The Paschal Full Moon 2019

A comparison between two different optics: Canon EF 400mm f/5.6L and Celestron C5 with corrector

Full Moon on April 18, 2019. Image taken 14 hours before the opposition. (Canon optics) Full Moon on April 19, 2019. Image taken 10 hours after the opposition. (Celestron optics)

Notice that the atmospheric conditions are not exactly identical at 24 hours interval. For instance, an optical system having a larger aperture will be more affected by the turbulent layers in the atmosphere (cf. astronomical seeing). Only a comparison in a lab and under rigorously identical conditions is relevant. This has been performed for characterizing the Canon and the Celestron optical setup. Short summary of the results: The better resolution at the center of the image is obtained with the C5 + Corrector, but the better uniformity of the field is clearly provided with the Canon lens. Click on this link for visualizing the results © Michel Willemin

The longest Lunar Eclipse of the 21st Century

The Lunar Eclipse rising over Aaberg (BE, Switzerland) on July 27, 2018 Five stages of the eclipse on July 27, 2018 observed from Prêles (BE, Switzerland)


The Moon

The Moon on March 23, 2018 @ UTC 21:25
Setup: Canon EOS M6 + 400mm f/5.6 L, Settings: Exp 1/500 s, f/8, ISO 500
© Michel Willemin

Other images of the Moon

The Moon on April 21, 2018 Mare Nectaris, lunar craters Theophilus, Cyrillus and Catharina on April 21, 2018

Saturn Occultation by the Moon

November 3, 2001


This paragraph describes the Saturn occultation by the Moon of November 3, 2001. The entrance phase was visible between 20:56:57 and 20:58:22 (UT) and the emerging phase between 22:00:50 and 22:02:28 (UT). The occurrence of such a phenomena is unfortunately not frequent, but it happened several time on the period 2001-2002.

Image taken after the Saturn occultation. To see the full resolution, click on the image. There are several concentric rings around Saturn. The brightest ring is separated from a fainter outer ring by what is called Cassini's division.

Experimental setup

Instrumentation : Schmidt-Cassegrain telescope with F = 2030 mm, f/10 + IR BG39
Camera : Philips Vesta Pro Scan, mounted at the prime focus, exp. 40 ms for all pictures showns on this page
Processing : The only post-processing correction concerns contrast/intensity for some pictures.
Time : November 03, 2001, from Affoltern am Albis (Switzerland), © M. Willemin

Occultation images

Click here to see the occultation movie
(*.gif) (592 kB)

Images of the Moon

These images have been taken between the entrance and the emerging phases of the occultation. The experimental setup is identical and the exposure time is still 40 ms for all pictures.



Zoom on Saturn

The two following zooms on Saturn are obtained from the image displayed on the top of this page. The image processing (Fourier analysis/correction) has been performed by Raoul Behrend. The division of Cassini becomes clearly visible. For further enhancement of the resolution, multiple shots images with statistical averaging are required. The example presented here is close to the limit achievable with a single shot image obtained with a 200 mm aperture telescope.

The next images are obtained from the combination of 13 single shots with exactly the same setup as described above. The image processing (unsharp masking and image addition) has been performed with the freeware Iris 3.5.4. The resolution can be further increased by compositing a larger number of images.


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