• 12th August 2022 - Friends Observing

    Perseids Meteor Shower - 10pm @ Dome

    If the sky is clear, the Friends will meet at the Dome to observe the Perseids meteor shower. This event is weather permitting, updates will be posted nearer the time


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 27th June 2022

  • Astronomical twilight does not end until 21st July
  • With no moonlight, this week is optimal for deep sky observing. Interesting targets include: Globular Clusters such as M13 and M92 in Hercules, the Coathanger asterism in Vulpecula, the Ring Nebula (M57) in Lyra, the double star Albireo in Cygnus as well as the arc of the Milky Way across our summer sky – a treat by naked eye or to explore with binoculars
  • The Moon is New on Wednesday
  • The Sun currently has two active regions: AR 3038 & 3040. The sunspot number is 31
  • There are no visible evening ISS passes this week


Visit the What’s Up! archive


20th June

Radcliffe Society: The final meeting of the year was enjoyed by ten members of the society who joined GKWJ, JAG and CJW at the Dome for an attempt to launch two small model rockets. Three sizes of motor were available: A, B and C, increasing in power. The first task was to establish safe practice for launch and landing. Wind speed, direction and maximum altitude were accounted for to identify a safe landing zone. Two A motor launches were completed successfully, with measurements taken of altitude and distance, max altitude being 63m. The first B motor launch was then attempted. Lift off was a success, but the parachute descent was far slower than predicted and the rocket found its landing spot in a tree. The parachute of rocket number two was modified to decrease its descent duration and it was launched. Unfortunately, whilst it did indeed descend more rapidly, it too found a tree, albeit a different tree, as its landing spot. Max altitude of the B motor rocket was 124m. No C motor launch was attempted. Much fun was had by all and some interesting science was carried out. Next meeting: 19th September

14th June

Outreach visit: 18 members of Owl Class (Years 5 & 6) from Oare Primary School, together with a teacher and two parent helpers, enjoyed a guided tour of the Observatory with JAG, ably assisted by a L6 pupil. There was much excitement as they looked at the Sun through eclipse glasses and realised that it appears to be the same size as the Moon, being 400 times larger but also 400 times further away from us. Inside the Dome, they appreciated the importance of red light in maintaining night vision, watched their pupils shrink as the white light dazzled them, opened and rotated the roof, admired ’the oldest computerised telescope in the world’ and asked lots of excellent questions, the last of which was ‘Can we come back for another visit when it’s dark, please?’

8th June

Observing: The twilight waxing Gibbous Moon was observed by GKWJ and JAG, who were carrying out tests of two new eyepieces. Purchased with help from the Friends and funds raised by the sale of two redundant eyepieces, the new Tele Vue eyepieces offer optimum quality for increased magnification observing with the 10-inch. Copernicus, Tycho and Clavius craters were viewed at 140x magnification with a 27mm Panoptic and 224x with a 17mm Nagler. The contrast and detail were superb, despite the poor seeing, and the eyepieces will definitely enhance future observing

26th May

Friends Observing: Unfortunately, cloudy skies prevented the Dome from being opened for solar observing. Instead a small group of Friends joined CEB and GKWJ on Zoom to consider the progress of Solar Cycle 25

23rd May

Outreach Visit: The Eton Group Heads of Physics annual meeting was held at Marlborough College this year and following a morning of discussion, including a presentation on the British Astronomy and Astrophysics Olympiad (BAAO) by CEB, the 12 attendees enjoyed a visit to the Blackett Observatory with GKWJ in the afternoon

19th May

External Talk: CEB delivered the lecture ‘Illuminating the dark ages – the era of James Webb’ at Green Templeton College, Oxford to a large audience, as part of this year’s Astronomy for All lectures series. This was the 46th lecture in the series originally convened by CEB in 2006

10th May

Radcliffe Society: A small group of society members met for the May meeting with GKWJ and JAG. Our 2022 RAS GCSE Poster Competition prize winning pupil gave a presentation on his winning entry, GKWJ gave a Latest News round-up and then the group started its investigation of rocket science with a selection of videos. We started to plan our own small rocket launch attempt for the June meeting, looking at kit required and the potential risks associated with a launch. Next Meeting: 20th June



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