Pegasus Astro Club

Aladin could be thought of as an astronomy browser. Instead of the internet, Aladin browses through astronomy images, density maps, and other astronomy sources, e.g. Hubble images, the Simbad database, and the VizieR service. You select the item you wish to view and it automatically downloads a view of the item selected.

This program provides access to professional quality telescope images in several wavelengths. In effect you are looking through a very large telescope. The images are downloaded from the internet so some displays take a few seconds to update—your results would depend of course on the connection speed and on how many databases are being utilized. One can apparently download files for offline viewing.

I could superimpose various views in to one and I could open up to 16 panels with images in each.

It was one of only two programs which indexed every star and deep space object in my test sample as well as showing several images of each item. You can also point at a specific location using the right ascension and declination coordinates. You can bookmark views.

Since Aladin is a sky atlas image viewer and not a planetarium program it has no solar system objects in its index. Obviously there could be images of the solar objects in many of these images but it's beyond my ability to locate them.

Requires Java 1.5 and runs under Windows, Linux, and Mac.

Computer Aided Astronomy (aka C2A) was also fairly easy to use. Its index is second only to Cartes du Ciel in thoroughness. There are several additional catalogs for download.

There are a lot of images included with the program. Unlike several of the other planetarium programs the images are viewed through a separate window in the image browser. If there is an internet connection, the program can download images from either the ESO or the STScl sky surveys for display in either the image viewer or directly in the planetarium field of view.

I liked the data section to the left of the planetarium window with the details about the object on display. I liked the ability to move forward or back through recent views and the ability to bookmark views.

Computer Aided Astronomy has an ephemeris generator which can generate tables for the sun, planets, moon, comets, and asteroids between any two dates. There are tools to generate trajectories of planets, asteroids, and comets between any two dates. One tool shows the moon phases for the entire month. The Ecliptic View tool displays an animated view of the solar system with comets and asteroids.

Computer Aided Astronomy can control a computerized telescope mount.

Windows only.
 

Cartes du Ciel (aka Skychart) is a very easy to use planetarium program. Its in depth index found every object in my test sample with the exception of UGC 9128. Additional catalogs for stars down to magnitude 16 (UCAC3) are available on the website, along with several specialty catalogs. There are instructions for adding the entire PPMXL catalog (magnitude 20), which I didn't attempt as it required 148 GB of hard disk and 24 GB of ram.

Cartes du Ciel has a calendar calculating ephemerides for twilight, planets, sun, moon, comets, asteroids, and solar and lunar eclipses between any two dates. And there is a variable star observer with the predictions of minima and maxima for many variable stars for the next couple of cycles.

Cartes du Ciel can control a computerized telescope mount.

The program includes images of many deep space objects right in the planetarium window. I didn't notice any actual stellar images or planetary images. However, the online documentation indicates that planetary images are available in the Linux version. No bookmarks.

Windows, Linux, and Mac versions.
 

Stellarium creates fairly realistic views of the sky. The basic program has over 600,000 stars (roughly up to magnitude 9.9) with another 240 million available as add-ons. This is the only free program that shows constellation groupings for other cultures.

The zoom in shows actual images of planets and some deep space objects.

Stellarium provides many visual effects, including the Milky Way, twinkling stars, shooting stars, clouds, and light pollution. Several landscapes are included.

The telescope control plug in allows Stellarium to control a computerized telescope. The Satellites plug in calculates and renders satellites in Earth orbit from NORAD/TLE data.

Its catalog is weak in comets and asteroids.

Windows, Linux, and Mac versions.
 

Celestia is a space travel simulator. You can travel throughout the solar system, to any of over 100,000 stars, or even beyond the galaxy. There are add ins to expand the catalogs and images of comets, stars, solar system objects, and deep space objects. You can even add in fictional objects such as Star Wars, Star Trek, Babylon 5, etc.

I feel this is a fun way to view many of the objects themselves. There are images of many solar system objects, e.g. Deimos and Ceres.

As this is a simulator and not a planetarium program, Celestia does not indicate constellations, have telescope controls, or have a method for pointing to a specific location, e.g. RA 02:31:49.09 dec +89:15:50.8. (Not intended as a criticism—just an observation.)
 

WorldWide Telescope comes in two versions, Windows Client and Web Client. Both versions are very similar and work equally well. If connected to the Internet the Windows client automatically downloads images that aren't already in the catalog.

The Windows Client version can control a computerized telescope.

Its catalog is weak in comets, asteroids, and planetary moons, e.g. only Jupiter shows moons.
 

(Diurutkan berdasarkan rating dan kualitas) 

Dari perhitungan astronomi, pada tanggal 19 Maret 2011 Bulan dalam peredarannya mengelilingi Bumi, akan berada pada posisi paling dekat dengan Bumi, disebut sebagai posisi perigee.

Tentunya dalam peredaran mengitari Bumi, Bulan akan selalui melalui posisi perigee, tetapi posisi perigee tersebut tidak selalu berada pada angka yang tepat sama, tetapi bervariasi sepanjang waktu.

Pada tanggal tersebut, yang pada saat itu Bulan dalam fase Purnama, dalam perhitungan merupakan jarak yang paling dekat ke Bumi semenjak 18 tahun yang lalu. Lalu? Apa yang akan terjadi? Beredar kabar di dunia maya, bahwa pada saat tersebut, akan terjadi bencana alam yang sangat dahsyat, mulai dari badai besar, gempa Bumi sampai dengan letusan gunung berapi. Sepertinya seram sekali! Tetapi benarkah itu?

Mari kita tinjau satu persatu, pertama, fenomena ‘supermoon’, ini sebetulnya adalah fenomena alam yang biasa terjadi. Pada suatu ketika, dalam peredarannya di langit, Bulan-Bumi-Matahari bisa berada dalam satu garis lurus, biasanya pada saat itu bisa terjadi  bulan baru atau bulan purnama. Dan bila pada saat bulan purnama, Bulan berada pada posisi perigee, maka keadaan ini oleh para ahli astrologi (bukan ahli astronomi!) disebut ‘super moon’! Jadi istilah super moon bukanlah istilah astronomi, tetapi istilah astrologi.

Kedua, pada tanggal itu, akan terjadi bencana alam? Tentulah dalam siklus alamiah, Bulan mempengaruhi terjadinya gaya pasang surut laut di Bumi, dan ketika Bulan ‘mendekat’, tentulah pengaruh gravitasi Bulan menjadi lebih besar (demikian yang dikatakan hukum gravitasi Newton). Akan tetapi, apakah bila pengaruh gravitasi Bulan menjadi lebih besar, akan terjadi bencana alam? Mari kita sedikit berhitung dengan matematika. Ambil rata-rata jarak Bumi-Bulan 382900 km, sedangkan pada tanggal 19 Maret 2011, Bumi-Bulan berjarak 356577 km, atau ‘mendekat’ sejarak 26323 km, atau hanya 6,87% lebih dekat dibanding rata-rata.

Dengan jarak yang sekecil itu (6,87%), akan menyebabkan dampak yang luar biasa? Seperti biasa, efek pasang surut terjadi setiap hari, dan bila resultan vektor gaya gravitasi Bulan & Matahari menjadi lebih besar maka efek pasang surut menjadi lebih besar.

Tentunya pada saat ketika purnama ditambah perigee, gaya gravitasi menjadi lebih berpengaruh, tetapi, dari studi geofisika yang telah banyak dilakukan, tidak dtemukan adanya dampak yang signifikan pada keseimbangan energi Bumi. Gempa Bumi, letusan vulkanik, ataupun berbagai fenomena di Bumi lebih disebabkan keseimbangan energi di Bumi, seperti pergeseran lempeng Bumi, sedangkan efek pasang surut oleh Bulan, tidaklah cukup kuat menggeser keseimbangan energi tersebut, yang artinya ‘super moon’ tidak akan menyebabkan bencana alam.

Mungkin dibutuhkan seorang Superman yang datang dari planet Kripton untuk menggeser keseimbangan Bumi, karena Superman mempunyai kekuatan yang jauh lebih besar dibanding kekuatan super moon; tetapi kita tahu bahwa superman adalah tokoh rekaan, sebagaimana bencana akibat super moon adalah telaah astrologi. Kalau sudah demikian, pertanyaan berikut, apa yang akan terjadi di tanggal 19 Maret yang akan datang?

Yang pasti Bulan akan tampak lebih ‘besar’ 14% dan 30% lebih cerlang di Banding ‘biasanya’, dan kesempatan yang langka untuk menikmati Bulan, sembari memotretnya, atau sekedar nongkrong-nongkrong sembari minum coklat hangat dan menikmati kudapan di malam hari (bila langit cerah).

sumber : http://langitselatan.com