Saturday, October 31, 2015

Summer giving way to fall

The humid, hot and hazy weather is finally giving way to cooler and clearer weather, at least between storm systems. Fall is normally the driest part of the year in my area, but that was not the case this year with a series of intense downpours that flooded my area. Once things dried out and a period of clear weather arrived, I drove out to the dark site with the 15-inch and began observing both favorite objects and others of interest that I haven't seen before.
NGC-6791 is an ancient and faint open cluster in Lyra which I have observed before but rarely have seen due to it's large apparent size and the faintness of it's stars. At a visual magnitude of 9.5 and an apparent size of 16-arc-minutes, this object is much fainter than it's apparent magnitude suggests. From a very dark site I've seen it as a mass of faint to very faint stars, which number in the thousands through my 10-inch. From the light polluted sites I normally use, it appears as a faint mist peppered with faint stars. It's quite easy to locate by star-hopping because there's two stars nearby that point out it's location.
In Pisces there's hordes of galaxies, but most are challenging to see at all in smaller telescopes. This quartet of galaxies however is easier to see than most, the brightest member on paper being the largest galaxy NGC-7782 which shines at magnitude 12.4. It shows a weak central brightening and was about 2 to 2.5 arc-minutes in length. The other members are all smaller but have bright cores. That combined with their much smaller apparent sizes actually makes them easier to pick out from the sky glow, even faint little NGC-7781 was spotted immediately. NGC-7779, has an apparent magnitude of 12.6, while NGC-7778 and NGC-7781 shine at magnitudes 12.7 and 14.2 respectively. Their apparent sizes of 1.6, 1, and .9-arc give all three a higher surface brightness than NGC-7782. This is a nice quartet of galaxies for a medium to large aperture telescope, with a fifth galaxy that was seen but not sketched just outside of the field of view. NGC-7780 is similar to NGC-7782 in magnitude and appearance. It lies just to the north of NGC-7782.
Over in Aries is another quartet of galaxies, made up of NGC-877, 871, 876 and 870, almost like a galactic "double-double" galaxy. However, I missed NGC-870 which is the faintest and smallest of the four. NGC-877 is the brightest, with a magnitude of 11.8 and an apparent size of 2.3 arc-minutes. It shows a very elongated, lens like outline and a bright central region, consistent with a barred-spiral galaxy nearly face on. NGC-876 is a tiny elongated object at a nearly right angle to its larger neighbor, and shines feebly at magnitude of 13.8, but because of it's tiny apparent size of 2.1 X .4 arc-minutes, the inner core of this edge on galaxy was readily visible, NGC-871 looked considerably fainter than NGC-877, with a sharp drop off in brightness along one side. The tiny and round galaxy NGC-870 lies nearby but remained invisible to me. NGC-871 shines at magnitude 13.2 and has an apparent size of  1.2 arc-minutes in length. It's oriented almost due north-south, with the southern end pointing towards NGC-870. That galaxy shines at magnitude 15.5 and is nearly stellar with an apparent size of about six arc seconds. If your skies are very dark and you have a large telescope, the galaxies UGC-1761 and FGC-270 also lie in the field, but they are even fainter than NGC-870.
Like Pisces, Pegasus is a rich hunting ground for anyone interested in observing galaxies. One lesser known but reasonably bright galaxy is the spiral galaxy NGC-7137. This relatively low surface brightness object was not difficult to find with the 15-inch due to it's apparent magnitude 12.7 and a apparent size of 1.6-arc minutes. This is a peculiar galaxy that has a round shape and it punctuated by bright knots in photographs with a bright outer ring. From dark sites a very large telescope would show interesting details in this galaxy, but under the rather poor seeing that night I did not try higher magnifications. It did appear just a little lumpy however,
NGC-976 is another Aries galaxy I had wanted to check out, and finally got the skies to do that.
It's fairly bright at magnitude 12.4 and it's small apparent size of 1.6 arc-minutes gives it a fairly high surface brightness. NGC-976 showed a strong brightening towards the center and an oval outline, with hints of patchiness where it's spiral arms are. It's Hubble classification of Sb makes it a twin of the Andromeda Galaxy, which is consistent with the large central brightening. This galaxy was well worth the effort to locate.
 
In addition to the objects above, I spent time gazing at M-31 and it's companions, M-33 and the face on spiral galaxy M-74 in Pisces. I also examines the Pisces galaxy NGC-182, and looked at the Veil Nebula. Since then the sky conditions have remained poor for observing deep sky objects. With luck, soon I will be able to observe them at the Deep South Regional Stargaze and put more of them onto paper.

Tuesday, September 29, 2015

Breaks in the weather

After a very cloudy, murky and rainy summer, even for the sub-tropical Gulf Coast, some breaks in the weather came my way. Two weeks ago I drove out to the darker site the local club uses for its members only stargazes, and found myself alone there. At first it looked like the weather was going to render the trip futile, but the sky conditions improved as the evening wore on. By 10 p.m. skies were as clear as I had seen them for months, and the Milky Way was clearly visible overhead. The Great Rift was apparent. Other deep sky objects such as the Andromeda Galaxy and the Lagoon Nebula were visible to the unaided eye, along with the very evident light pollution from my city and others around it. Nevertheless, the seeing was not unbearably bad for a night where a weather front had just passed by and the transparency was good. After setting up and waiting for darkness to fall, I initialized the digital setting circles began observing. It was a poor night to be looking at the moon and planets, but a good one for galaxies and nebulae.
 
I had a number of objects in mind for observation and or sketching that I haven't seen before, but most were too faint for the 15-inch under the sky conditions I normally have to work with. So I looked at many familiar object to take in the view and enjoy the first decent night that came along without a bright moon to wash out faint deep sky objects. One such object was the trio of galaxies NGC-7769, 7770, and 7771 in Pegasus. NGC-7769 and 7771 I've easily located with my 10-inch, but the much smaller and dimmer galaxy NGC-7770 went unseen until I turned my 15-inch on the trio. The brightest galaxy of the three is NGC-7769 at magnitude 12.1. It is a Sa or Sa-b spiral galaxy with a nearly round or somewhat elongated shape. NGC-7771 is at magnitude 12.3 with a highly elongated shape and a bright core. Faint little NGC-7770 is round and shines feebly at magnitude 13.6. Under poor skies it's a difficult object to see. 

 
Of the fifteen globular clusters discovered during a survey at the 48-inch Schmidt telescope at Mt. Palomar Observatory, Palomar 8 is by far the easiest other than Palomar 9 which is also known as NGC-6717. Faint, but fairly large, it has been spotted with small telescopes from dark sites. However from the light polluted area where I observe from, I have only found it with the 15-inch so far. The fact that even along the Gulf Coast, it doesn't get very high in the sky and unfortunately that means I was looking at it through a lot of light pollution, Still at 111X it was quickly located using my lap top and Sky Tools software, which interface with the Sky Commander digital setting circles I use. The globular cluster shows a weak central brightening, and at times it did seem to show hints of a few of its stars. While at the site, I tried my luck on the much fainter and smaller globular clusters Palomar 10 in Sagitta and Palomar 1 in Cepheus. Neither one was visible through my telescope, due to the brightness of the sky.
 
While at the site, I mostly looked at familiar objects that are soon to be out of sight, such as the Lagoon and Omega Nebulas, the globular clusters M-22, M-28 and M-55. The pair of globular clusters near the tip of the "spout" in Sagittarius, NGC-6522 and 6528 made a fine showing at 111X in the same field of view, as did the globular cluster NGC-6540 and the planetary nebula NGC-6445. I spent some time looking over the Veil and the Crescent Nebula in Cygnus, and spotted the open clusters King 10, 18 and 19 in Cepheus for the first time. The galaxy NGC-6946 and the open cluster NGC-6939 were a striking pair amid the dense star fields along the Milky Way. Soon the annual Deep South Regional Stargaze will be held, and I am preparing to attend this year. With luck, the weather this weekend will be good and I can revisit the summer Milky Way before turning my attention to the numerous fall galaxies in reach of my telescopes.

Saturday, June 13, 2015

Two comets and springtime galaxies

 
 
The past few months saw few opportunities for observing deep sky objects from darker sites than my driveway, so I concentrated on the moon, planets and bright deep sky objects observable from home. I was also experimenting with an inexpensive video camera recording close ups of the moon and planets. Although my telescopes do not track objects, I was able to record surprisingly good video imagery with the camera plugged into an inexpensive laptop computer. I will begin posting video clips once I learn how to edit the raw video files. It was not until last weekend did the weather cooperate when I could drive to darker skies. So I loaded the 15-inch into the car and set up at the airstrip as it grew dark and began the hunt.
 
 
Among the first objects to be observed was the now distant comet C2014Q2Lovejoy. Surprisingly it was still bright in the telescope and still showed a tail, although it was diffuse and a faint pseudo-nucleus was visible. Shining at magnitude 8.6, Lovejoy is still visible in small telescopes and large binoculars. The comet is still fairly well placed for observation because it's near Polaris, the North Star. Now at 2.6 astronomical units from Earth, time is running out to get our last looks at this long period comet. It's now 2.3 astronomical units from the Sun and thus passing through the inner asteroid belt, and that is causing the comet to fade. Soon it will only be visible to large professional telescopes before fading from view, never to return.
 
 
At any one time there's at least ten or twelve comets that might be accessible to amateur telescopes, even though most would be tough to see because they are in the glow of twilight or very faint. However the periodic comet 22P/Kopff is well placed for observation close to the bright galaxy M-61 in Virgo and is reasonably bright at 12th magnitude. It's no more difficult to see than many of the galaxies in the area, appearing as a round glow with a pseudo-nucleus in the center. This comet has an orbital period of 6.4 years and an inclination of 5 degrees, which keeps it close to the ecliptic and the influence of Jupiter's gravity. This comet is closing in on perihelion this October in the constellation Ophiuchus. reaching a magnitude of 9.5 at maximum. Soon thereafter it will be lost in the twilight.
 
 
This time of year is prime time for galaxies in the evening before the summer Milky Way rises high in the east, so I concentrated mainly on galaxies. Among them was the peculiar interacting galaxy NGC-4656 in Canes Venatici, the hunting dogs. NGC-4656 is interacting with NGC-4631 The Whale Galaxy and it's small elliptical companion NGC-4627. In this gravitational shoving match, NGC-4656 is clearly the worse for wear, because it's deformed into a hockey stick like shape. Its odd shape was quite evident through the 15-inch at 227X despite the hazy skies. NGC-4631 did show it's whale like shape with the small elliptical galaxy being the "calf." Both galaxies under good skies hardly need a 15-inch for a good view, an 8-inch will show both quite nicely, although I never seen the small elliptical companion to NGC-4631 through my 6-inch.
 
Other objects observed that night included M-51, the Whirlpool Galaxy and it lenticular companion NGC-5195. The distorted structure of both was visible at 227X. The face on spiral galaxy M-101 showed it's spiral arms faintly, and the galaxy M-108 displayed hints of the ragged dust clouds across it's body seen in photos. Nearby the planetary nebula M-97 revealed the central star and the two dark regions in it's disk through an O-III nebula filter.
 
I made the attempt to find the very remote Leo galaxy NGC-3196, a massive lenticular system that is close to 700 million light years from Earth. A search of the area turned up a "maybe"  but I'll have to revisit the area at a later time to confirm it. Other galaxies though were far easier to spot. NGC-4008, 4004, 4016 and 4017 were all located in quick succession. All were quite small and fairly faint, but not very difficult. They appeared as ovals or elongated objects with a bright central core. I was not certain if I saw any trace of NGC-3944, but NGC-3902 was a fairly large, faint glow with a weak central brightening. The pair of galaxies NGC-3713 and 3714 on the border between Ursa Major and Leo appears as faint ovals with brighter cores. These galaxies are bound to one another gravitationally and lie 300 million light years away from us.
 
I spent some time looking at Coma Berenices galaxies, starting with the Messier objects M-64, M-85, M-88, M-98, M-99 and M-100. The enormous black eye was apparent on M-64, while the others ranged from face-on to nearly edge on in orientation. Other galaxies I observed were the Coma Berenices Galaxy Cluster members NGC-4911, 4921 and 4923. NGC-4911 and 4921 appeared as ovals with brighter centers, NGC-4923 was a faint blur close to NGC-4921. In Bootes I observed the interacting galaxies NGC-5544 and NGC-5545, which together resembles an exclamation mark. Before taking down the telescope for the night, I looked at M-104 in Virgo, which displayed it's dust lane and very bright nucleus clearly. I also got very good views of Jupiter and Saturn. On Jupiter the Great Red Spot was transiting across the face of the planet, and on Saturn I glimpsed the Encke division in the outer A-ring. The moons Enceladus, Tethys, Rhea, Dione and Titan were also obvious without the need for using my computer to determine which is which. It has been months since I was able to get to darker skies for observing galaxies and nebulae, and I enjoyed the opportunity immensely.




Thursday, February 12, 2015

Lovejoy is here

The weather for the past few months was more often than not rainy, cloudy and sometimes windy, which made for fewer than usual opportunities to observe. When it was clear, it was also cold enough to make sketching at the telescope difficult. However, I did manage to seize a few good opportunities to observe a number of winter objects, Jupiter and the comet C/2014Q2 Lovejoy.
NGC-743 is one of dozens of less well known open clusters in Cassiopeia. Resembling a bevel square or "V," it shows up well even from home. Shining at magnitude 7 or so with an apparent size of 7 arc-minutes, it stands out well in a medium power eyepiece. It's easily visible from my driveway in the middle of a metropolitan area.
Another winter object I observed many times is the planetary nebula IC-2149 in Auriga. Bright and very small, it require high magnifications to make out it's 10 X 15 arc-second disk readily. IC-2149's oval disk also showed two brighter zones aligned with the long axis that flank the central star. The total magnitude of 10.7 makes it visible in small telescopes and from light polluted areas. A fine object for high magnifications and nights of steady seeing.
Comet C/2014Q2 Lovejoy was deep in the southern sky until December and out of reach of northern amateur astronomers. Once it moved into central Puppis it came into view from my house. Soon after that it was high in the evening sky and moving towards Taurus and Perseus.
From the local club's darker site, the comet clearly showed a tail and occupied much of the field of view through the 24mm Explore Scientific 82 degree eyepiece. At home though much of the outer coma was not visible. At home through the 15-inch Lovejoy was a very diffuse object with a small bright inner region surrounding a very bright pseudo-nucleus where the nucleus is.
Even though my 6-inch Lovejoy was bright and easy to find. Moreover I saw it with the unaided eye from the club's darker sky site and even from my front yard. Lovejoy is now receding from us and fading as it goes. At present it's at 5th magnitude and about 90 million miles from Earth. Therefore if you haven't got a look at it yet, look for it now before it fades to invisibility and becomes lost in the twilight.