Monthly Archive for April, 2006

Observation On 26 April 2006

Published on April 26, 2006 in Stargazing Notes. View Comments

I waked up on 5am this morning to finish my homework. Afterthat, I was to sleep but the sky attracted me. The bright Venus attracted me at first. When I was setting up my telescope, the sky was really amazingly beautiful because of the decoration of the stars!

Objects Planned To Observe
Planets

  • Uranus

Objects Observed
Planets

  • Uranus
  • Moon

Stars

  • Vega
  • Altair

The Uranus was quite poor in seeing (The idiot street light spoilt the view actually! :angry: ). It was a blur blue planet. :( But, I was appreciated as this was the first time I observed Uranus.

I also observed the stars which were used by the telescope used to do the alignment. They were Vega and Altair.I observed them because of during the time I center the stars, I saw a lot of stars around them and curious to know who were them but sadly I didn’t have time for it. :(

The last objects I observed was the Moon. At that moment, the telescope was turned off so I controlled the telescope manually. The crescent Moon was very clear in viewing even the sky was quite hazy. I wish I took the picture!

Observation On 22 April 2006

Published on April 23, 2006 in Stargazing Notes. View Comments

The observation yesterday is rather disappointed. It is started on 9.00pm 22 April 2006. The sky was said to be clear according to the weather forecast but who knew, the clouds were so thick at that moment. :( This totally spoilt my stargazing party and made all my friends were diappointed. What did we observe last night were aeroplanes (they were moving so fast!), street lights, trees over the street, goods in neighbours’ houses (not so social work) :D and the only star, Arcturus.

Objects Planned To Observe:
Planets

  • Jupiter
  • Saturn
  • Uranus (before dawn)

Meteors

  • Lyrid Meteors

Objects Observed:
Star

  • Arcturus

Terrestrial Objects

  • Tea Pots :lol:
  • Coconut Trees :clap:
  • Street Lights’ Bulbs :D
  • Aeroplanes =))

Lyrid Meteor Shower

Published on April 21, 2006 in Astronomy News. View Comments

I am so excited when I know this information from SpaceWeather.com!

Quote From SpaceWeather.com

Every year in late April Earth passes through the dusty tail of Comet Thatcher (C/1861 G1), and the encounter causes a meteor shower–the Lyrids. This year the shower peaks on April 22nd.

The best time to look, no matter where you live, is during the hours before dawn on Saturday morning, April 22nd. If you wake before 2 am and watch the sky until sunrise, you can expect to see at least a dozen meteors. Counts typically range from 5 to 20 meteors per hour. Observers in the country will see more, observers in the city less.

Lyrid meteors appear to stream from the bright star Vega, more or less, as shown in the sky map below:
Lyrid Meteor Star Map By SpaceWeather.com
In fact, the Lyrids have nothing to do with Vega. The true source of the shower is Comet Thatcher. Every year in April, Earth plows through Thatcher’s drawn-out dusty tail. Flakes of comet dust, most no bigger than grains of sand, strike Earth’s atmosphere traveling 49 km/s (110,000 mph) and disintegrate as streaks of light–meteors!

Lyrid meteors are typically as bright as the stars in the Big Dipper, which is to say of middling brightness. But some are more intense, even brighter than Venus. These “Lyrid fireballs” cast shadows for a split second and leave behind smokey debris trails that linger for minutes.

Occasionally, the shower intensifies. Most years in April there are no more than 5 to 20 meteors per hour during the shower’s peak. But sometimes, when Earth glides through an unusually dense clump of comet debris, the rate increases. Sky watchers in 1982, for instance, counted 90 Lyrids per hour.

I choose to quote down this message from SpaceWeather.com due to this is an ‘emergency’ news and I have to spread it out as fast as I can. Anyway, good luck in spotting Lyrid Meteor Shower! [-o<

Observation On 19 April 2006

Published on April 20, 2006 in Stargazing Notes. View Comments

I start my observation at 9.34PM (GMT+8) on 19 April 2006. The sky is a little bit hazy (best for planets!) :D.

Objects Observed:
Planets

  • Mars (blocked)
  • Jupiter
  • Saturn

Stars

  • Rigel Kentarius
  • Sirius

Nebulaes

  • Great Orion Nebulae (blocked)
  • Crab Nebulae (blocked)

Yesterday sky was really wonderful comparing to the days which were cloudy and rainning frequently. The viewing of the planets were extremely good. I saw more details of Jupiter and Saturn through my Super Plossl 26mm eyepiece. I had also used a blue filter to observe them. I saw a little more details of them. :yeah: But sadly, Mars was blocked by my house. :(

As the sky was so clear, there were quite a number of stars at the direction of west which were not good in visibility when the sky was hazy and cloudy. One of them who caught my attention was the Rigel Kentarius. From what I got through the telescope, it was a double star. I’ll look it up what exactly it is. Sirius, as I have mentioned before, it’s the brightest star at the night time sky. My telescope always uses it to be the alignment stars.

I am quite sad about the viewing of the nebulaes. Two of my favourite nebulae(at the moment), ie, Great Orion Nebulae and Crab Nebulae. They were blocked by my house. :(

I will be trying to observe Uranus(George) tomorrow before dawn. I hope the sky is steady enough. :)

Observing Planets Under A Little Hazy Sky?

Published on April 18, 2006 in Stargazing Notes. View Comments

Aren’t the astronomers hate the hazy sky? Apparently, it is not. It is more depended on the objects that they observe. If you are going to observe DSO(deep sky objects) as well as other faint objects, or astrophotography(except plantes photography), you must have a stable and clear sky to get amazingly good result! :D

Why is the sky with a little haze is the best to observe planets?

Shall I quote the words from my telescope dealer? ;)

Malaysia has hazy skies most times because of the great amount of water vapour and condensate in our highly humid climate. These reduce the sky transparency which is very important for observing most deepsky objects that are relatively faint. Planets are bright objects and “tranparency” is less of an issue. However there are lots of surface details that can be seen in planets but only if the sky is steady, or in other words, if the “seeing” is going. A clear and transparent sky is not always accompanied by good “seeing”…infact the opposite tends to be the case. When the sky is very transparent, the air temperature tends to drop rapidly (because of uninhibited thermal raditation from the land surface) and this causes air movements and turbulence which cases bad “seeing”. You can detect bad seeing by presence of wildly twickling stars. Stars in Malaysian skies infact “twinkle” less because we do not have rapidly falling temperatures at night and to some degree this seems to be so because of the moderating influence of the high humidity. So a slighly hazy sky, rather than a very clear sky tends to be steadier, has better “seeing” which is good for observing fine details on planets and the moon because they do not “swim” around as much in turbulence.

The high humidity of our air however causes the main frustration we experience here: after sunset wen the temeperature drops a little, that small drop in temperature is enough to condense water droplets out of the water vapour…and we see clouds forming almost immediately after sunset. Clouds block verything from view. If humidity is not so high, the slight haze that forms does not block the planets from view, but they do block faint deepsky objects.

The reason Northern Chile is such a superb place for astronomy is the coastal mountains have dry air that gives excellent transparency and the proximity of the strong and constantly cold Humbolt Current keeps temperatures fairly steady, providing very good seeing as well! Unlike other deserts (llike in Australia & Africa), the Atacama does not experience extreme temperature swings between day & night…it is just extremely dry at all times (again because of the Humbolt Current).

He takes Malaysia(my country) as the example to explain this phenomenon as Malaysia is near to equator. Thus, the weather here is always hazy and cloudy. :( He has also explained the reason I like to observe the planets. :yeah: So now, do you know why a little hazy sky is even better than a clear sky when it comes to planets observation?

New Moon Is The Time

Published on April 16, 2006 in Stargazing Notes. View Comments

Most of the astronomers do not do the celestial observing as known as stargazing at the full moon night. It’s because the full moon light is so bright that it blocks the light coming out from the faint objects, especially deep sky object. Even the bright objects such as the major planets, Sirius (Dog star, the brightest star, mag.-1.44) will become fainter. :(

At the new moon night, you can only see the lights from the stars. It’s so fantastic to do observing of any type of celestials objects. This is the greatest day to do astrophotography too! All of the objects are relatively brighter due to the absense of the Moon. :yeah: That’s why I always do the observing at new moon night. :D

What Is A Barlow Lens?

Published on April 13, 2006 in Eyepieces. View Comments

Meade 2X Apochromatic Barlow Lens
If you own a telescope, you must know what is a Barlow lens. It’s invented by Peter Barlow (1776-1862), an English writer on pure and applied mathematics. Barlow lens is a concave lens which is place between the primary mirror of telescope and eyepiece to increase the magnification of the eyepiece which is currently used.

A 2X Barlow lens is widely found in the market. It doubles the magnification of your eyepieces, thus it’ll double your collections of eyepieces. It saves your money! When you choose your Barlow lens, you must select the Barlow lens which is same with your eyepieces in barrel sizes. For my LX90, it uses the 1.25″ format of barrel size.

If you can manage to buy a Barlow lens with better coating, go for it! It’s because if the light transmission of the Barlow lens is bad, increasing the magnification just doesn’t worth it.

Where to put the Barlow lens? It’s quite simple to use the Barlow lens indeed. First, install the eyepiece holder. Afterthat, drop in the Barlow lens and following by the eyepiece. Then, you got it!

Select Your First Telescope (Episode IV: Catadioptrics)

Published on April 10, 2006 in Astronomical Instruments. View Comments


Finally, this article has entered the last episode! I myself love the catadioptrics the most because it’s considered lighter than most of the others. One of the reason is they are always mounted on altazimuth mount instead of equatorial mount which is heavy since it has to be equipped with counter-weight. :(

Catadioptrics use a combination of mirrors and lenses to fold the light and form an image. Catadioptrics are the most popular type of instrument, with the most modern design, marketed throughout the world in apertures of 3.5 inches and larger. There are two popular designs of these mirror/lens “hybrids,” the Schmidt-Cassegrain(right top) and the Maksutov-Cassegrain(left down). I myself own a Schmidt-Cassegrain. :)

Let’s start the introduction of both types of telescopes! :yeah:

Meade 12

Schmidt-Cassegrain

In the Schmidt-Cassegrain, the light enters through a thin, aspheric Schmidt correcting plate, then strikes the spherical primary mirror and is reflected back up the tube, where it is intercepted by a small, secondary mirror. This reflects the light out an opening in the rear of the instrument to form an image at the eyepiece.

Advantages

  • Best all-purpose telescope design, combining the optical advantages of both lenses and mirrors, while canceling their disadvantages
  • Amazingly optics with razor-sharp images over a wide field
  • Superb for deep-sky observing or astrophotography
  • Very good for lunar, planetary and binary star observing
  • Great for terrestrial viewing
  • Closed-tube design reduces image-degrading air currents
  • Compact and portable
  • Ease of use
  • Durable and virtually maintenance-free
  • Offer large apertures at reasonable prices(less expensive than equivalent-aperture refractor designs)
  • Greater accessories availability
  • Best near-focus capability of all designs

    • Disadvantages

  • More expensive than reflectors at equal aperture
  • Slight light loss due to obstruction by the secondary mirror

    • Meade ETX125PE

    Maksutov-Cassegrain

    The Maksutov design is a catadioptric (using both mirrors and lenses) with basically the same advantages and disadvantages as the Schmidt. It uses a thick meniscus-correcting lens with a strong curvature and a secondary mirror that is usually an aluminized spot on the corrector.

    The Maksutov secondary mirror is typically smaller than the Schmidt’s giving it slightly better resolution for planetary observing. The Maksutov is heavier than the Schmidt and, because of the thick correcting lens, takes a long time to reach thermal stability at night in larger apertures.

    Conclusions: Before I start my conclusions, I would like to thanks www.telescopes.com for allowing me to use their information such as the advantages and disadvantages of all the telescopes and the technical informations for references.

    I shall start the conclusions now. :) If you haven’t made up your mind that what types of the objects you are interesting in, I suggest you to get a catadioptric as it’s the combination of refractor and reflector so it does well in terrestial viewing and celestial observing including deep-sky, lunar & planetary, galaxy as well as others. It’s really amazing! I personally don’t like neither reflector nor refractor because of their limitation of applications. That’s why I have a Schmidt-Cassegrain at the moment. :yeah: Please let me know if you have any further question. :D

    Select Your First Telescope (Episode III: Reflector)

    Published on April 9, 2006 in Astronomical Instruments. View Comments

    Celestron C8-N Reflector
    Reflectors usually use a concave, parabolic primary mirror to collect and focus incoming light onto a flat secondary mirror that in turn reflects the image out of an opening at the side of the main tube, into an eyepiece for viewing.

    The easiest way to identify a reflector is by looking at the location of its eyepiece holder. It’s always near the top of the telescope itself. :)

    Let’s look at the advantages and disadvantages now. <:-p


    Reflector


    Advantages

  • Lower cost per inch of aperture than refractors and catadioptrics because mirrors can be produced at less cost than lenses in refractors in medium to large apertures
  • Reasonably compact and portable
  • Excellent for faint, deep-sky objects, such as remote galaxies, nebulae and star clusters, because of their larger apertures
  • Deliver very bright images with few optical aberrations.

    • Disadvantages

  • Not suitable for terrestrial observation
  • Slight light loss due to obstruction from the secondary mirror

    • Tomorrow, I will write about my favourite, the catadioptrics as well as the conclusions of these episodes! :yeah:

    Select Your First Telescope (Episode II: Refractor)

    Published on April 8, 2006 in Astronomical Instruments. View Comments

    Celestron NexStar 102 SLT

    I have mentioned that there are mainly 3 types of telescopes. They are refractors, reflectors and catadioptrics. :) I am going to tell what are the advantages and disadvanges of them. I hope you can make up your mind after reading this article. ;) By the way, the long contents made up my mind to divide this post into total of 4 episode. Sorry for the inconvenience caused. :P

    I am going to list out the advantages and disadvantages of refractor now.

    Refractor

    Advantages

  • Simplicity of design contributes to ease of use and reliability
  • Require little or no maintenance
  • Excellent for lunar, planetary and binary star observing, especially in larger apertures
  • Good for distant terrestrial viewing
  • Offer high-contrast images with no secondary mirror or diagonal obstruction
  • Render good color in achromatic designs and excellent in apochromatic, fluorite and ED designs
  • Sealed optical tube reduces image-degrading air currents and protects optics
  • Have permanently mounted and aligned objective lenses

    • Disadvantages

  • More expensive per inch of aperture than reflector or catadioptrics designs
  • Heavier, longer and bulkier than equivalent-aperture reflectors and catadioptrics
  • Cost and bulk factors limit the maximum practical aperture size
  • Not very suitable to view small and faint deep-sky objects(DSO) because of the limitations of practical aperture.

    • Let’s continue the list of reflector tomorrow. :yeah:

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