Thumbnail: Moon

Tonight, I saw the moon in my tele­scope. If it was a full moon, it would have filled the eye­piece. I could study the craters, the land­marks, and the pat­terns of dust on the sur­face. I grabbed my cam­era with a mod­estly long 100mm lens, mounted it on my new tri­pod, and took a pic­ture. Unless I get a lens with a longer focal length, it’s the best I’ll ever get in cap­tur­ing the moon with a sen­sor1.

It was a great night for observ­ing, the fore­cast said, with no cloud cover, good trans­parency2, good see­ing3, and decent dark­ness. I had my warmest clothes on, as I was warned that com­fort and moti­va­tion are some of the most impor­tant things in obser­va­tional astronomy.

I used a crater on the moon to cal­i­brate my red-dot find­er­scope. Then I used the find­er­scope to fol­low the arm of the big dip­per to Arcturus, the curve of which led me to Saturn, just under Denebola and in the con­stel­la­tion Virgo this year.

With the naked eye, Saturn looks like another bright star, but at 100x mag­ni­fi­ca­tion, Saturn becomes a small and sharp sphere. The rings were clean but indis­tin­guish­able from each other, with the gas giant cast­ing a dra­matic shadow across them.

I looked 68 min­utes into the past4, until Saturn slowly drifted out of view.

  1. I have no plans on get­ting into prime focus astropho­tog­ra­phy — in which the tele­scope is used as a lens — because the astron­omy equip­ment required is much more expen­sive. [↑]
  2. Calculated from the amount of water vapour in the air. [↑]
  3. Estimated from tur­bu­lence and tem­per­a­ture dif­fer­ences in the atmos­phere. [↑]
  4. Saturn was 8.505AU or 1,272,330,990km away, which takes about 4080 sec­onds for the light to hit our eyes from there. [↑]