Thursday, 15 September 2011

An afternoon in the Sun

On September 09th we observed the Sun in H-alpha at ESAC, in front of Leo's office.

We used Leo's Coronado on Michel's Celestron mount. The attachment point was tied with a hand-made fixation by Manuel, that held well during the observation.

After direct observation through the eyepieces, we tried two types of cameras to capture the images. Here it is a mosaic image of 5 frames (~1 min video), with Barlow and the Toucam.

The image processing was as follow:
  • The original sequence (video) was shot slightly dark not to saturate the pixels
  • The 1 minute sequence was stacked into an image
  • The image was stretched down to DN 85 to enhance the disk features
  • Mosaic was built with Photoshop with slight intensity adjustments.
  • A color map was applied in Photoshop to show in the same image the limb features and the surface details, with a natural color
This image was taken with the Canon EOS DSLR from Manuel (stacking 24 images of 1/20 sec).

Here it is the SOHO EIT304 image closest to the ones above (~18:00 local), for reference.

Friday, 9 September 2011

Iridium Flare

On 2011-08-05 between 21:30 and 21:32 UTC, I imaged an Iridium flare with a Canon EOS DSLR camera fixed in azimuth an elevation. The track and the change of brightness is very clear in the image.

The flare was produced by Iridium 60 and it achieved magnitude -5 at the location (40.184N,6.305W) in Boada (Salamanca-Spain). Estimated maximum magnitude was -8 at the flare centre located at a distance of 10 km. Central position of the flare in altitude and azimuth was (40, 70(ENE)). I recommend to observe these flares because it is quite impresive event. During few seconds the flare is the brightest element in the sky. Unavoidable to use heavens-above to forecast the flares in your location.

Thursday, 8 September 2011

Jupiter through the Club's telescope, 30 August 2011

This image was taken with the Phillips Toucam and the club's telescope (Celestron CGEM, 925 EdgeHD) on 31st August around 2am, by Manuel Castillo, Santa Martinez and Miguel Perez Ayucar. A Barlow magnification lens was used to augment the size of Jupiter. The viewing conditions were poor, so we observed Jupiter between stratus clouds. The image is a processed (Registrax5) stack of a 2min video using the webcam.

Jupiter, visible

We tried also the IR filter, but we could not see the planet! Probably due to the bad cloudy viewing conditions.

The Swan

Here's a picture of the Swan nebula (M17), very close to the Eagle. This was done in just 2 minutes (2 x 60 sec) with my usual equipment.

Wednesday, 7 September 2011

Still learning...

The Eagle nebula (3 x 60 sec exposures). Not too sure on how to convert the raw B&W exposures into colour... anyhow, the dark pillars and patches of the nebula giving the characteristic "eagle" shape are clearly seen there.

2011-09-06: More Supernova Images

Last Monday, around 23:00 UTC, I tried to take a picture of the supernova in M101 from a dark place in Salamanca (Boada) using my C8 with its default mechanical fork mount. It was aligned manually using the AR and DEC scales together with an illuminated micrometric reticle eyepiece. Without any computerized aid (i.e. no GOTO function)! As imager I mounted a standard Canon EOS DSLR in the prime focus together with a focal reducer to convert the usual F10 of the scope into an effective F3.3. The purpose was to configure a very fast imaging ensemble. However, this configuration has the inconvenient of a significant image distortion out of the optical axis. The used focal reducer design is not able to flat the prime focus over the large size of the Canon CMOS sensor. Despite of this problem, the alignment and imaging configuration allowed non guided exposures of 3 minutes. Finally, the Moon limited the effective exposures to 90 secs.

As a first test for the alignment, I tried to image M51. The image below shows the result. It has been composed stacking 4 exposures of 60 secs. Later I found that M51 houses a recently discovered SN. It is marked by a red arrow in the image. For SN identification, this image can be compared with another image of M51 that I posted here on 2007/06/22.

Then, I pointed to the main target of the night and I take several exposures. The following image shows M101 and its SN signed by a red arrow.. It is the result of the stacking of 6 exposures of 60 secs and 4 exposures of 90 secs.

My final impression of this experience it that the results are not bad, specially if it is considered that they are produced with a manual alignment.

Supernova sn2011fe update

On Sunday 4th, I managed to image the galaxy again from the darker skies of Robledo de Chavela with my usual equipment (Celestron Newton reflector 150 f/5, CG5-GT GoTo mount and Orion Starshoot DSI II imager). Thanks to a careful polar alignment, this time I could take several 2-min. exposures. The image shown is a raw format image (i.e. no color conversion) created from a stack of 6 2-min exposures of the galaxy (T=720 sec). The SN is becoming very bright!

Monday, 5 September 2011

First images with the club's new telescope (Celestron CGEM 925 EdgeHD)

We have used the warm and clear nights in August to go out observing at ESAC. We used the ESAC Astronomy Club new telescope, a celestron CGEM, with 9,25" EdgeHD tube. Light conditions are poor on-site but we managed to get some good first images. The images shown in this entry date from the night of the 27th Aug 2011.

We tried faint objects first, the Dumbbel Nebula M27 and the Ring Nebula M57. The images are shown here. The alignment was not great so we could only apply relatively short exposures before objects were moving noticeably. Dumbbel nebula image is a stack of 8 images of 10 second exposure each, with the Club's Meade DSI camera. The magnification of the telescope (2.3m focal) is quite large so only a fraction (around half) of the bubble is seen. No focal reducer was used.

Dumbbel Nebula, M27

We also tried M57, the Ring nebula. This was much better captured by the camera. The image is a stack of 9 images of 10 second exposure time each. The central star is seen, as well as the delicate redish and greenish colors of the gaseous remains.

Ring Nebula, M57

We waited until Jupiter rose over the horizon and over the glare of our particular Messier object, the M-503, and tried the Phillips Toucam to image the planet and its moons. K3CCD was used for capturing the image sequence, and Registrax v5 for stacking and image processing. The image is generated from a webcam clip of 1 min duration and black&white mode.

Jupiter in b&w

The last image is a color one with the Toucam, 2 seconds 'avi' clip. K3CCD was used for capturing the image sequence, and Registrax v5 for stacking and image processing. The Red Great Eye is noticeable in the right side of the South band. Also Io (left), Europa (right high) and Ganymede (right low) are visible.

Jupiter in color

These first images are very promising, and we expect to improve in the future with better tracking, images exposures, capture options, and post-processing.

Saturday, 3 September 2011

Supernova SN 2011fe in M101

Excerpt from the Wikipedia article at SN 2011fe, initially designated PTF 11kly, is a star undergoing a type Ia supernova event, discovered by the Palomar Transient Factory (PTF) survey on the 24 August 2011 during an automated review of images of the Messier 101 from the nights of the 22nd and 23rd of August 2011. The star, formerly a white dwarf, is located in Messier 101, the Pinwheel Galaxy, 21 million light years from Earth. It was observed by the PTF survey very near the beginning of its supernova event, when it was approximately 1 million times too dim to be visible to the naked eye. It is the youngest type Ia ever discovered.

We took this image on Friday, 26th August from ESAC (2 days after discovery). The supernova is clearly visible in the image (enclosed by a green circle), as shown in the comparison image from the KPNO Schmidt camera. The orientation is standard, i.e. N on top and E to the left. The image was taken with my Celestron 6" Newtonian reflector mounted on the CG5-GT mount and an Orion Starshoot DSI II color camera. The image is the sum of 3 one-minute exposures (we took neither flats nor dark frames but connected the thermoelectric cooler) . The sky quality was very poor due to light pollution (as usual at ESAC).