[BAA Comets] Some questions on working towards ICQ report

Tue Jul 29 14:17:32 BST 2014

Hi again Tony,

One point I overlooked. The objective of the CCD Astrometry and Photometry procedure is to produce
visual equivalent magnitudes from CCD images therefore you should not be using a red filter (if that
is what you mean). FoCAs requires that you image unfiltered. 

Regards

Roger D

Hi Tony,

Answers to your questions (feel free to ask more at any time).

1) If the tail goes off the edge of the image you measure from head of comet to the edge and record
that distance using the 'greater than' (>) symbol in COBS.

2) Can't help you there so I suggest you contact Julio Castellano at orodeno2 at yahoo.es (for any
FoCAs problems). You could also try the mailing list at
https://es.groups.yahoo.com/neo/groups/Cometas_Obs/info

3) You are correct in what you say but I use a single image which seems to give similar results to
others. Richard Miles has shown that the longer the exposure the larger the coma. I will have a look
at mine sometime to see what difference it makes.

4a) ICQ code is not the same as the MPC code. For ICQ code I suggest you use, as COBS registration
page mentions and you stated, first three letters of surname plus xx.  

4b) The ICQ code for CCD images using a red filter is lower case k. See
http://www.icq.eps.harvard.edu/ICQKeys.html for all relevant codes.

4c) You should reference the catalogue you use for photometry in the ICQ/COBS report. For MPC
reports I show the catalogue used for photometry in a COM line as below. The astrometry catalogue is
automatically included above the observation lines.

COD G68
OBS R.Dymock
MEA R.Dymock
TEL 0.61-m f/10 reflector + CCD
AC2 roger.dymock at ntlworld.com
ACK G68_2014_02_27-1
COM CMC-14 used for photometry

NET UCAC-4

0052P         C2014 02 25.11478 05 04 19.79 +32 59 34.5          16.0 N      G68
0052P         C2014 02 25.12170 05 04 20.62 +32 59 31.7          16.0 N      G68
0052P         C2014 02 25.12865 05 04 21.45 +32 59 28.9          16.0 N      G68

I understand an observation to be a single visual observation of an object or a single CCD, or
stacked, image of same but it's not a question I have been asked before so someone may correct me on
that.

When you have worked through the total procedure I will update it with any points your have raised
which need clarifying.  

Regards

Roger Dymock
Email: roger.dymock at ntlworld.com
Tel: 023 92647986
Skype: rogerdymock67 or
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 Tony
Angel
Sent: 28 July 2014 11:04
To: Comets-disc at britastro.org
Subject: [BAA Comets] Some questions on working towards ICQ report

Hi,

I have just about worked through Roger's Tutorials - I have done everything upto but not including
COBS, but before I can produce an ICQ Report I have a few outstanding problems.

1. Tail length. What do you do when the tail goes off the edge of the image. Sometimes I cannot
image with the C14 F11 and the 4" F4 during the same run.
2. In FoCAs I cannot get the E-mail setup to work - anyone using hotmail with FoCAs? (not a show
stopper)
3. Coma diameter and Tail length. Do I base this on stacked or single image? Logic tells me to use
stacked because a short image may not collect enough information. For example this morning's C/2014
E2 stacked shows a coma of some 12 arc minutes, but a single image about 3.75 arc minutes.
4. COBS Registration
    a) ICQ code: is this the same at the MPC code or is it something else I need to apply for soon?
(Yes I know that I can put ANGxx in that field)
    b) What is observation method - is it "C" for me, or it something else because I am using an
SBIG CCD which is in the red?
    c)  Default reference star catalogue - do I put down the one I use for astrometry or the one I
use for photometry?

Once I get into COBS I might have a few more question LOL

Finally, what is meant by an observation from the Section point of view?    

Thank you in advance. : )

Tony
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