An observing milestone


Ted Forte
 

Greetings from BBAA west.  Arizona’s sky has been suffering from the smoke.  We had a few nights with good clarity last weekend, but most nights are marred by a haze.   It was yet another night of reduced transparency here last night, but this time the seeing was also rather poor. In my last few observing sessions this month, the poor transparency has been offset by better than average seeing.  Last night, there were few redeeming features and when the wind started to pick up, I had had quite enough and so I quit rather early.

 

Before I did, however, I achieved a milestone. I finally logged my last Herschel object. 

 

Anyone trying to observe the whole of Herschel’s “non-stellar” discoveries has to make some selections. I had settled on a list of 2,517 objects.   Nominally, the list is 2,500 items long, which is the sum of the objects published in Herschel’s three catalogs.  But, many of the objects published in the catalogs were duplicate observations of the same nebulae, and some have been lost or never really existed.  So that reduces the list somewhat.  For instance, the Astronomical League’s “Herschel 2500” is actually only 2,383 objects long.

 

After trimming away the published objects that don’t belong, you can then re-expand the list by adding those objects that were very likely discovered but never published, and also add to the list those objects that were credited to other discoverers but probably rightly belong to Sir William. The final tally is usually agreed to be in the range of 2,513 to 2,517 objects.  For the most part, I have accepted Dr. Wolfgang Steinicke as the final word on what does or does not belong.

 

I’ve been waiting months for my final unseen Herschel object to come around. I logged, IC 1339, a 14.3 magnitude galaxy in Cap, first thing last night – and with it put the Herschel 2500 project to bed! And it only took me 28.5 years!

 

While that is technically true, I really only assigned myself the goal of completing the Herschel 2500 a couple of years ago, so perhaps I’m not quite the slacker that that 28.5 year span suggests. 

 

Ted

 

 

 

 

 

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