François' Blog

New finder scope (MiniBorg 50mm)

Filter drawer - open position

Filter drawer - with filter in place

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Testing the table for the Nuit des Etoiles.

It worked fine, allowing continuous viewing for the public, at least 15 minutes without readjusting the view.

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The table is finished. I added two struts and made a light varnish.

First tests tonight with the binoculars, before I try the Dobson.

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I started this equatorial table, taking as a model the excellent articles by Reiner Vogel and Ed Jones. Here are the steps:

With two pieces of ash, I make a mortise and a tenon

I cut a circle segment..

.. which is routed with an angle of 43 degrees (my latitude)

.. the resulting piece is cut lengthwise at an angle (difficult to determine - I used trial and error)

then assembled with a biscuit jointer.

The mobile part is ready to glue up.

Starting to assemble the fixed part. I bought the DC motor, regulating circuit and reducing gear from

Detail of the drive cylinder, made of wood covered with heat-shrink tubing for traction

The south pivot uses a window hinge

The north-east bearing

First trials

The table is almost finished, with its electronic box and leveling screws.

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19 Jun 2015

Sky Map


This is a view of the night sky, with planets (in red) at their current place computed from Jean Meeus' "Astronomical Algorithms"

You can zoom and scroll the globe, and click on stars to show their name.

Credits: d3 library: Mike Bostock / Jason Davies ("Rotate the World" example)

Ephemeris: Peter Hayes

The star database comes from the astronomy nexus

The constellation lines and boundaries come from the PP3 program

The next steps are to add deep-sky objects, and to show the sky in proper azimuthal projection, using the browser's location services to find the user's place on the earth.

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16 Jun 2015



After my renewed interest in astronomy last year I joined a club, (SPICA in Cagnes sur Mer), which gives access to the 40cm Newton Amateur Telescope of the Côte d'Azur observatory in Calern, above Grasse.

40cm Newton Amateur Telescope

I also purchased, first a 6 inch Vixen Newton on GP2 mount, then a 30cm made by Pierre Desvaux / Dobson Factory) with a mirror from John Nichol.
Then of course a few eyepieces: a 24mm Panoptic, an 11mm Nagler and a 5mm Takahashi LE.

The wooden Dobson design has the advantage of being easy to customize. Here is my setup for finding objects: a Rigel Quickfinder and Takahashi 6x30 optical finder. This combination works fine for me. No GOTO, no digital setting circles! just Erich Karkoschka's Sky Observer's Handbook, the 12inch mirror and a dark night.

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After ten years using the Textpattern CMS, I decided to move my venerable website to another system. There is nothing wrong with Textpattern, in fact I still prefer it to Wordpress, but I got tired of the complicated backup system (mySQL database) and the lack of version control. Also, I still feel the nerd's urge for new software.

I found that the latest trend is flat-file CMS, did a quick review and settled on GRAV. It took only a few minutes to get it up and running on my iMac, and a few hours to migrate all articles and images. It looks very powerful, extensible, and actively maintained. Also, I can version control it easily with Perforce.

Next actions:

  • add features, (picture gallery, javascript)
  • improve the appearance,
  • write more posts...

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Nice weather and perfect snow through Fontanalbe (Vallée des Merveilles) - 1st February 2015.

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