Saturday, November 22, 2014

2014 Deep South Regional Stargaze

After attending the 2014 Spring Scrimmage at the same site, I drove out and spent four days and nights attending the long awaited 2014 Deep South Regional Stargaze, held annually near Norwood La.. It was well worth the effort, given that all four nights featured good if not excellent sky conditions and clouds intruded only on one night for several hours before retreating for the rest of the night. While attending the DSRSG I finally had an answer to a long standing issue with my dew heaters I was stumped trying to figure out. After a conversation with Ron Keating, who makes and sells the Dewbuster dew heater controllers, I realized I was placing the temperature probe for the secondary mirror in the wrong location. Once I corrected the problem by inserting it behind the secondary mirror, the heater worked perfectly without creating annoying heat blooms that wreck the view. And while there I logged dozens of NGC, Arp, Perek-Khoutek, Sharpless and Palomar objects I had never seen before when I wasn't looking at old standbys and favorites.
Among the first object that I observed with the 15-inch was the rapidly receding comet C/2014E2 Jacques among the stars and deep sky objects of Aquila. Much smaller and fainter than the last time I observed it more than a month before, it still showed a subtle forked tail and a brighter inner region in the center of the coma. While a shadow of what it once was, C/2014E2 Jacques was still well worth observing even though it glows at around 12th magnitude or so. Soon it will be out of reach of any amateur telescope, but others are now inbound that will take its place.
After spending time observing other deep sky objects in Sculptor I have observed in the past, including the bright galaxy NGC-253 and globular cluster NGC-288, I looked for other objects I have yet to see for the first time. One such object was the Sa spiral galaxy NGC-24, which shines at magnitude 11.5 and is some 6 arc-minutes long. As such it's surface brightness was reasonably high, which enabled it to be visible despite the sky glow from Baton Rouge some 50 miles to the south. I did see a brighter central region and it appeared a little "wooly" around the edges. That is consistent with it being a spiral galaxy, which is littered with star forming regions and star clouds along it's spiral arms.
In Aquila can be found dozens of planetary nebulae, ranging from nearly stellar disks barely resolvable at very high power to large, ghostly rings or disks. Sharpless2-71 is definitely one of Aquila's more unusual planetary nebulae, with an irregular, lopsided structure with an apparent bright central star. It is in fact a foreground object, the true central star shines very feebly at 19th magnitude. The brighter outer rim is missing on one end and the darker central void merges into the surrounding sky. This planetary nebula looks more like a faint comet than a planetary nebula, but it does respond well to an O-III filter. Sharpless2-71 eluded several attempts to locate until I succeeded at the DSRSG. It was one of the most satisfying finds I had for months.
Palomar 11 is one of 15 faint globular clusters found by Palomar observatory through a survey funded by the National Geographic Society. This globular cluster's located along the fringes of the Milky Way in eastern Aquila. It has eluded numerous efforts to find it. Until that is I brought the 15-inch to bear on it at the DSRSG, where skies are considerably darker than where I usually observe. At 227X it appeared as a round, faint glow with a slightly brighter center. I thought I glimpsed a slightly granularity around the edges, but for the most part aside from the slight central brightening, Palomar 11 was otherwise featureless. The main prize was in finding it, and efforts to find Palomar 10 and 12 failed to reveal them through the same telescope.
In Aquarius numerous galaxies await the amateur astronomer. While most are faint, there's a number of easy objects for 8 or 10-inch telescope under reasonably good skies such as the spiral galaxy NGC-7184. This 11th magnitude system has a Hubble classification of SBc and also shows evidence of a burst of star formation in a ring shaped region around the nucleus. Also in the field appear the galaxies NGC-7180, 7185 and 7188. NGC-7180 is a 12.6 magnitude SO system whereas NGC-7185 is a magnitude 12.2 elliptical system. The final galaxy, NGC-7188 is a Sb system with a magnitude of 13.2. All three are some 60 million light years away, while NGC-7184 is a far larger and more massive galaxy 40 million light years behind them.
Aquarius is well known for being home to the bright globular cluster M-2, there is another globular cluster farther away, fainter and far harder to see. NGC-7492 is a very faint and challenging object under light polluted skies, and until I looked for it at the DSRSG the only other place I seen it from was a site in the middle of the Conecuh National Forest with my 10-inch. NGC-7492 is some 8 arc-minutes across and weakly shines at 11.3. Like Palomar 11 I saw what appeared to be slight granularity around the edges, possibly because the brightest stars shine at around magnitude 15.5. This globular cluster is some 84,000 light years away and is rapidly approaching us at the velocity of some 125 miles per second.
Andromeda has many more objects for amateur astronomers beyond the Andromeda Galaxy and several other well known examples. One such object is the NGC-80 galaxy group, whose members include NGC-81, 82, 83, 85, 86, 91, 93, 94, IC 1564 and MCG+04-02-010. NGC 80 itself is a 13th magnitude, round object with a brighter core. NGC-83 is another round 13th magnitude object while the third galaxy's identification is either NGC-90 or 91. Accepting NGC-90 as the correct identification  for this galaxy,  this spiral system shines around magnitude 14. A fourth galaxy, which is most likely NGC-85 appeared at the very edge of the field at 227X. The distances of these galaxies ranges from 240 to 290 million light years away.
Arp 273 is one of more than 300 interacting and peculiar galaxies cataloged by the American astronomer Halton Arp in the 1960's. This object consists of two galaxies that grazed each other with dramatic results that are apparent in photos taken by large observatories and the Hubble Space Telescope. However these galaxies are 340 million light years away and shine barely above 14th magnitude. Both galaxies put together are 1.7 arc-minutes across, giving them a reasonable surface brightness. They appeared as a lopsided oval spot with a brighter center and a faint streak that is the intruder galaxy whose gravity severely distorted and disrupted the larger galaxy. Even at the DSRSG Arp 273 was not an easy object for me to find with the 15-inch, but finding it brought me a good deal of satisfaction.
NGC-160 is a 13th magnitude oval galaxy with a brighter core that responds well to fairly high magnifications dues to it's small apparent size of 2.2 arc-minutes. NGC-160 lies 240 million light years from Earth. It's featureless appearance is consistent with it being an lenticular galaxy or possibly a transitional S0/Sa spiral galaxy.
NGC-214 is a 13th magnitude barred spiral galaxy which at 227X appears as an elongated object with a brighter core. It's small apparent size of 1.9 arc-minutes in length is due to it being oriented between face and edge on and it lying 200 million light years away from us. Little of it's structure otherwise was visible through the 15-inch at 227X.
While attending the DSRSG I also observed dozens of other objects that were seen for the very first time in the constellations of Andromeda, Aquarius, Cygnus, Aquila, Sculptor, Pisces and Cetus. Numerous NGC, IC and Messier objects well known to me were also observed such as the Andromeda and Triangulum galaxies, The Cygnus Egg Nebula, The Veil Nebula, The Ring Nebula, and the Orion Nebula receives attention. I also showed numerous deep sky objects to passerby, including a University of South Alabama physics professor and his students when they were not looking through an 8-inch Celestron SCT he brought along. The DSRSG this year saw the best weather I experienced in years. The turn out was also very good, with over 100 people attending. I am now looking forward to the upcoming 2015 Spring Scrimmage, where I can peruse spring and summer deep sky objects.

Saturday, September 27, 2014

A hydrogen star and a fading comet.

Last weekend saw the most pleasant weather for stargazing for weeks, with clear skies and much less humidity than usual. Indeed, I was wearing a battle dress uniform blouse because temperatures dropped enough for it to get cool outside. The sky's transparency was also very good, evident by the fact I saw the Milky Way clearly except for the region near the southern horizon. With the near limitless numbers of galaxies, nebulae and star clusters to choose from, I set up the 15-inch then connected the Sky Commanders to my Toshiba laptop before commencing observations. Through the use of Sky Tools3, I can now locate any sort of object anywhere in the sky, not just deep sky objects and the planets the Sky Commanders alone are designed to locate. I now have the means to locate comets and asteroids far more easily than before, with C/2014E2 Jacques being the first. I've also observed the main belt asteroids 1 Ceres and 4 Vesta from home using this setup. Novae Cygni 2014 was also found this way from the driveway. To protect the computer from dew and keep it warm and dry, I made a plywood enclosure with a clear plastic top. Slots allow the mouse and the data cable to be plugged and unplugged from the laptop's USB ports without removing the computer. to keep the screen from dazzling my eyes at night, I bought a red screen filter and also use the night vision mode Sky Tools has. When placed over the screen then in the enclosure, there is little stray light from the computer to bother others observing nearby.
Once it became completely dark, I set about observing several objects I was interested in. One of them was the comet C/2014E2 Jacques, which is fading but still well placed for observation. That night it was passing in front of the asterism Collinder 399, or the Coat Hanger as it's popularly known. While it faded from the last time I drew it, the inner core became more noticeable and the tail looked less fork shaped. The best view was at 298X, which alleviated the interference from the dense star fields behind the comet. This comet is already 1.2 A.U. away from us, and soon would be out of reach of all but large telescopes and users of CCD cameras. Fortunately, there's always other comets to take this one's place for amateur astronomers to observe and photograph.

Scorpius is soon to be lost in the Sun's glare, so I spent time observing several objects there. One of them was the curious open cluster Collinder 333. This is a fairly small and not very concentrated open cluster, but for a curious group of five stars shaped like a perfect pentagon. At the top of the pentagon was a bright orange red star. Many Collinder star clusters are not terribly conspicuous, but this one was easy to spot even at low power. The central core almost looks like it could be some sort of logo.

Although I always am looking for objects I've never seen before, some objects like M-57 I observe time and time again. Through small and large telescopes it always shows considerable structure under good skies. However, one feature has eluded repeated efforts to spot. Many planetary nebula's central stars are visible through my telescopes, even my 6-inch. However, that is not the case with M-57, the central "hole" is filled with very evident nebulosity that usually hides the central star when the seeing is poor or mediocre, or magnifications are not high enough. I have searched for it a number of times with my 10 and 15-inch telescopes at high magnifications without success. The seeing was just not good enough until last Saturday night, or I wasn't expecting the central star to barely shine above the nebulosity in the central hole. When a fellow observer remarked the central star was visible, I turned my 15-inch to M-57 then raised the magnification to 425X, then 572X. Sure enough after staring at the nebula for a minute or so, the central star flickered into view at 425X. The view softened at 572X so I returned to 425X. I started staring again and saw the central star appear and disappear repeatedly. The central star appeared to be fainter than 15th magnitude visually, even though it's listed magnitude is about 14 in most catalogs. Even in telescopes much larger than mine, the central star can be difficult to see. The central star is shining some 200 times brighter than the Sun with a surface temperature of 125,000 degrees Celsius. The central star has ejected the current nebula less than 2,000 years ago, but there is also an older much larger nebula around it that is about 3.5 years across. Aside from the central star, the darkening along the long ends of the nebula was also evident along with hints of other features seen in photos. The nebula's magnitude is 8.8, and lies 2,300 light years from Earth. The diameter of the visible nebulosity is about one light year, and it is expanding at a velocity between 20 and 30 kilometers per second. M-57 responds well to narrow band and O-III filters, as well as high magnifications. It is also observable from light polluted locations and under moonlit skies. M-57 is very easy to locate and has been one of my top favorites among the nebulae ever since I started observing deep sky objects.

Another planetary nebula I observed last weekend was Campbell's Hydrogen Star in Cygnus. Also known as PK064+5.1, this nebula is quite bright but much tinier than M-57. It gives itself away by the strong red color of the central star with a fuzziness around it. Raising the magnification to 425X revealed a tiny disk around a reddish star that is slightly brighter around the rim and next to the central star. Last night I searched for it again from my driveway and succeeded in locating it despite the streetlight across from my house. Other than the peculiar color and the slight brightening around the star and the outer rim, I did not see any other signs of structure in this planetary nebula.

Other objects observed that night included the proto-planetary nebula PK80-6.1, or the Cygnus Egg Nebula, the globular clusters M-15, M-22, M-62, M-9, M-19, M-13, M-92 and M-80. I also looked at all three sections of the Veil Nebula, the Crescent nebula and the North American nebula. I've also stopped to observe Saturn, Uranus and Neptune. My trip to the airstrip last weekend paid off in several hours of good observing with like minded folks. Soon the Deep South Regional Stargaze will be held near Norwood LA, and I am currently preparing to attend this year.

Sunday, August 31, 2014

Comet Jacques

Recently windows appeared in the very murky weather that prevails during the summer here along the Gulf Coast. One such window appeared last weekend, which gave me the opportunity to observe a number of old favorites, and to get a good look at an approaching comet. Upon setting up the 15-inch, I discovered the azimuth encoder was slipping badly, so instead of sketching some objects I had on my list, I opted to sketch a couple of summer favorites and Comet Jacques, now an easy object for small telescopes and binoculars.
M-8 or the Lagoon Nebula is probably the finest and brightest object of it's kind in the summer skies visible from the northern hemisphere. Shining at an apparent magnitude of 5.8 and covering a region of sky about 1.5 degrees across in long exposure photos, this object fills most of the field of view at 83X. The 24mm Explore Scientific eyepiece I was using gives a true field of view one degree across in the 15-inch, so I was only seeing the brighter inner region. Light pollution hides the faint outer regions, but when views through an O-III filter from the airstrip a wealth of bright and dark regions appears. The star cluster within the nebula is itself a very nice object to observe. Both are 5,500 light years from Earth. From a truly dark site M-8 would overflow the field with bright and dark patches, streamers and fans of gas and dust. The Hourglass feature was very apparent, and so was the dark channel between it and the enclosed star cluster that gives this nebula it's name. Under good skies M-8 is a wonderful sight even through small telescopes and large binoculars.
M-16 or the Eagle Nebula is another famous nebula, though not as bright as M-8 even though it too is a 6th magnitude object. It extends across an area of sky some 35 arc-minutes wide and is 7,000 light years from Earth. It displays a eagle or at least a flying bird like shape at 111X through an Explore Scientific 18mm 82 degree eyepiece and an O-III filter. With the filter it was easy to make out, without it light pollution at the site rendered it barely visible despite the massive light grasp of the telescope. Visible in the center of the nebula as an irregular triangular dark region are the Pillars of Creation. Other dark nebula are present as well, but I did not see them that night. M-16 was visible through the finder and I also made out nearby M-17 clearly as well.

Comet C/2014E2 Jacques is now an easy object visible in the evening sky as soon as darkness falls. Ever since it came into view in the predawn skies, it has been getting brighter even though it is now outward bound from the Sun. First spotted by the Southern Observatory for Near Earth Asteroids Research in Brazil last March, this comet is now at closest approach to Earth at a distance of .56 A.U or 52 million miles. In July it passed 7.9 million miles from Venus. This is a long period comet which takes 12,000 years to complete it's next orbit around the Sun. At aphelion, it's more than 1,600 A.U. from the Sun, some 13 times farther away than Voyager 1. At the time I observed it at 227X, it was at about seventh magnitude. Lacking a clearly defined nuclear region, it resembled a lopsided elliptical or face-on spiral galaxy with a weak central core. There was persistent signs of a very faint tail. Over a period of 24 hours from the previous night when I observed it from the driveway, it's motion was very evident. It was also clearly visible through the finder scope and was well worth the effort to track down. C/2014E2 Jacques will be close enough for a good view for the next few weeks or months. If you wish to see it before it fades, this is the time to get the best possible view.

While my plans for that night were a bust, it was still an enjoyable evening to be under the stars. I has a nice view of Saturn, observed a number of planetary nebulae and globular clusters, and looked at the Andromeda and Triangulum galaxies. Other objects I observed included Seyfert's Sextet and NGC-7331 in Pegasus, a twin to the Andromeda Galaxy that is 23 times farther away from us. I have since fixed the problem with the azimuth encoder and am looking ahead to the next opportunity to observe under dark skies

Friday, June 20, 2014

The Bear and the Lion

The weekend before Memorial Day was the last chance for several weeks to observe objects from a site darker than my driveway, so I drove out to the local club's site and found that I had it all to myself that night. Once it got dark, I went to work on the galaxies of western Ursa Major the Great Bear and Leo Minor, the Little Lion. Some of these objects I have observed before, but did not sketch.
Comet C/2012K1PANSTARRS is still visible as soon as darkness falls, but it's edging towards the Sun and soon will be lost in it's glare. It will however reappear in the morning sky and remain a nice comet for amateur telescopes. Through my 15-inch it showed a very short tail and a strong inner core. The location of the nucleus was marked by a fuzzy star like nucleus, which is of course far larger than the actual nucleus itself. This comet is getting brighter as it approaches the Sun, and well worth the effort to observe with a small telescope or a good pair binoculars.
The galaxy NGC-2985 appeared as a bright and small oval object with a magnitude of 10.5. This Sb spiral galaxy has an apparent size of 5 arc-minutes, it's delicate spiral arms forming a fainter zone around the relatively large and bright nuclear bulge. This galaxy is well within the grasp of uses of small telescopes under good skies.

The galaxies NGC-3065 and 3066 form an interesting pair through the 15-inch at 298X. NGC-3065 is a type SO lenticular galaxy with an total magnitude of 12, it's small apparent size of 2 arc-minutes makes the surface brightness reasonably high and the use of high magnification advantageous. NGC-3066 is noticeably fainter, and looks elongated while NGC-3065 appear round with a weak central brightening. NGC-3066 is a peculiar SBb barred-spiral galaxy, it's central bar and core making it appear elongated when in fact this one arc-minute wide galaxy is nearly round.

The nearly edge on spiral galaxy NGC-3198 was an easy find, with a brighter core and a slightly woolly appearance. This magnitude 10.2 galaxy had an apparent length of over 8 arc-minutes, making it a good object for a 6-inch under good skies. This system is actually very much like M-33 and NGC-2403, a large Sc class spiral galaxy with numerous regions of ongoing star formation.

NGC-3254 in Leo Minor might not be rated high on many observer's to do list, but it's a quite worthwhile galaxy for amateurs interested in galaxies. This edge-on system is quite bright and shows a bright inner core, as well as stand up well to high magnification. One side of the inner core seemed to have a sharper boundary than the other. Shining at magnitude 11.5 and extending some five arc-minutes in length, this system resembles the Andromeda galaxy thanks to it's Hubble classification of Sb. This galaxy unlike Andromeda is closer to edge-on than our nearest large galactic neighbor. The galaxy brightens rapidly towards the center and along the plane of it's disk.
NGC-3348 is a very small, but quite bright galaxy that has no problem penetrating the murkiness of my area's skies. Shining at magnitude 11.2 and an apparent size of 2 arc-minutes, this object is round with a brighter center. In appearance it resembles a comet and responds to high magnifications very well.

NGC-3504 is one of many galaxies to be found in Leo Minor, the little lion.
It's a 11th magnitude barred spiral galaxy that is 2.7 arc-minutes across, with a bright inner region made up by the galaxy's central bar and nucleus. The galaxy brightens towards a bright core, with a faint haze around the central bar where the spiral arms are. This galaxy has a Hubble classification of SBb, and shows twin helices flanking the central bar in long exposure images.

In the same medium power field as NGC-3504 is another galaxy, NGC-3512. Unlike NGC-3504, NGC-3512 is a face-on Sc spiral galaxy that spans 1.6 arc-minutes and shines at a magnitude of 12.4. At 298X, NGC-3512 appears as a round faint patch with weak central brightening. Together both galaxies form a nice pair at 181X. I also observed the Ring Nebula in an unsuccessful effort to find the central star, looked at M-82 and it's fading supernova and perused a number of other galaxies. Last but not least, I spent some time observing Jupiter, Mars and Saturn. As the night wore on, the seeing settled down enough to allow superb views of Saturn at 425X, showing the belts on the planet and it's largest moon Titan as a tiny orange disk.

Thursday, May 22, 2014

Spring Scrimage

More than three weeks ago I attended the "Spring Scrimmage" held at the site where the Deep South Regional Stargaze is held every fall. There I stayed for two days and two nights observing mostly galaxies and the planets with the 15-inch Dob and a few other folks' telescopes too. The weather was quite good Friday night and steadily worsened the following night until it was no longer worth observing. While I looked at a number of favorite objects, I looked for some unfamiliar objects and made these sketches Friday night. I also made use of newly acquired astronomical software and a laptop to locate and observe the comet C/2012K1PANSTARRS. During the day I updated my logs and toured the area surrounding the Feliciana Retreat Center.
One object I sought out was a trio of galaxies on the Virgo-Coma Berenices border. Comprised of three edge-on spiral galaxies canted at angles to one another, all fit comfortably in the 18mm Explore Scientific 82 degree eyepiece at 111X. The brightest member is the tenth magnitude system NGC-4216, which seemed to show a hint of its dust lanes and a very bright inner core. It spans more than eight arc-minutes and is some 40 million light years away. The next brightest galaxy is NGC-4206, fainter and smaller it was still quite easy to spot. I noted a central brightening and a similar appearance to NGC-4216, which shines at magnitude 12.5. NGC-4222 is even fainter and required some effort to pull out of the sky glow. This Sd spiral galaxy shines at magnitude 13.5 and has an apparent length of 3.5 arc-minutes.
While the Virgo Cluster is the largest concentration of galaxies visible to amateur telescopes, there's many more visible in lesser known constellations such as Lynx. Turning the 15-inch to the Lynx galaxy NGC-2832, I was surprised to find three others in the field of view at 227X. The brightest is the E4 elliptical galaxy NGC-2832, which shines at magnitude 11.5. Overlapping it is another much fainter and very tiny galaxy, NGC-2831. Appearing as a brightening in the halo of the larger galaxy, this minuscule object shines at magnitude 13.4 and is less than a arc-minute across. Next to NGC-2832 and 2831 is another much fainter edge-on system is also present, but 15th magnitude NGC-2830 eluded me. Two more galaxies, NGC-2829 and IC-2460 shine at magnitude 15 in the same field of view. Both are very faint, elongated fuzzy spots less than an arc-minute long with brighter centers. I suspect the view of these galaxies would be far better from a very dark site, I was not quite able to tell if IC-2460 was elongated or round and which was it was pointed.
Right now we have another PANSTARRS comet in view, but unlike the comet of last year this one is conveniently located for evening observation among the stars of Ursa Major. At about eight magnitude it's easy for the 15-inch, folks were having no problem seeing it with small telescopes. At present comet C/2012K1PANSTARRS is both high in the evening sky and well away from the Sun. It will remain well placed for observation until late June. After remaining near the Sun for over two months, it will again be well positioned for observation in the predawn skies.
Lynx has numerous galaxies, but only one that could be honestly called a bright galaxy. NGC-2403 is similar to M-33 in Triangulum, a face on Sc spiral galaxy 12 million light years away. It's extends across 18 X 11 arc-minutes of sky and shines at magnitude 8.4. Frequently mistaken for a comet, this galaxy showed hints of the spiral arms and it's brightest star forming region. Nearly 1,000 light years across that H-II region has its own NGC-designation, NGC-2404 and is comparable to the Tarantula Nebula in the Large Magellanic Cloud. The galaxy would be far more impressive had the skies been clearer and darker, but I was lucky to get the one good night I got during the Spring Scrimmage.
In Lynx I came across the pair of galaxies NGC-2798 and NGC 2799 while looking through a list of objects of interest within that constellation. NGC-2798 has an apparent magnitude of 12.3 and an apparent size of 2.8 arc-minutes. NGC-2799 shines at magnitude 14 and is 2 arc-minutes in length. Together they form the pair of peculiar galaxies, Arp 283. Both galaxies are tugging on each other hard, evident in their distorted and disturbed structure. NGC-2798 and 2799 are Sba and Sbm type galaxies respectively, and both had a quite high surface brightness. I did not see any sign of their tug of war at 227X, but this is a promising object to return to at a darker site.
Other objects I observed were Mars, Jupiter and Saturn, and scores of other galaxies. I looked at a number of Virgo, Coma Berenices and Canes Venatici galaxies, along with others in Hydra, Draco and Hercules. I also observed a few Ursa Major galaxies including M-82, whose supernova is still visible. It was a very nice night on Friday, but the weather was poor Saturday and I took the telescope down by 10 p.m. Nevertheless, I got some amazing views of the planets, Syrtis Major and the polar caps on Mars were very clearly visible. Jupiter showed eddies along it's belts, and Saturn's rings showed both the Cassini and Encke divisions. I am planning to attend the Spring Scrimmage again next year to sketch more spring galaxies, weather permitting.

Wednesday, April 30, 2014

Springtime galaxies

Last weekend saw the arrival of a reasonably good night, naturally I took the opportunity to look for some objects I wanted to see for the first time or get drawings of. So I drove out to the airstrip and set up the 15-inch while the sun was still up. After assembling the telescope and setting up the computer, it was time to collimate it and allow the cooling fan time to get the primary mirror closer to the falling ambient temperatures after sunset. Once it became dark enough to see some bright stars, I initialized the digital setting circles and the night's observing began. There was only about three and a half hours to observe under dark skies, because the waning gibbous moon rose just before midnight. So I concentrated on a few objects of interests in the constellations Lynx, Sextans and Pyxis.
NGC-2818 is an open cluster and planetary nebula in the southern constellation Pyxis with a planetary nebula appearing among its stars, like the Messier object M-46 in Puppis. While the open cluster was underwhelming through the murk near the southern horizon, the planetary nebula was easy to make out with an O-III nebula filter in place. It was fairly bright and large, looking somewhat apple core or barbell shaped. Shining at 8th magnitude and spanning nine arc-minutes, the star cluster is not particularly spectacular, but this planetary nebula would be impressive if it was higher in the sky from my location. It shines at a magnitude of 11.6 and is 35 arc-seconds across. I saw no other signs of structure or the central star that excites the nebula's gasses into fluorescing in visible light. To distinguish it from the star cluster, the planetary nebula often is referred to as NCC-2818A.

NGC-2537 is one of many galaxies in the northern constellation Lynx, which is now high in the skies after dark. This is an irregular dwarf galaxy that has peculiar bright patches in it that create the appearance of a bear paw, hence the nickname "Bear Paw Galaxy." It is also known as Arp-6 This object is an irregular system of type Sd, with a magnitude of 11.7. It's fairly small apparent size of 1.7 arc-minutes gives it a fairly high surface brightness. Also in the field can be found two other galaxies, one being NGG-2537A, a background galaxy at least 20 times further away than NGC-2537 in the foreground. The other is IC-2233, a faint edge on galaxy that eluded my 15-inch, probably because the skies were not very transparent that night. It lies 18 arc-minutes to the SE of NGC-2537 and forms a pair with NGC-2537A, which is unrelated to IC-2233. NGC-2537A was visible as a faint, round, fuzzy spot, which is all that can be seen of this very remote face on-spiral galaxy.

NGC-2549 is a lenticular galaxy of type SO also located in Lynx, but larger and brighter than NGC-2537. Shining at magnitude 11.2 and an apparent length of 4.2 arc-minutes, this galaxy has a relatively high surface brightness. This galaxy appears as an elongated object with a bright core, but is otherwise featureless because it's not forming new stars due to a lack of gas and dust. As a consequence, NGC-2549 mostly populated with older yellow and red stars.

In the inconspicuous constellation Sextans lies a number of galaxies modest telescopes can reveal under good skies. However, the murky and light polluted skies of my area demand a fairly large telescope to merely see many of these galaxies that are visible to smaller telescope at dark sites. NGC-3044 was however an interesting find that showed up quite well as the sky conditions worsened as the night progressed. Oriented south-southwest to north-northeast, this 12th magnitude edge-on galaxy appears as a slash of faint light some 5-arc minutes long. It was quite easy to make out at 142X. NGC-3044 is a SBc barred-spiral galaxy that resembles the Draco galaxy NGC-5907, but much smaller and fainter.
Another galaxy in Sextans worth a look is the face-on Sc type spiral NGC-3423. Small and round, this galaxy has a brighter center and spans some 3.8 arc-minutes of sky and has an overall magnitude of 11.2. This object bears magnification well, a point in it's favor because it is quite small as the drawing shows for a visual observer. I did not see any evidence of it's numerous H-II regions or it's spiral arms.
While at the airstrip, I brought along a red-filtered lap top computer which was helpful in locating these objects. I also tried out a shelter I made to keep the computer dry and warm enough to function properly, it was quite cool and very damp that night. Hazy skies and poor seeing were the order of the night, and the moon rising at midnight forced an end to observing deep sky objects for the night. I did get another look at the fading supernova in M-82, Mars and Saturn.; The seeing was certainly not the best for the planets, but with it being more often than not overcast locally, I take any chance I can get to look at them.


Sunday, April 6, 2014

Winter and spring deep sky objects

Winter has finally drawn to a close and with the departure of the cold comes hordes of galaxies as soon as it becomes completely dark. Nevertheless, some winter objects remain in view and therefore I observed a few of them before they are lost in the glare of the Sun. Along with the arrival of warmer temperatures nights are getting shorter and all of the major planets are visible now at some point during the night. It is still stormy and murky most of the time, but a few good nights have come along, good enough to make taking the 15-inch to a darker skies worth the effort. The drawings shown here were made over a two week period last month. 
The Ursa Major galaxy M-82 is one of my favorite galaxies, but recently a bright Type 1A supernova has appeared there. I have been following it ever since I learned of it's eruption. Reaching a peak brightness of about magnitude 10, it was unmistakably visible even at home despite the heavy light pollution. Here in this drawing the supernova was shining at about magnitude 11.7 as it fades towards invisibility. The last time I examined M-82 the supernova was still visible, but now it's too faint to still see from my house at a magnitude of 12.9. If you wish to see this supernova, look for it now because soon it will be out of range of all but very large professional telescopes and those equipped with ultra-sensitive cameras. It is quite a thrill to witness an event that actually happened 12 million years ago.
 The southerly constellation Columba the Dove is poorly seen if not invisible from the U.S. and Europe, but contains both Milky Way and extra-galactic objects within it's confines. The brightest and best of these objects is the bright, small and concentrated globular cluster NGC-1851. It can be seen in small telescopes as a small, round, fairly bright object that resembles a comet with an intense inner core. It's hindered by the low elevation in my local skies, but through my 15-inch it breaks up into stars, resembling a southern version of the Pegasus globular cluster, M-15.
Auriga has many, many open clusters, nebulae and even a globular cluster in it's borders. One such object I have always been interested in is the open cluster NGC-1893 and the emission nebula that surrounds it, IC-410. The sky conditions at the time were quite poor, but when I put a narrow band nebula filter on the eyepiece regions of faint nebulosity appeared. The most prominent was a ring like patch with a darker center and spangled with stars.
While Orion is well known for the Messier objects M-42, M-42 and M-78, it has dozens of less well known objects that are worthy of study. One object I wanted to make the acquaintance of was the ninth magnitude open cluster NGC-2112. Fairly small and perhaps consisting of two dozen stars, it is an inconspicuous object amid the dense star fields and hordes of brighter nebulae and star clusters. It spans 11 arc-minutes and required 227X to distinguish from the surrounding star field.
The bright, rich and large open cluster M-35 is undeniably one of the finest object in the winter sky, and I have observed it many times over the years. It does however share the field of view with a much more massive and distant open cluster that is six times farther away from us than M-35. That star cluster lies some 2,800 light years away. It's some 100 million years old, and had a total population of at least 500 stars across an area about 25 light years across. NGC-2158 normally appears as a small fuzzy comet like spot some 15 arc-minutes away from the center of M-35 and lies at the enormous distance of at least 16,000 light years. To my amazement, it showed partial resolution into stars at my house on a good night, and resolved into a swarm of very faint stars at the club's darker sky site. This star cluster has an age of some 800 million years, the brightest Main Sequence stars having a spectral type of F0. Shining at magnitude 8.6 and an apparent size of 5 arc-minutes, NGC-2158 is worthy of close scrutiny for those with larger telescopes, and makes a nice showing together with M-35 in smaller instruments.
NGC-2420 is another ancient open cluster in Gemini, with a total population of at least 1,000 stars and an age of 1.7 billion years. It is also 3,000 light years from the plane of the Milky Way's disk and is 30 light years across. It's right now some 33,000 light years from the center of the Milky Way, placing it some 8,000 light years away from Earth. Shining at magnitude 8.3 and spanning 10 arc-minutes of sky, this massive and aged open cluster curiously has the same chemical composition of our Sun and Solar System. It readily resolved into stars through the 15-inch despite the rather bad skies that night, and doubtlessly would reveal it's nature to users of 8 and 10-inch telescopes under good skies at dark sites. Most open clusters disintegrate under the relentless gravitational forces of the Milky Way's disk, but NGC-2420's orbit around the galactic center and it's high mass enabled it to hold onto at least 1,000 of it's original compliment of stars. Many red-giant and helium burning stars exist in the star cluster, along with white dwarfs.
As winter gives way to spring, Ursa Major and it's swarms of galaxies near and far rise high into the sky as night falls. The entire constellation is riddled with every type and size of galaxy imaginable, so I opted to concentrate on the brighter ones in Ursa Major's head. NGC-2742 is fairly faint and large, with an obvious nuclear region and a slightly wooly halo at 181X. It is a spiral galaxy of type SC shining at magnitude 11.7 with an apparent size of 3 X 1.5 arc-minutes. It's oval outline is oriented almost exactly east to west. Overall, a nice example of a type-Sc spiral galaxy whose inclination is between face and edge-on. The galaxy NGC-2768 lies 40 arc-minutes away to the southeast.
NGC-2768 is another fairly bright Ursa Major galaxy I have observed before with smaller telescopes. This tenth magnitude object is 8. X 4.3 arc-minutes long and has a bright central core. Unlike NGC-2742 which is forming stars, this galaxy is a lenticular or disk shaped system dominated by old yellow and red stars. It is lacking in interstellar dust and gas from which new stars form, as a consequence it appears more featureless than it's neighbor through the telescope. It also has nearly the same orientation in the sky as NGC-2742.
NGC-2787 is a barred spiral galaxy shining at magnitude 10.9 and has an apparent size of 3 X 2 arc-minutes. This SB-O galaxy was small, oval and had a bright core, though I did not plainly see the central bar at 227X. I had a difficult time determining which way the galaxy was oriented as I made this sketch, perhaps because the bar is nearly at right angles to the rest of NGC-2787's featureless disk.
NGC-2810 is a small elliptical galaxy with a bright center but otherwise it appears as a featureless, circular glow. Shining at magnitude 12.3 and being only two arc-minutes across, this galaxy is one of the less impressive systems in Ursa Major at 227X. I had thought I glimpsed a star like nucleus in this galaxy, but its faintness and small apparent size is due to small size and or lying at an immense distance from Earth.
NGC-2880 is brighter than NGC-2810, shining at magnitude 11.6 and spanning 2 X 1.2 arc-minutes of sky. Like NGC-2768 however, this is a lenticular galaxy of Hubble classification SB-O. It shows it's oval outline and a brighter center, but is otherwise featureless due to the absence of spiral arms or star formation. It does however respond well to higher magnifications and stands out better against the sky due to the much higher surface brightness than NGC-2810.
NGC-2950 is an eleventh magnitude object that spans three arc-minutes in length. It lies next to a convenient guide star for those who star hop to objects. It is either a lenticular or a transitional system between a barred spiral and a lenticular galaxy. What appeared in the 15-inch at 227X was a fairly bright, oval object with a very bright central core. The halo around it was much fainter and the object's small apparent size enabled it to show up well through the worsening skies. Soon after observing this galaxy, it was clear the skies were about to give out. So I observed a few more objects, then took down and packed away the telescope for the trip home.

Sunday, February 2, 2014

Supernova in M-82

About two weeks ago, the brightest supernova in over 20 years has erupted in the nearby galaxy M-82, which is 12-million light years away in the constellation Ursa Major. I wanted to see it as soon as it appeared, but rain and clouds have moved in until three nights ago. When clear weather arrived, I loaded the 15-inch telescope into my car and drove to a darker site than my driveway.

Upon turning my telescope to M-82, I was immediately rewarded with success. There in the central region of the galaxy the supernova was glaringly apparent at magnitude 10.5 or so. It clearly occurred in a dusty region of the galaxy, which has dimmed the supernova by about two magnitudes. The supernova is a type 1A, which occurs when a white dwarf star accumulates so much mass from another star that it becomes unstable, collapses, then explodes from runaway nuclear fusion that spreads through the entire star in seconds. Most white dwarfs are mostly made of carbon and oxygen, so when nuclear fusion occurs in them those elements are rapidly transformed into other elements ranging from neon to nickel. The star was totally destroyed in the explosion and since the supernova actually occurred 12 million years ago, the star is in reality long gone. As for the galaxy itself, the dust lanes and bright regions across it's length were plainly visible through my telescope at 227X.

M-82 and its supernova weren't the only objects I observed that night. One object I stopped to look at was the bright open cluster NGC-1664 in Auriga. Large and bright, it is a fine sight in small and big telescopes. This star cluster is large and rich in bright and faint stars, with a curious kite or Ginko leaf shape. This open cluster has an apparent magnitude of 7.6 and an apparent size of 18 arc-minutes across.

Lepus the Hare has a number of moderately bright and faint galaxies, one of which is the nearly edge-on spiral NGC-1888. Small and moderately bright, this object has an oval outline.  Along one side there's a sharper border where one of the main dust lanes are. The nuclear region was fairly bright and prominent, but over all this galaxy was fairly dim, and hindered by the light dome from my city. This 12th magnitude galaxy is about 3 arc-minutes long and bear magnifying fairly well.

In Auriga lies the open cluster NGC-1893, which is surrounded by the faint emission nebula IC-410. I saw little of it mainly because I concentrated on the cluster and did not use my nebula filters to search it out. The star cluster itself is quite large, rich and appears to have a dark, starless void in it. Spanning 11 arc-minutes and shining at a overall magnitude of 7.5, NGC-1893 sports a rich population of both bright and faint stars.
NGC-2192 is a very different star cluster than NGC-1893 and 1664. While they consist of brighter, younger stars, NGC-2192 is composed of much older and fainter stars. Indeed it's impossible to see from a light polluted area because it fades into the surrounding star field. From a reasonably dark site it is easy to locate with a medium or large aperture telescope as a faint, oval collection of faint and very faint stars. NGC-2192 shines at a magnitude of 11 and an apparent size of 6 arc-minutes.
While known for it's nebulae and star clusters, Gemini also has it's share of moderately bright and faint galaxies. NGC-2339 is a SBbc spiral galaxy that shines at a magnitude of 11.6 and an apparent size of 2.7 by 2 arc-minutes. It is moderately faint with a weakly brighter central core and nearly oriented north to south. There is also a faint star in front of one end of the central bar. This is probably the brightest and easiest of Gemini's galaxies for amateurs to see.

NGC-2389 is another face-on spiral galaxy in Gemini with a classification of Sc. Much smaller and fainter than NGC-2339, this galaxy shines at magnitude 12.8 and an apparent size of 1.4 X 2 arc-minutes. Also visible was the nearby oval galaxy NGC-2388. Shining at magnitude 13.9 and a mere arc-minute long, this spiral galaxy is much harder to see, it took jiggling the telescope to confirm its reality.