astronomy

FireFox Extension for Cloudy Nights Forums: version 1.0.0 has been released!

The first public version of cn_ubb_enhance , a free FireFox extension that enhances your Cloudy Nights user experience, is a fact! You can download it here: http://shutterfreak.net/xtra/firefox/cn_ubb_enhance/cnubbenhance-1.0.0.xpi Version 1.0.0 is a complete rewrite since version 0.5 as a 100% native FireFox addon. No more GreaseMonkey meddling and related potential security issues. This version contains the following fixes and changes:

cn_ubb_enhance - Enhance your Cloudy Nights user experience

The Cloudy Nights forum is one of the most popular astronomy forums on the Internet. This page presents a way to enhance your user experience when participating on Cloudy Nights when browsing with Firefox (sorry, no other browser can be supported):

Partial eclipse of the Moon on Dec 31st, 2009

On December 31st, 2009 most of us will be treated by a partial lunar eclipse. Indeed, the Moon will be darkened by part of Earth's shadow on this year's last Full Moon, and this month's second Full Moon (sometimes called a 'Blue Moon'). Only the Americas will not be able to witness this eclipse.

Herald-Bobroff chart references for the SAC database of deep-sky objects

The Saguaro Astronomy Club (SAC) Database is the result of more than 20 years of devotion to create and maintain a list of more than 10,000 worthwile deep-sky objects within reach of many amateur astronomers. The database is managed by Steve Coe and has a historic data format. It contains lots of information about these objects, such as the object type, celestial coordinates (RA and Dec), brightness, position angle etc. but also links to charts in the first release of Uranometria 2000.0 and in the Tirion Sky Atlas 2000.0.

August 16, 2008: Partial lunar eclipse

Lunar eclipses are beautiful events where you expect to see a full moon but instead you see Luna obscured while it crosses Earth's shadow. On August 16, 2008 there was a partial lunar eclipse, 15 days after August 2nd's solar eclipse.

Two things connect both eclipses. First it's common to have solar and lunar eclipses around the same time. Second, both events were challenging to observe due to high altitude clouds in Brussels.

Wireless EQDirect - a Bluetooth connection to your Synta mount

2007 was the year that I bought my first dual-axis mount: an Orion Sirius EQ-G. This mount is virtually identical to the Skywatcher HEQ5 with the recent motorization. Apart from it being an affordable mount with decent performance, it also features lots of interest from enthusiast amateur astronomers, either eager to enhance the mount's performance (see the EQ6 Yahoo! Group), or even to give it advanced computerized control for free (see the EQMOD Yahoo! Group).

All facts mentioned above have influenced my final decision to get the non GoTo "SynTrek" variant of the Orion Sirius EQ-G (the GoTo version of the handcontroller is "SynScan"). Nine months later I decided to acquire an EQDIR module from Shoestring Astronomy, along with the EQCBL-01 mating cable. I then installed the free planetarium software Cartes du Ciel, the free and standardized ASCOM Platform (free, Windows platform), and the latest EQMOD ASCOM drivers allowed me to control my mount from my laptop. I was impressed by the relative ease with which all was installed and how the hardware and software collaborated without major issues.

The only real problem I witnessed was a mere usability issue: since I observe mainly on a small balcony or on a remote location, the cable connecting the mount to the PC was often in the way. For a permanent setup this most likely is not a problem, but in my case I was thinking in terms of «this can be done in a more user friendly way». Hence I decided to look at wireless solutions to replace the RS232 serial link with the mount.

Aligning an equatorial mount

The earth rotates about its axis once every day. When observing an object with a telescope, we have to compensate the rotation of the earth. An equatorial mount compensates this motion if the following 2 conditions are met:

  1. its polar axis is parallel with the polar axis of the earth;
  2. the mount rotates about its polar axis at exactly the same rate as the earth rotates about its axis

The first condition is met if the mount is correctly set up. The procedure of setting up an equatorial mount is called polar alignment.

Disassembling a JMI NGF Mini2M motorized focuser

Note: I will shortly publish updated instructions

I take no responsibility nor do I claim the instructions given below will yield success. The instructions below are only provided for help. Please do not misuse the information provided on this page.

The Mirror Cell - PLOP simulations with a central obstruction of 75mm (unequal forces on the support points)

Computation with a true central obstruction of 75mm, allowing for refocus shift

Contents

Central obstruction: 75mm

Part overview of 'p8_1_7' cell Part overview of 'p9_1_8' cell
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