• 24th September - Friends Event

    Friends Drinks Party
    Dome 6:30pm

    The Friends will gather at the Dome at 6:30pm for the annual drinks party. This is the 17th anniversary of the Friends of the Marlborough Telescope!

  • 27th September - FRIENDS EVENT

    Observing Four Planets
    8:30pm - Weather Permitting

    The Dome will be open from 8:30pm for the Friends to enjoy views of Jupiter, Saturn, Uranus and Neptune through the Cooke 10 inch. The event is Weather Permitting - updates will be issued here nearer the time


    Blackett Observatory Radio Meteor Detection System

    The radio meteor detection system Live Stream is available to view online 24/7 right now...



Marlborough College

Welcome to the Marlborough College Blackett Observatory, home to the largest refracting telescope in Wiltshire. The Observatory is a key facility for the study of Astronomy by pupils at Marlborough College, but is also open to the public through the Friends of the Marlborough Telescope membership scheme.

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What's Up!

Week of 13th September 2021

  • Astronomical twilight ends at 21:22 BST at the start of the week and at 21:06 BST by the end of the week
  • Neptune reaches opposition on Tuesday, when it will be opposite the Sun as seen from Earth. It will be best placed for observation, appearing at its brightest, though still faint at mag +7.8, so binoculars or a telescope will be needed to see the planet. Look southeast in the constellation of Aquarius through the evening
  • Saturn (mag +0.4) and Jupiter (-2.8) continue to dominate our evening skies. They will be joined by the waxing Gibbous Moon towards the end of the week
  • The Moon is First Quarter on Monday
  • The Sun currently has 5 active regions: AR2863, AR2864, AR2866, AR2868 and AR2869. The sunspot number is 93
  • The ISS makes multiple visible evening passes this week as follows:
    Thursday: 21:27, SW to SSW, max 14°
    Friday: 20:41, SSW to SSE, max 23°
    Saturday: 19:57, S to ESE, max 17° & 21:32, WSW to SW, max 31°
    Sunday: 20:47, SW to ESE, max 46°


Visit the What’s Up! archive


7th September

Observing visit: GKWJ hosted a visitor at the Dome, recounting the history of the Blackett Observatory and the Cooke 10-inch telescope. A second night in a row of near perfect dark and clear conditions allowed a fabulous observing session, starting with the planets: Saturn and 5 moons, Jupiter and 4 moons and Neptune. Next up were M15 (globular cluster), M31 (Andromeda Galaxy, with spiral arm detail observed), Almach (beautiful double star in Andromeda) and the Double Cluster. Finally, the visitor, who is an expert planetary imager, gathered data of Jupiter through the 10-inch to create this fantastic image

6th September

Observing: GKWJ & JAG saw in the start of the new academic year with a great observing session through the 10-inch. Wonderfully clear skies, no Moon or wind and near perfect seeing gifted the finest views of Saturn and 5 moons at up to x237 magnification, Jupiter with the GRS and its 4 Galilean moons, including a moon shadow transit of Io and finally the pale blue disc of Neptune. GKWJ then took images of the Milky Way over the Dome

Milky Way over the Dome

26th August

Olympiad team training camp: CEB joined the UK BAAO team and leaders for the week long 2021 International Olympiad on Astronomy and Astrophysics training camp, based at the Cavendish Laboratory in Cambridge. The team of 5 (3 girls and 2 boys) were introduced to observing techniques, specifically solar observing and analysis of multi-wavelength images, to prepare them for the Observational round of the IOAA to be held remotely in November from Bogota, Columbia.

12th August

Friends Observing: A small group of Friends met with CEB, GKWJ and JAG at the Dome to observe the Perseids Meteor Shower. The forecast was correct and the cloud cover cleared from the West as the group assembled from 22:00 BST. During the first hour 17 Perseids and 2 sporadics were seen. Meteor recording was carried out in earnest for the hour 22:00 to 23:00 UT, when 39 Perseids and 3 sporadics were observed and recorded, including 4 fireballs. It was a magnificent night with a beautifully clear sky, no Moon and the Milky Way clearly visible arcing over the sky. A wonderful return to observing at the Dome for the first Friends session in some 18 months due to the Covid pandemic restrictions


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