Frequently Asked Questions

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 Coordinated Investigations Of Comets (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 C/2013 A1 (Siding Spring) 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 Siding Spring from all possible observatories. This means several things, but primarily that we raise awareness among major observatories of the potential science benefits to studying Siding Spring, 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 Siding Spring.

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 Aug – Oct 2014, when new observations will be happening rapidly back-to-back as the comet approaches and passes Mars.

Q. When did the Campaign begin? When will it end?
A. The formation of an observing campaign for comet ISON, the previous CIOC focus, 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 Siding Spring passes significantly by Mars in Winter 2014/2015. 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 Siding Spring?
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 Siding Spring will certainly be posted on that feed, as well as announcements of new blog posts, light-curve updates, etc.

About Comet Siding Spring [aka Comet C/2013 A1 (Siding Spring)]

Q. How big is Comet Siding Spring?
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 10 kilometers (6 miles) for the radius of Comet Siding Spring's nucleus.

Q. How bright will Comet Siding Spring 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 magnitude +9 in mid-September 2014 as viewed from Earth. This is bright enough to be seen using binoculars or a backyard telescope. It will likely be significantly brighter than this for an observer on Mars, although note that because it will be so close to Mars the brightness will be spread out over a large area and the average surface brightness may not be much different.

Q. How bright is Comet Siding Spring right now?
A. On 2/20/2014, when this was written, amateur astronomers have found the comet to be magnitude ~14. Every week or so we are updating our "light-curve" for Comet Siding Spring, which you can find on the Comet Siding Spring "Current Status" page.

Q. What is so special about Comet Siding Spring?
A. In many respects, Comet Siding Spring 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 passing closer to Mars than any comet has by the Earth in recorded history; and 2. It is fresh from the Oort Cloud. The combination of these two features makes Siding Spring a unique comet and thus an observing target rich with scientific potential.

Q. Where is Siding Spring in the sky right now?
A. Obviously this question is time dependent... At time of writing (late Feb 2014), Siding Spring is not naked eye visible, and thus finder charts are not really useful. It has also started to go quite southerly, so observers in the Northern Hemisphere will have a tough time finding it. For Southern Hemisphere observers, though, It is currently faintly visible in moderate-sized telescopes for observers with clear skies. To locate it you will definitely need to refer to the Minor Planet Center's ephemeris for comet Siding Spring. If/when comet Siding Spring becomes naked-eye visible then we will certainly post finder charts on the website.

Q. Will Siding Spring survive past the Sun?
A. Comet Siding Spring will not be coming very close to the Sun during this perihelion passage, and we expect it will survive to head back out of the inner solar system in Spring 2015. However, there is always some small chance (perhaps a few percent) that a comet will disintegrate unexpectedly, so don't hold us to this prediction!

Q. Is Siding Spring 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 Siding Spring 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 Siding Spring

Q. When will be the best time to view comet Siding Spring?
A. As discussed above, Siding Spring is not expected to become a naked eye comet. Its high scientific interest comes primarily from its unprecedented close approach to Mars. If you want to see it with your own eye, your best bet is to find a star party at your local astronomy club sometime in the early fall of 2014, when it should be visible with a small telescope. Any eye-popping close up images from spacecraft at Mars will come around October 19, 2014. We will be sure to direct you to the best pictures as soon as they become available.

Q. Where in the sky will the comet be?
A. We have created several observability plots that will guide you in terms of whether it will even be possible to observe the comet. Obviously by mid-October, the comet will be extremely close in the sky to Mars. This will make it very difficult to see as it's not predicted to be a particularly bright comet, and will certainly be much fainter than the planet itself. Nonetheless we encourage observers to attempt imaging. Unlike with comet ISON, where there was real physical risk involved with observing a comet near the Sun, there is no such concern with comet Siding Spring. Worst-case scenario is you'll get an over-exposed shot of Mars.

Q. Are there any locations on Earth that will be better than others for viewing Siding Spring?
A. If you have access to some nice tall mountains, that's a huge help! But in general comet Siding Spring will be much better for Southern Hemisphere observers than those in the Northern Hemisphere. In the weeks leading up to its close approach to Mars, Siding Spring will move rapidly northward. In early September it will barely be visible to northern hemisphere observers, but by the time of its closest approach to Mars, Siding Spring should be visible to most observers around the world. Again, refer to our observability plots for guidance here.

Miscellaneous Questions

Q. What danger is there, if any, to the spacecraft we have on and around Mars? Will rocks from the comet hit and damage those spacecraft?
A. This is really one of the very biggest questions surrounding comet Siding Spring, and was a primary motivation in forming this observing campaign. For a while there was genuine concern that spacecraft could be at risk from debris trailing behind the comet. Now, however, it looks like the spacecraft will probably be OK. Based on a report made in June 2014, we have a blog post detailing the risk assessment for our Martian fleet.

Q. Where are the latest NASA images of comet Siding Spring?
A. For the ISON Campaign, many of you were very attentive in paying attention to the observing calendar that we had posted and we had lots of questions along the lines of "Spaceraft/Observatory xyz took data yesterday. Where are the images??". 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 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 Siding Spring 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. If in doubt, CONTACT US!

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 Padma's Facebook group and Elizabeth's Amateur Observer's Program.