• 12th August 2022 - Friends Observing is ON!

    Perseids Meteor Shower - 10pm @ Dome

    GREEN LIGHT! The forecast is clear and this event will go ahead. The Friends will meet at the Dome from 10pm to observe the Perseids meteor shower. Please park at the Pavilion and walk up to the Dome


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 8th August 2022

  • Astronomical twilight ends at 23:16 BST at the beginning of the week and at 22:55 BST by the end of the week
  • The Perseid meteor shower peaks on Friday. Under dark skies the Perseids can produce around 100 meteors per hour, but this year the Full Moon coincides with the peak and will drown out all but the brightest meteors, so expect a much lower ZHR. The Perseids are caused by Earth passing through debris deposited by comet 109P/Swift-Tuttle
  • Saturn reaches opposition on Sunday, the point in its orbit when it lies directly opposite the Sun from Earth. It will appear larger and brighter than usual at 18.8 arcseconds and magnitude +0.3, making this the best time to observe the planet
  • The Moon is Full on Friday
  • The Sun currently has five active regions: AR 3068, 3071, 3072, 3073 & 3074. The sunspot number is 69
  • There are no visible evening ISS passes this week



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11th August

BAAO Team Training: CEB led the observational training at the Dome for the 5 UK 2022 BAAO team members who fly out to Georgia to compete in the International Olympiad on Astronomy and Astrophysics next week. The residential visit has become an annual event in Marlborough as part of an Oxford based training week. The 4 boys and one girl, all 18 and post A-level were supervised by one of the Team Leaders and a past medalist (China 2018). The afternoon was used for solar work and the 4 sunspot groups were viewed in solar scopes and the ETX with white light filter. The 10 inch was used with the H-alpha filter to view a large prominence and good chromosphere detail. Once relatively dark, a series of observational tasks were carried out, naked eye, binocular and telescopic, using the ETX and small Newtonian scopes. The 10 inch was used to view the Full Moon (excellent views of Copernicus and Tycho ray craters) and then Saturn (too close to the Moon to see its moons), Jupiter, Vesta, Uranus and Mars. 3 very bright Perseids were seen during the evening and the radio detector was registering 20 meteors an hour

3rd August

Summer School Observatory Tour: The final Observatory Tour of Summer School 2022 started with 26 guests under a clear sky in Court, spotting Vega and Arcturus as they emerged in the fading twilight. The group walked up to the Dome, but by the time they arrived, the sky had clouded over! GKWJ, JAG and DGR entertained the visitors both inside the Dome and outside. DGR set up the Celestron 8-inch outside on the observing platform and announced that Saturn was visible through growing gaps in the cloud. Its moon, Titan could also be seen. The breaks in the cloud grew, allowing a partial sky tour with the Milky Way clearly visible. A rising Jupiter was the next target in the 8-inch, with three Galilean moons visible. The 10-inch was slewed to Saturn, but unfortunately the sky rapidly deteriorated, clouding over and brought an enjoyable visit to an end

27th July

Summer School Observatory Tour: 23 guests from Week Three of the Summer School visited the Dome with GKWJ, JAG and DGR. It was cloudy, so as in Week Two, they enjoyed ‘The Cloudy Show’

20th July

Summer School Observatory Tour: 11 students from Week Two at the Summer School visited the Dome with GKWJ, JAG and DGR. It was cloudy, so they were given an overview of activities at the observatory, a history of the Cooke 10-inch and a slide show of images taken through the 10-inch and at the Dome

13th July

Summer School Observatory Tour: 33 Week One Summer School guests joined JAG and DGR at the Dome for the Observatory Tour. Conditions were partly cloudy, but the enthusiastic star gazers were able to spot, through gaps in the cloud, many major stars and prominent asterisms, as well as the ISS (and other satellites), a meteor (much to DGR’s annoyance, who had his back to it) and the rising supermoon. Inside, the visitors were briefed on the need for a warm room and dark adaption and the history of the 10-inch was outlined. The clouds may have put a slight damper on the occasion, but visitors still left with big smiles on their faces

7th July

Staff Visit: A member of College staff visited the Dome with JAG in the evening twilight. The First Quarter Moon was viewed through the Celestron 4-inch and the Sun was viewed through eclipse glasses, along with the solar spectrum when paired with diffraction glasses

30th June

Scholars Visit: 9 Remove Scholars with their current tutor and next year’s tutor visited the Dome with GKWJ. The question ‘Are we alone?’ was considered, with an in-depth look at the search for extraterrestrial life across our galaxy, including the Drake Equation, which gave a result of 3.75 intelligent civilisations currently resident in the Milky Way – the search for them continues…



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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