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View Full Version here: : Comet Lovejoy 4-1-12 plus possible Aurora?


tilbrook@rbe.ne
04-01-2012, 08:24 AM
Hi,

Comet Lovejoy still visible to the unadaided eye, just!
Also possible aurora?
Right at the bottom of the image there is a red glow, looks like it might be an aurora, did anyone else see this?
I only say possible, because this is in the direction of Adelaide. But the usual colour in images is yellow for light pollution.

Camera Canon 1100D
18 to 75 zoom at 18mm f/3.5 ISO 3200
7 x 20 sec exp 3 darks 1 flat.
Processed in DSS and Photoshop.

Cheers,

Justin.

Liz
04-01-2012, 11:06 AM
Great image there Justin, and still very visible in your pic, could you see the comet visually?
Unsure re reddish colour??

renormalised
04-01-2012, 11:13 AM
Nice shot there, Justin:):)

The reddish cast.....don't know.

glenc
04-01-2012, 11:17 AM
Nice images again Justin.
The best part of the tail is about 16d long.
Here is the aurora map. http://www.swpc.noaa.gov/pmap/pmapS.html

tilbrook@rbe.ne
04-01-2012, 11:30 AM
Hi,

Thanks for the comments.

Liz, just visible to the unaiaded eye. I guess this will be the last time with the moon coming in to contention.

Glen, thanks for the aurora information, this will be handy.

Cheers,

Justin.

Lester
04-01-2012, 03:45 PM
Nice image again Justin. Was cloudy here, perhaps tomorrow.

All the best.

andyc
05-01-2012, 11:13 AM
Some auroral tips available here:
http://www.swpc.noaa.gov/Aurora/

Your magnetic latitude, combined with the intensity of the aurora (measured by the Planetary K index) will give you an idea of whether auroras are likely to be visible from your location.

The following map gives the approximate equatorward boundary for the oval under different conditions:
http://www.swpc.noaa.gov/Aurora/globeSE.html

Australia is quite favourably placed in relation to the south magnetic pole (currently 64.5deg S, 138deg E), almost due south of Adelaide. So our magnetic latitude is higher than our geographic latitude - eg Hobart's magnetic latitude is higher than Edinburgh's, despite being 13deg closer to the equator. Despite this, from Adelaide, you'll still need a planetary K index of >=8 - ie a full geomagnetic storm - in order for the lights to be visible. (They'll be visible a few degrees of latitude north of the oval, but much lower in the southern part of the sky).

If your picture was taken in the early hours of the 4th Jan, it probably wasn't aurora, as the planetary K index was much too low:
http://www.swpc.noaa.gov/alerts/k-index.html

The nearest POES passes shows some levels of activity in the early hours of the 4th, but well south of even Tassie:
http://www.swpc.noaa.gov/pmap/Plots.html

Very nice picture though! :)

tilbrook@rbe.ne
05-01-2012, 07:26 PM
Hi, Andy.
Thanks for all the aurora info.
I think the glow is light pollution, it still shows up as red on the inividual frames, and I'm guessing comes from using high ISO and it's somewaht enhanced with the proccessing.

Cheers,
Justin.

astronobob
06-01-2012, 06:00 AM
Nice one, Trippy colouring : ) Eta showing nicely also . . Cool !

Erg
07-01-2012, 01:16 PM
Great info Andy.

I now understand that blue on POES plots is the geographical data limit and has nothing to with the auroral oval itself.

A real DOH! moment for me.

Erg