Wednesday, 24 December 2008

2008-12-23: Venus in UV, Blue and NIR

Equiped with a new set of interferential filters, I tried to image Venus from Majadahonda to check if something could be discriminated in the atmosphere using the filters that I have. The camera was the usual Phillips Toucam Pro with the following set filters manufactured by Edmund Optics: 400 nm, 450 nm and 880 nm with respectively 50, 80 and 50 nm of FWHM. The telescope was my Celestron 8" SCT. As Venus is still very far from us, I used a 2x Barlow to increase as possible the size of the disk in the camera detector. The following image is the result of the stacking of 80 images with the false colour combination R:880 nm, G: 450 nm and B:400 nm.
It is well known that the Venus atmosphere presents some UV absorvers. They are distributed in atmospheric dark bands that could be constituted by chlorine or/and sulfure compounds. It is known since the Mariner 10 captured the firsts closed images of the planet. At present, Venus Express is observing the atmosphere in UV to better understand the composition of these bands and their paper in the atmospheric circulation.
In order to detect some atmospheric detail, I tried to exploit that the Phillips Toucam Pro has some sensibility in the UV and the 400 nm interferential filter has some band pass in the near UV. However, anything was observable. Maybe the band pass of the filter should be shorter to detect better the radiance contrast produced by the different molecular especies or perhaps the scale of the atmospheric bands is very low and their removed by the stacking required to reduce the seeing.

Tuesday, 2 December 2008

2008-12-01: Triple Conjunction

To be completed...

2008-08-17: Green Flash

To be completed...

2008-06-07: Summer Globular Clusters



To be completed...

Friday, 29 August 2008

Yet more DSI images...

The images below were taken from ESAC using the DSI camera and the 6" AS-GT reflector. The sky transparency was not very good and at some point got cloudy.

M27 - A single exposure of 1 minute, saved as 3-colour FITS. Histogram modified with DS9.

M57 - a single 1 minute, saved as 3-colour FITS file

M13 - a single 8 sec exposure, saved as 3-colour FITS. Two different ranges for
displaying purposes

Wednesday, 14 May 2008

New tests with the DSI camera...

On May, 1st-2nd, I performed a few new tests with the DSI camera (thanks to Manuel who kindly provided to me) attached to my Newton telescope (6", f/5) and the CG5-GT mount. These are single-shot images (i.e. not an average of a number of individual exposures) and the dark frames were too short. While the quality is not very good (e.g. very noisy background), they're nice on average so I post them. Exposure times are: 60 sec (M51), 30 sec (M104), 60 sec (M81) and 8 sec (M3)

Thursday, 21 February 2008

2008-02-21: Total Lunar Eclipse III

As a first draft result of the coordinated observation, I have produced an anaglyph showing a moment of the Lunar Eclipse in 3D.

The first picture was posted in Cielo Sur in answer to the coordinated observation by Leonardo Julio, Alejandro Tombolini and Adriana Fernández from Arenales y Agüero, Capital Federal, Argentina . It was captured with a Meade LX 90 telescope and an Olympus Evolt E-500 camera (provided by Silvia Smith). The second image was captured from Majadahonda (Madrid) by Manuel Castillo using a 9 cm/F10 Matsukov-Cassegrain Telescope and a Canon400D camera at 01:56 GMT. It was selected identifying the corresponding stereoscopic pair in a sequence covering all the Moon immersion in the Earth Shadow. Alignment and scaling was performed using conventional image processing techniques.

2008-02-21: Total Lunar Eclipse II

During the last night, the clouds were a big problem here in Madrid. We had a good window at the beginning of the eclipse. Therefore, the immersion in the shadow was easily visible. However, just after the totality, the conditions degraded a lot. Some open clouds permited to picture part of the totality but the emersion observation was quite difficult because the distribution and thickness of the clouds complicated seriously the imaging.

The following image was captured shortly after the maximum of the eclipse (03:31 GMT) with a 9 cm/F10 Matsukov-Cassegrain Telescope and a Canon400D in the primary focus at 1600 ISO and 5 seconds exposure.

Despite all these problems, I captured a sequence of all the eclipse. It can not be used to produce a video because the captures were not continuous. But, I hope that the individual frames can be used to produce 3D images of the sequence if finally somebody in the other hemisphere was lucky. As soon as I have more info I will post it here

Tuesday, 19 February 2008

2008-02-21: Total Lunar Eclipse I

For the observation of the total lunar eclipse of next February, 21th 2008 eclipse, we are participating in a coordinated observation of the total lunar eclipse of Next February, 21th 2008 from SouthAmerica and Western Europe.

The main data of the eclipse is shown below:

The eclipse has different characteristics of difficult repeatibility:

- All the eclipse will be visible from both Western Europe and South America.
- It is the last total lunar eclipse in the next 7 years which is visible in its integrity from South America.
- It is the last total lunar eclipse in the next 6 years which is visible in its integrity from Western Europe.
- Before the eclipse, the Moon will pass between two bright stars: Regulus (Mg. 1,41) y 31 Leonis (Mg. 4,4).

These characteristics permit the development of two interesting activities using simultaneous observations from Europe and South-America:

- The production of a 3D video of all the eclipse combining images taken from both hemispheres. It could be the first times it is produced.
- Using the two bright stars and the Moon imaged from both hemispheres, estimation of the Moon-Earth distance by means of the measurement of the Moon paralax. It has a similar educational value than the determination of the astronomical unit by means of the Venus transit.

Complementary activities are:

- Timing of the five penumbra and umbra limb contacts.
- Timing of the umbra immersions and emersions of certain surface features.
- Timing of star ocultations during totality.
- Monitoring of possible Lunar transitory effects during the totality and the final phase of the penumbra.

Interested people from South America have been invited through Cielo Sur, an argentinian amateur astronomy webpage. Also personal invitations will be adressed. From Europe, the Astronomic Group of Madrid with some people of the ESAC astronomy club will be involved in this activity together with other teams from Spain. As observing from only one region the weather can be a problem, we have contacted teams observing from other parts of Western Europe to assure as possible the imaging of the eclipse from this hemisphere. So, ESOC & ESTEC astronomy clubs have been invited despite they have not the best weather during February.

As outputs of this activity and with credit to all the participants, it is expected to produce a stereoscopic video of the eclipse, a report gathering all the provided results and educational material for a practical Earth-Moon distance calculation.

Amateur astronomers from everywere in the visibility area are specially encouraged to participate in this event. Everybody can participate in this observation using from small binoculars to large size telescopes. A guide with details of all the observable phenomena is available here.

The main coordinator of the activities and the main author of the observation field guide is Alberto Martos. He is an experienced Moon explorer. He worked in the Madrid ground control of the Apollo missions (XIV-XVII) and Skylab and worked in VILSPA until his retirement last year in the mission control of different ESA missions (IUE, ISO and XMM). At present, he is member of the Astronomic Group of Madrid.

Wednesday, 13 February 2008

2008-02-09: Orion Nebula - M42

The following image was captured from Majadahonda (Spain) using a C8 SCT with a Canon Rebel 400D attached to the primary focus. It is the result of the combination of three exposures of 60 seconds in RGB with and ISO of 1600.

Monday, 21 January 2008

2008-01-19: Mars one month after the oposition

During the last weekend, the Moon and Mars were in a conjuntion of less than two degrees. Of course, we met for the event. So, Alberto Martos, Fernando Rodriguez and me were in the backyard of Alberto's house "Villa Urania" in Villaviciosa de Odón with all our equipment to register the astronomic encounter. The following image shows the conjuntion. It was taken with a Canon400D camera with a 300 mm APO objective around 23:45 GMT.

Of course, the real excuse for the meeting was to observe and image Mars. Still it is very close to its oposition, nearly one month after, and it is possible to take detailed pictures of the surface.

The Mars imaging was performed around 23:30 GMT with a 8" SCT with a Toucam Pro webcam, a blocking NIR filter and a two Barlow lens ensemble. The focal length of the SCT telescope is 2 meters. Therefore, the effective focal length using together one 2x and one 3x Barlow lens should be around 12 meters! (probably the effect is not exactly multiplicative... a detailed calculation should be made...). 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 shows the final result.

The next image resulted forcing slightly the histogram and sharpening modifications.

Several video tracks were captured also using a NIR pass filter. However, the high attenuation introduced by the Barlows difficulted greatly the focussing. As a consequence any of the captures have produced acceptable NIR images.