This week's Carnival of Space, at Starts With a Bang, has an Oscars theme. Check it out!
Clear skies!
Read More! Click Here for Full Post >>
Thursday, February 28, 2008
Carnival of Space #43
Read More! Click Here for Full Post >>
NASA To Slam Moon with Impactor
NASA is planning a mission to the moon, but there will be no humans or rovers to speak of. Their mission is to slam an impactor probe into the moon's south polar region. Although this seems like a rather destructive and barbaric mission, it actually has good scientific merit. The mission will be known as the Lunar Crater and Observation Sensing Satellite, or LCROSS. The premise for LCROSS stems from a discovery by NASA's Lunar Prospector that showed abnormally high concentrations of hydrogen in the Lunar south polar region. Scientists have speculated that the hydrogen could be associated with water ice locked deep under the Lunar surface. By impacting the surface at a very high velocity, the impactor can throw Lunar debris into space, where it can be analyzed further by the host spacecraft.
The Lunar probe will be comprised of two main segments. These include the Shepherding Spacecraft, and the Centaur impactor. The Centaur impactor will weigh about 4,400 pounds (2,000 kgs). Once in orbit about the Moon, the Centaur impactor will separate from its host spacecraft and begin its descent towards the surface. The impactor will slam into the surface at a velocity of approximately 1.6 miles per second (2.5 km/s), and is expected to eject over 1,100 tons of Lunar dust. The Shepherding Spacecraft will then fly through this cloud of dust, and sample it using onboard sensors. LCROSS will be launched along with the Lunar Reconnaissance Orbiter on October 28, 2008. Impact is scheduled for February of 2009. I'll keep the site updated with any news of whether this event will be visible to amateur astronomers. I would imagine that one should be able to see it in moderate sized telescopes.
This won't be the first time a space agency has punched a heavenly body, however. NASA's Deep Impact mission slammed into Comet Tempel 1 in 2005, and the ESA made a recent Lunar impact with Smart-1 in 2006. This recent trend toward violent impactors has some astronomers and scientists concerned, however. While good scientific data is obtained from such events, some believe that these missions are too destructive to their targets. Surely, a few more craters on the moon won't hurt, right?
Clear skies!
Image courtesy of NASA/AMES.
Read More! Click Here for Full Post >>
Wednesday, February 27, 2008
Reflectors versus Refractors
I'd like to take a few minutes to discuss one of the most fervently debated topics in amateur astronomy. Of course, one's personal preference and budget comes into play here, but hopefully this article will help to dispel some of the inevitable rumors and misconceptions out there.Which is right for you? The answer to this question, for you, may be one or the other, both, or neither! (Don't forget compound scopes!) I'm going to keep this article from being biased in one direction or the other; there'll be no scope bashing here!
We'll start by discussing both of the major telescope types' configuration and workings. Then we'll discuss each one's particular advantages and disadvantages. Each individual scope will have its own inherent advantages and disadvantages. There are far too many types of telescopes to cover in depth in one article, so we'll be speaking mostly in generalities.
To start off, we'll take a look at the reflecting telescope. The most common type of reflecting telescope is the Newtonian telescope. The Newtonian telescope uses two mirrors to focus the light into a cone. The primary mirror establishes this cone, and the secondary mirror bends this cone so that it can be viewed from the side of the telescope. An eyepiece is then used to view this image. The image to the left is a representation of the typical Newtonian telescope. The common Dobsonian telescope is also a Newtonian, albeit with a different mount.
The Newtonian design is a very popular telescope, and many of the entry level telescopes are Newtonians or Dobsonians. This is usually because the Newtonian design is very simple. The two mirrors are relatively cheap to manufacture, and are mechanically very simple. Therefore, one can make a Newtonian with a large aperture for very little money. The aperture of the telescope is a measure of how large the objective lens or mirror is. Basically, the bigger the better, and some Dobsonians are huge! I have a 10" model (which weighs almost 70 pounds with base), and that is considered medium sized! Some companies are producing Dobsonian telescopes as large as 30+", for a cost less than a used car.
The Newtonian design is not without flaws, however. The primary mirror of a Newtonian uses a parabolic shape. One drawback of this mirror shape is the aberration known as coma. Coma is an optical aberration that makes stars near the edge of the field of view appear as a tiny check mark. Coma can degrade sharpness of extended nebula and galaxies, and impact views of star clusters. Coma is more readily apparent in fast, large telescopes, although it can be corrected and/or reduced using a Parracor eyepiece. Another drawback of this design is the central obstruction. The secondary mirror sits inside the light cone, so it does slightly reduce contrast. A Newtonian telescope must also be collimated, or have its mirrors aligned, quite frequently. This sounds like a daunting task, but it is really quite easy with a few days experience.
Next, we can discuss the refracting telescope. The refracting telescope works on an entirely different principle than the reflecting telescope. The image to the right shows the basic workings of a refracting telescope. Light enters the objective lens and is focused through several more lenses, then passes into an eyepiece. The refracting telescope is the oldest design for a telescope: it is the type of telescope that Galileo used to view the moons of Jupiter. Because of this, some people feel a nostalgic connection to the refracting design, a true telescope in a sense.
An advantage of the refracting design is that it has no central obstruction. Its entire aperture is clear, and hence, tends to give higher contrast than a reflecting telescope. Another nice thing about the refractor is the position in which you observe. Typically, a refractor will be outfitted with a 90* diagonal mirror before the eyepiece. This makes it so you can observe by looking down into the eyepiece, which is much more comfortable than some of the contortions that an equatorially mounted reflector can get you into. Also, a refractor is nearly permanently aligned. The objective lenses and such don't need frequent collimation as do reflectors. Refractors are pretty much ready to go after a cool-down period.
Refracting telescopes, however, also suffer from an optical aberration. While they don't display a reflector's coma, they do have what is known as chromatic aberration. Chromatic aberration is due to the fact that lenses bend light of different colors with different indices of refraction. This means that the different colors of an object will come to focus at different points. Chromatic aberration can become especially apparent when viewing bright objects such as the moon or planets. High-end refractors, called apochromats, use special lenses to reduce or nearly eliminate chromatic aberration. These telescopes can be quite expensive, however. Refractors also cost much more per inch of aperture, due to the precision demanded of their multiple lenses. You won't see a 12" refractor for a working man's budget!
While reflectors and refractors may not be the only types of telescopes, they are the two main categories. One other common type, however, is the compound telescope. The compound telescope is a "best of both worlds" telescope. It combines pieces of the refracting and reflecting design, using both mirrors and lenses. Some advantages of this design are its long focal length, for high magnification and its small central obstruction, for better contrast. This design is not as expensive as some high-end refractors, but it is very large, and can be quite heavy. They also take a long time to reach thermal equilibrium due to their large, enclosed design.
Think about it this way: refractors are the shiny Ferraris and Lamborghinis of the telescope world, while reflectors are the powerful muscle cars of the telescope world. They both go fast and are fun to use, but go about doing so in a completely different way. For a beginner, I would recommend a Dobsonian, not just because they're my favorite, but because they're cheap, big, and easy to use. If you're budget supports a large refractor, this is also a great option.
The different types of telescopes, however, should not be looked at as competitors, but rather as complements to each other. It is not uncommon to see a refractor piggy-backed onto a reflector. This is because where one falls short, the other excels, and vice versa. The two should be used to complement each others' capabilities. Many people have several of each kind! I hope that this article has helped you in understanding the differences between the different types of telescopes. Whether you're a new astronomer looking to see which type to buy, or a veteran of one camp curious about the other, its good information. Next time you get a chance, look through another type of telescope, you might just come to like that design, too!
Clear skies!
Images courtesy of Celestron.
Read More! Click Here for Full Post >>
Sunday, February 24, 2008
Objects in Telescope
I saw these stickers on a Cafepress store, and thought it was funny, so I ordered one. Here it is installed. It says "Warning: Objects in telescope are farther than they appear"
Clear skies!
Read More! Click Here for Full Post >>
Thursday, February 21, 2008
Lunar Eclipse Composite Image
February 20, 2008's total Lunar eclipse really was something to see! It was a nice dark eclipse, with a rusty red coloration during totality. This image is a composite of 9 images taken from Youngstown, Ohio during the Lunar eclipse. The images were taken with an Olympus 8MP SLR with a 300mm equiv. telephoto lens. The time of each image is listed underneath in Universal time. The red coloration at totality comes from sunlight that has been refracted by the Earth's atmosphere. Enjoy!
Composite Image of the February 20, 2008 Lunar eclipse.
Clear skies!
Read More! Click Here for Full Post >>
Carnival of Space #42
Carnival of Space #42 is available now at Chris Lintott's Universe. Check it out!
Clear skies!
Read More! Click Here for Full Post >>
Satellite USA-193 Destroyed
Satellite USA-193 has been successfully struck with a Standard Missile 3 on Wednesday night at about 10:30 PM EST over Hawaii. USA-193 was a spy satellite that had lost power some time ago. To prevent the satellite from reentering the atmosphere and releasing its hydrazine fuel, US officials shot the satellite out of the sky. China conducted a similar exercise last year. The event was not visible from my midwestern location, but the debris cloud from the event may make several passes over the US. This video shows the expected path of the debris cloud after the satellite's destruction.
Watch for debris reentering the atmosphere over the next few days. It will appear somewhat like a meteor. If you see anything, please leave a comment. I'd be interested to hear about sightings!
Clear skies!
Read More! Click Here for Full Post >>
Feb. 20th Eclipse Previews
Here are some preview pictures of the images I got tonight. Please forgive the quality, they've been crudely processed, and I'm tired and ready to sleep. I'll have the full composite up soon enough. It really was a nice eclipse, although very cold!
Clear skies!
Read More! Click Here for Full Post >>
Meteor Strike on Tape!
Breaking News!
An Idaho Air National Guard security camera at Gowen Field in Boise, Idaho, captured this meteor like object as it ripped through the atmosphere and appears to have impacted the surface at 5:30 AM PST. Not many details are currently available, but I'll fill you in as I get them.
Anyone else see this?
Clear skies!
Read More! Click Here for Full Post >>
Wednesday, February 20, 2008
Change of Weather
Looks like the weather decided to cooperate after all! I might get to see this eclipse!
Clear skies!
Read More! Click Here for Full Post >>
STS-122 Makes Safe Landing
Space Shuttle Atlantis landed safely at NASA's Kennedy Space Center today, after a two week stay in space. Atlantis' STS-122 mission was to put the ESA's Columbus space station module into orbit and dock it with the International Space Station. According to NASA, the mission went "very well". Among the astronauts of STS-122 were Commander Steve Frick, Pilot Alan Poindexter, Mission Specialists Leland Melvin, Rex Walheim, Stanley Love, Dan Tani and ESA astronaut Hans Schlegel.
Space Shuttle Atlantis after touchdown.
Image courtesy of NASA/Bill Ingalls.
Video courtesy of NASA.
Image courtesy of NASA/Bill Ingalls.
Commander Frick was quoted,
Here is a video of STS-122's final approach and landing at NASA's Kennedy Space Center, viewed both from the ground and from Atlantis.
"The station missions now are so busy ... It's been a tremendous experience. We were very excited and pleased to bring Columbus to the International Space Station."
Here is a video of STS-122's final approach and landing at NASA's Kennedy Space Center, viewed both from the ground and from Atlantis.
Video courtesy of NASA.
Hot on the trail of Atlantis is Space Shuttle Endeavor, which is scheduled for launch March 11th. Atlantis will return to its hangar to get ready for its August mission to the Hubble Space Telescope.
Read More! Click Here for Full Post >>
Tuesday, February 19, 2008
US-193 Scheduled for Destruction
The US-193 satellite has been officially scheduled for destruction on February 21st, 2008 at 03:30 UTC. The satellite will be shot down near Hawaii, in restricted airspace over the Pacific Ocean to avoid debris reaching land. US-193 had lost power and communications a while ago, and its orbit has been decaying since. So if you're on the West coast, keep an eye out at this time. More information on US-193's destruction is available here. Here on the East coast, we probably won't be able to see the event, but we might get to see the debris field. Also notice that the destruction of this satellite falls in line with the upcoming lunar eclipse. Probably a pure coincidence, though.
Ground track during US-193's destruction.
Clear skies!
Read More! Click Here for Full Post >>
Just My Luck - Weather
As is typical of my bad luck, the forecast currently calls for the clouds to clear out right after the eclipse ends. Wonderful...
Blue squares mean clear skies, white means cloudy skies.
Read More! Click Here for Full Post >>
Funny Scope Sticker
I found these hilarious stickers on a Cloudy Nights forum member's (imjeffp) CafePress store. Its a 3" x 5" sticker, so it would fit nicely beside the focuser. I'm gonna get one, its only $2.99!
I'll post pics of it once I receive it!
Clear skies!
Read More! Click Here for Full Post >>
Sunday, February 17, 2008
Are Rocky Exo-Planets Common?
Could rocky, Earth-like exo-planets exist? If so, how common are they? This question had plagued astronomers for years, until recently. Early discoveries of exo-planets were mostly of the so-called "hot Jupiter" planets. These types of planets were monstrous planets, some larger than Jupiter, and orbiting very close to their star. This at first looked discouraging to astronomers hoping to find an Earth-like exo-planet. It turns out, however, that the reason astronomers are finding so many hot Jupiters is that the current method of detecting planets is only sensitive enough to detect very massive planets by measuring the wobble imparted on its parent star. However, new data from the Spitzer space telescope point towards rocky, terrestrial exo-planets being more common than we had thought.
Astronomers started their hunt by choosing six sets of stars similar in mass to our own, but differing in age. Then, by utilizing Spitzer's infrared capabilities, astronomers can estimate the temperature of the star's surrounding dust cloud. Dust near the center of each stellar system would be warmer than the more distant dust. Astronomers can look at the distribution and temperature of this dust, and get useful data about the star's evolutionary progress. Michael Meyer, of the University of Arizona, Tucson, has found that after 300 million years of evolution, most of the dust which corresponds to planet formation is gone.
This, of course, does not imply that these stars have rocky exo-planets. It does, however, imply that stars between the ages of three million and 300 million years are undergoing similar planet-forming stages as our own solar system. Using this data, astronomers have estimated that up to 62% or stars may either have or are creating rocky, terrestrial exo-planets. This may be an optimistic estimate, but it points to a universe where planets like our own are not a freak accident.
More information
Clear skies!
Read More! Click Here for Full Post >>
Thursday, February 14, 2008
Carnival of Space #41
Carnival of Space #41, hosted at New Frontiers, is the largest yet, with 22 space blogs participating this week! Check it out for the latest space news and happenings!
Clear skies!
Read More! Click Here for Full Post >>
US to Blow Failed Satellite Out of Sky
Lately, there has been much ado in the media about satellite US-193. This satellite is a National Reconnaissance Office satellite. In other words, it's a spy satellite, on a classified mission. There's not much one can hide from amateur astronomers, however, as the satellite can often be seen in the afternoon. Click here for information on when you can see it. It has been known for some time now that it had lost power and communications and would be re-entering the atmosphere at some point. Now, the government is concerned about this re-entry and is actually planning to blow the satellite out of the sky, before it reaches the surface.
US-193 weighs about 5,000 pounds. While a good portion of this mass would burn up in the atmosphere, about 2,500 pounds could impact the surface. This could cause major damage in a populated area. Another concern is that the satellite's hydrazine fuel, a hazardous substance could be dissipated upon impact. This would mean nearly 1,000 pounds of toxic fumes being thrown into a possibly populated area. If the US were to destroy the satellite in space, it could disperse the hydrazine harmlessly. The trouble is, there's only a short window in which it could be effectively destroyed. If the missile were fired too late, it would not only defeat the purpose, but would be extremely difficult. This is because as the satellite re-enters the atmosphere, its motion will become mostly erratic.
Another reason that the government wants to shoot down this satellite is its very purpose itself. The satellite is a spy satellite, so the US government would not like it to fall into the wrong hands, if any parts survived. This exercise is also a good excuse to test out new "Star Wars" style weapons defense systems. Last year, China destroyed one of its own satellites using a ground based missile. This could be an attempt to show, "We can do that too." What better excuse to destroy a satellite? Could this be the next Cold War in space? Most likely not. We'll probably see the conspiracy theorists come out of the woodwork on this one.
Hopefully, this satellite will be destroyed when on the night side of the Earth, visible to amateur astronomers. If details come up about the time and location of its destruction, I'll keep you posted.
Clear skies!
Read More! Click Here for Full Post >>
Wednesday, February 13, 2008
Columbus Lab Open for Business
The International Space Station's new Columbus laboratory is now open for business. The 23-foot long, 10-ton research laboratory was opened for the first time Tuesday, Feb. 12, 2008. The Columbus module will be used mainly for microgravity research both internally and externally to the module.
NASA officials have commented that the opening went reasonably well, all things considered. Theres was a small cooling system glitch in the beginning, but nothing that will hamper the overall functioning of the laboratory. Astronauts wore protective gear upon first entering the module, just in case of any debris that had shown up during launch and transport.
Getting the Columbus lab setup, however, is going to be a chore. Astronauts from STS-122 are going to be extending the mission by one day in order to get the Columbus lab fully assembled and ready to go. Atlantis is now scheduled to return on Feb. 19.
Clear skies!
Image courtesy of NASA TV.
Read More! Click Here for Full Post >>
Monday, February 11, 2008
Name a Satellite!
NASA and Sonoma State University's GLAST (Gamma-ray Large Area Space Telescope) satellite will be the first space-based observatory to monitor powerful phenomenon such as black holes, gamma ray bursts, and dark matter. The GLAST name, however, isn't very catchy, so NASA is hosting a "name that satellite contest", much like they did for the Spirit/Opportunity rovers.
The satellite launches in mid-2008, and names for the mission should be submitted by March 31, 2008. According to their website,
The form also requires a 25 word or less summary of why you think they should choose your suggestion. Give it a try, they might just choose yours!
Clear skies!
Image courtesy of NASA E/PO, Sonoma State University, Aurore Simonnet.
Read More! Click Here for Full Post >>
A List of Galaxies
The other day, I posed this question to the members of the Cloudy Nights forum: "What are some good face-on spirals?" Among some of the responses I received was this list. This list compiles the 200 brightest galaxies in the night sky. It also gives RA/Dec coordinates for each, along with their magnitude, type, and orientation as viewed from Earth. I'm going to be using it to plan observing sessions.
Clear skies!
EDIT: I have made this list of galaxies available as a Microsoft Excel .xls file here.
Read More! Click Here for Full Post >>
Sunday, February 10, 2008
Interactive STS-122 Flight Plan
NASA has put a new interactive flight plan for STS-122 on their website. The interactive Flash application allows users to view the shuttle's schedule and relevant pictures. Simply roll the mouse over each day to see the astronaut's agenda for that day.
STS-125 has become known unofficially as the "Voyage of Columbus", due to its cargo, the Columbus laboratory. The Columbus laboratory is a European Space Agency contribution to the International Space Station. The Columbus laboratory's main purpose during its 10-year mission is to further study the effects of microgravity on biological and other specimens.
The Columbus module in Atlantis' cargo bay.
Some events for the STS-122 mission include docking the Columbus module on day 4 and several spacewalks for maintenance of the ISS.
Images courtesy of NASA/JPL.
Clear skies!
Read More! Click Here for Full Post >>
Thursday, February 7, 2008
Full Lunar Eclipse - Feb. 20, 2008
On the night of February 20/21, 2008, viewers on the night side of the Earth will observe a total lunar eclipse, which occurs when the moon passes directly behind the Earth, and enters its shadow. Observers in the Americas, Europe, and Africa will be posed for the best views.
The following table represents the predicted timetable for the lunar eclipse, as provided by Curt Renz, whose helpful astronomy website can be found at www.curtrenz.com/astronomical.html.
00:37 UT – Moon enters penumbra (gray fringe shadow)
01:43 UT – Moon enters umbra (dark inner shadow)
02:18 UT – 50% of Moon’s diameter covered by umbra
03:01 UT – Totality begins (magnitude 1.000)
03:26 UT – Maximum eclipse (magnitude 1.105)
03:51 UT – Totality ends (magnitude 1.000)
04:34 UT – 50% of Moon’s diameter covered by umbra (magnitude 0.500)
05:09 UT – Moon exits umbra (dark inner shadow)
06:16 UT – Moon exits penumbra (gray fringe shadow)
The times given in this table are Universal Time (UT), also known as Greenwich Mean Time (GMT), for the night of the 20/21. Therefore, these times are mostly in the very early morning of the 21st, just after midnight UT. To find your corresponding local time, subtract your time zone's offset from this number. So for example, Eastern time is GMT-5, so I would subtract 5 hours from each of the times listed here, so 00:37 UT becomes 7:37 PM EST. Central time is GMT-6, Mountain time is GMT-7, and Pacific time is GMT-8. Other time zone offsets are available here.
The moon will actually appear to turn a blood red color during maximum eclipse. This is an optical effect due to the refraction of sunlight by the Earth's atmosphere. Red light is bent most readily and is projected upon the face of the moon. Also notice Saturn's close proximity to the moon during the eclipse. I'll be setting up a composite shot of the eclipse with Youngstown's skyline, assuming skies are clear. This, however, is a slim chance in Northeast Ohio...
This is the last total lunar eclipse until two total eclipses on December 21, 2010, and June 15, 2011, so don't miss it!
Clear skies! (hopefully)...
EDIT: A composite image of the eclipse that I made from Youngstown, Ohio is available here.
Eclipse timetable courtesy of Curt Renz.
Read More! Click Here for Full Post >>
Carnival of Space #40
Carnival of Space #40 is published, and available at Orbiting Frog. This week's Carnival uses a really slick Java interface. So go ahead and check it out!
Clear skies!
Read More! Click Here for Full Post >>
Tuesday, February 5, 2008
Magellanic Clouds Reach Out
Previous theories of the Large Magellanic Cloud and Small Magellanic Cloud (LMC and SMC, respectively) proposed that the two dwarf galaxies were doomed to spiral around the Milky Way until finally merging with their parent galaxy. Then evidence from the Hubble Space Telescope suggested the opposite, that they were merely passers-by. Now, the tables have turned one more time. Recent observations from the Australia Telescope National Facility have shown that the Magellanic clouds are leaking hydrogen into the Milky Way, in a sweeping arc of gas called HVC306-2+230.
Image courtesy of John Rowe Animations.
This sweeping arc of gas, if it were visible to the naked eye, would pierce the Milky Way in the Southern Cross. Of course, this changes our perception of the Magellanic clouds. This new-found evidence points more to the fact that the clouds have been long partners with the Milky Way, in their spiraling path into the Milky Way. Astronomers aren't abandoning old theories, however, as more data are needed to really put this mystery to bed.
Original press release ->
Clear skies!
Read More! Click Here for Full Post >>
Monday, February 4, 2008
Secondary Collimation Tip
During collimation, I sometimes find it difficult to remember which way each screw on the secondary moves the image of the primary. So I marked them on the secondary holder, so as I'm looking at the screws, I can see which way each one moves the primary's image, as seen from the eyepiece.
Clear skies!
Read More! Click Here for Full Post >>
Why Not to Rely on the Laser Collimator
This is why you shouldn't rely solely on the laser collimator to check your Newtonian or Dobsonian's collimation. The other night, I spent an hour or two getting my scope precisely aligned using a Cheshire collimation tool. Just out of curiosity, I inserted the laser collimator in the focuser drawtube and this is what I see...
The laser dot should be pointed precisely in the center dot of the primary mirror. At first, I thought I had not collimated my scope very well, but when I put the Cheshire back in, everything was dead on. And the Cheshire does not lie. The reason the laser is so far off is because the laser itself is not collimated very well (or at all) from the factory. The laser is also prone to huge errors due to mechanical slop in the focuser and elsewhere. The Cheshire method is much more reliable, as this image proves.
Clear skies!
Read More! Click Here for Full Post >>
Lessons From Asteroid 2007 TU24
Last week's close approach of Asteroid 2007 TU24 had many people concerned. This was all for naught, however, as astronomers knew that it would not impact the Earth. Still, the internet was chock full of sensationalized videos of people being genuinely scared of this asteroid. On the other end of the spectrum (the logical end, I might add) was Phil Plait, of Bad Astronomy. His video settled it once and for all. So its obvious that Asteroid 2007 TU24 posed no danger to us. But what if it had? Now that