aim of this project is to upgrade the current 13” refractor telescope and control systems at the Spaceguard Centre in Wales to provide data essential for the prediction and prevention of dangerous asteroid or comet impacts on the Earth.  

• Project Diary

A diary of progress on the SNAP Project can be found below.

• Project Summary

It is imperative for the long-term survival of human civilisation that potentially hazardous asteroids and comets are detected and tracked to provide adequate warning of collisions with the Earth.  With such warning appropriate action could be taken to prevent potentially catastrophic impacts.  The extent of the hazard and the measures required for its mitigation are well documented. 

The Spaceguard Centre is a totally independent institution without external funding.  With its parent organisation, Spaceguard UK, it is widely recognised as a leader in the field of public information and education relating to Near Earth Objects (NEOs).  Since its establishment in January 1997 Spaceguard UK has grown into the largest national Spaceguard organisation in the world.  Our Visiting and Associate membership covers most of the world's expertise in NEO studies, and provides a tremendous foundation of knowledge and experience.  We have close ties with the Spaceguard Foundation, based in Rome, and Spaceguard organisations around the world.  We have active contacts in 23 countries.

We need to progress the project to make a real contribution to NEO research.  The equipment currently installed at The Spaceguard Centre was designed for general astronomy, and our next goal is to upgrade the facility for producing essential astrometric and photometric data on NEOs in support of the Minor Planet Centre in the USA and the Spaceguard Central Node in Italy.  A future development will be remote operation via the Internet.

The upgrades and equipment specified in this proposal will produce astrometric data on the majority of NEOs that are discovered by current detection programmes, and will make a significant contribution to the global “follow-up” capability.  For serious astrometric follow-up observations of recently discovered minor planets (including NEOs) a large aperture telescope is essential to reach the required limiting magnitude.  A refractor is the most suitable design, but they are generally too expensive at the required aperture.  The instrument at the Spaceguard Centre is one of the largest of its type in the country, but the main lens is in need of refiguring to eliminate an unacceptable degree of spherical aberration and astigmatism. 

The mechanical and electronic systems that control the telescope need to be upgraded to provide the standards of accuracy required by the Minor Planet Centre.  This will include the replacement of the control PC (currently a Pentium 100) to run the required software and to provide an Internet link via satellite broadband (already installed).

Charged Couple Device (CCD) cameras are the most widely used sensors for astrometry and astronomical imaging.  The most efficient CCD cameras available are equipped with a 1K by 1K pixel array for accurate astrometry.  A field of view of approximately 2 arc seconds per pixel is optimum.  The Apogee AP8 is the commercially available camera that most closely fulfils these requirements.

The telescope dome at the Spaceguard Centre has to be automated, so that the aperture automatically follows the telescope.  In addition, the unique glass window in front of the telescope requires a demisting system.

• Project Costs

•  An Outreach Project

 In addition to astrometry (and photometry) the SNAP project equipment is suitable for a large number of other astronomical projects.  Although the primary role of the installation will be NEO follow-up observations, when time permits, it can be used, in conjunction with any partners in the project, for observations and data collection for other programmes.  A limited amount of accommodation could be made available at The Spaceguard Centre for observers who could also have access to the in situ link to the Faulkes Telescopes.  All such arrangements will be negotiated on a case-by-case basis.

The 13” telescope is also an ideal instrument for public and educational observing, and will be used in conjunction with the other telescopes at the Spaceguard Centre for public observing sessions, and for schools.  A variety of instruments can be used, including the CCD camera, low-light video and direct observation eyepieces.  In addition, for daytime astronomy visual and Hά solar filters are available, allowing students to safely observe the Sun.

•  The Öpik Telescope

  Once refurbished, the 13” refractor will be re-commissioned as “The Öpik Telescope” to commemorate the enormous achievements of Ernst Julius Öpik.

 Ernst Julius Öpik was born in Port Kunda, Estonia on 23 October 1893 and was educated at Tallinn High School and Moscow Imperial University.  After four years at Moscow Observatory he became Director of the Astronomy Department, Tashkent.  From 1921-1944 he was an Associate Professor at Tartu University, and from 1930-34 visiting scientist at Harvard University.  As a former volunteer to the White Russian army, he vehemently opposed the Bolshevik Revolution and, when Soviet occupation of Estonia was imminent, he moved, first to Hamburg, and lastly, in 1948, to Armagh Observatory where he remained until 1981.  He died in Bangor, Co Down, Northern Ireland on 10 September 1985.

 Öpik was one of the most outstanding astrophysicists of his generation, with wide-ranging interests in the physical sciences.  Among his many pioneering discoveries were the first computation of the density of a degenerate body, namely the white dwarf 40 Eri B, in 1915, the first accurate determination of the distance of an extragalactic object (Andromeda Nebula) in 1922, the prediction of the existence of a cloud of cometary bodies encircling the Solar System (1932), later known as the “Oort Cloud”, the first composite theoretical models of dwarf stars like the Sun which showed how they evolve into giants (1938) and a new theory of the origin of the Ice Ages (1952).

Öpik made many contributions to our knowledge of the minor bodies of the Solar System and founded the meteor research group at Harvard.  His statistical studies of Earth-crossing comets and asteroids are fundamental to our understanding of the motions of these objects and how they impact on Earth.  His predictions of cratering on Mars were dramatically confirmed 15 years later by planetary probes.  In recognition of his work, Minor Planet Öpik was named after him.  (Courtesy of the Armagh Observatory)

 The grandson of Ernst Julius Öpik, Lembit, has been a champion of the Spaceguard project in the House of Commons, and is largely responsible for the current government interest in the subject of Near Earth Objects.

 PROJECT DIARY

11 June 2003 - The 13" lens was removed from the telescope.

Removing a 60 lb Apochromatic oil-spaced triplet that is enclosed in a 110 lb bronze cell from a 1 1/2 ton balanced assembly is not a fun undertaking.  Only after the telescope had been secured in the vertical position using ropes could the lens removal begin.  Without any drawings or instructions this process was interesting!

Let the fun begin!

Vertical, and ready to go

Now raise the hydraulic floor ....

Until the cell rests on a padded table.

Unbolt the front of the cell, and lower the floor (fingers crossed).

Lift cell and lens to the floor and wonder what to do next.

Whatever we did, it worked!

A 13" empty tube!

18 June 2003 - Lens delivered to Mr Esmond Reid in Cambridge.

Esmond Reid kindly agreed to take on the task of refiguring the lens to bring it up to specification.  Having consulted with Professor Sir Martin Rees, the Astronomer Royal it became clear that there are few optical engineers in the country willing to attempt such a task, and we are indebted to Mr Reid for his courage!  At our meeting we were joined by Jim Hysom, a well known optical engineer who has shown great interest in the project.

Let's check this monster out!

Mmmmm

24 June - Letters sent to a number of high street opticians soliciting financial support for the project.

Those contacted include:

• Specsavers

• Vision Express

• Rayners

• Boots Opticians

• Dolland & Aitchison

25 June 2003 - Local press jump on the story. 

An interview on Shropshire radio and a front page article in the Shropshire Star.

27 June 2003

The Western Mail follows with a short article.

Boots Opticians reply regretting that they cannot support the project.

30 June 2003

Decision time.  Es Reid has figured the two outer surfaces of the lens until there is no more astigmatism change.   However, but the oil viscosity between the elements of the triplet seems to be so large that movement seems impossible.  To try to separate the elements could be a very dodgy operation: due to the thin oil layer any dirt could scratch badly.  However, the safest option would be to figure the relatively astigmatism free centre 11 inches or so and mask the rest off.  But, to quote Es, "I don't think there is a short cut to good performance."

2 July

The decision is made.  After a discussion with Andrew Thompson, the owner of the telescope, we decided to go for "the Full Monty".

3 July 2003

Es Reid, with great courage, has split the three elements of the triplet lens, and is preparing laps to start refiguring the four remaining surfaces.

The two flat mirrors used in the folded optics design have been sent to Es for inspection.

5 July 2003

It appears that one of the two flats is OK, but that the other is hopeless.  A new 4" flat will be needed.

7 July 2003

Specsavers reply regretting that they cannot support the project.

15 September 2003

To Cambridge to collect the refurbished lens and flats.

22 September 2003

There followed a long period of adjustment to ensure that the lens was precisely squareand collimated. There were not a lot of clear nights during the autumn!

November 2003

A generous donation from the FAIR Society allowed us to purchase a USB adaptor for the CCD camera, and a flip mirror" eyepiece holder for the 13". The former radically reduces the integration time for CCD images, and the latter makes acquiring targets a piece of cake!

January 2004

Starlight Xpress changed the chip in the CCD camera from colour to monochrome, increasing sensitivity.

February 2004

Phillips Toucam Pro webcam fitted to the telescope for fun. The first image, produced by stacking 15 frames, wasn't bad.