Interest Areas: Visual Observation
Visual Challenge Object May 2020 - NGC 4567/8
Posted on April 8, 2021
NGC 4567 and NGC 4568 are a pair of spiral galaxies in the Virgo cluster of galaxies that are in the beginning stages of collision with one another. They were discovered by William Herschel in 1784. They were first referred to as the “Siamese Twins” by 19th century astronomer L.S. Copeland. They do not show any actual visual evidence of interaction and it was once thought they may just be a line-of-sight alignment, but 21st century studies using infrared data are beginning to see evidence that the galaxies are truly interacting.
Visually, the galaxies are both around 11th magnitude and so should be visible in a modest telescope from dark skies. They do not show any particularly notable individual details; it’s really their proximity to each other that makes the view. At lower magnifications they will appear as a very small double oval, likely sharing the field of view with the brighter galaxies M58 and NGC 4564. My recent log entry for these galaxies is as follows:
16” f/4.5 reflector at 203x
Two elongated ovals joined at one end; the long axes of each galaxy form about a 60 degree angle to one another; did not note any nuclear concentration in either galaxy; fairly evenly bright to the edges.
To locate the Siamese Twins, first locate the constellations of Leo and Virgo. The heart of the Virgo galaxy cluster is located between Denebola (β Leonis, the lion’s tail) and Vindemiatrix (ε Virginis, the hand of Virgo). Then locate the fainter star ρ Virginis to the east-southeast of Vindemiatrix (ρ is still a naked-eye star at our Dark Site). From there you can hop slightly northeast to the considerably bright galaxy M58. From M58, NGC 4564 is just north of it, and the twins then just north of 4564. At 61x with an 82 degree apparent field eyepiece, I could fit all four galaxies within the same field of view. Your results may vary with your equipment, but the point is that these galaxies are not far apart. See the charts below for more assistance in locating these objects.
The HAS VSIG would love to hear about your own visual observations of NGC 4567 and 4568. Send them to me at [email protected] or just share them to the VSIG list server (contact me to subscribe to that list also).
Visual Challenge Object April 2020 - NGC 3893/3896
Posted on April 8, 2021
The purpose of the visual challenge object is to encourage visual observation and to help each other improve our observational skills. It will help us reach this goal by comparing our observations, so please share your observations with the VSIG.
During April, Ursa Major will be high in the sky over Polaris. There are many cataloged galaxies in Ursa Major's boundaries, giving us lots of targets to hunt down and observe. As a visual challenge, the pair NGC-3893/3896 is of interest. William Herschel discovered both galaxies in the spring of 1788. The primary, more extensive of the pair, is NGC 3893. It is a face-on spiral galaxy about 55 million light-years away and is 93,000 light-years across. It has a visual magnitude of 10.7, making it readily visible in small aperature scopes. NGC 3893 is 4.4 arcmin in diameter, for reference that would be half the length of M82. This gives you insight as to how it will appear in your eyepiece; consider observing M82 first to get a perspective with the eyepiece you plan to use. You will find this galaxy pair by moving south along a line from Phecda to one degree north of Chi Ursa Major, the first star in the rear legs of the great bear. There are two predominant spiral arms with uneven brightness due to high surface brightness and numerous areas of emission nebulosity. Look closely to detect that it is a barred spiral. The other of the pair, NGC 3896, is much smaller and dimmer and will take effort to observe. NGC 3896 is only 3.3 arcmins separated from the more massive NGC 3893. Some studies suggest what we see as NGC 3896 is the remint of a galaxy that had previously passed through NGC 3896. Professionals with access to large telescopes have detected a faint trail interaction between the two.
Let us hope for an excellent dark sky soon, and please put this galaxy pair high on your observing list.
- Ed Fraini
Visual Challenge Object March 2020 - NGC 3628
Posted on March 7, 2020
Since the upcoming new moon is Messier Marathon time, I decided this latest observing challenge ought to be an object that won’t take you too far away from the Messiers. So, I introduce you to NGC 3628, the third member of the famed “Leo Trio” which also includes Messier objects M65 and M66. NGC 3628 is somewhat fainter than the two Messiers, but still probably could have been bright enough for Messier to view, though there is no record of him observing it. Instead, 3628 was discovered by William Herschel in 1784, four years after Messier’s discovery of the other two galaxies. Though it is the faintest of the three galaxies, 3628 is probably the most visually interesting. It is edge-on to us, with a very prominent dust lane. It is also quite irregular in shape, giving us insight into a violent past for the galaxy, likely a past interaction with the other two galaxies. You can find 3628, along with M65 and M66, about halfway in between Theta (θ) and Iota (ι) Leonis.
The HAS VSIG would love to hear about your own visual observations of NGC 3628. Send them to me at [email protected] or just share them to the VSIG list server (contact me to subscribe to that list also).
Visual Challenge Object Feb 2020 - NGC 2261
Posted on January 29, 2020
NGC 2261 – Hubble’s Variable Nebula
NGC 2261 is a bright diffuse nebula in the constellation Monoceros. It was discovered by William Herschel in 1783. It became quite famous in the early 20th century as Edwin Hubble and others observed the object showing very different appearances in different photographs. It is now theorized these variations are changes in the shadows cast by dust clouds around the embedded star R Monocerotis. The nebula was also the subject of the very first image taken by the 200-inch telescope at Palomar Observatory in 1949.
Somehow in all my years of observing, I had not managed to get a look at NGC 2261 until just this Sunday, and I wish I had done so sooner. It is a lovely object, definitely worth coming back to. It is around 2 arcminutes across in size, so it is large enough to be noticed easily at low power, but small enough to want to use high power to examine it in detail. I made my observation with my trusty 16”, but don’t worry; it is bright enough that it should be easily visible from our Dark Site in considerably smaller telescopes. My log entry is as follows:
Transparency very good
16” f/4.5 reflector at 131x
Cone-shaped or fan-shaped nebula; tip points to the south and is starlike; surprisingly bright; seems slightly brighter on the edges of the fan than in the center; this effect is exaggerated when an OIII filter is used, though the overall response to the filter is not very good
The HAS VSIG would love to hear about your own visual observations of NGC 2261. Send them to me at [email protected] or just share them to the VSIG list server (contact me to subscribe to that list also).
What’s Up, Houston – September 2018
Posted on September 2, 2018
By Joe Khalaf, Vice President and Outreach Chairperson – Houston Astronomical Society
Welcome to the first edition of What’s Up, Houston. This will be a monthly article to highlight some of the neat things those of us living in the Houston area can see by simply looking up. Some of these items will require “looking up” with binoculars or a telescope for the best views, so if you don’t own either of those, be sure to look for an upcoming outreach event by the Houston Astronomical Society to try and catch a glimpse of what the heavens above have to offer.
Though we’ve passed opposition for Mars, Jupiter, and Saturn, September is still a great time to observe these planets during the evening and night times. For those who don’t know, opposition is when a planet with an orbit further away from the sun than ours (basically, every planet except Mercury and Venus), happens to lie on the opposite side of the sky from the sun. This also happens to coincide closely to the closest approach that planet has to earth. Subsequently, these planets appear biggest and brightest around these times. These three planets, as well as Venus, make for a great set of targets for telescopes and binoculars.
Looking west/southwest, bright Venus lingers over the horizon for about an hour after sunset, then sets for the rest of the night. Because Venus is an “inferior” planet (i.e., its orbit lies between the earth’s orbit and the sun), it’s shape often mimics that of the moon – with multiple phases, including thing crescents and “half” Venuses.
As seen from Houston on September 7, 2018 @ 7:00PM Image courtesy of Stellarium
Moving to the east, we run across Jupiter – king of the planets. Even a modest pair of binoculars can reveal up to four Jovian moons, but through a telescope is where Jupiter really shines. Dynamic Jupiter often revels great atmospheric features, including several colors bands and storms, but keep an eye out for any shadows being cast on the upper cloud layers by transiting moons.
Move further east and we run across Saturn. Through a telescope, we see Saturn’s rings facing us favorably for observations. The rings always look Those with a big enough telescope and good conditions should be able to see the Cassini Division, a dark line separating the outermost large A ring and the inner B ring.
Lastly, as we move even further east, we see ruddy, orange Mars hanging like a beacon in the night. This most recent Mars opposition brought the red planet closer to the earth than it’s been since 2003, and it won’t be as close as it was then until the 2035 opposition.
While Mars has certainly shrunk a bit from that opposition back at the end of June, it’s still a great time to go out and observe the planet. During opposition, a global dust storm engulfed Mars, making it difficult – if not impossible – to see any surface features. Well, that storm has died down a bit and making out surface features, such as the polar ice caps, Valles Marineris – one of the longest and deepest canyons in the solar system, and Mons Olympus – the tallest volcano in our solar system.
That’s just a small sample of what’s up in Houston this month. If you get a chance, head outside and look up, or even better, join the Houston Astronomical Society at a public outreach event and take a look through our telescopes. Until then, may you have clear skies!
Science Hobbyists Needed for a National Study
Posted on December 27, 2012
This may be of interest to some club members:
Are you a science hobbyist? We need your help with a new National Science Foundation sponsored research study that will investigate the characteristics and educational experiences of people who are active in science hobbies. More and more people are engaging in science hobbies; schools and science centers would like to know more about the characteristics of science hobbyists and how these organizations might better support hobbyists’ networking and education.
What will happen if you take part in the study? The information gained from this research can help science educators and researchers understand how to better teach science in schools and museums, and how to design better community-based science programs. Participation in this study is voluntary. Information you provide will be anonymous. If you complete the survey, you may elect to enter a drawing for a $100 Target gift card.
Dr. Gail Jones
North Carolina State University
The Art and Science of Visual Astronomical Observations
Posted on August 3, 2012
HAS Program Chair and Master Observer Brian Cudnik has graciously made his new eBook available for complimentary download right here on the HAS Website. It's titled "The Art and Science of Visual Astronomical Observations" and it's a great homage to some of the awe-inspiring aspects of observing at the eyepiece. It's also chocked full of practical techniques for observing and suggestions for how visual observers can contribute to the science of astronomy. In Brian's own words...
The purpose of this book is to provide the visual astronomer, especially the beginner, a greater sense of appreciation of each object he or she observes. In addition, I want to instill a greater sense of wonder for the universe as a whole, to discover for oneself one‘s place in the universe and the privilege to be able to contemplate these ideas. Most of the chapters in this book will be divided into two parts, the “art” (named―“appreciation”) section and the “science” (or “application”) section. You may say, “Sure it may be just a ‘white dot’, but consider what is hidden in that ‘white dot’…”; I want to help with the second by discussing the physical nature of the ‘white dot’, I hope to stimulate observers’ interests to keep looking. This is the “art/appreciation” portion of the book, which also seeks to share my own passion for these things. The “science/application” part of the book outlines how amateurs who either cannot afford the sophisticated equipment becoming more widely available, or just prefer to use their own eyes to view celestial objects, can make a contribution to astronomy as a science.
More on the Transit of Venus
Posted on June 1, 2012
Jim Wessel of the Johnson Space Center club was kind enough to share this great presentation on the imminent Transit of Venus (June 5th, don't miss it!). You'll need PowerPoint to view this...check it out.
Also, the NASA Space Place Team has posted a fun fact page with 'more about this special kind of eclipse and how to view it safely at the new Venus transit'.
The Faintest Objects Visible to the Naked Eye
Posted on January 22, 2012
Observing Forms and Templates from Jeremy Perez
Posted on October 1, 2011
In addition to an extensive gallery of incredible sketches, this site offers some excellent observing templates available for download. Check them out!