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Old 06-02-2013, 05:31 PM
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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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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
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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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Old 06-02-2013, 05:41 PM
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Astroman (Andrew Wall)
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Nice Article SUzy. I hope people do get to look at it also.
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Old 06-02-2013, 05:51 PM
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astroron (Ron)
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Even I could find it with all that info Suzy
Good article
Cheers
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Old 06-02-2013, 06:12 PM
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Two nights ago I checked its position on SkySafari but couldn't find it in the sky. Then last night I realised I SkySafari was set to the wrong date!

So I finally got a look last night with my 80mm refractor. Hoping to get a bigger scope on it this weekend.
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Old 06-02-2013, 06:23 PM
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That's a great write up Suzy.

I'd like to jump in with some more screen grabs from Starry Night. Ignore the tail, it is the default setting in Starry Night. This is Comet Lemmon's position for tonight, 6th Feb 2013 at 2100hrs EST (1100 hrs UT).

Every clear night I have been out tracking this comet with my trusty 7x50 binos. It is moving quickly.
Attached Thumbnails
Click for full-size image (6th Feb 2100 EST.jpg)
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Click for full-size image (6th 2100 Octans.jpg)
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Click for full-size image (6th 2100 zoom.jpg)
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Old 06-02-2013, 07:33 PM
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Stu: Yaaaaay, go for it & please keep those screen grab updates coming, thank you! I tried at first to do it myself off my sky programme but major fail urrrgh!
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Old 06-02-2013, 10:23 PM
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Suzy, this is what CdC gives for the next 12 days. FOV is 74 degrees.
Click image for larger version

Name:	K12F060.jpg
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Size:	195.8 KB
ID:	132021
The grey area at the bottom is my horizon line.
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Old 07-02-2013, 12:04 AM
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Andrew, that's a great map, I love the tracking line- thank you so much!
All these maps from you and Stu are going to be so helpful for people, you guys are just the best.
I will be linking this thread onto the IIS facebook page as I sense some people on there are keen to see it but don't know how to go about it. So it's not just helping the people on here, we will be able to reach and help a lot of people. I couldn't go to sleep at night (well I can now I've done this! lol) unless I'd done what I could to give everyone a fair go at seeing this comet come our way. You guys have done good (as usual I might add!).

Ron, I'm so glad my information helped you. Smarty.
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Old 07-02-2013, 01:10 AM
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Thanks Suzy. I saw Comet Lemmon this morning with 20x80s through a hole in the clouds.

Last edited by glenc; 07-02-2013 at 05:21 AM.
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Old 07-02-2013, 08:50 AM
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Thanks Suzy, now all i need is a clear night sky, crossing my fingers
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Old 07-02-2013, 02:59 PM
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Postion - 7th Feb 2013, 2100 hrs EST (1100 hrs UT)

For those who are new, I hope you have clear skies and can bag your first comet. As mentioned in my last post, ignore the tail. It is a default setting in Starry Night. Mitrandir's map (post #7) will cover the position of this comet over the next few days. Happy hunting.

Suzy, I am not into facebook but have had a look at the IIS public page and I love your work.
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Old 07-02-2013, 10:06 PM
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Sky X Map - Comet Lemmon's Position Tonight

I have found the Sky X maps quite good and have attached a JPG image from the program. It would have been better to attach a PDF copy because you can zoom in or out to show excellent detail. The best PDF file size I could manage is 540K, 40K over the IIS limit. If someone knows how to reduce the size of a PDF file please let me know
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Old 08-02-2013, 01:07 PM
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Position - 8th Feb 2013, 2100 hrs EST (1100 hrs UT)

Ignore the default tail shown in the Starry Night.
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Old 08-02-2013, 03:44 PM
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d

Quote:
Originally Posted by UniPol View Post
I have found the Sky X maps quite good and have attached a JPG image from the program. It would have been better to attach a PDF copy because you can zoom in or out to show excellent detail. The best PDF file size I could manage is 540K, 40K over the IIS limit. If someone knows how to reduce the size of a PDF file please let me know
Hi Steve,

If you have the full version of Adobe Acrobat, under Advanced is a tool called PDF Optimizer. It should allow you to downsample the pdf and thereby reduce it's size.

Cheers, Paul.
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Old 08-02-2013, 07:36 PM
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Thanks Paul, yes, I have the full Acrobat version and downsampling worked a treat, looks like I'll have to read the user manual to get the most out it. I have attached a chart for tonight which hopefully may be useful to some members.
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File Type: pdf Comet Lemmon 8-02-13.pdf (348.7 KB, 71 views)
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Old 08-02-2013, 08:50 PM
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Comet Lemmon's tail is definitely visible in 20x80 binoculars.
I suspected it last night and the night before, tonight it is obvious.
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Old 08-02-2013, 09:16 PM
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Thanks guys! Thanks to your descriptions and maps my wife and I saw our first comet.
It was clear in our 10x30 binoculars as a fuzzy circle.
Star hopping we went from Beta hydrus, which was the nearest naked eye star where we were. Then in the binoculars moved to the left to three stars gamma-octans. Put these 3 stars at 2 o'clock and the comet was at 7 o'clock.
Cool.
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Old 08-02-2013, 09:29 PM
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Thanks very much for doing this Stu. I found it each time straight away thanks to your clear post.

Greg.
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Old 08-02-2013, 09:32 PM
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Steve, TheSky6 gave me this on Win7 using the PDF printer - without any compression needed.
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Old 09-02-2013, 02:43 PM
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Position - 9th Feb 2013, 2030 hrs EST (1030 hrs UT)

It turns out that Starry Night's tail length is close to what is showing up in astro images. Amateurs with larger scopes and dark skies are reporting that they can make out a faint tail and a hint of colour. Amateurs with bino's are not seeing a tail yet, instead it looks a little like a diffuse globular cluster with a bright core.

As Suzy has been encouraging beginners to do; if you are new to Astronomy get out there and bag your first comet.

Edit: Dodgy spelling , but i've already being quoted. grama, grammer, grammar.....
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Last edited by Shark Bait; 09-02-2013 at 05:37 PM.
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