• 26th September - Friends Event

    Planetary Observing - Dome @ 8.30pm

    If the sky is clear, the Dome will be open from 8.30pm for Friends to observe the planets: Jupiter, Saturn, Uranus and Neptune. This event is weather dependent, please check here for updates

  • Morning of 9th November 2022

    Friends Trip to Herschel Museum, Bath

    There are still a few spaces left for the Friends Trip to the Herschel Museum in Bath for a private guided tour. We will enjoy the current exhibition that recognises the 200th anniversary of the death of William Herschel. The cost for the trip is £10 per person. Please contact Gavin to book your place


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.

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What's Up!

Week of 26th September 2022

  • Astronomical twilight ends at 20:49 BST at the beginning of the week and at 20:34 BST by the end of the week
  • Jupiter reaches opposition on Monday, the point in its orbit when it will be opposite the Sun from Earth. This is the best time to view the planet as it will appear largest and brightest in our sky as it is also at perigee, its point of closest approach to Earth. Jupiter will be 3.95 AU (591 million km) from Earth (its closest in 59 years!), with an apparent size of 49 arcseconds and a magnitude of -2.9. Look for the brightest object in our southern sky at an altitude of about 38° by midnight
  • The two lunar clair-obscur effects known as the lunar X and V will be visible in the early evening of Sunday, look along the terminator to find them. They are caused by sunlight catching certain parts of crater edges and higher regions
  • The Moon is Waxing Crescent all week
  • The Sun currently has six active regions: AR 3102, 3105, 3107, 3108, 3109 & 3110. The sunspot number is 128
  • The ISS makes the following visible evening passes this week:
    Monday 20:19, W to ESE, max 87° and 21:56, W, max 16°
    Tuesday 19:30, W to E, max 86° and 21:07, W to SW, max 43°
    Wednesday 20:18, W to SE, max 62° and 21:56, W to WSW, max 12°
    Thursday 19:30, W to ESE, max 77° and 21:07, W to SW, max 25°
    Friday 20:18, W to SSE, max 36°
    Saturday 19:29, W to SE, max 49° and 21:07, WSW to SW, max 13°
    Sunday 20:17, W to S, max 19°



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23rd September

Friends Drinks Party: Around 50 Friends assembled at the Dome to celebrate the 18th anniversary of the Friends of the Marlborough Telescope. A beautiful evening allowed the party to be held outside on the new observing patio and the gathering enjoyed flowing drinks, served by barman JAG, and endless sandwiches! There was a great mix of familiar faces and many new Friends, who were welcomed to the group by all. Guest of honour, ex Director of the Observatory, Charles Barclay, addressed the gathering and made the official public handover to the incoming Director, Gavin James. GKWJ then spoke, thanking Charles for all his tireless work for the Friends since its inception and presented him with a framed print of the famous ‘observing blackboard’ from the classroom wall. GKWJ continued on to outline future events and various initiatives that he aims to introduce in the coming year. A very timely overhead ISS pass at 19:36 made an impressive first observation for the Friends in this new year. As the partygoers dispersed, Jupiter shone brightly (mag -2.9) in the southeast and wispy cloud accented a beautiful clearing sky

16th September

GCSE Observing: A clear sky allowed GCSE observing to start earlier than usual this new academic year. Members of the Remove and Hundred joined GKWJ and DGR at the Dome in two separate groups. The Remove were first and following an introduction to observing at the Dome, they enjoyed great views of Saturn in the 10-inch, with moon Titan visible, followed by Jupiter and all four Galilean moons. The planets were also viewed in the two ETXs and Celestron 8-inch outside. Then it was the Hundred’s turn; first they sketched Jupiter, with particular attention to the position of its four brightest moons. They then observed Saturn, with two moons visible (Titan and Rhea). To finish, they returned to Jupiter to sketch the new position of its four Galilean moons, noting with care their movement over the relatively short timescale

10th September

Planetary Imaging: GKWJ and JAG dusted down the 10-inch after the summer holidays and attempted to capture images of Saturn and Jupiter. Some success was had, but poor seeing resulted in sub-optimal image quality

12th August

Friends Observing: Over the course of the evening, 15 Friends joined JAG at the Dome to observe the peak of the Perseid meteor shower. The rising Full Moon was not an issue at the start of the session, but became increasingly intrusive as the evening progressed and it rose in altitude. Despite the moonlight, a total of 20 Perseids were spotted as well as 3 sporadic meteors during the two hours of observing. Some meteors were very bright, estimated to be magnitude -4, drawing ‘oohs’ and ‘aahs’ from the group of meteor spotters

Outreach Visit: A local relative visited the Dome with JAG. The Sun was viewed with eclipse specs and solar scopes



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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