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Old 06-02-2013, 05:31 PM
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Suzy
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Location: Brisbane, Australia.
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So You Want To See Comet Lemmon And You Don't Know How To?

How to find Comet (C2012) F6 Lemmon with binoculars or small telescopes just by using these easy directions.

Comet Lemmon is such a fabulous comet to observe at the moment- I really hope as many people as possible will get see it. Which is why I've done this little article- in the hope that it will be of some help to people who are new or inexperienced to this hobby, so they too can look up & enjoy this comet.


First of all:

A clear sky will give a better view- if clouds are visible either side of it, it may appear fainter (unless of course the clouds cover it!). That's the experience I've been having anyway.


A moonless night will give you a better view. Keep an eye on the moon's rise and set times. See here.


You will need to make sure that the Southern Cross is high enough & visible away from obstacles so you can measure with your hand the 22 degree distance to Octans from alpha Crucis.
Have a look here on how to do it: HOW TO MEASURE THE SKY WITH YOUR HAND.
Using this method, you need to close one eye and hold out your outstretched hand.



So let’s start star hopping now.

Click image for larger version

Name:	Comet Lemon Chart by Stu.jpg
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Size:	81.6 KB
ID:	132001 (look further down this thread for updated screen grab maps- thanks guys).


Look south.


Orient this map to suit your sky (Stu, I hope you don't mind me using your screen grab!).
Find the Southern Cross and head to alpha Crucis- it’s the brightest star there sitting at the bottom of the cross on its right.


Now locate the next group of stars beside it- you’ll see a group of stars in a sort of X shape- that’s Musca. Look for the brightest star which is alpha Muscae sitting in the middle. Hop to that in a straight line from alpha crucis (6 degrees).


Next we head into Octans where the comet is currently travelling through. On the map, Octans is a triangle shaped constellation. Delta Octantis marks the tip of the triangle.


Now it gets just a wee bit tricky but certainly not difficult. Continuing this straight line into the south celestial pole which lays here, measure 15 degrees from alpha Muscae to find delta Octantis. This is where we need to be right now to look for the comet. We’re looking for a faint star yellow star(is faint in light pollution) named delta Octantis. In binoculars it’s quite obvious in the star field as as a bright, yellow star. Depending on your sky, you may have to (as I do) let your eyes dark adapt for 10mins or so and stare out that area and it should pop out.


If you’re using binoculars, line up the bridge of the binocular onto delta Octantis. Bring your eyes to the binocular and you should have the star within view.


Now slowly cruise a bit down and to the right. Today (5th Feb) it’s sitting 3 degrees away from delta Octantis, on the 7th Feb. It will be 7 degrees away from it, just to give you an idea of how fast it’s moving. As long as you follow that straight line in the following days and perhaps note the star field or asterisms to jog your memory, you’ll have a good idea where to keep looking for it.


On the 10th Feb. It’ll be sitting right next to (within one deg) of beta Octantis, which is the star bottom right of the triangle. See what I mean about following that straight line?


What will it look like? Through binoculars it looks very much like a globular cluster. It’s very apparent, and it will look like a hazy ball. No tail is visible at the moment thru binoculars and perhaps unlikely through a small scope either, but it’s sheer size will still give you that awe factor. No, you won’t see the green colour (photographs show colour), instead it will appear greyish. Using averted vision, you will see the comet brighter and larger. This is done by putting the object to the right of the centre of your binocular, looking slightly down your nose, while looking out of the corner of your eye (this area of the eye is more light sensitive in the dark).


On the 15th Feb, it will come within 3 degrees of the spectacular globular cluster 47Tuc (aka 47 Tucanae/aka NGC 104). This is the second largest and brightest globular cluster in the sky. So keep following that straight line for this meeting. Ensure your observing times allow you a good horizon as it’ll be sitting fairly low then. In binoculars you should be able to get both the comet and this globular cluster within the same field of view. And if you’ve got a camera and a tripod with a lens suitable to capture it, it should make for some awesome pics.



A fun project to do with this comet.

It’s moving very fast, so it can be a lot of fun to sketch the star field as it traverses the stars. If you monitor it for even only 30 minutes, you will be amazed at how far it’s moved! Keep a log of your sketches, it’ll be fun looking back at them in time to come and you have the memories of viewing a comet that’s coming our way and hopefully make naked eye visibility around March 26th with hopefully a nice tail on show. This comet is getting brighter and brighter as its coming towards us!

Just to give you an idea, here is a sketch I did on Comet Lemmon on Sunday 3/2/2013. Pay no attention of what I've written next to "size" on the form... the next word was "big" .

Click image for larger version

Name:	My Sketch-Comet Lemmon 3-2-13.jpg
Views:	216
Size:	189.4 KB
ID:	132000


Here are my observations using different instruments to give you an idea of what to expect.

I’ve observed this comet across three different instruments and each provide excellent views of it. My 10x60 binos show it as a fuzzy round patch, similar in view of a globular cluster seen thru them.
My 4” scope now makes this object brighter and larger- a good size in an eyepiece, still a fuzzy round patch but quite remarkable all the same.
My 10” dob shows it up brighter and larger again with a very bright disc in the centre. It’s almost like I could see the rock in the centre with the sun shining off it, but a comet nucleus isn’t evident in instruments are size (that’s for NASA).The tail wasn’t evident, but next time I will look a bit harder as I wasn’t really looking for it at the time. This comet is about the size of a globular cluster at low magnification in a scope, too me it looked like a GC pulverised leaving just gas and dust!

Good luck, clear skies and have fun everyone!


P.S. Another chart here.
http://www.heavens-above.com/comet.a...lt=0&tz=UCTm10

Last edited by Suzy; 07-02-2013 at 01:43 PM. Reason: added info about chart updates re Stu's screen grabs.
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