Monday, April 16, 2018

Southern Belle


 Rain, rain, rain... my astronomical activities are certainly taking a bath right now. Fortunately, in this age of the internet, I can hook up with some remote-control telescopes, located in areas which are much more likely to have clear skies. One such telescope is located in Chile and is made available to members of Slooh.com, an organization oriented to the world-wide astronomical community.

Some of the most impressive astronomical objects are located in the southern sky, visible at night only from areas close to, and south of the Earth's equator. One of those objects is Eta Carina.

Here is a quote from Wikipedia, the free encyclopedia:

The Carina Nebula (catalogued as NGC 3372; also known as the Grand Nebula, Great Nebula in Carina, or Eta Carinae Nebula) is a large, complex area of bright and dark nebulosity in the constellation Carina, and is located in the Carina–Sagittarius Arm of our galaxy (Milky Way). It has an estimated distance between 6,500 and 10,000 light-years (2,000 and 3,100 parsec) from Earth.

The nebula is contains many other objects, from the intrinsically brightest star in our galaxy to several star clusters, gaseous star-forming regions, and other interesting sights.  It is one of the largest diffuse nebulae in our skies. Although it is some four times as large and even brighter than the famous Orion Nebula, the Carina Nebula is much less well known due to its location in the southern sky. It was discovered by Nicolas-Louis de Lacaille in 1752 from the Cape of Good Hope.



a wide-field view of (η) Eta Carina

Here's a larger image of Eta Carina Nebula's core.


At this time, we have no plans to travel south; from a narrow point of view, to take a photo of this nebula/star assembly remotely saves the money. None-the-less, it would be nice to see this southern belle directly, it is a beauty even in binoculars, though you won't see the colours seen in the two images.

Saturday, April 7, 2018

Astronomical gems



Something which is unfortunately not seen from our latitude is one of the oldest and likely the largest concentrated accumulation of stars in our galaxy. It is a globular cluster, of which there are about 200 or so associated with "us". These clusters are very old, they have been around for about 10 to 12 billion years. Our own universe is calculated to be about 13.7 billion years old, so they have existed for most of that time.

This particular one is best seen from the night sky close to, and at latitudes below Earth's equator. It can be seen by the naked eye as a fuzzy star in the constellation Centaurus, and is accordingly named like a star: "Omega Centauri" (a mix of a Greek letter and Latin constellation name). It turns into an amazing view when seen through a pair of reasonably large binoculars or wide-field telescopes. As a photographic object, it truly "shines", much like a box of diamonds.

Since it is unobservable from our area, and since the current weather prevents any outdoor observing of the sky, I decided to resort to "old trusty", and acquired an image of Omega Centauri via a remote-controlled Slooh.com telescope, located in Chile. This is a favorite object for many astrophotographers and has been recorded thousands of times. Robert Conrad, the Observing Director in our Vancouver centre of the RASC posted his excellent photo in NOVA (March/April edition), our bimonthly news letter.

Here is my wide-field image of Omega, cropped to centre it in the frame:


Omega Centauri

This globular cluster contains about four million stars. That is about 10 times the number contained in M13, the most impressive globular in our sky (but not visible with my unaided eye, at least). Some estimates say that the average distance between the stars in Omega Centauri is less than one light year. Can you image the blazing night sky you would see on a planet that orbits one of those stars?

The orbits of planets around any of these stars would likely be perturbed by the other close near-by stars to make them unstable, with local climate subject to large swings from hot to cold. That would make an evolution of life as we know it unlikely. Well, it's nice to speculate.





Sunday, April 1, 2018

Something "new"


 Nova

N CMa 2018


At left of the two pictures below is the pertinent cropped section of the nova image I obtained using a remote-controlled Slooh.com telescope. For reference, I reproduced a section of the map produced by Robert Conrad, using the American Association of Variable Star Observers AAVSO Variable Star Plotter regarding the AAVSO Alert Notice 627 in relation to the discovery of the nova. The nova was discovered in Japan on March 24 by Yuji Nakamura in Japan using a 4" photographic reflector telescope (called an astrograph). Robert Conrad, who is our Director of Observing at our Vancouver RASC centre, and who diligently digs out and observes new events in the sky, notified our observers about this. Spectroscopic observations, using larger, professional telescopes, classified this nova as the classical type.


P
 Left: Image of Nova      Right: A section of AAVSO map of Nova location.



Here is an excerpt from Wikipedia:

Classical nova eruptions are the most common type of nova. They are likely created in a close binary star system consisting of a white dwarf and either a main sequence, sub-giant, or red giant star. When the orbital period falls in the range of several days to one day, the white dwarf is close enough to its companion star to start drawing accreted matter onto the surface of the white dwarf, which creates a dense but shallow atmosphere. This atmosphere is mostly hydrogen and is thermally heated by the hot white dwarf, which eventually reaches a critical temperature causing rapid runaway ignition by fusion. From the dramatic and sudden energies created, the now hydrogen-burnt atmosphere is then dramatically expelled into interstellar space, and its brightened envelope is seen as the visible light created from the nova event, and previously was mistaken as a "new" star. A few novae produce short-lived nova remnants,[1] lasting for perhaps several centuries. Recurrent nova processes are the same as the classical nova, except that the fusion ignition may be repetitive because the companion star can again feed the dense atmosphere of the white dwarf.

Novae most often occur in the sky along the path of the Milky Way, especially near the observed galactic centre in Sagittarius; however, they can appear anywhere in the sky. They occur far more frequently than galactic supernovae, averaging about ten per year. Most are found telescopically, perhaps only one every year to eighteen months reaching naked-eye visibility. Novae reaching first or second magnitude occur only several times per century.

More details can be obtained by linking to https://en.wikipedia.org/wiki/Nova .

You can't be bored if you are interested in astronomy. There is always something new in the sky.







Wednesday, March 14, 2018

Serendipity



On March 11, at late dusk, I happened to walk out onto our back porch, and, as is usual for anyone into astronomy, I looked up at the sky. In a gap between a neighbour's house and a bush across the laneway separating us, I spotted a fairly bright object. It was not so bright as Venus would be, but about the brightness of Jupiter. Waiting for a minute or so to make sure it wasn't some distant airplane approaching our international airport, I decided that this object was likely the planet Mercury. Knowing that Mercury was near the most favourable (for our latitude) elevation this year, I quickly checked the position using one of my computer programs and grabbed my 60Da camera, went back outside, aimed, and took a picture. The camera was set on manual, unchanged since I last used it for the lunar eclipse described in my January 31 post. 

The screen showed only Mercury and a trace of street light reflection on the gutter of the above-mentioned house, otherwise, things were completely black. In other words, the image was severely underexposed. So I attempted another shot with a more appropriate setting, but nothing happened. Another one, again nothing. I finally realized that the the battery indicator showed a completely discharged battery. I went inside to swap in my spare, and making sure the camera was operating normally again, then went back outside, only to find the Mercury had sunk out of sight. So the underexposed image was the only one available. 

With the help of the Preview program in my laptop, which has some elementary processing features, and Photoshop, I began trying to squeeze as much as I could out of that image. The final result was of poor quality, but none-the-less, it showed sufficient detail to display what the view was like. It's amazing what one can do with today's graphics programs. In the days of using and developing colour films, and printing colour prints in my own (chemical) darkroom, this feat would have been impossible.

Here is the processed picture:




The original image:



Mercury is the planet closest to the Sun. As a result, it is usually hard to see it because appears only close to the Sun most of the time, and is swamped by a bright sky. Many people have probably not seen the planet Mercury "live" before, even many professional astronomers in the past, and perhaps even now.

The second of Mercury's greatest "Sun separations" (the proper name is elongations) this year, from the Earth's point of view, occurs on March 15, it will be somewhat higher in the sky than shown in the picture above. The weather since the 12th has been cloudy and rainy, so I haven't been able to see Mercury since. This planet's elongations occur several times a year, this year there are seven, three in the evening, and four in the morning. The current evening one leaves it high enough in our local sky to make it the best of this year for us. 

Since I saw Mercury this time only by coincidence, I'd say this was a serendipitous occasion.

A follow-up:

On March 15, when Mercury was at its greatest elongation, as mentioned above, the sky was clear, and I set out to photograph both Mercury and Venus at dusk.

Here's the picture (processed to enhance contrast). It is a hand-held Canon 60Da photo through a Sigma 18 - 200mm telephoto lens, set at 100mm, f8, 1/20sec, ISO 800, slightly cropped:

Thursday, March 1, 2018

Bubble Nebula and M52


Lately, I've had the bad luck to try for some images on the Slooh.com telescopes on the Canary Islands. These remote-controlled telescopes have been inactive for the last few times I've tried to capture images, due to unsuitable weather. A couple of months ago, I used one of the remote-controlled telescopes on December 20, 2017 to get an image of both M52 and the Bubble Nebula (both located in the Cassiopeia constellation). Here is a picture:

Star cluster M52 at upper left,  Bubble Nebula at lower right.

Classified as an open star cluster, Messier 52 (NGC 7654) is located in the Cassiopeia constellation. It was discovered by  Charles Messier in 1774. M52 can be seen with binoculars. Distance estimates range between 3,000 and 7,000 light years. This uncertainty is caused by interstellar absorption of light. There are an estimated 190 stars in the cluster. The poorly known distance, and the numerous foreground stars make a determination of a more accurate number of cluster members difficult to determine.


The Bubble Nebula (NGC 6735), is a Hydrogen emission nebula also located in the constellation Cassiopeia (you'll need a minimum 10" telescope and a dark sky to see it faintly). The stellar wind from a massive hot, young central star is the cause of the "bubble”. The nebulous cloud itself is illuminated by the hot central star whose high-energy light is causes the cloud to glow. William Herschel discovered the cloud in 1787. Its distance is also uncertain, interstellar light absorption affects estimated distance, which is listed as 7,100 - 11,000 light years. The star causing the bubble is thought to have a mass of about 44 times the mass of our Sun.

Wednesday, January 31, 2018

Blue, blood, and "Supermoon" eclipse


On January 31, 2017 morning, I got up to have a look at, and take some pictures of the total lunar eclipse which has been hyped as the "blue, blood, eclipsed Super Moon". As the weather gods would have it, there were variably transparent clouds everywhere. I took a total of 356 pictures, many of which were of poor quality because of this. To control the camera, which was attached to a tracking mount, I used my 27" iMac, loaded the Canon EOS control program, and connected the camera to one of the computers USB ports. The program allows remote control of various camera functions, including exposure and ISO ratings.

I set up the Canon 60Da camera at the window inside my office. This window is on the west side of our house and fortuitously looks out on that part of the sky in which the eclipse took place. An old Pentax 200mm and a 2x Barlow lens (both Pentax threads) resulted in an effective 400mm telephoto lens; this combination was attached to the 60Da by means of Pentax-thread-to-Canon adapter. In order to get reasonable quality images, I opened the office window, and took out the mosquito screen. That meant that the office got really cold; when daylight arrived there was frost on the roof of houses and frosty cars. To make this 5-hour photo session more comfortable, I set up my MacBook Pro laptop, using VNC, to communicate with the iMac in the office over my internal computer network. VNC was set to show and control the iMac screen in the office. I set up the MacBook in the kitchen to keep warm and kept the office door closed.

Here is a picture taken near the beginning of the eclipse:



The Moon at the beginning of the eclipse (with clouds - image cropped from a wider original)


The cloud situation was variable throughout the whole eclipse. This meant that I had to experiment continuously with exposure times and ISO settings (the reason why I took so many images). But whenever I hit the correct exposure, I could suppress the clouds and bring out the actual image of the eclipsed moon. This image was taken under those conditions:


The partial phase - the bright part is highly overexposed in order to bring out the colour inside the Earth's shadow. This colour of the shaded part is caused by the Earth's atmosphere refracting the Sun's light into the shaded part. If you were on that (shaded) part of the Moon, the Sun would be covered by the Earth, but Earth would be surrounded by a red "sunset" ring.

This is an image of the Moon at mid-eclipse through a fortuitous, short "clear" hole in the clouds:
 

The Moon at maximum eclipse.  It is illuminated by the Earth's atmosphere's refracted sunlight light only.



The cloud situation got worse after the eclipse total phase was finished. The Moon was also much lower in the west. Here's another through a "cloudhole" shot. It was the last clear one:


Partial phase past totality.



The final image below. A thick bank of clouds rolled in and covered the Moon completely. The variable clouds earlier fortunately occurred in the right time frame to see most of the eclipse.


"Good bye". The thick black cloud bank spelled eclipse end for me.


Thursday, December 28, 2017

Running Man


Today, I finally had a chance to post, after two months of no activity on this blog. I managed to obtain a space image of one of my favourite space objects, and to give a reason for my protracted "absence".

Regarding absence: In October we spent time in Germany with our many friends there. The main reason we travelled there was the 80th birthday celebration for a long-time friend (we've known each other for about 40 years). It was a joyous occasion.

We returned home with some foreboding though. My sister-in-law had been diagnosed with lung cancer at the beginning of September; when we returned, we found her in a very advanced stage of the disease. All of our family were constantly involved in making her life comfortable, but she died in November. Since then, my wife, being the executor, has been very busy with all the legal aspects (there are many) of following the instructions in her will. I help where I can, but I have no legal standing in this matter. To make matters even more sad, we also lost the last of three of my wife's very close, life-long friends (they all were bridesmaids at our wedding 53 years ago) to an apparent heart attack. All these occurrences, and ensuing activities left no time for our hobbies.

Now regarding the space image: I finally connected to one of the remote-controlled Slooh.com telescopes on the Canary Islands and managed to acquire a picture of the Running Man nebula. It has an appropriate name, considering the events mentioned above. I leave it to you to discern the shape which gives that object its name.

(click on picture to enlarge)

The Running Man nebula

This is a "reflection nebula"(actually three separate ones), a vast cloud of hydrogen gas and dust, located near the famous Orion Nebula and illuminated by bright stars in the vicinity. Its distance is about 1,500 light years and it is about 7.5 light years in diameter. Wikipedia has a good description.
Here's the link:  https://en.wikipedia.org/wiki/Sh2-279


Thursday, September 21, 2017

End of (star) life



 When old giant stars come to the end of their life, they often expel copious amounts of their atmosphere into the surrounding space. What remains behind is their extremely hot central cores, which emit a lot of their light in the ultraviolet range of their spectra. This high-energy light makes the ejected atmospheric gases fluoresce in a variety of colours and gives a hint of what elements they contain. That helps determine the chemistry of the star of which these gases were originally a part.
These fluorescent gases are called a "planetary nebula". This is a misnomer, they are nothing like the planets in our solar system.

 Here is a picture of the first planetary nebula discovered - the "Dumbbell Nebula", which I obtained via a Slooh.com remotely controlled telescope (located on the Canary Islands):



A concise explanation for the theories regarding the cause and reasons why planetary nebulae exist can be found here:

https://en.wikipedia.org/wiki/Planetary_nebula

Not all stars end their life being surrounded by a planetary nebula. It appears that the mass of a star plays an important role in their generation. The sun is likely too small for this to happen.

A colorful way to go...

Tuesday, September 19, 2017

A Very Long Way Out




One of my astronomical activities I personally much enjoy are the public daytime and nighttime astronomy events. Among the objects we observe are the Sun, the Moon, our planetary system, and "deep sky" objects, such as star clusters, gas nebulae, and our own galaxy, as well as far away galaxies. I'm particularly happy when people exclaim a "wow" about what they are seeing (nowadays the word is probably "cool"). Among those objects is the planet Saturn with its rings and moons, Jupiter and its moons, the planet Mars (when it is close to Earth), our Moon with its craters, the planets Venus with its phases and Mercury - difficult to see because it is so close to the Sun. Usually, we can see some of these "spectacular" objects in the sky at the same time.

This brings me to the subject of distances in our own solar system. By definition, the average distance from the Sun to the Earth (150 million kilometers) is called an "Astronomical Unit", AU for short. It takes light more than eight minutes to travel that distance. So we see the Sun as it was over eight minutes ago. Light travels 300,000km in a second - it could travel around the Earth (circumference 40,000km) more than 7 times a second. The average distances from the Sun to Mercury is about 1/3 of an AU, to Venus 2/3AU, Earth 1AU, Mars 1.5AU, Jupiter 5.2AU, Saturn a little less than 10AU, Uranus 19.2AU, Neptune 30AU,  Pluto varies from about 40 to less than 30 AU, it was recently closer than Neptune. We can see all the planets only because they are illuminated by the Sun; we see them in"reflected" sunlight.

The distance light passes in each minute can be called a light minute, so the Sun is over eight "light minutes" away. Similarly, the distance traveled by light in an hour can be called a "light hour", distance traveled by light in a year is a "light year" - the standard unit for expressing the distance to stars, Nebulae, other galaxies and anywhere else in the universe outside the solar system.

The planets beyond Saturn look less spectacular in a telescope; they get as less attention on our public nights. It is possible to gain a better "look" by taking pictures through telescopes. Here is an example of the planet Uranus, I took through a Slooh.com remote control telescope, located on the Canary Islands.

The three faint "stars" you see next to Uranus are some of its moons. They are fairly difficult to see, because the brightness of Uranus. I processed the image in Photoshop to make them more easily visible.

As mentioned above, Uranus is a little less than 20 AU from the Sun. That means that it takes sunlight more than two-and-a-half HOURS to reach Uranus, and another two-and-a-half hours for that reflected sunlight to get back to Earth. Nothing can travel faster than the speed of light - our fastest spacecraft can travel at most about 50,000km per HOUR at present. That's equal to 13.9 km per second, which makes it about 21600 times slower than the speed of light, i.e at a speed of 50,000 km/h it takes 26,100 times 2.5 hours (6.1 years) to reach Uranus, travelling in a straight line. However, all orbits around the sun and the travel paths of space probes are curved, so the time that trip takes is even longer. No wonder that it takes many months or years to get to any of the other planets at speeds we can achieve with present rocket technology.

Now, if you want, consider how long it would take for us to reach even the nearest star, which is about 4.3 light years away, with our currently fastest spacecraft (see appendix).

The universe is huge, and things are A Long Way Out.

Appendix:
To calculate the approximate time it would take to reach Proxima Centauri (the nearest star to us, excepting our Sun, which is also a star as seen from outside the solar system), calculate the number of seconds in a year, then multiply the result by 300,000. That would give you the distance which light travels in one year (that's called a lightyear, and it is a distance, not time). Multiply this number by 4.3. Now you have the total distance, in kilometers, to Proxima Centauri. Devide that number by 50,000. The result is the number of hours it would take to get to Proxima Centauri. Devide that number by 24, for the number of days, devide again by 365.25 (the number of days in a year). Now you would have the number of years it takes with current technology to get to the nearest star.



Monday, August 21, 2017

Eclipse!


To show today's partial solar eclipse (it was not total here) to the public, several of us - members of the Vancouver Centre of the Royal Astronomical Society of Canada (RASC) - set up solar and "white light" filtered telescopes at Telus Science World here in Vancouver. We also gave out hand-held eclipse viewers - we had a limited number, and have none left now.

The eclipse had been advertised extensively world-wide. Telus Science World (and we) anticipated a large crowd, and that certainly was the case. People queued up more than hour before the beginning of the eclipse. The line-up at each of our telescopes was in the hundreds all through the eclipse; someone mentioned that a total of about ten thousand people were in attendance inside Science World and at our telescopes. It was a grand occasion. We have had similar reactions at other events (though not the huge crowds of today). I think it shows that, when it comes to finding things out about what goes on in space, people have an innate interest.

At the time near maximum of the partial eclipse, when the sun was only a crescent reminscent of a young or old Moon, the sunlight turned into an unusual bluish/gray colour and was noticeably fainter. A drop in temperature was also felt by most people. It is odd to see faint sunlight under an absolutely clear sky. It was not like sunset or sunrise - those are commonly red.

This was a very successful event; perhaps we have steered a few young people in the crowds to study and get involved with working in astronomy, and/or related sciences. There is really no boundary between any of the sciences; STEM technologies underly most of them, particularly astronomy and space travel.


Why don't we order up another eclipse soon, we all had a great and fun time.

Sunday, August 13, 2017

The missed Perseids.



As is a tradition by now, our local centre of the Royal Astronomical Society of Canada helps out at Aldergrove Park near Abbotsford when the Perseid meteor shower peaks annually on August 12. The park administration sets up a tent for us, and reserves some space nearby for us to set up telescopes. Some of our members, and sometimes invited speakers, give several talks regarding astronomical events (past, present, and future). It's a rain-or-shine occasion. If it rains, telescopes are not set up outside, but may serve as exhibits inside the tent.

The Aldergrove Park administration promotes this event. This is the only time in the year at which overnight camping is allowed in the park. Over a thousand people usually attend.

Well, as the weather gods would have it, it turned cloudy just as the evening approached, and started raining towards 11pm. After the eleven days of wildfire smoke, which covered our area during all the preceding, sunny days, and which was finally cleared out by wind from the south-west, this was a disappointment. None-the-less, we are told by the park administration that about 1500 people showed up. During the evening, several hundred of them came to visit our telescopes and tent.

Since we had hoped for some break in the clouds, we set up about half a dozen telescopes early in the evening. Well, there were no breaks, so we ended up looking at the details of distant trees, and also explained to a number of curious campers how different types of telescopes work, and why they are a primary tool for the exploration of the universe. We packed up our telescopes just before the rain started; the talks in the tent continued. Our activities ended just before midnight; had it been clear, we would have stayed all night for the public to have a look at interesting astronomical objects - the Perseid meteors especially, of course. Well, we hope that next year's Perseid meteor date will have a clear night sky.

After the lengthy period of enforced astronomical inactivity, due to the smoke, to satisfy my wanting to do something about it, and before the event at Aldergrove Park started, I had set up a session to automatically take a picture of Fireworks Galaxy, in which a new supernova recently appeared. This galaxy is the home of ten recent supernovae in the last century; there may have been others of which we are unaware before then. This is an unusual frequency of such events in any given galaxy.

The remotely controlled Slooh.com telescope on which I reserved time to take the image is one of several located on the Canary Islands. These telescopes are dedicated to the use of the astronomy community world-wide. Here is a description in Wikipedia:
https://en.wikipedia.org/wiki/Slooh

I retrieved the Fireworks Galaxy image from Slooh.com this morning and did a bit of processing on it with Photoshop and Pixelmator. Here is the original:



The original image shows almost no trace of the Fireworks Galaxy
(compare to the processed image below)


Processed with Photoshop and Pixelmator


 Cropped, and enlarged.

As usual, click on each image to see a magnified version.

Patrick Wiggins, in Utah, discovered this supernova on May 14, 2017. Some type of stars go "supernova" at the end of their lives, when they have used up most of their internal "fuel". A good description of supernovae is found here:
https://en.wikipedia.org/wiki/Supernova

Even though we did not see the Perseids,  I at least got something astronomical out of yesterday.



Tuesday, July 25, 2017

Again Astronomy


The nice, warm weather we're having at this time inspired me to take another picture from my very limited view of the sky here at our house. We're located close to Metrotown (lots of light pollution) and our horizon is blocked by high-rise buildings and close-by trees.



The original image of M13 - the fuzzy "star" at the middle right.




The cropped and enhanced image of M13



The original fainter image at the top, showing a little fuzzy patch, is a picture of the globular cluster M 13 in the constellation of Hercules. Exposure was 30 seconds, ASA 800. This "source image" was taken with a 200 mm lens coupled to a 2x Barlow lens, making the combination equal to a 400 mm lens. The effective f-ratio was f 8.

The close-up is an enhanced image of M 13. You can see that the source image contains a lot of hidden detail. The camera used is a Canon 60Da, the source image is in "Raw" format, which preserves much of the detail captured in the image. The detail can be extracted with appropriate graphics software (I used Pixelmator and Preview for this purpose). 

Click on the images for a larger view.

We call our galaxy the "Milky Way" because we're inside it and it appears to us as a "stripe" of stars in the sky so numerous and faint that they melt together to look like "spilled milk". The globular clusters surround our otherwise "pancake-shaped" galaxy in a kind of sphere centered on the core of our galaxy. Other galaxies also have globular clusters. Globular clusters are considered to contain some of the oldest stars in our galaxy. There are estimated to be somewhere between hundred thousand and a million or so stars in each globular cluster. You can see a detailed picture in my previous post regarding M53, another "local" globular cluster (https://penmachinedad.blogspot.ca/2017/07/this-is-why-hubble-space-telescope-hst.html).

Wikipedia describes them like this: A globular cluster is a spherical collection of stars that orbits a galactic core as a satellite. Globular clusters are very tightly bound by gravity, which gives them their spherical shapes and relatively high stellar densities toward their centers. Most globular clusters in our galaxy show a lack of O and B type stars, an indication of their great age. The globular clusters in the Milky Way are all estimated to be at least 10 billion years old and therefore contain some of the oldest stars in the galaxy. A typical galaxy may contain up to a few hundred globular clusters; our galaxy, the Milky Way, has somewhere between 125 and 200 globular clusters orbiting the galactic center. Most globular clusters are found in the large spherical halo of a galaxy.

My very modest photographic effort gives you a bit of an idea about all this. It's amazing what "every-day" digital cameras can do.





Saturday, July 22, 2017

This is why the Hubble Space Telescope (HST) exists.


Astronomers are constantly looking to get finer detail about the universe, in order to better understand  it's evolution. We are also trying to find "life as we know it" elsewhere, both on  planets and moons in our own solar system, and other planetary (exoplanet) systems. Traces which could be attributed to "life" are very hard to detect, and this effort requires all the details we can possibly gather. 

Optical and radio telescopes, underground particle, cosmic radiation, and gravitational wave detectors, and other ingenious devices constantly collect, and highly trained people analyze these data to come to some more detailed conclusions about the answers to these endeavours.

One of the major steps in acquiring more detailed information occurred when the Hubble Space telescope started collecting data in 1990. So far, it has sent back more than 1.3 million images, according to NASA. I don't think that any telescope on Earth has done so.

Below is an image I acquired via the half-meter remote-controlled slooh.com telescope on the Canary Islands, and also downloaded a picture of the same globular cluster from the Hubble Space Telescope site.

The slooh.com telescope is of a size which many amateur astronomers also have in their own, private observatories. The HST is a larger telescope which orbits Earth, its mirror is 2.4 meters across. The difference in the details is obvious. The slooh.com telescope would show more detail if it were placed in orbit as well but not nearly as much, because of its smaller size. The reason for space-based telescopes is that this does away with all the interference caused by the Earth's atmosphere and man-made light and other pollution.

There are now other types of telescopes in space, most of which are dedicated to collecting data at wavelengths which are blocked from the surface of the Earth (ultraviolet, x-rays, deep infrared, certain radio frequencies, etc.).

All of this so that more details about the universe can be obtained.


M 53 imaged through a slooh.com remote-controlled telescope




M 53 as seen by the Hubble space telescope, also remote-controlled 


Monday, July 17, 2017

Space is impressive


The Whirlpool galaxy
(click on image to enlarge)
 I took this image through a remote-controlled slooh.com telescope on the Canary Islands. It can be seen as a small nebulous patch through binoculars.

Charles Messier, an astronomer who was an avid "comet hunter", generated a catalog of astronomical objects which, at the time and using rather smaller telescopes, could be mistaken for comets, because they appeared as faint and nebulous patches, just as comets do when they are far from the sun.

Charles Messier (Wikipedia)



These patches are listed from M1 to M110 in Messier's Catalog, and the Whirlpool galaxy is listed as M51. Messier did not recognize its shape. This spiral galaxy is about 25 million light years distant. The bright patch shown above M51 is what looks like the core of another galaxy (called a Seyfert galaxy), which seems to interact gravitationally with M51. This companion galaxy is listed in the NGC catalog as NGC5195. It was discovered in 1781 by Pierre Mechain and does not appear in Messier's catalog, although some astronomers list the pair as M51A and M51B.

The spiral structure of M51 was discovered in 1845 in Ireland by William Parsons (3rd Earl of Rosse) by means of a then giant 1.8 m reflecting telescope, called the Leviathan of Parsonstown - at the time the largest telescope on Earth. M51 was not recognized as a galaxy, separate from our own galaxy (the Milky Way), until Edwin Hubble (the Hubble Telescope in orbit around Earth is named in his honour) determined the distance of it. This distance puts M51 far outside the Milky Way and makes it a little more than one third as large. That still means that it probably contains about 150 billion stars. Edwin Hubble also determined that the universe is expanding, with far-reaching effects on cosmology and our general understanding of the evolution of the universe.

We know now of billions of galaxies - as numerous as the stars in our Milky Way. The Hubble Space Telescope shows that galaxies appeared very early in the existence of the Universe.

Impressive indeed.





Tuesday, June 27, 2017

Something Astronomical

 
Whenever our area experiences something less than a clear sky, it it still possible to take pictures of the deep sky by using a remotely controlled telescope. Here is my effort:


The Lagoon Nebula
(click on the image)



This nebula is a Hydrogen interstellar cloud whose dimensions are about 55 x 20 light years and which is about 4000 light years distant. It contains a star-forming region (the bright area) and can be seen with binoculars. The bright stars to the left are an open star cluster in the foreground. This image was taken through a half-meter remotely controlled Slooh.com telescope, located on the Canary Islands. Once downloaded, the picture can be enhanced by means of freely available graphics programs.

Under dark a dark sky, the nebula is an impressive sight, but you will not see the colours shown in the image. The human eye is not capable of showing colours at faint levels of light. That's why astronomy involves sometimes gigantic telescopes. If a telescope has a larger diameter it will collect more light. That allows subtle details to be detected, particularly if photography is employed. Photographs exposed for sometimes many hours will show colours and details undetectable by eye.

The best direct (i.e human eye) views of these faint objects are obtained under a dark sky, away from all the light-polluted cities.

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