[BAA Comets] Comet 117P/Helin-Roman-Alu

[Roger Dymock]

Hello Amar,

Glad to be of service. 

To estimate tail length go to
http://www.britastro.org/projectalcock/CCD%20Astrometry%20and%20Photometry.htm There
are a couple of methods described towards the end of the document.

Regards

Roger Dymock
Email: roger.dymock at ntlworld.com
Tel: 023 92647986
Skype: rjvdymock
MPC Observatory Code: 940
Project Alcock http://www.britastro.org/projectalcock/


-----Original Message-----
From: comets-disc-bounces at britastro.org [mailto:comets-disc-bounces at britastro.org] On
Behalf Of amar sharma
Sent: 15 March 2013 12:25
To: BAA Comets discussion list
Subject: Re: [BAA Comets] Comet 117P/Helin-Roman-Alu

Hello All,

Thanks to Roger's intimation and me being with the CCD during the night, I had a go
at 117/P thinking it will be too faint for me and my conditions.

However, I was impressed to see a tail, which will be bettered in longer exposures
and from darker skies [I am limited against both; non-guiding and background glow in
our skies].

https://picasaweb.google.com/100263423283309558687/FaintCometsAndSupernovae#585554209
1238648290

or

http://tinyurl.com/c8ko8m9

I got it in 2 minute sub-exposures with our C-14 and SBIG ST8XME. How do I estimate
the tail length? The above image is cropped.

You should get better of the tail in 3 minute and more exposures from darker skies.
Reminiscent of 49/P H-M-P and 19/P Borrelly at a time. Do post your images.

Thanks, Amar A. Sharma.

--- On Thu, 14/3/13, Roger Dymock <roger.dymock at ntlworld.com> wrote:

From: Roger Dymock <roger.dymock at ntlworld.com>
Subject: [BAA Comets] Comet 117P/Helin-Roman-Alu
To: comets-disc at britastro.org
Date: Thursday, 14 March, 2013, 9:47 PM

Might be worth imaging as it appears to be brightening (1 mag brighter than JPL
Horizons predictions) and has a decent tail.

Regards

Roger Dymock
Email: roger.dymock at ntlworld.com
Tel: 023 92647986
Skype: rjvdymock
MPC Observatory Code: 940
Project Alcock http://www.britastro.org/projectalcock/



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