Astronomy, Photography and Weather

General Category => Astronomy & Space => Topic started by: brianb on September 02, 2008, 07:03:22 pm



Title: Two Boattinis imaged in one night!
Post by: brianb on September 02, 2008, 07:03:22 pm
Last night (Sep 1st/2nd) the sky cleared in the small hours - the transparency was not brilliant but it was better than we've had for a while. I decided to have a go at imaging the two Boattini comets - C2007/W1 which is very close to alpha Arietis
(http://www.bbhvig.uklinux.net/C2007W1-0902-300.jpg)

and C2008/J1 which is still very close to the North celestial pole
(http://www.bbhvig.uklinux.net/C2008J1-0902-300.jpg)

Both images made by stacking 20 x 30 sec exposures using a 300mm f/4 lens on a driven mount on my Canon 5D. Images have been cropped giving approximately 3x "digital zoom". There is some evidence of dewing on the lens; focus is not as good as it should have been (I must be out of practise) and the image of C2007/W1 contains a curved "fuzzy" above and slightly to the right of the comet which may be a ghost image of alpha Arietis.

Both of these comets were just about visible in my 8" LX90 x59 - C2007/W1 is very diffuse and C2008/J1 is faint.


Title: Re: Two Boattinis imaged in one night!
Post by: Paul on September 02, 2008, 07:43:30 pm
Brian, those are both very impressive images! I thought of having a go at C2007/W1 until I realised it comes up right above the megawatt lights of Larne Harbour, so I gave up on that idea for the time being.

Driven by Astrotrac or Meade?

Paul.


Title: Re: Two Boattinis imaged in one night!
Post by: brianb on September 02, 2008, 07:48:32 pm
Quote
Driven by Astrotrac or Meade?
I got lazy & just piggybacked the camera on the scope ... set my interval timer & went for a cup of coffee! Got a nice hour's break for my eyes between variable star observations.


Title: Re: Two Boattinis imaged in one night!
Post by: martinastro on September 02, 2008, 09:48:23 pm
Excellent work Brian, and every nice images. Glad to see captures of these two from N. Ireland. I was actually out looking for W1 last night visually at 03.30 using the 8.5" but couldn't see it due to mist in the air which destroyed the trans. I will try again tonight. Cheers.  :)


Title: Re: Two Boattinis imaged in one night!
Post by: Paul on September 04, 2008, 07:55:29 am
Well I've had a look for C2007/W1 but I'm not at all sure I've got it. The two bright stars in this crop of a 50mm f1.7 shot are Hamal (left) and Sheratan (right) and I'm looking above right from Hamal (this taken 2300 03/09/2008). Anyone any idea which of the faint smudges might be Boattini?

(http://www.pevans.me.uk/images/aries080903.jpg)


Title: Re: Two Boattinis imaged in one night!
Post by: brianb on September 04, 2008, 11:34:07 am
I've taken the liberty of downloading your image and adding a box to indicate the position of the comet at 2300 UT Sep 3rd. Sorry but I don't see any sign of the comet within it.
(http://www.bbhvig.uklinux.net/aries080903.jpg)
(Broken link as I seem to be having problems uploading to my web hosting service. Sometimes happens ... I'll try uploading again when it's fixed)

If it helps at all with processing.... I find the best thing to do is to make an S shaped curve which rises very steeply just above the level of the background fog, this brings faint low contrast objects into as much relief as you can get. For comets it also helps a lot to turn the colour saturation right up as the cometary coma glows a distinctive green colour in digital shots.


Title: Re: Two Boattinis imaged in one night!
Post by: Roman White on September 13, 2008, 10:25:22 am
Brian, what a sucess! It is nice to see the C/2007W1 again, over 2 months after perihelion.

I had seen the C/2007W1 for the last time on Aug.02, and in September I don't even make any efforts to find it, it is to faint already. The next hunt for me is C/2008A1, starting from mid-October.
OMG! I hadn't yet uploaded my W1 Boattini observations on my website. If only there were no tech problems to appear (my PC wasn't working for last 2 weeks), these observations would have already been on the web. I'll try to update my 'comets' section until the end of the month.

Martin, have you seen the W1 Boattini or you have missed it?