February 2023 – News
Outreach Visit: A group of 12 Upper Sixth pupils and two members of staff from Hardenhuish Academy, Chippenham, visited the Dome with GKWJ. The sky was predominantly cloudy, though this was thin enough in parts to allow the group to observe the Waxing Gibbous Moon in an ETX before going into the Observatory. The group then enjoyed a tour of the facility, a selection of images of objects photographed through the 10-inch and other instruments at the Dome, the radio meteor detector live feed was observed, but only one event was seen, and the Wetton meteorite collection was handled and discussed.
A level Observing: In a new initiative for the Observatory, a group of 12 Lower Sixth Physics A level pupils came up to the Dome with their Beak, CJW. The plan was to capture some stellar spectra with GKWJ and analyse the gathered data. Unfortunately, it was cloudy, with the occasional break, so it was not possible to capture the spectra. However, gaps in the cloud allowed the session to start with a look at the First Quarter Moon through the two ETXs. The group then moved inside to look at the kit and techniques needed to obtain a spectrum. Existing data sets of stars Menkalinan, Rigel, Capella and Betelgeuse were then processed and analysed. Much good learning took place. At the end of the session, on stepping outside, the sky was clearing.
As GKWJ was departing, he noticed a faint red patch of sky low to the horizon in the north. Aurora alerts had been issued, but could this really be the aurora over the Blackett Observatory?! On continued observation, it was clear that the red patches were not light pollution as they were changing over time. GKWJ set up a camera and proceeded to capture images of the Northern Lights at the Observatory, an extremely rare event.
The Aurora captured over the Blackett Observatory
Friends Observing: A rare and perfect coincidence occurred for this year’s Friends lunar observing session: an incredibly clear sky, a still atmosphere and an interesting First Quarter Moon phase. This led to fabulous seeing, perhaps even a I/II on the Antoniadi scale. 14 Friends participated in the session. An ETX was set up outside with eyepiece adapter to allow smart phone photography and one Friend set up their own telescope to observe. At the 10-inch, we started with the 41 mm eyepiece at 93x magnification and a whole view of the Moon. Exquisite detail was observed, especially along the terminator, where the changing illumination of features was noticed over time. Magnification was increased to 140x and various areas of the lunar surface were observed in greater detail; highlights included the escarpment Rupes Altai, and craters Theophilus, Posidinius and Sacrobosco, with three smaller craters within the main crater. Given the near perfect seeing, the magnification was successfully increased to 224x and the hunt for craters Armstrong, Aldrin and Collins in the Sea of Tranquility began. Armstrong, with a diameter of just 4.6 km, was quite readily identified, a first for most at the eyepiece. The other two crew members could not be seen, so in a brash move, the 2x PowerMate was added to the optical train, increasing magnification to 448x, a first for the 10-inch, approaching its theoretical maximum magnification of 500x. The neutral density filter was removed and, amazingly, whilst the seeing was noticeably worse, perhaps down to a III, fine detail was easier to observe and in the patches of clarity, both Aldrin (diameter 3.4 km) and Collins (2.4 km) were positively identified by all observers. A wonderful evening of lunar observing that pushed the capabilities of our spectacular old telescope.
Staff Observing: 11 guests, a mix of staff, their family and friends, visited the Dome on a beautiful clear evening. GKWJ gave a sky tour around the constellations on view, taking in the Plough, Polaris, the waxing crescent Moon, Venus, Jupiter, Mars, the Pleiades (M45) and the Orion Nebula (M42). M45 and the Andromeda Galaxy (M31) were viewed in binoculars. The group then moved to the 10-inch, first observing the Moon, then M42, on to Mars, a star patch in Perseus, which included a star registered for a friend of one of the visitors, and ending on double star Almach.
GCSE Observing: 10 pupils from the Remove joined GKWJ at the Dome. On arrival, they observed the waxing crescent Moon through the 10-inch. They then progressed through a worksheet on field of view and magnification, with tasks including a sketch of The Pleiades (M45) through binoculars, an estimation of the diameter of the Orion Nebula using a 40mm eyepiece in an ETX, an estimation of the sidereal period of the Earth by timing the passage of Sirius across the field of view of an ETX with a 16mm eyepiece, and finally a sketch of the double star, Almach, through the 10-inch to estimate its angular separation.
Friends Observing: 11 Friends joined GKWJ and JAG at the Dome to observe Comet C/2022 E3 (ZTF). Unfortunately, the day’s perfectly clear sky was spoiled by the time the session started as cloud rushed in from the south. Thankfully there were sufficient gaps, at times substantial, to allow all observers to see the comet in the 10-inch. It is dimming significantly now and slowing down across our line of sight as it moves away from Earth. Sketches were made at measured time intervals to allow a speed estimate to be calculated; a figure of 28 km/s was obtained, which is in reasonable agreement with the ‘official’ figure of 33 km/s.
GCSE Observing: It was the turn of the Remove Astronomers to observe and GKWJ set up a range of instruments for them to attempt a worksheet on field of view and magnification. 10 pupils arrived and first observed the rising Waning Gibbous Moon in binoculars – a glorious sight. The 10-inch was tracking Comet C/2022 E3 (ZTF), the 8-inch was on the Orion Nebula (M42) and the two ETXs were on Betelgeuse. Unfortunately, while the comet was being observed, the run of clear skies came to an end as cloud flooded in from the North. The session was cut short.
GCSE Observing: The Hundred Astronomers joined GKWJ at the Dome on a clear, cold moonlit night. Comet C/2022 E3 (ZTF) was observed in the 10-inch, showing definite signs of dimming, but the main purpose of the session was to finish observations for the Aided Observing Tasks. Sketches to determine the effects of light pollution were made, the apparent magnitude of Algol was observed and star trail photos were taken. GKWJ gave a masterclass on processing and analysing star trails images for the length of the sidereal day project.
Radcliffe Society: A rare alignment occurred for this term’s fixed meeting of the Radcliffe Society – a clear sky and a comet near the Zenith! 11 members of the Society joined GKWJ and JAG at the Observatory, where they observed Comet C/2022 E3 (ZTF), first through binoculars, it was not visible by naked eye as a 99% Waning Gibbous Moon drowned out the fainter objects and the comet was about mag +5.8. Two other members of staff also visited to view the comet. It was then observed in an ETX, the 4-inch refractor and the 10-inch. Everyone made a sketch of the comet relative to the background stars through the 10-inch, noting the time of their sketch. Then a second sketch was made around 20 minutes later. This allowed calculations to be made to estimate the comet’s speed across our line of sight. Values of between 35 km/s and 65 km/s were obtained. The ‘official’ value is around 50 km/s.