Saturday, 16 November 2013

A plane crossing the Sun

A plane flying over the European Space Astronomy center, ESAC, in Madrid, was captured in this h-alpha image of the Sun, on 06-Nov-2013.

The images were acquired with a Coronado SolarMaxII-90 BF30 from the ESAC solar observatory Helios, by Elena Leiva. Real time solar images (weather permitting) are posted in

Sun explosion

The Sun delighted us on 06 November 2013 with a magnificent explosion. The material was ejected from a region close to the active sunspot, as shown on this h-alpha sequence of images.


The images were acquired with a Coronado SolarMaxII-90 BF30 from the ESAC solar observatory Helios, by Elena Leiva. Real time solar images (weather permitting) are posted in

Thursday, 14 November 2013

2013-11-13: Comet C/2012 S1 ISON

Yesterday, around 6:05 UTC, I imaged the comet ISON from Majadahonda. The fact that the magnitude was +8.5 together with the relative position of the comet at low altitude over Madrid City from Majadahonda . It difficulted seriously to image the tail of the comet. However, I obtained the following images in black and white and colour stacking around 20 pictures at exposures of 5 secs. The individual pictures were captured with a Canon 60Da DSLR camera through a C8 telescope working at F/10. The main elements of the coment are evident: the nucleus, the coma and the dust tail. The ion tail developed two days ago is not visible in the images.

As the comet is much brighter after the outburst of today (around +6.5),  weather permitting, I hope to have a better opportunity the coming days.

Thursday, 7 November 2013

2013-11-03: Solar Eclipse from Madrid and Bermuda Eclipse Intercept Flight

Few people of the club observed the hybrid solar eclipse of last week in different ways. Although only a small fraction of the eclipse was observed from Madrid, we were able to observe the eclipse despite of a persistent thick fog. Once it cleared I captured the following white light  image of the eclipse from Majadahonda at 12:45 UTC.  

At 13:53 UTC, Miguel Perez Ayucar and Elena Leiva captured this H-alpha image from ESAC. 

During the eclipse, Michel Breitfellnet captured the following image from the Quiron Hospital in Pozuelo where he was recovering from a surgery. He projected the Sun through a hole in a paper sheet and imaged it with a smart phone. At the moment, Michel is recovering at home. We are sure he will be back very soon.

Another different experience was the one enjoyed by Leo Metcalfe. He participated in an eclipse intercept flight from Bermuda and he captured the following image and video.

Information about the video is in the Leo´s channel in youtube and images of this experience are here. The APOD chosen for 2013-11-07 was captured in this flight.

2013-10-09/10: GRANTECAN - La Palma - Canary Islands

Thanks to a visitor observation time assigned to the team of Miguel Sanchez-Portal, we were fortunate to enjoy an observing night with the GRANTECAN 10.4 meter telescope in Roque de Los Muchachos Observatory (La Palma Island). The images and video shows the magic of this place for astronomy.

The following image is a false colour quick look of one of the observed objects: Abell370. A cluster of galaxies at 4775 Mly.

2013-08-09/15: Green Flashes from Sopelana, Bizkaia

The following green flashes were captured on 2013-08-09 and 2013-08-15 from Sopelana, Bizkaia with HDD video. 

It is a phenomenon between  fact and fiction popular by Jules Verne novels and northern legends. Actually it is an optical phenomenon caused by the atmospheric refraction of the last Sun rays before sunset. A short documentary describing both the history and science of this event is in the following video. 

This documentary of BBC Coast S07 E01 (on air on 2012-05-13) incoporates the Green Flash that I captured from the same place on 2008-08-17 to illustrate the observation of the event from the Western Islands, UK.

Saturday, 27 April 2013

The scales of the Solar System: ISS, Sun and bird

A new stacked image of the International Space Station transiting the Sun on 20 April 2013, illustrates the different scales in the solar system, as a bird coincidentally crossed the Sun just a second before the ISS.

ISS and bird transiting the Sun

The apparent sizes (in the picture) of the objects Sun, ISS and bird are comparable, but their real sizes and distances are vastly different.

Sketches showing the geometry of the different objects (size/distance ratio exaggerated for illustration)

Object [pixel size in image, angular size, real size, distance to camera]
Sun  [ 796 pix, 32 arcmin, ~1.400.000 km, 150.000.000 km]
ISS  [   16 pix, 39 arcsec,              109 m,                645 km]
Bird [   22 pix, 53 arcsec,             ~20cm,                ~ ??  m]

One can deduce from the image that a 20cm bird should have flown 86m away from the camera.

Can we say something about how fast these objects were? Certainly. The ISS crossed the Sun in ~1.16sec, and the bird in ~1.04sec (images taken at 25fps). From these vales one can derive that, while it took around the same time for both objects to cross the Sun, the bird was flying at an apparent speed of ~7m/s, the ISS was flying at ~5.4km/s.

To obtain the real speed, one should know in which direction the object was flying. While for the bird it is difficult to know, the ISS geometry is well known, and at that moment was at ~40deg elevation from the horizon. This yields a ~7km/s real speed for the ISS.

Monday, 22 April 2013

ISS transits the Sun

This white-light image shows the International Space Station transiting the Sun on 20 April 2013, at 17h 35min 32sec. It was captured from the Valmayor reservoir, in Valdemorillo, Madrid, Spain. The active sunspot group number 1726 is visible in the center of the image.

ISS crossing the Sun: frame stacking

The ISS crossed the limb of the Sun in ~1.2sec. The image was taken with a Canon EOS 500 in video mode (25fps, full HD) through a Messier R102 Optical tube with a Baader solar filter. A Coronado SolarMaxII 90 BF30, in piggyback, also recorded the transit. H-alpha images are still being processed.

ISS transit, movie in normal speed

ISS transit, movie in 4x slow motion

The observing team

Friday, 22 March 2013

2013-12-18: A new observation of the PanSTARRS Comet

The following figure shows together two observations of the comet on 2013-03-14 and 2013-03-18: 4 and 8 days after its perihelion pass. As this non-periodic comet is moving away from the Sun, in the images it can be observed that the cometary activity is being reduced. The nucleus, coma and tail glowing are fading as it can be seen in the visible and false colour images.

The third column of images show the image after application of a Larsen-Sekanina filter (Sekanina Z., Larson S. M., 1984. The Astronomical Journal 89,571.). It is a rotational gradient filter that allows to observe fine morphological structures around the comet. So, the morphological changes in the nucleus, the coma and the tail become quite evident. Although there is also a change in perspective as the coment is moving away, comparing the images it can be observed an activity reduction in the extension and density of the tail, the size of the coma and the fine jets emerging for the nucleus.

Friday, 15 March 2013

2013-03-14: Pan-STARRS Comet from Madrid

Today, as in the previous days, the cloud coverage in Madrid difficulted seriously the observation of the comet. However, few holes opened at last time allowing to capture few pictures of the comet.

The following picture has been generated stacking 15 images captured on 2013-03-14T19:14 UTC with a DSLR Canon EOS 60Da through a 20 cm SCT.

The same picture shown in HDR shows very well the nucleus of the comet together with the dust tail and other glowing structures.

Thursday, 14 March 2013

2013-03-12: First look to the Pas-STARRS Comet from ESAC

Although the weather was incredibly bad, few moments before the comet went below the horizon, the sky opened a small window and I "catched it". The following image is a stack of 10 pictures of the comet.


 The following image has been produced  stacking 10 pictures of the comet.

The sequence of images is in this video:

Sunday, 17 February 2013

2013-02-15: 2012 DA4 Observation from ESAC

Last Friday, 7 of us with few guests met at ESAC to observe the closest approach of the asteroid 2012 DA4. Although the clouds, together with the light polution, endangered the observation at the beginning of the night, during the event the weather was good enough to observe and image the asteroid. Finally we mounted the Wouter 12 inch Dobsonian and the Michel 8 inch Newtonian.  In order to record the event, instead of the telescope of the club, we mounted the ESAC Photo club 400 mm TeleLens (thanks!!!) together with a Canon 60Da DSLR in a CG5 Celstron mount for the sideral tracking. After use this TeleLens, I cannot assess the general conclusion stated in the last post. So, at least this one allows a field flattening good enough for astronomy. The following video is a time lapse movie of the party in the top of U building.

Thanks to Wouter Van Reeven, we were able to see the asteroid from the beginning of the night. We must recognize that without his observational ability with his 12 inch Dobsonian the success of the observation was seriously compromised. Really it was complicated to observe the event.  He showed us how to use SkySafari in a iPad to guide the observation and he also provided the sky maps with the track that allowed to record the asteroid pass in the area of Ursa Major. The following video shows the track in this area when the asteroid was moving away from the Earth..

In order to better appreciate the track, it is recommended to see the video in youtube at the maximum resolution (HD1080). The following sky map was produced by Wouter to show the apparent track as seen from ESAC. The purple square indicates the area shown in the video.