[BAA Comets] Amateur discovery of C/2012 S1 (ISON)

[Richard Miles]

I've a few comments and questions re. amateur discovery of comets and 
asteroids:

That Artyom and Vitali found a magnitude 18-19 object moving at about 
0.20"/min at a solar elongation of just 59 degrees was in itself strongly 
indicative of the object being a comet.  There was only a tiny possibility 
that it was on our side of the Sun and that it was a NEO.  The much more 
likely scenario was that it was distant at around 5-7 AU.  O.K. it's 
ecliptic latitude at discovery was about +8 deg, which may have meant it was 
a Centaur-like asteroid but given this location and brightness, such an 
object would almost certainly have been discovered before now.

So I wonder what would be best practice for amateurs engaged in comet 
hunting following discovery of a mover such as this one?

One option for the discoverers would have been to wait for a second night 
before reporting on the NEOCP.  The initial survey detection was a firm one 
such that it would easily be picked up over the next few nights. The 4 
discovery images could have been followed up with a much longer time-series, 
the stacking of which would then have revealed the presence of the coma. 
Furthermore given its elongation and magnitude, in the short run, it was not 
likely to have been found by others.

What do others think? Should a second night be obtained in certain cases 
(and if so which) before reporting via the NEOCP?

Richard Miles
BAA

----- Original Message ----- 
From: "maiki666" <maik at comethunter.de>
To: <comets-ml at yahoogroups.com>
Sent: Tuesday, September 25, 2012 8:53 AM
Subject: [comets-ml] Re: C/2012 S1 (ISON)


> Andreas,
>
>> 1) could anyone explain to me, why this comet is not named 
>> Nevski-Novichonok? According to CBET 3238 both have noticed the object on 
>> images taken with a 0.4m telescope. So, the comet was neither discovered 
>> automatically, nor with an "not-amateur"-instrument. Thus I can not see 
>> any difference to R.H. McNaught or other professionals, who discover 
>> comets on images taken with big scopes - and take the merit in naming.
>
> I'll give it a try:
>
> I'll cite from the CBET:
>
> "Nevski and Novichonok first reported the object to the Minor Planet 
> Center with no mention of cometary appearance,and it was posted on the 
> MPC's NEOCP webpage as an apparently asteroidal object..."
>
> and
>
> "After the object was posted on the MPC's NEOCP webpage, other CCD 
> astrometrists commented on the object's cometary appearance (including one 
> or two such reports received before Nevski's e-mail to the Central Bureau 
> noting cometary appearance)."
>
> I think these remarks are the explanation for the naming. The cometary 
> identity was not initially detected by the discoverers, but first by the 
> follow-up astrometrists.
>
> I think this procedure is taken for all comets. This is why we have Lemmon 
> and Catalina comets and comets with discoverers names from those surveys. 
> There are also Siding Spring comets and McNaught comets.
>
> If this is a good procedure or not I won't judge.
>
> Maik