Tag Archive for 'Telescopes'

Hubble Space Telescope Upgraded

Published on May 20, 2009 in Aerospace and Astronomical Instruments. View Comments Tags: , , , , .

hubble-space-telescope-from-atlantisHubble Space Telescope

Our beloved Hubble Space Telescope (HST) launched 19 years ago has now been upgraded by NASA space shuttle mission STS125. The Servicing Mission 4 is Hubble’s last repair mission, so the crew members of STS125 riding on space shuttle Atlantis are the astronauts who touched HST one last time. After the refurbishment of  HST, it is expected to work fine until 2014 and by then, it will be replaced by James Webb Space Telescope (only on infrared).

Hubble Space Telescope is now equipped with 2 new instruments, Wide Field Camera 3 (WFC3) and Cosmic Origins Spectrograph. Its Advanced Camera for Survey down in 2007 and Space Telescope Imaging Spectrograph failed in 2004 are now back to online. HST is also reloaded with new batteries, six new gyroscopes, a refurbished fine guidance sensor, a new outer blanket layer and a soft capture and rendezvous system.

The WFC3 has higher resolution and wider field of view than Wide Field and Planetary Camera 2 (WFPC2). It will be used to study dark energy and dark matter, formation of individual star and discover extremely remote galaxy which helps us know more about the early universe. The COS is key to understand galaxy evolution, the formation of planets, the rise of the elements needed for life, and the “cosmic web” of gas between galaxies as spectrograph can reveal the elements by breaking lights into spectrum.

Direct-proof-of-dark-matter

Direct evidence of dark matter. Imaged by HST.

Hubble Space Telescope has long been delivering Earthlings amazing astronomical discoveries and stunning pictures. Now, its ability has been enhanced to a further step that it can do 10x better than before. The secrets of the dark matter and more exoplanets may soon be revealed. We shall anticipate more jaw-dropping discoveries by HST.

I am sure that the info above is not able to satisfied your hungers, read NASA SM4 Essentials. Don’t miss it!

By the way, I am curious about the privacy that the only female astronaut, K. Megan McArthur has. What do you think?

Cracked Corrector Plate: LX90AT

Published on April 12, 2009 in Telescopes. View Comments Tags: , .

shattered-lx90-corrector-plate

Did you ever try to break your scope before? I doubt you dare. I maybe the first LX90AT user with the cracked corrector plate.

Here the story begins.

If anyone remembered my previous post about disassembling the LX90AT, you should know why I removed the corrector plate. Yes, I dropped a toothpick into the OTA from the visual back. All of the nightmare started from here. I bought a Purosol Optical (PO below) and their microfiber cloth as I planned to clean the corrector plate. In the end, I cleaned the primary mirror as well because the PO claimed that the solution was enzyme based and would not hurt the coating. That’s true, just that the microfiber cloth left quite a lot of fiber behind.

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Galileo Scope Ready To Ship

Published on March 10, 2009 in IYA2009 and Telescopes. View Comments Tags: , .
Aperture: 50mm; Focal Length: 500mm

Galileoscope™ is now on sale at USD15 @ Galileoscope official website.

What’s a Galileoscope? In celebration of International Year of Astronomy 2009, a team of leading astronomers, optical engineers and science educators developed a high-quality but low-cost telescope kit. At just USD$15, you can own the Galileoscope which is even better than the one used by Galileo Galilei himself since 1609.

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75 Telescopes Ranked

Published on February 19, 2009 in Telescopes. View Comments Tags: .

If you’re a computer enthusiast, you must be familiar with the benchmark score obtained from 3dMarks, PC Mark, Everest, PCMark, Prime 95 and so on. Is there anything similar to represent the performance of telescope? Well, there’s is and someone did it in the form of scores too.

Credits to Mr.Yoshida Hiroshi, he has done a review on 75 telescopes. He reviewed them visually and scored them. The photographic performance of the telescope is not taken into account. I would say this is just a reference for you but not solely the factor to consider a telescope.

Before buying a telescope, I suggest you read through the reviews posted at forums like cloudynights.com and most importantly, join a stargazing session with someone who already owned a telescope. You will know better what to expect.

Here you read the rankings, cz-telesco.bbs.coocan.jp
The content is in Japanese, you can use Google translator to translate into English or any other language you prefer.

Microsoft WorldWide Telescope

Published on May 13, 2008 in Softwares. View Comments Tags: , .

After long waiting since the talk by Roy Gould and Curtis Wong in Feb 2008, Microsoft WorldWide Telescope is finally available for download.

This is a really great art of masterpiece. It features the photos taken by ground-based observatories and space telescopes. There’re terrabytes of images at research grade resolution. I am not sure how to do research with it but it’s totally full of marvelous sceneries. Beware, your harddisk might be filled up with all these images. :P

It also allows you to point your telescope to the target you currently focus on by installing the ASCOM component. This software certainly comes in handy when we do public outreach.

Explore it yourself!

Microsoft WorldWide Telescope

PS: I’m going to do a review of this stunning virtual telescope soon.

8″ SCT The Best?

Published on March 17, 2007 in Beginner and Telescopes. View Comments Tags: .

Before anything starts, I want to explain AA. AA is my own abbreviation, it’s Amateur Astronomer in full.

Edwin's 8What’s the common requirement of an AA’s scope? Unless you are a serious AA with deep pocket, you won’t have an observatory that allows you to mount a gigantic telescope inside. Some AA travels to the dark site with his scope or just move his scope from his house to the backyard. It can’t be too heavy. So, portability comes into one of the major considerations. We want to get the largest aperture within the portability.

8″ SCT has it all. For example, my fork mounted LX90 has an aperture of 203.2mm, 2000mm focal length and weights about 24kg. I can carry it around easily. (Not for a marathorn though)

Left: 8″ LX90 of Erwin Kats from Netherlands.

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Light Gathering Power (Light Grasp)

Published on October 23, 2006 in Beginner and Telescopes. View Comments Tags: .

Celestron CGE-800We determine how powerful a telescope is mostly by resolution and the light gathering power. So, what is light gathering power?

Left is a Celestron CGE-800 which has a light gathering power of 843.

The light gathering power of a telescope is the theoretical ability of a telescope to collect light compared to your fully dilated eye. It takes both aperture and your fully dilated eye into factors. The larger the aperture, the higher the light grasp. It is directly proportional to the square of the aperture.

To calculate this, first, you have to divide the diameter of aperture (in mm) by the diameter of fully dilated eye (7mm for a normal young man) and then square the result. For instance, an 8″ telescope has a light gathering power of 843 [(203.2/7)² = 843].

What Is Focal Ratio and Exposure Factor?

Published on October 1, 2006 in Beginner and Telescopes. View Comments Tags: , .

The focal ratio is the ratio of the focal length to the aperture. So, a telescope with a 2500 mm focal length, and 250 mm aperture is a f/10 scope. A scope with a smaller focal ratio always benefits the users in imaging as it shortens the exposure time. Some people will call it photographic speed.

Why it takes more time to have the same result using the same imager but a slower telescope? Let’s say I have a f/5 and f/10 telescopes and both of them have the same aperture. Let’s make them 8″. Now, I move from f/5 to f/10. Since the aperture is fixed, focal length is the only increasing factor. In this case, it is doubled. As the image you see is in 2 dimensions, it needs a least 2 rays of lights to form an area. Therefore, the lights are spreaded into a factor of 4. In conclusion, you take 4X more the exposure time to get the same S/N.

*S/N refers to Signal/Noise ratio

Below is the formula to calculate the exposure factor,

Exposure Factor = (Focal ratio 1)^2 / (Focal ratio 2)^2

Once you figured out the exposure factor, you know how much is A scope faster than B scope or vice versa.

Calculate Your Camera and Telescope Resolution

Published on August 24, 2006 in Beginner, Cameras and Telescopes. View Comments Tags: , , .

To master your imaging platform, you’ll have to know the resolution of your setup. The setup mentioned is consisted of a telescope optical tube assembly (OTA), a mount and a camera.

Let’s say, if your setup’s resolution is sub arcsec/pixel (less than 1 arcsec/pixel), you need a very stable and precise mount, usually a high end German Equatorial Mount (GEM), for this. As the resolution is higher (the lower the value of arcsec/pixel), your setup is more sensitive to vibration, atmostpheric turbulence, wind, flexure between optical tube and GEM head and the mis-polar-alignment. In a simple phrase, the margin of error is limited.

Therefore, before you start taking image, you should know the highest possible resolution of your setup so that you do not end up with a imaging resolution that exceeded the conditions allowed. Nobody likes poor quality photo. Well, let’s get into the math part.

To calculate the resolution, follow the simple formula:

Resolution (arcsecond) = [CCD Pixel Size (in micron) ÷ Focal Length (mm)] * 205

Credit to Webfoot at Cloudy Nights forum for providing this formula. :D

Autoguiding By Imager

Published on June 8, 2006 in Astrophotography, Beginner and Cameras. View Comments Tags: , , .

Meade LPI ImagerIsn’t it a GoTo telescope is capable of tracking celestial objects? Why do I need the autoguiding? :-\

At first, tracking is just similiar to guiding. For instance in the Autostar Suite from Meade, tracking allows you to define a bright spot (centroid) that it (Autostar Suite) will use to anchor images when combining (stacking) them into one image.

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