FAQs

Here are a few of the most frequently asked questions we receive. If these don't help you answer your question, please contact us and we will get back to you (and may add your question to the list here!).

About the CIOC

Q. What is the CIOC?
A. The Comet ISON Observing Campaign (CIOC) is a team of comet scientists and observers that is dedicated to encouraging NASA's ground and space-based observatories in obtaining as many observations of Comet ISON as is possible. The Campaign is also highly encouraging of non-NASA entities (ground and space-based), and any/all other professional and amateur astronomers in doing the same.

Q. What exactly does the CIOC Team do?
A. The CIOC Team Members actively encourage and facilitate observations of comet ISON from all possible observatories. This means several things, but primarily that we raise awareness among major observatories of the potential science benefits to studying ISON, encourage them to take any observations that are possible/feasible for them to do, and allocate as much telescope time as their resources allow. We also offer scientific information on comets and guidance in the types of observations needed; coordinate the cometary community in focussing their efforts; encourage data sharing and collaboration; and keep the astronomical community informed on the latest status of Comet ISON.

Q. What DOESN'T the CIOC do?
A. We do not collect, store or archive anyone's data. Images that observers take will remain their own data (or that of the corresponding observatory), and it is up to those observers or observatories to share or archive the images. Aside from important news items and the occasional “pretty picture”, the CIOC and this website will NOT be storing large volumes of images. We do expect to be posting new news relatively frequently during the months of Oct – Dec 2013, when new observations will be happening rapidly back-to-back as the comet approaches Mars, Mercury, the Sun, and Earth.

Q. When did the Campaign begin? When will it end?
A. The formation of an observing campaign for comet ISON was suggested by NASA at the January 2013 Small Bodies Astronomy Group (SBAG) meeting #8. The CIOC Team was assembled shortly after that and the CIOC announced in February 2013.
There is no formal end date to the Campaign, but we will wind down the observational activities once the comet begins to fade significantly in perhaps late spring/early summer 2014. Much of this depends on the comet's behavior, however. Should it fade out earlier than this then we will scale down our activities accordingly. Once the comet is no longer a major science target, we will move into a data analysis phase where we'll be encouraging data sharing and collection, and the sharing of results, etc.

Q. Is there a mailing list I can subscribe to? Where can I get "breaking news" about Comet ISON?
A. We don't yet have a mailing list but that is something we are looking into, so stay tuned to this website for that. As for breaking news, you can bookmark or follow @SungrazerComets (aka CIOC Team member Karl Battams) on Twitter. Anything new and exciting about ISON will certainly be posted on that feed, as well as announcements of new blog posts, light-curve updates, etc.

About Comet ISON

Q. How big is Comet ISON?
A. We don't have a definite figure on this yet, but we do at least have a range. Observations from the Hubble Space Telescope put an upper limit of about 2 kilometers (1.2 miles) for the radius of Comet ISON's nucleus, while observations from the Spitzer Space Telescope indicate that ISON's nucleus has to be at least 200-meters (0.12 miles) in diameter. So we we know that it's somewhere in this range, which makes it a somewhat smaller than average to average sized comet.

Q. How bright will Comet ISON get?
A. If we could answer this with certainty, we would also be able to give you next week's winning lottery numbers! Even though the comet continues to brighten, we simply do not know yet how bright it will be, but right now we still think it might briefly reach negative magnitudes in the hours surrounding its closest approach to the Sun.

Q. How bright is Comet ISON right now?
A. Every week or so we are updating our "light-curve" for Comet ISON, which you can find on the Comet ISON "Current Status" page.

Q. What is so special about Comet ISON?
A. In many respects, Comet ISON is much like many of the few thousand comets we already know of. It's a loosely-packed mixture of dust and gasses, trapped in a low-density iceball. It's not even a very big comet (see above). But there are two very unique aspects to it: 1. It is a Sungrazing Comet; and 2. It is fresh from the Oort Cloud. The combination of these two features makes ISON a unique comet and thus an observing target rich with scientific potential.

Q. Where is ISON in the sky right now?
A. Obviously this question is time dependent... At time of writing (late Sep/early Oct 2013), ISON is not naked eye visible, and thus finder charts are not really useful. It is, however, visible in moderate-sized telescopes for observers with clear skies, but to locate it you will definitely need to refer to the Minor Planet Center's ephemeris for comet ISON. If/when comet ISON becomes naked-eye visible then we will certainly post finder charts on the website.

Q. When will ISON be visible to me in the sky?
A. First, this depends on the extent to which ISON brightens up, and assumes that it actually survives perihelion! Elsewhere on this site we have outlined the possible outcomes for the comet, so with those in mind we will assume for the purposes of the FAQ that ISON does actually perform at least reasonably well. In that case, most observers should hopefully be able to get at least a glimpse of it in late October before it begins to get too close to the Sun. Viewing it during this period will require at least binoculars, however. Naked eye visibility will hopefully happen in the weeks immediately following perihelion (it's closest point to the Sun), where Northern Hemisphere observers in particular should be able to see it in early December. We do not have any viewing charts on this site yet, but point you to amateur astronomer and blogger Stuart Atkinson's ISON Atlas for December 2013, which gives some very nice charts for when and where to see ISON.

Q. Will ISON survive past the Sun?
A. When the CIOC Team met in August we had an informal vote amongst our group as to whether we thought ISON would survive passage past the Sun. We were more-or-less divided right down the middle, and again we have no choice but to say "we don't know". Comet ISON is certainly extremely close to what astronomers call the Roche Limit, which is the distance at which a soild body can reach a massive gravitational object (i.e. the Sun) before that intense gravitational field literally pulls the object apart. The Roche Limit can not be applied directly to comets; it assumes a somewhat solid body, and comets, much more like fluffy dirty snowballs, are anything but solid. When we factor in ISON's predicted density and make assumptions about its structural "strength" we find that it sits almost exactly at the Roche Limit, which means that this really could go either way and neither outcome would be a surprise to us.

Q. Is ISON a danger to Earth? Can it change direction and hit Earth?
A. Some people might snicker or sneer at this question but it's by far the most frequent question we receive, and there's really nothing wrong with asking it. So, for the record, Comet ISON is not going to get anywhere close to being a threat to Earth in any way whatsoever. It is on a very predictable path through space, and nothing within the laws of physics will move it out of that path. (Also, as much as we in the CIOC love studying comets, if we truly thought one was going to hit the Earth then there are several things on our personal "Things To Do Before Comet Apocalypse" lists that would take precedence over writing FAQs and blog posts!)

Observing Comet ISON

Q. When will be the best time to view Comet ISON?
A. Assuming it survives in some form or another, Comet ISON should be briefly visible to many observers in late October and early November, but the greatest potential for viewing -- including naked eye viewing -- will be in early to mid-December.

Q. Where in the sky will the comet be?
A. In general, in the West to WNW right after sunset. We don't yet have sky charts on this web site so instead point you to amateur astronomer and blogger Stuart Atkinson's ISON Atlas, which gives some very nice charts for when and where to see ISON during each of the next few months.

Q. Are there any locations on Earth that will be better than others for viewing ISON?
A. If you have access to some nice tall mountains, that's a huge help! But in general comet ISON will be much better for Northern Hemisphere observers than those in the Southern Hemisphere. (The latter have been more than spoiled over the past few years with Comet McNaught and Lovejoy, to name but a couple, so the North was due its turn!)

Sungrazing Comets

Q. What is a Sungrazing Comet?
A. A Sungrazing Comet is a comet that gets so close to the Sun it actually grazes its outer atmosphere (called the 'solar corona'). There is no formal definition of how close a comet needs to get to the Sun in order to be called a "Sungrazer", but the CIOC's Matthew Knight did address this in an earlier blog post.

Q. How many Sungrazing Comets do we know of?
A. Prior to 1995, there were maybe a dozen or two confirmed Sungrazing comets. Since that time, however, the ESA/NASA SOHO satellite has been operational, and it's "coronagraph" telescope has enabled amateur astronomers and citizen scientists to discover over 2,500 previously unknown comets! In fact Sungrazing comets account for about half of all known comets for which we have orbits!

Q. Is a Sungrazing Comet made of different material than a "regular" comet?
A. No, not at all. All comet's have slightly different compositions, sizes, densities, etc, but there is nothing unique about Sungrazers in this respect. They just happen to be on an orbit that takes them extremely close to the Sun.

Miscellaneous Questions

Q. Where are the latest NASA images of Comet ISON?
A. Many of you have been very attentive in paying attention to the observing calendar that we have posted. But we want to remind folks of a couple of points:
1) The CIOC is just a coordinating group. We have absolutely no control over what each facility, whether space or ground-based, releases to the public. Most of the facilities also have some restrictions as detailed in a previous blog post and so might not yet have images to release! But, in general, you really should contact those facilities about their images.
2) It takes time to get the data. While ground-based facilities have continuous contact, with space-based assets, we may need to wait for the data to first get downloaded. Unfortunately, it doesn't always happen right away, because communicating with space assets is an expensive and very limited resource. Priority is given to current/active missions. Some of the space assets being utilized completed their prime missions a long time ago and are not considered active, so they are lower in the queue for downloading data.
3) The dates in the calendar are in most case just possible observing windows and proposed observing dates and do not guarantee that ISON will actually get observed. We will try to follow up with some of the projects for them to give updated information (whether or not they got to observe and collected data; links, if they did,...), but you should regard those dates as just possible observations and NOT guaranteed observations. Many things can and sometimes do go wrong. For ground-based facilities, weather can wipe out an entire observing run. For space-based assets, you have the problem of things finally breaking on older spacecraft.

Q. Can I take quotes or images from this website?
A. This website contains exclusively public-domain information, and we stand by all the content we put on here. Thus we do not prohibit individuals from taking quotes and images from the site. What we do ask is that anywhere you quote us, you also include a link back to the page from which the quote is taken. If quoting from a blog post then we request you credit the author of that blog post, and if you quote from a general information page you can just credit us as the CIOC. Please do not call us”NASA”! We are not NASA (even though we like them a lot). If you use any of the images that are on the website, be sure to give appropriate credit to the project/observers that took those images. And finally, if you do "quote mine" from the site, we would ask that you do not quote us out of context or try and change the overall meaning or intent of the page from which the quote was taken.

Q. Where can I find more information about participating in the CIOC?
A. Our resources page is a great place to start. In particular note the links to the Facebook group and the Amateur Observer's Program. We would also recommend you watch the presentations given at the end of Day 1 of the Comet ISON Observer's Workshop (the last video in the list: "Professional-Amateur Synergy").

Do you have a burning question about Comet ISON, the CIOC, or something along the same lines as the above? Contact us! We are trying our best to respond to every question, and several previous questions have helped inspire this FAQ page.