Featured Deep-Sky Object - M33 - Triangulum Galaxy

It has been a while since we published a post covering featured deep-sky objects. In the past, we have been posting articles regarding objects in the night sky such as galaxies, nebulae, and star clusters complemented with images taken by the staff of Insight Observatory using a remote robotic telescope on the iTelescope network. Due to our recent projects such as automating a 32" Dobsonian telescope, assisting the W. Russell Blake Planetarium with its newly installed digital imaging theater, and implementing our Astronomical Telescope for Educational Outreach (ATEO-1), we simply haven't had the time or resources to do so (which is actually not a bad problem to have).

M33 - Triangulum Galaxy imaged on the Astronomical Telescope for Educational Outreach by Insight Observatory.

Well, it's about time we started again. In recent weeks we have been performing tests on the ATEO remote telescope, preparing it for educational and public use. As numerous images of deep-sky objects during testing were acquired, we figured why not post them on our blog as a "Featured Deep-sky Object". The first deep-sky object to feature is M33, the Triangulum Galaxy imaged by Insight Observatory Managing Member / System Engineer, Muir Evenden. Muir imaged the Galaxy with our 16" f/3.75 Dream Aerospace Systems astrograph remote imaging telescope with a 5-minute exposure with the luminance filter, stacked with 2 minutes of red, green, and blue filter exposures. These images were then stacked and processed using PixInsight. Post-processing was then done in Adobe Photoshop by Insight Observatory Managing Member / Project Developer, Michael Petrasko. The result of the image detail is surprisingly impressive considering there are not many exposures comprising the final image.

The Triangulum Galaxy is a spiral galaxy approximately 3 million light-years from Earth in the constellation Triangulum. It is cataloged as Messier 33 or NGC 598 and is sometimes referred to as the "Pinwheel Galaxy", a nickname it shares with Messier 101. The Triangulum Galaxy is the third-largest member of the Local Group of galaxies, behind the Milky Way and the Andromeda Galaxy. It is one of the most distant permanent objects that can be viewed with the naked eye.  Using a small pair of binoculars with a wide field of view, the galaxy is easily detectable. Being a diffuse object, its visibility is strongly affected by small amounts of light pollution. It ranges from easily visible by direct vision in dark skies to a difficult averted vision object in rural or suburban skies.

Read More

Galaxies 101 - A Primer to the Types of Island Universes

Spring is the time of year when our night sky is enriched with a plethora of galaxy types. On a dark night, we can often see a "hazy" band of light that stretches across the sky. This band is part of our own Milky Way galaxy, a gigantic collection of stars, gas, and dust. Far beyond the Milky Way, there are billions of other galaxies, some similar to our own and some very different, scattered throughout space to the very limits of the observable universe.

M101 - Spiral Galaxy in Ursa Major Imaged on T11 by Michael Petrasko and Muir Evenden

Types of Galaxies:

Astronomers classify galaxies into three major categories. Spiral galaxies look like flat disks with bulges in their centers and beautiful spiral arms. Elliptical galaxies are redder, more rounded, and often longer in one direction than in the other, like a football. Galaxies that appear neither disk-like nor rounded are classified as irregular galaxies.

Spiral Galaxies:

Spiral galaxies usually consist of three components: a flat disk, an ellipse-shaped formed bulge and a halo. The disk contains a lot of interstellar gas and dust, and most of the stars in the galaxy. The gas, dust, and stars in the disk rotate in the same direction around the galactic center at hundreds of kilometers per second and are often arranged in striking spiral patterns. The bulge is located at the center of the disk and consists of an older stellar population with little interstellar matter. The near-spherical halo surrounds the disk and is thought to contain copious amounts of dark matter: matter that acts gravitationally like "normal" matter but that can't be seen! Astronomers infer the presence of this dark matter by the motions of stars and gas in the disk of the galaxy, as well as older stellar populations in the halo-like globular clusters. The young stars in the disk are classified as stellar population I, and the old bulge and halo stars as population II.

M104 - "Sombrero Galaxy" in Virgo - The image was taken on  iTelescope.com's T21 by Sam P. and Tom M. from PCIS.

Astronomers classify spiral galaxies according to their appearance by using the Hubble scheme. Those with pronounced bar structures in their centers are called "barred spirals" and are classified "SB" (examples are given in brackets). Galaxies with conspicuous bulges and tightly wound spiral arms are called "Sa" (Sombrero galaxy) or "SBa" (NGC 3185). Galaxies with prominent bulges and pronounced spiral arms are classified as "Sb" (M31, M81) or "SBb" (M95, NGC 4725). Other spirals with loose spiral arms and a small bulge are classified as "Sc" (M33, M74, M100) or "SBc" (M83, M109).

There are some galaxies like M84, M85, and NGC 5866 that are disk galaxies without any spiral structure. These galaxies are called "S0" or lenticular galaxies. Though the origin of lenticular galaxies is still debated the most plausible explanation to date is that the gas and stars that would reside in the galaxy disk have been stripped by interactions with the hot gas in clusters and groups of galaxies. From their appearance and their stellar contents, they look more like ellipticals rather than spirals and have often been misclassified due to this fact. For instance, misclassification has occurred for both the Messier object examples listed above.

Elliptical Galaxies:

Elliptical galaxies are ellipsoidal agglomerations of stars, which usually do not contain much interstellar matter. Photometric studies of elliptical galaxies suggest that they are triaxial (all three axes of the ellipsoid are of different sizes). Unlike spiral galaxies, ellipticals have little or no global angular momentum, so different stars orbit the center in different directions and there is no pattern of orderly rotation. Normally, elliptical galaxies contain very little or no interstellar gas and dust and consist of old population II stars only. Elliptical galaxies are classified according to the Hubble scheme into classes "E0" to "E7", in increasing order of ellipticity. Thus E0 galaxies appear round like M89 while E6 galaxies like M110 and NGC 3377 are almost cigar-shaped.

The largest galaxies in the universe are giant elliptical galaxies. They contain a trillion stars or more and span as much as two million light-years - about 20 times the width of the Milky Way. These giant ellipticals are often found in the hearts of galaxy clusters. For example, the giant elliptical galaxy M87 is found in the heart of the Virgo Cluster.

Elliptical galaxies also constitute some of the smallest galaxies in the universe. These galaxies are called dwarf elliptical galaxies and dwarf spheroids. Relative to normal ellipticals they are very faint and are often found in galaxy clusters or near large spiral galaxies. For instance, there are 9 dwarf spheroids like Leo I which are satellites of our Milky Way galaxy.

Irregular Galaxies:

A small percentage of the large galaxies we see nearby fall into neither of the two major categories. This irregular class of galaxies is a miscellaneous class, comprising small galaxies with no identifiable form like the Magellanic clouds (the Large Magellanic Cloud and Small Magellanic Cloud are two satellite galaxies of the Milky Way) and "peculiar" galaxies that appear to be in disarray like NGC 1313. There is no discernable disk in these systems, although they often have copious amounts of gas as well as high rates of star formation. Irregular galaxies are often found to be gravitationally interacting with galaxies nearby, which often accounts for their ragged appearance.

Read More

Toyotas, iPads and Galaxies... Oh My!

Waiting for my vehicle to be serviced has never been so exciting! Yesterday as I waited for my Toyota Rav4 SUV to be serviced in the dealership's waiting room, I experimented with iTelescope.net on my iPad. iTelescope.net does not recommend using Safari as a web browser (only Firefox and Chrome), however, because the Toyota dealership had such good wi-fi reception, I thought I would experiment and make an attempt to image a galaxy from iTelescope.net's remote robotic telescope location at Siding Spring Observatory, Australia. 

M83 - Barred Spiral Galaxy in Hydra  - 300 sec. exposure

The iTelescope.net remote robotic telescope "Launchpad" page in Safari worked flawlessly until I got to the "One-Click Image" page that lists a catalog of recommended objects with the exposure times already programmed. I was not able to execute the "Submit Image" button. The workaround for this was to go into the "Single Image" page and manually set the object desired as well as the exposure settings. After inputting the settings, the "Acquire Image" button worked just fine. The object I imaged was the barred spiral galaxy, M83 in the constellation of Hydra. Messier 83 (also known as the Southern Pinwheel Galaxy, M83, or NGC 5236) is a barred spiral galaxy approximately 15 million light-years away. It is one of the closest and brightest barred spiral galaxies in the sky, making it visible with binoculars and small telescopes. Six extragalactic supernovae have been observed in M83 making the object a good candidate for the part of a continued supernova search program.

The instrument I used via my iPad to capture the above image of M83 was the Medium Deep Field (T9) which is a 12.5" Ritchey-Chrétien Cassegrain with a long focal length of f/9. This telescope is typically used for imaging & some photometry. It has a selection of color imaging filters and a photometric V filter. It is teamed with an STL-11000M CCD Camera. T9 is a prime imaging platform in the southern hemisphere and is capable of brilliant narrowband imaging with several Astro Photo of the Day (APOD) prizes under its belt already. It is a highly reliable telescope that has enabled countless iTelescope.net users to capture southern glories as well as valuable science data. It has often been used in Hubble Space Telescope support missions.

After having success imaging a galaxy visible from the other side of the globe, using my iPad, I feel that making appointments that require extensive wait times just got a lot more painless!

Read More