• 25th May 2023 - Friends Observing

    Solar Observing - Observatory @ 2.30pm

    The Observatory will be open from 2.30pm for Friends to observe the Sun (safely!) in white light and hydrogen alpha.


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. It is open to the public through the Friends of the Marlborough Telescope membership scheme. School and Society visits are welcome, please contact the Director to arrange your visit.

FIND OUT MORE      Become a Friend      CONTACT

What's Up!

Week of 27th March 2023

  • Astronomical twilight ends at 21:28 BST at the beginning of the week and at 21:41 BST by the end of the week.
  • Venus (mag -4.0) is bright and conspicuous in the evening twilight towards the western horizon at an altitude of around 25°, climbing ever higher through the week. It is followed by Mercury (-1.0) much closer to the horizon at around 8° altitude.
  • The Spring sky is dominated by the constellations of Leo and Virgo, home to a plethora of galaxies. Use a telescope to hunt down ‘faint fuzzies’ such as the Leo Triplet of galaxies and Messier 87, the giant elliptical galaxy Virgo A.
  • The Moon is First Quarter on Wednesday.
  • The Sun currently has 8 active regions and the sunspot number is 105.
  • There are multiple visible evening ISS passes this week as follows:
    Monday: 21:06 (-3.6) W to SE, max 60°
    Tuesday: 20:17 (-3.7) W to ESE, max 75° & 21:54 (-1.9) W to SW, max 23°
    Wednesday: 21:06 (-2.6) W to SSE, max 34°
    Thursday: 20:18 (-3.0) W to SE, max 46° & 21:56 (-1.1) WSW to SW, max 12°
    Friday: 21:07 (-1.5) W to S, max 18°
    Saturday: 20:18 (-1.9) W to SSE, max 25°


Visit the What’s Up! archive

Latest News

What's been going on at the Blackett Observatory

29th March

Friends Outing: A group of 21 Friends, including GKWJ and JAG, visited the National Space Centre in Leicester for this year’s Friends Outing. The plethora of exhibits, ranging from a Soyuz space craft, a piece of Moon rock and a signed first edition of Yuri Gagarin’s autobiography that has been to the ISS twice, once with Helen Sharman and then with Tim Peake, right through to detailed and interactive explanations of a multitude of astronomical facts and figures kept the group enthralled for the day. The highlight was a guided tour by the Curator of the Museum, who showed us his favourite exhibits, telling us their stories with his expert knowledge. All this combined with a stunning show in the largest planetarium in the UK made for a superb day out.

23rd March

Sun-Earth Day Lecture: Over 60 pupils and Friends attended the 2023 NASA/ESA Sun-Earth Day Lecture in the Garnett Room. Delivered by Nick Howes FRAS, the lecture had the overtly dramatic title “OMG – We’re All Gonna Die!”. Nick examined the dangers we face on Earth from space, the greatest of which is an impact with a large comet. Despite a delayed start to the talk due to a new visitor sign in procedure, the audience thoroughly enjoyed the thought provoking lecture and a host of searching questions were asked.

21st March

Outreach Visit: 6 Year 6 pupils from Broad Hinton Primary School and two parents visited the Dome with GKWJ. The evening was cloudy, but the group enjoyed a tour of the Observatory and were fascinated by the Wetton meteorite collection.

2nd March

Outreach Visit: A group of 20 children and parents from the Gloucestershire Home Education Hub visited the Dome with GKWJ on a clear, cold, moonlit night. The session started outside with a Sky Tour, including a view of the conjunction of Venus and Jupiter close to the western horizon. The group moved inside to observe Jupiter and its four Galilean moons in the 10-inch. Outside again to continue the sky tour, this time including a closer look at The Pleiades (M45) through binoculars. The session ended back inside with a fabulous view of the Waxing Gibbous Moon through the 10-inch.



Visit the News archive

All Sky Eye

The Latest View from the MCBO

The All Sky Camera operates from 30 minutes after sunset through the night until 30 minutes before sunrise. The latest image is updated automatically every 5 minutes and the time lapse video is refreshed each morning at around sunrise. Click the still image to view a large version


Latest Still Image

Most recent time lapse video