About the charts

These charts were created using the fantastic SKY SAFARI app for the Android operating system. I downloaded it into my phone just a couple of days after getting it, and am knocked out by it every day. It’s like they found a way to lure the night sky into a box then gave everyone who wanted one a copy. Just brilliant!

Here’s what they show…

Looks good! BUT…


These images are to be used and considered as FINDER CHARTS ONLY. The planetarium programs and Android apps they were created with cannot EVER accurately simulate the true appearance of a comet in advance, because no-one can, not really. All these images do is provide you with a guide where to look, and when, ok? They all show strikingly long tails, but DON’T TAKE THE TAIL LENGTH TOO SERIOUSLY! The tail angle on each image is correct, but a) that only represents the ion or “gas” tail of the comet in question, consisting of material blown directly away from the comet nucleus by the solar wind, and b) the comets’ dust tails aren’t shown because their length and appearance simply can’t be calculated either in advance or by this software. PANSTARRS and ISON are both likely to have extensive and curved dust tails which aren’t shown on my charts. And pleasenote that the tail lengths shown on the images is not to be trusted too much either; it’s just drawn in by the software to represent “a comet tail”, with some attempt to simulate its possible length. Honestly, just use these images on these pages as a rough guide to where to look for these comets in 2013, ok?

Also, please bear in mind…

* They’re created for MY observing latitude, in the north of England, which is around 55 deg N. So they might not be accurate for you.

* We really have NO IDEA what this comet (or PANSTARRS, to a lesser degree) is going to do as it nears then whips around the Sun. These pics are simply designed to show you WHERE it will be, not what it will look like, OK?!?! šŸ™‚

Having said all that, just go play with the pics.. and look forward to what could be an AMAZING show at the end of 2013…!!

NOTE: It’s important to say again that these charts are for observers living in the northern hemisphere, specifically at mid- to high latitudes, because that’s where I live. If you live too far away from that area, they probably won’t be much use to you. But if you have access to an astronomy planetarium program you can easily generate your own charts. And Android phone users can download the SKY SAFARI app which already has Comet ISON in its database. And if you live in the southern hemisphere, these charts will be utterly useless, obviously – but if you (yes, you reading this!) want to generate some finder charts for your part of the world, and send them to me, I’ll happily put them up for everyone to see and use. But I won’t be doing it myself.

3 Responses to “About the charts”

  1. Great work, thanks!

  2. Note that the tail direction calculated here is for the straight gas tail – the usually much more prominent and spectacular dust tail (that turned McNaught and Lovejoy into Great Comets) often points to a completely different direction plus can fan out over a wide angle. Modelling its shape beforehand is next to impossible, though, because both the dust particle size distribution and temporal development of dust production would have to be known. Thus there doesn’t seem to be any software around that even tries to show what a dust tail may look like.

    • Thanks for that, some very good points. Looking forward to following this comet, and its story, as time passes…

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