Binocular Variables

Many interesting variables are within the range of binoculars, and there are a few which can be estimated with the naked eye - though extinction must always be allowed for. Naked-eye variables are Betelgeux, Alpha and Gamma Cassiopeiae, Alpha Herculis, Delta Cephei, Kappa Pavonis, Beta Doradus, and various others the comparison stars can be looked up from the maps and notes in the previous section. If only one pair of binoculars is available, a good pair may be 7 x 50 (magnification 7 diameter...

Variable Stars

Fortunately for us, our Sun is a steady, well-behaved star. It may have periods of unusual activity, when its disk is disturbed by spot-groups and flares, but at least its output of energy does not alter greatly over the lapse of hundreds of centuries. Other suns are not so quiescent. Some of them vary in brightness from day to day, even from hour to hour, either regularly or in an erratic manner. They swell and shrink, and their temperatures change with their fluctuations, so that any planet...

The Lunar Maps

The following outline maps have been constructed from two photographs. The whole lunar surface is covered, but the method has two disadvantages. First, the formations near the eastern and western limbs are under high light and are consequently not well seen. Petavius, for instance, in the southeast, is really a majestic crater 100 miles across, and when anywhere near the terminator it is a magnificent object, but under this lighting it is hard to make out at all. Second, the photographs were...

Proper Names of Stars

Some of the stars have been given proper names. Most of these have now fallen into disuse, but because they are still produced occasionally, the observer may find it useful to have a list. The names listed here are by no means all that have been given, but include the more important examples. A few stars have more than one name (Eta Ursae Majoris can be Benetnasch as well as Alkaid), and some names can be spelled in more than one way (Betelgeux can be Betelgeuse or Betelgeuze). It is clearly...

Jupiter Transit Work

The diagram opposite shows Jupiter's main belts and zones SPR South Polar Region SSTZ South South Temperate Zone SSTB South South Temperate Belt STZ South Temperate Zone STB South Temperate Belt STrZ South Tropical Zone SEB South Equatorial Belt (often double SEBs south component SEBn north component) EZ Equatorial Zone E Band Equatorial Band NEB North Equatorial Belt NTrZ North Tropical Zone NTB North Temperate Belt NTZ North Temperate Zone NNTB North North Temperate Belt NNTZ North North...

The Constellations

In the following list, an asterisk indicates that the constellation was listed by Ptolemy X, that much or all of the constellation is invisible in Europe. Zodiacal constellations are distinguished by the letter Z. Constellations English Names Remarks First Magnitude Corona Borealis The Northern Crown * Crux Australis The Southern Cross X Acrux, Beta Crucis Cygnus The Swan * Deneb Equuleus The Little Horse * Eridanus The River Eridanus *X Achernar (X) Gemini The Twins *Z Pollux Leo The Lion *Z...

Map XVI Pavo Indus Tucana Grus Phoenix Microscopium

This is the region of the Southern Birds. I have found that the best means of identification is to locate Alpha Pavonis by using Alpha Centauri and Alpha Trianguli Australe, as shown in the key map. Of all the groups, only Grus is distinctive. PAVO. The brightest star is Alpha (2.1) then follow Delta,Eta and Beta (each 3.6), and Kappa (4.0 at maximum). Alpha is rather isolated from the rest of the constellation. Delta is 19 light-years away and is very like the Sun in every respect it is...

Telescopic Variables

Again I give only a few specimen examples and charts. There are so many variables within range of even a 6-inch telescope that no single observer can hope to deal with them all, and one has to make out a personal list. My own (2004) included 51 stars, which is as many as I could manage others will certainly be able to do better. The following charts are inverted, for telescopic use. R Cygni. This is extremely easy to find, since it lies in the field with the 4th-magnitude star Theta Cygni -...

The Nearer Planets

There was a time, not so long ago,when most amateur astronomers concentrated almost exclusively upon the members of the Solar System. This is not true today, but of course the Moon and planets remain favourite targets - and despite the space probes, there is still a great deal about them that we do not know. Even a small telescope will show details on some of them, so let us consider the planets one by one. The four members of the inner group - Mercury, Venus, the Earth and Mars -are solid,...

Map XII Key Map Orion

Orion is on view for a large part of the year - all through the hot season - and is out of view only during the winter. Now, of course, Rigel is at the top and Betelgeux at the bottom the Belt stars point downward to Aldebaran and upward to Sirius. Canopus can be located by using Zeta and Kappa Orionis, and Canopus and Sirius point to the Twins, Castor and Pollux. Regulus and the Sickle can be found by taking a sweep from the lower part of Orion through Procyon, as shown in the key map. Canopus...

Map XIV Carina Vela Puppis Pyxis Volans Antila

Gamma Velorum Map

This map is occupied the old Argo Navis, which has now been divided up into smaller constellations. Crux, Beta Carinae, Canopus, and Sirius form a magnificent curved line that cannot be misidentified. The Falso Cross is made up of Epsilon and Iota Carinae, and Kappa and Delta Velorum. The whole region is exceptionally rich and is crossed by the Milky Way. CARINA. This contains Canopus, which is inferior only to Sirius. Canopus has an F-type spectrum, and is usually described as yellow, though I...

Map IV Orion Lepus Eridanus Taurus Cetus Auriga Columba Caelum Fornax

The times of rising and setting of Orion, in England, were given in the notes on Map II. Capella is just circumpolar but can almost graze the horizon. Perseus is shown in part and also Triangulum. ORION is probably the most glorious constellation in the heavens, and is easy to recognize. Betelgeux is a fine sight with a lower power spectrum M orange-red , and Rigel is brilliantly white. Rigel appears only very slightly less brilliant than Arcturus and Vega. The other leading stars are Gamma...