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 Post subject: Comet 2015 F5 SWAN-Xingming
PostPosted: Tue Apr 28, 2015 10:32 am 
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On checking the BAA Comet Section's website http://www.ast.cam.ac.uk/~jds/ at the weekend, I realised that there was a "new" comet to look out for: C/2015 F5. It reached perihelion on 28-Mar, and was actually discovered the following day, using images from the SWAN instrument on the SOHO satellite. But now it's moving rapidly away from the Sun and fading quickly, so by the time I tried to look for it on Sunday it was down at 11th magnitude (although it was quite high in the sky, close to Capella).

Despite the bright moonlight and patchy cloud, I did an imaging run of about an hour using my Atik 16IC camera on the back of my StarWave 80ED refractor operating at f/4.6. I couldn't see any trace of the comet on my 2-min exposures, but inspired by our Chairman's recent post on faint-object imaging (http://www.boltonastro.co.uk/forums/viewtopic.php?f=4&t=764) I had a close look at my stack of 24 images. After calibration, registration, addition, masked gradient removal and logarithmic stretching (all in IRIS), I could just make out a faint turquoise smear across the middle of the frame, about the right length for the comet's apparent movement over that period:
Attachment:
File comment: Stack of 24 exposures of 1 & 2-min using 16Ic on 80ED refractor
smear.png
smear.png [ 473.84 KiB | Viewed 3548 times ]

Then using the TRANS2 function in IRIS, I re-registered my image-set on the comet:
Attachment:
File comment: Comet SWAN-Xingming on 26-Apr. Stack of 24 images with extensive processing in IRIS!
swan-x_26apr.png
swan-x_26apr.png [ 268.73 KiB | Viewed 3548 times ]

This is certainly the faintest comet I've ever captured, and I even got some colour in it too!


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 Post subject: Re: Comet 2015 F5 SWAN-Xingming
PostPosted: Tue Apr 28, 2015 3:09 pm 
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Well done Ross - less is definitely more with small Apos. Aperture fever is perhaps a thing of the past.


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 Post subject: Re: Comet 2015 F5 SWAN-Xingming
PostPosted: Wed May 20, 2015 8:00 am 
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DRatledge wrote:
less is definitely more with small Apos. Aperture fever is perhaps a thing of the past.

Yes indeed - see my latest acquisition: http://www.boltonastro.co.uk/forums/viewtopic.php?f=6&t=773&p=2995


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 Post subject: Re: Comet 2015 F5 SWAN-Xingming
PostPosted: Wed May 20, 2015 1:50 pm 
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Ross, I have just been on the Heavens Above website and under the Comet section their are maybe 6 or 7 comets which are able to be visualised at this time as well as the above comet you have mentioned. Maybe something you will be able to take pictures of.

http://www.heavens-above.com/Comets.asp ... =76&tz=GMT
Peter.


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 Post subject: Re: Comet 2015 F5 SWAN-Xingming
PostPosted: Wed May 20, 2015 3:47 pm 
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PMiskiw wrote:
Ross, I have just been on the Heavens Above website and under the Comet section their are maybe 6 or 7 comets which are able to be visualised at this time


Not sure about that Peter: they're either a bit too faint at the moment or too low from our latitude - here are their current magnitudes:
Attachment:
File comment: Data from the BAA Comet Section
comets.png
comets.png [ 45.52 KiB | Viewed 3454 times ]


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