Thursday, 20 December 2007

Merry Christmas & Happy New Year from ESAC

Merry Christmas & Happy New Year!

Joyeux Noël et Bonne Année!

Fröhliche Weihnachten und ein glückliches Neues Jahr!

Vrolijk Kerstfeest en een Gelukkig Nieuwjaar!

Buon Natale e Felice Anno Nuovo!

Boas Festas e um feliz Ano Novo!

Glædelig Jul og godt nytår!

God Jul och Gott Nytt År!

Eg ynskjer hermed dykk alle ein god jul og godt nyttår!

Kala Christougenna Ki'eftihismenos O Kenourios Chronos!

Feliz Navidad y Próspero Año Nuevo!

Tuesday, 11 December 2007

2007-12-01: Mars one month before the oposition

This post shows the results of our second tentative imaging Mars close to its oposition. In this case, the people meeting in Satan Hill were Leo, Michel, Roberto and me. Again, the Leo's Dobsonian 65 cm telescope was used together with a Toucam Pro webcam, blocking and pass NIR filters and a 3x Barlow. The captured video tracks were stacked with REGISTAX and the histograms modified to show the best contrast. Additionally, an unsharp mask was applied to enhance as possible the contrast of the surface details.

The following image was captured around 2:30 GMT with the NIR blocking filter.

The next one was captured around 2:30 GMT with the NIR pass filter.

A combination of both images substituting the red channel of the firs image with the second one produces the next image.

In the north cap, the winter CO2 froze can be observed extending to the south of the polar regions. Now, as the planet is closer, both the RGB and NIR images show more details of the surface than in our previous tentative. However, the poor seeing during the observation degrades the sharpness of the images. Despite that, the observed regions can be clearly identified. The following image has been produced by Leo forzing a little the sharpening to remark some of the Mars regions.

2007-11-07: Mars two months before the oposition

This post shows the results of our first tentative imaging Mars close to its oposition.

On November 7th, 2007, Leo and me were at Satan Hill in ESAC to try to image mars with the Leo's a Dobsonian 65 cm telescope. The following images show our best results with the Toucam Pro webcam, blocking and pass NIR filters and a 3x Barlow. The captured video tracks were stacked with REGISTAX and the histograms modified to show the best contrast.

The following image was captured around 1:30 GMT with the NIR blocking filter.

The next one was captured around 1:30 GMT with the NIR pass filter.

A combination of both images substituting the red channel of the firs image with the second one produces the next image.

The planet disk shows a well defined phase yet and both the RGB and NIR images show very well different details of the surface. The image is centered in Chryse planitia with Syrtis Major appearing in the terminator. In the north cap, the usual winter CO2 froze can be clearly observed far from the polar regions.

Wednesday, 5 December 2007

Comet 17P/Holmes

After some time dedicated to other astronomical topics, I'm back to share my images of comet 17P/Holmes.

This comet suffered a very spectacular eruption on Oct. 24, 2007. In less than 24 hours, the 17th magnitude bright of the comet increases by a factor of nearly a million, becoming a naked-eye object. From this day it has been expanding while it was crossing the constellation Perseus. Now, it is vanishing and it nos as spectacular than before but now it has a diameter bigger than the Moon that can be very well appreciated by the naked-eye from very dark places.

During the first two weeks the comet was bright enough to be observed from the center of the cities. Thus, I put my equipment in front fo the window and I captured the images I show you. All the images have been captured with a C8 SCT and a Canon 400D camera with exposures of 20 seconds at 1600 ASA.

The following image shows the evolution of the coma of the comet between 3 days after the eruption and one week.

The next image is an anagliph of the previous images using the aparent movement of the comet on the stars background. If you have red&blue glasses you can appreciate a 3D view of the comet in front of the stars.

An animated gif helps to evaluate the comet growth in during only one week.

The last image was taken with 30 seconds exposure on Oct. 30 at 19:30 GMT. Later the histogram was forced a little to show the exterior green halo of the comet. It is erupted matter that emits green light because its interaction with the solar wind. It is green because its composition and it can be well observed because this matter has not enough density to reflects sufficient solar light (mainly white) to mask this emission.

Additional images of the comet showing its evolution from the first eruption until now can be found in this webpage or this one.

Friday, 16 November 2007

First test with the C150/NGT and the club's DSI camera : 17P/Holmes 3rd Nov.

This single 30 sec image of 17P/Holmes is the very first test imaging with the 150 mm Newton telescope and the DSI camera. Due to the very rough polar alignment, star trails are evident even with this short exposure. More (and much better) images of the Holmes comet can be found here

Tuesday, 23 October 2007

M42 2007-10-20/21

As the Saturday night was specially good for observation from ESAC, Leo, Michel and me met here to observe something after the moonset. Despite the good atmospheric conditions, the light pollution was important (more than other times?...), thus we pointed the telescope to one of the brightest deeps ky targets: the Great Nebula of Orion (M42).

The following two images show the results. Both images were captured using a C8 SCT with a Canon Rebel 400D attached to the primary focus. Using an ISO of 1600. The first one is the result of the combination of three exposures of 30 seconds with wide band RGB filters.

The second image is a combination of two exposures of 60 second with narrow filters Red:H-alpha and G: OIII and a 30 seconds exposure with a wide band Blue filter.

After we pointed the telescope to Mars but the images must be still processed. As soon they are, they will be posted here.

Thursday, 18 October 2007

Fabra Observatory 2007-10-09

Last week, I was with a friend, Antonio Bernal, at the Fabra Observatory of Barcelona (map) using a 1900's 38 cm double refractor (visual and photographic) measuring double star separations with a restored micrometric fil counter (from 1900 too). The following pictures show the telescope in operation.

This telescope was widely used during 100 years for astrometry and several minor solar bodies were discovered from here. As a result they have spanish names (Hispania, Barcelona, etc.). The observatory has also a huge collection of photographic plates covering around 80 years. Think about what they can produce if they are digitalized one day... However, the most spectacular achievement was the discovery of the atmosphere ot Titan in 1908 by Comas Sola, the observatory founder, observing the satellite limb darkening. It was published in 1908 in Astronomische Nachrichten and confirmed by Kuiper in 1944.

Today, the telescope is in operation but due to the high light pollution caused by the city it can be used only for some astrometric and planetary observations. The following pictures of the dome and the city show clearly the effect of the light pollution.

After its restoration, Antonio is using the telescope to measure today the separation of double stars that were reported before 1950. So, he hopes to update the double star catalogues confirming the observations and derive orbital information of the double systems. Additionally there are also public visiting tours and in special events they organize some public observations.

Monday, 1 October 2007

Sputnik-1 - 50 years anniversary

Next Thursday, October 4th, 2007, is the 50 anniversary of the Sputnik-1 launch.

It is very surprising for me that ESAC has not any scheduled activity. Some people, me too, consider that it was the beginning of our business and it should be celebrated. The space part of course... (the astronomy part is probably the second oldest business of the human history... ). Therefore, to solve in some way this lack of celebration, I have made a simulation of the event and I post it here.

It is a Celestia simulation of the first Sputnik-1 orbits. The orbital elements are tabulated in the NORAD archives and they are valid for October 1957. After the high atmosphere drag and other low orbit perturbations caused the decay of the orbit until the satellite catastrophic reentry in the atmosphere in January, 1958. It reproduces quite well the reported passages.

The spacecraft attitude is an inertial extrapolation of the attitude of the launcher after the deployment.

The rotation period (around 6 revolutions per minute) was roughly estimated with the observed rotation of the Faraday field of the dipoles of the antennas. Rotation arund the major revolution axis was reported by Bracewell and Garriott in 1958 in a paper in nature.

A good historical compilation of the events behind the Sputnik can be found here. In the following links, some historical movies about the event can be found.

An acceptable dramatic reconstruction is shown in the BBC documentary "Space Race". Some excerpts of the series can be found also in youtube.

Tuesday, 11 September 2007

Bonilla 2007-09-08/09

Following the invitation of Alberto Martos for the last Saturday, I attended to the Mirador de las Estrellas (Google Earth Link). It is the observation area that the Agrupacion Astronomica de Madrid has in Bonilla, Cuenca. There, despite the bad state of the atmosphere, we were able to capture the following images. The first one is centered in the central part of the Andromeda galaxy (M31) and the second one the Hercules Globular Cluster (M13).

Both images were captured using a C8 SCT with a Canon Rebel 400D attached to the primary focus. Using an ISO of 1600, the M31 image was captured with an exposure of 3 minutes and the M13 image with an exposure of 30 seconds. The posprocessing of the first image consisted in a HDR rescaling followed by a median filtering. The second one was produced modifying the histogram levels and aplying a median filtering.

Friday, 10 August 2007

M4 2007-08-08

During last night I connected a Canon EOS 400D camera to my C8 SCT to check the images that can be obtained from Majadahonda. As a first test, I pointed the telescope to M4 (Cat's Eye) Globular Cluster in Scorpio (Mag. 7.5). The following picture shows the result of an exposure of 1 minute in the focal plane with the histogram modified to reduce the light pollution.

NIR Summer Experiences

During my summer holidays in the Pyrenees, I have made some experiments combining visible and NIR images taken with a modified 3M digital camera. As chlorophyll reflects very well the NIR radiation, my intention was to verify this phenomena using the same filters that we use for astronomy. The selected target was the vegetation of the hight mountain terrains to show how it invades the different altitude levels. The following pictures show together the visible and the NIR infrared images to better appreciate the differences.

Wednesday, 1 August 2007

M63 2007-07-14

The following picture is a 5 min. exposure image of the Sunflower Galaxy (M63). It was taken from ESAC around 1:00 GMT of 2007-07-14 with the Meade DSI camera and a C8 SCT with a 0.33 focal reducer. The central part of the galaxy and its structure is clearly visible but the diffuse area is only apparent because the low contrast caused by the poor darkness in ESAC.

Monday, 9 July 2007

Moon 2007-06-29

As promised, close to the full Moon to reduce shadowing effects (2007-06-29 21:30 GMT), I repeated the multispectral imaging of the ejecta complex around Copernicus crater. The following picture covers the same area than the images posted before but excluding the Erathostenes crater. The false color combination was the same (Red:NIR; Green:G; Blue:UV). The color was also saturated in order to better appreciate the different responses.

Tuesday, 26 June 2007

Moon 2007-06-24

On Sunday (2007-06-24 22:30 GMT) and from Majadahonda, I imaged the Moon in UV, RGB and NIR with a C8 and a DSI Meade Camera. I tried to check if the response of different surface materials could be characterized from the Earth surface. For this purpose, the images should be as zenithal as possible. However, due to the date, the images were taken close to the terminator. The false color combination was (Red:NIR; Green:G; Blue:UV). This color was saturated in order to better appreciate the different responses.

The first image shows the Copernicus and Erathostenes craters and it is centered in the large ejecta complex surrounding Copernicus.

The second image is centered in the Montes Apeninnus that separate the Mare Imbrium and the Mare Vaporum. The large crater of the image is Archimedes and the smaller ones are Aristillus and Antolycus.

Using this false color combination, the different surface responses can be discriminated. However, the fact that the images are very closed to the terminator difficults the direct mapping of the surface elements. This could be solved removing the illumination effects using an elevation model or taking the images as close as possible to the full Moon. This last option seems more feasible for testing...

Monday, 25 June 2007

Deep Sky Tour at ESAC 2007-06-22

Last Friday, Leo, Michel, Fernando and me met here to try to image Venus with the UV filter and The Leo's telescope. After some trials and errors, the results were unsuccessful... it seems that we have lost some training using the Dobsonian with a Barlow... Later than the Moonset, we tried to image some deep sky objects from ESAC. Despite the light pollution, the bad seeing and a non-accurate tracking, some good deep sky images were taken. We used a C8 telescope with a 0.33 focal reducer and the DSI Meade CCD camera. The exposures ranged from 45 sec. to 1.5 minutes. Of course, we tried with some of the easiest Messier objects.

M51 Whirlpool Galaxy M82- Cigar Galaxy M27 - Dumbbell Planetary Nebula
M20 - Trifid Nebula

Thursday, 21 June 2007

Celestial Line 2007-06-20

Last night in Majadahonda, the sky cleared and I photographed an infrequent alignment of the Moon, Regulus, Saturn and Venus (from left to right). This alignment marks approximately the ecliptic. Technically it is the place where lunar and solar eclipses take place. However, during the last two days, the Moon has been eclipsing all the elements that has been encountering along the line... it seems that at least in this case the ecliptic definition could be extended a little...

Wednesday, 20 June 2007

Small Astrophoto Tour 2007-06-18/19

Yet I am testing my Baader U Filter. So, I tried to take again a picture of the Venus atmospheric features with my C8 Celestron from Majadahonda. In the previous post referred to Venus imaging, I showed a firsts UV picture. But there is something strange... it seems that a ghost image appears superposed to the main image. After some research in the technical specifications I discovered that the Baader U-filter has some small transmission in the NIR. If the observed object doesn't has a large emission in the UV, the NIR contribution can achieve the same magnitude. It should explain the detection of superposed double images slightly separated by the atmospheric refraction. In consequence, to use adequately the Baader U-filter it is necessary to combine it with a NIR blocking filter or a blue wide band filter to remove the NIR contribution.

The following image is the first result after combining the U-filter with a NIR blocking filter (the Astronomik NIR blocking filter, the Baader one blocks also the UV). In order to increase the exposure, instead the Toucam Webcam Pro, I used a CCD (Meade DSI) with a filter wheel. However, due to a large seeing and the low height of Venus at the imaging, large atmospheric distortions affected the image. After the stack of 10 images with 0.7 secs exposure, this is the best I achieved. Yes... I know any atmospheric feature is visible. Next time I will image early and with a better seeing.

After the Venus set, all the equipment was mounted. So I decided to perform a small astrophoto tour. The next image is the result to combine 40 images of Jupiter of 0.003 secs each.

The image shows the M22 Globular Cluster. For the generation of this image, 80 images of 15 secs were combined.

Thursday, 14 June 2007

Apophis: the End of the World is Nigh?

Talk from Mark Kidger on June 14th, 2007 at ESAC
Download pdf

A world with oceans...

This could be the look of the red planet 2.000 millions of years ago!

Perron et al, NATURE| Vol 447| 14 June 2007

Wednesday, 13 June 2007

2007-06-11: Venus in UV - First Test

Last month I adquired a Baader U filter to observe Venus. Two days ago I did my first test with the filter using my C8 and a Toucam Pro webcam. The sensibility of the camera is very low in UV. Therefore, I used the camera at the limit of gain and exposure. The following images show the result with the webcam CCD in the focal plane after a postprocessing with Registax.

There some estructure was clearly visible in UV in the Venus atmosphere. But when I tried to use a Barlow lens to magnificate the image, I reduced the luminosity of the image out to the detection range of the camera. What to do?. To increase the diameter of the telescope ( I think in Leo's telescope...) or use a CCD with a wider detection range. However, a larger exposure can difficult seriously the seeing compensation in posprocessing...

Monday, 4 June 2007

Sun in H-Alpha 20070601

Despite of some problems with the electrical current in the Satan site, last Friday we imaged the Sun in H-alpha using the Leo's CORONADO telescope again. The following images show the full disk and the prominences.

I post also some images of the observers and the equipment. Only Michel, Leo and Me are in the pictures but Ricardo and Luis were also here.

Wednesday, 30 May 2007

Sun in H-alpha 20070529

Finally, the sky cleared and yesterday (2007-05-29), Leo, Michel and me went to the hill to test the new solar telescope of Leo. Thus, around 17:45 GMT we captured some images with a small digital camera (Werlisa SLIM 30 Pro) attached to the telescope. After some processing, the following image was produced:

The image processing was as follow:
  • The original caption was transformed into a grayscale image.
  • The grayscale image was transformed into a RGB image.
  • A color map was applied to each channel of the RGB image to show in the same image the prominences and the surface details simulating as possible the observed colour.

Thursday, 24 May 2007

Sun Dogs

I know that anybody is for the conversion of the astroclub into an astrometeoclub ;)... but I cannot resist the temptation to put here a meteo picture again... Last days the changing weather shows several amazing phenomena. The new meteo event posted here is a Sun Dog (parhelia) taken from Majadahonda during the 2007-05-19 afternoon. It is caused by the ice crystals hosted in the clouds when the light passes throught their side faces. The phenomena is very well described in this link. Here you can find also a SW to simulate the different ice halos that can be produced by the Sun depending on the size of the ice crystals.

Looking for some related info, I found a good place gathering this kind of images in the same way than the Astronomy Picture of the Day (APOD) website. Of course, it is the Earth Science Picture of the day (EPOD) website!.

I promise that the next time I will post something more "astronomical"...