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Thu, 10 Dec 2015 - Getting Ready for the Geminids (part 4): Records

 

If the weather is kind and you get clear skies around Geminid maximum, how should you record what you see?

 

You could of course just sit back and enjoy the spectacle.

 

However, it is always good to keep a record of what you have seen

- either for your personal records - so that you have something to look back on at a later date.

- or so that your observations can be used by groups, such as the SPA Meteor Section or the IMO, to keep track of the year to year changes in the activity of the Geminids.

 

Report forms are available from the Meteor Section downloads page, but most observers nowadays use Notepad or Excel to submit their reports. The most important issue is to make sure that your report includes the key information, which is described below.

Page down to the end of this article to see an extract from a completed Geminid report form.

Do let us know what you see. You can mail your reports to  meteor@popastro.com

 

Before You Start observing

Before you go out to observe, however, here are some basics:

  •         Wrap up well against the cold

  •         Make sure that you know the location of the Geminid radiant (have a look on the above chart)

  •         Make sure that your watch is accurate

  •         Make sure that you are using a dim red torch or an ordinary torch covered with red tape

  •         Make sure that you have plenty of blank notebook pages on which to record the meteors

  •         Make sure that you have several pens/pencils (you will lose some in the dark!)

  • Wait 10-15 minutes for your eyes to adapt to the dark
  •         Memorise a few stars of each magnitude (Sirius is mag -1, Capella mag 0, Pollux mag 1, most stars of the Plough & Cassiopeia mag 2, delta UMa mag 3). More can be seen on the graphic shown below.

 

The Basic Info about your Meteor Watch

Whichever recording method you use, there are some pieces of key information that you should always record

-       - Names of the observer(s)

-       - the night on which you observed – it is best to give the date before and after midnight (e.g. Dec 13-14), just so there is no confusion later

-       - when your observations started & ended – also make a note of the times of any breaks in observing. Times should be recorded in GMT.

-       - the location of your observing site – e.g. the name of a town/village and county

-       - the sky conditions – e.g.  what % of the field of view was affected by cloud/other obstructions, was it hazy. How did this change during your observations?

-       - the Limiting Magnitude – a measure of how dark the sky background was –  this guide describes how you can determine the Limiting Magnitude.

 

What to Record for each Meteor

There is a choice between two recording methods

The simplest option is to simply count the number of Geminid meteors and number of sporadic meteors that you see in a given interval and possibly also record details of the most impressive meteors.

A better option (one which the SPA Meteor Section encourages) is to record details of each meteor. This makes it easier for you to compare your records with reports that you see from other observers. 

Details to record for each meteor

- the time at which it appeared to the nearest minute (in GMT, using the 24 hour clock)

- whether it was a Geminid or a sporadic. If the path of the meteor when traced backwards comes from near the star Castor, then it was a Geminid. The accompanying image shows two Geminids, imaged by Robin Scagell, whose paths traced backwards intersected just above the bright star Castor.

- its brightness to the nearest whole magnitude by comparing it with other stars in the same part of the sky (see examples in the earlier graphic)

- if a persistent train was left behind, record how long it lasted

- any other distinctive features such as colours, fragmentation, flares in brightness, etc.

For the most memorable meteors, also record the constellations they passed through

Try to write down this information as quickly as possible - you want to get your eyes back on the sky so you don’t miss any meteors!  Use abbreviations such as G for Geminid and S for sporadic.

If meteor rates get high, just focus on recording Times, Gem/Spor & Magnitudes and skip the rest of the info.

Here is an example of a completed report form:

 

Added by: Tracie Heywood