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Lord Rosse 72" telescope

at Birr Castle, Ireland


The NGC/IC Project is an attempt to correctly identify all of the original NGC and IC objects, starting with the original discoverer's notes and working forward in time to encompass the work of contemporary astronomers, both professional and amateur, such that the identity of each of the NGC and IC objects is known with as much certainty as we can reasonably bring to it from the existing historical record

If you're looking a full corrected version of the original NGC/IC with accurate positions, cross-identifications, size, mag, Hubble type, etc, check out Wolfgang's Steinicke's database also at the NGC/IC Project.

Steve Gottlieb also has observing notes on 5800 NGC objects.




Steve Gottlieb's NGC notes


Software review

The light pollution over Europe


Thanks to DMSP measurations of light pollution performed between 1996-97 Pierantonio Cinzano and his team have resumed the work began by Roy Garstang from Colorado University in the 80's and 90's. Their objective was to develop on the world scale a method to study the evolution of light pollution and its effects.

Cinzano and his team calibrated brightness data using readings from ground observatories and computed the effect of aerosols and topography on light propagation in the atmosphere.

The first resultat was published in year 2000 on P.Cinzano's website. His conclusions were published in 2001 in the Monthly Notices of the Royal Astronomical Society

Since that time, new light pollution maps have been released like Light Pollution Map that individuals can update with measurements of the night sky brightness using e.g. sky quality meters manufacturered by Unihedron.

A map based on Suomi NPP satellite pictures has also been released on Google Earthbuilder

Amateur can also contribute to these program by evaluating the light pollution over their observation site during their night sessions using their CCD camera.

CCD Amateur Measurements of Sky Brightness

The project is part of scientific activities of the International Dark-Sky Association, Italian section.


The Night Sky





Light Pollution Map

CCD Amateur Measurements of Sky Brightness


11 july 1991, by Chuck Vaughn

Crab nebula polarization (0-135)

by Kazuyuki Tanaka


At light, many objects present several vibrations planes or components (vertical, horizontal, oblique). Using two polarizing filters, you can eliminate one or another vibration plane by rotating one polarizing filter on the other one until light extinction. This technic can successfully be applied to study various celestial bodies, from the solar corona to moon deposits or pulsars.

The solar corona is constituted of two components, the "true" corona (K) from the Sun and the "false" component (F) constituted of cosmic dust attracted by its gravitational and magnetic fields.

Another interesting topic is using polarizing filters to looking for pulsars which activity polarizes light in their neighbour, like in M1.

A third amateur activity is to look for new or young dusty deposits on the Moon.

At last the glory or corona, this circle of rainbow surrounded by delicate shimmering rings that we can see aloft (inmountains or on the shady side of airplanes) can be observed through a polarizing filter. Take two pictures rotated through a right angle. They are needed for glory research. Remember that the smaller the droplets the larger are the rings. When you are low in altitude, the glory surrounds the spot where you are sitting (in mountain or in the airplane).

But simpler as all photographers should known, polarizing filters can be use to reduce reflectance of objects in which the light is slightly refracted or spread (looking at the sky, at sea, painting of metal, etc).

At last, a high-tech study should be trying to understand why the light continue to pass through an oblique polarizer in sandwich between a horizontal and a vertical one. Nobody knows... As if the fact to cut all vibrations planes will give birth to a new photon ! This is one of the numerous quantum enigma...






1001 URL


Thunders at night

Sprites above thundery cells


Many natural events can interest the astrophotographer from the solar eclipses, auroras, meteors or even the challenging solar analemma.

Beside these events that we all know, scientists are agree to recognize today there are many natural phenomena we don't understand yet or only partially, from the internal cumulo-nimbus activity (thunder clouds) to plasma discharge.

Even nowadays mother Nature hides many of her secrets. All phenomena linked to plasma and electromagnetic discharge in the air like Transient Light Phenomena (TLP) for example are very rare (Sprites and other jets) and need to be observe in situ. 

Dynamical and supersonic effects linked to turbolight and sonolight are rarely observed. Magnetohydrodynamic (MHD) is also a new science very promising which study can be ensure analyzing for example the effects produced by bolids, fireballs and large meteoroides penetrating the earth atmosphere.

In that regard, the Tunguska event appears to be one of the most surprizing phenoma of this kind.

Many of these studies are in the hands of physicians as they apply with forces the laws of quantum physics and thermodynamics. But this barrier does not mean an amateur observation is useless. On the contrary, a fan of such activities using professional instrumentation can conduct some of these researches as others analyse tektites using their boss's electronic microscope during their spare time.

But sometimes the eyewitnesses are also a very important information source to not discard.






English - French



And UFOs ?...

UFO sightings, these alleged observation of bright or colored "balloons", triangles and other cigars disturbe sometimes our environment. 

We have not to "believe" in UFO or extraterrestrials as we believe in God but try to understand the phenomenon and what really saw alleged witnesses.

Whatever is your opinion about UFO's we have to recognize that there is a pending problem for some decades that we cannot fully explain; the socio-psychological explanation does not resolve all problems. The few percents of unsolved observations justify that scientists continue to investigate objectively this very special field, sometime extraordinary to say the least.

Because the first work of a scientist is not to imagine theoretical explanations - as e.g. speaking immediately in terms of extraterrestrials - but rather to put all in place to collect physical data and readable pictures of the phenomenon. Then, after collecting a sufficient amount of data he could at last develop hypothesis and explicative models.

It is good to know geologists and physicians for example have found some correlations between earthquakes and some "UFO" sightings. Elsewhere, during the Belgian UFO flop, while witnesses observed an UFO from the ground, airborne radars locked on a unidentified target which confirmed, after analysis the presence of a material object in the air a few miles away. What for a material, what kind of object ? Nobody knows...

We are no more in the XIXth century when the witness of a meteorite falling was considered as a fool... and isolated from his community. Today we have tools and sophisticated instrumentation to analyze what happened.

All these kind of data have a high scientific value and such researches have to be continue with more support from the authorities, universities or political. Today an European organization support such research.

Unfortunately, scientists cannot access easily to the Hubble Space Telescope or satellites like Landsat or Spot satellites to check evidences of UFO presence but an international organization should. Therefore we have to support such initiatives in order they convince authorities there is something to do in the field.

But we have to solve another dilemma too. We currently have the tools to study the phenomenon but authorities refuse to give them to scientists because they cannot provide results. But how can we proof something if we haven't tools to study it ?... We turn in circle ! At last a few political begin to understand the nonsense of such an attitude.

In all these fields of environmental study any amateur observation quite a few complete - I mean completed with analysis, pictures, recordings, etc -  or visually confirmed by other witnesses can still help the professional community to understand what happened.

Usually such sightings are first reported to the police office whose reports are sent to national astronomy observatories, space centers or universities physics departments for analysis.

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