Thursday, 22 June 2017

ESAC Star Party 2017, 30 June

The ESAC Astronomy Club announces the annual Summer Solstice Star Party. This year it will take place on June 30, 2017, coinciding with the #AsteroidDay. The doors will open at 20:00, the programme will start at 20:30 and the observations with the telescopes will start at 22:30.

ESAC Star Party

  • 20:30 tour along the satellites at ESAC 
  • 21:30 presentation about astronomy in D building. 
  • 21:30 second tour along the satellites at ESAC 
  • 22:30 observation with telescopes, guided constellations tour, guided satellite spotting 
Astronomy master class
As always you, your family and your friends are invited to attend the star party. However, the way we want to register the invitees is different than previous years! We have created a Google form that you, the ESAC employee, will need to fill out for every person that you want to invite. The form can be found here. Please make sure to fill out all required items and to also inform us if your invitees plan to attend either tour along the satellites and/or the presentation about astronomy by ticking the appropriate boxes in the form. The number of visitors is limited to 450 and the number of participants of the presentation to 250.

Telescope platform
As in previous years you are required to bring your own food and drinks. We will take care of ice to cool your drinks though. The restaurant terrace will be open for you to eat at. Parking will be done at the ESAC parking and the guards will let your invitees enter as long as they are on the list. So make sure to fill out the form for each invitee! Finally, the first tour of the satellites will start at 20:30 sharp and the presentation at 21:30 sharp so please make sure to arrive on time.

From 22:30 onward we will point our telescopes at various objects in the sky, including Jupiter, the Moon and Saturn. We will dedicate several telescopes to taking pictures and we will make sure that you and the other visitors can make pictures with your own smartphones through those telescopes.

Image may contain: screen
Saturn Live projection during 2016 Star Party
Location: ESA - European Space Astronomy Centre (ESAC) Camino bajo del Castillo s/n, Urb. Villafranca del Castillo 28692 Villanueva de la Cañanda, Madrid, Spain

Please contact us in case you have any questions,
ESAC Astronomy Club

Tuesday, 6 June 2017

NGC 7000 imaged from my backyard

In the night from May 24 to May 25 I used my Canon EOS 700D mounted on my Sky Watcher StarAdventurer mount to take images of NGC 7000, also known as the North America Nebula. The camera is modified and has its IR-filter (Infra Red filer) replaced by a different filter that lets pass through more red light. So emission nebulae like the North America Nebula are ideal objects to image with this camera because they principally emit light at the very red wavelength of 656 nanometers, which get blocked by the original IR-filter.

Here is a picture of my setup:

I took 40 images of 3 minutes illumination each. Then I processed the images and rejected 4 of them based on statistics that give indications about the background noise and sharpness of the stars. The final result is this

Stay tuned for more images to come in the near future!

Friday, 2 June 2017

Tiangong - 2

The Chinese space station Tiangong -2 flew across the night sky over a location close to ESAC. The Moon, Jupiter and some clouds complete this night-sky portray.

The Chinese station is a cylindrical module of 10 meters long and 3.3 meters diameter, flying at altitudes around 370km. In this pass, the station came out of shadow at 23:12 CEST on the western sky at 10 deg elevation, crossed the Leo constellation at 62 deg elevation, and got into shadow again at 23:18 in the eastern sky. The apparent magnitude was approximately 1 mag.

The images were taken with a Nikon D3100 with 1sec exposure and a cadence of around 2 seconds.

Monday, 22 May 2017

Plane crossing the Sun

The ESAC Helios Solar observatory captures from time to time objects crossing the Sun disk. In this case, a plane crossed the Sun. The image was taken on Wednesday 26th April 2017 at 10:48:43 Madrid time from the ESAC Helios Solar observatory. Image in H-alpha band (665nm wavelenght) showing the hydrogen emission from the Sun's chromosphere layer. The active regions around two sunspots groups are visible in the image.

Image credit: CESAR Educational team. 

Monday, 15 May 2017

Comparing ISS transits. Sun transit at ESAC, 14 May 2017 (compared to Moon Jan 2017)

On Sunday 14th May 2017 the International Space Station ISS crossed the disk of the Sun as seen from the European Space Astronomy Center, ESAC.

ISS crosses the Sun

The above image is a superposition of thirty-eight consecutive frames captured on 14th May at 09:06:04 (24fps, Nikon D3100). The black silhouette is seen against the Sun photosphere background. The ISS is the largest man-made object in orbit, spanning the size of a football pitch. Despite its large size, it orbits the Earth at a distance of approximately 400 km, therefore looking tiny to telescope fanatics. Depending on the ISS orbit altitude and the Sun elevation over the horizon, its apparent angular size to the observer varies. That is clearly seen in the composite images below.

Comparison between two transits (Jan 2017 - May 2017)

In the image two ISS transits are placed side-by-side: the left one on Jan 2017, when the space station was flying at a slant range of 452km. The right one, on May 2017, at a slant of 930km (see ISS transits Moon over ESAC 14Jan 2017). The outcome is dramatic, as the resolving of the ISS body drops by half at a double slant range. Not only that, the image quality is considerably different. As the light crosses more layers of Earth's atmosphere, the 'seeing' worsens and the image turns less crisp (right image). On the other hand, an increased crossing time allows for more frames to be captured (38 versus 13). The phenomena is extremely fast in any case: the ISS took only 0.56 and 1.6 seconds to cross the Moon and Sun disks. Therefore careful location/timing planning was required to successfully capture it.

ISS-Sun crossings are common, but a crossing from a specific location on Earth is not. The observer, the ISS and the Sun must be precisely aligned. An ESAC group composed of Manuel Castillo and Miguel Perez Ayucar set up two telescopes with two Canon reflex cameras and a Nikon, in the back of the A-building, in the early morning. The ISS cannot be spotted before the crossing with solar telescopes, so the observation is done with a clock in hand, and basically in the blind. Everything was right at the precisely expected time. The geometry is so particular that the ground path where observers can see the event is only a few hundred meters wide. Therefore careful planning of the observation must be performed. The station flies at ~27000km/h therefore the transit takes is a blink of an eye to be complete. 

Thursday, 16 February 2017

Auroras in Kiruna

On January 30th and 31st 2017, few ESAC Astro Club members observed and recorded an auroral burst over Kiruna, Sweden. It was possible thanks to the Mars Express  Science Working Team and Science Operation Working Group meetings celebrated at the Swedish Institute of Space Physics  in Kiruna on January 31st and February 1st, 2017.

Auroras observed near Kiruna on 2017-01-30. Credit: M.Castillo/M.Breitfellner, 2017

Auroras are produced when the Earth magnetosphere is perturbed by the capture of the charged particles (mainly protons and electrons) that constitute the solar wind. When the particles enter in the atmosphere they collide with the existing gases (mostly Nitrogen and Oxigen) and excite the atoms that later reemit the absorved collision energy. The dynamics of the light emission depends on the magnetic interaction between both the Earth magnetosphere and the particles. As the particles are captured mostly through the magnetic field poles, the auroral lights are seen at high latitudes of northern and southern hemispheres.

Auroras observed near Kiruna on 2017-01-31. Credit: M.Castillo/M.Breitfellner, 2017

The solar wind stream depends on the solar activity cycle of 11 years. So, when the solar activity is high it is more probable to see auroras because there are more intense particle ejections. Currently the Sun is moving to the minimum of the present solar cycle, so the solar mass ejections are not very intense. However, other solar features release significant streams of charged particles. The Sun´s corona acts as a shield that decelerates and reduces the solar wind normally ejected from the photosphere. As the corona is constantly changing and reshaping due to its interaction with the solar magnetic field, sometimes an area opens in the corona, then a coronal hole is formed. As a consequence the solar wind increases significantly and it is followed by intense auroras around the Earth poles.

The observed auroral burst was produced by a G1 (Kp5) geomagnetic storm due to the arrival of a high speed solar wind from a large coronal hole in the Sun. This coronal hole can be observed in this video link of the Solar Dynamic Observatory of NASA. It formed behind the Sun and when it rotated and pointed to the Earth it released the charged particles that three days later produced the observed Auroras. A video showing the observed auroras in real time is here.

Friday, 10 February 2017

Sun Dogs - Parhelia

A really bright Sun Dog (parhelia) was visible on 09 Feb 2017 from Majadahonda. Gently falling hexagonal ice plates create this sky spectacle. The ice particles are located in the distant cirrus cloud formation. The vertical extent of the red hue seems to indicate large crystals, as they are subject to larger wobbling while falling.

Left Sundog with increased brightness towards the parhelic circle

Parhelia on cirrus cloud

If you want to learn more ..

Sundog formation (courtesy ATOPTICS)