Welcome to SJAstro.org
    astronomical snapshots by

 

 

SJAstro Page Index

 

(3200) Phaethon Observed
December 13, 2017

Since it was clear on the morning of December 13, 2017, I went to Swede Run in Moorestown, NJ, to see if any Geminid meteors would appear and to check out the location of the asteroid (3200) Phaethon, which is making a close pass by earth this week. I arrived around 2:15 am EST, and in the open field area, experienced the full effect of strong wind and temperatures in the low 20's F. Using 15x56 binoculars, I quickly identified the star field to the left of Mirfak (Alpha Persei), in particular, the string of stars starting at Nu Persei and arching up and to the right as seen in the SkyTools clip above (mouseover for labels). A couple of asterisms above the peak of the arch that bracketed Phaethon were easily seen, but Phaethon itself at magnitude 10.8 was too dim for these handheld binoculars in suburban skies (albeit, darker than my home skies). I saw a faint meteor in the binoculars while looking at this area. It moved from the top to the bottom of the field, and it wasn't until a little later that I realized Gemini was nearly overhead, so this meteor probably did radiate from there. I then decided, despite the cold and wind, to get out my 85 mm spotting scope (continued below).

 

I had the 85 mm scope set up about 2:30 am EST, and at the minimum 27x, quickly found the asterisms flanking (3200) Phaethon. Mouseover to see the outlined asterisms in this SkyTools clip, which is about 1.5 degrees wide. I then increased the magnification to the 60x maximum and inspected the area between the those asterisms (marked with fainter blue lines). My printed SkyTools chart did not have enough detail to directly pinpoint Phaethon, so I made a mental note of the star positions in the fainter center outline, and at 2:40 am, suspected the object labeled Phaethon was the one I wanted. However, I had to wait for distinct movement to be sure. At 2:50 am, the movement was confirmed. At 2:40 am, Phaethon was almost directly above a field star, and 10 minutes later, it was closer to, and above right of that field star as shown by the pale reddish overlay lines. At 2:40 am, Phaethon was at 44 altitude and 299 azimuth. By 2:50 am, the crescent moon was visible at the tree tops to the east (it rose at 2:37 am). The labeled track of Phaethon in this clip extends for 13'16", so during the 40 minute period between 2:20 and 3:00 am, it moved an average of 19.9 arc seconds/minute. Between 2:40 and 2:50 am, I also caught a faint Geminid in the east with unaided eyes.

 

 

22 Lunar Halo
December 7, 2017

 

On the morning of December 7, 2017, I was putting out the trash late, and as always, I looked up at the sky, even though it was generally cloudy. However, the clouds weren't thick enough to block out the 81% illuminated waning gibbous moon, in Gemini at 66 altitude, about 3.7 days past full. As a bonus, the clouds generated a 22 radius halo, and perhaps a slight corona close to the moon. This picture of them was taken at 2:54 am EST with a Canon 6D digital SLR camera on a fixed tripod and an Irix 15 mm f/2.4 Firefly lens, which provides an uncropped field 100 wide x 77 high with the "full-frame" 6D as seen here (calculated trigonometrically). It was exposed 1.6 seconds at f/4, ISO 1600, with 3600K white balance. To show the halo, the moon itself is greatly overexposed, so the phase isn't visible. Besides size reduction for this web page, no processing was applied.

The image below is a 16:9 crop of the original (with no other adjustments besides size reduction). Procyon (Alpha CMi) is now visible 18.4 from the moon at the 4 o'clock position inside the halo, and outside the halo, Betelgeuse (Alpha Ori) is 40.3 from the moon at the 2:30 o'clock position. Mouseover for labels.

 

 

Ross 128 / FI Virginis
November 25, 2017

With clear skies on the morning of November 25, 2017, I went to Carranza Field in Wharton State Forest, NJ, for the primary purpose of spotting the star Ross 128 (FI Virginis) and/or capturing an image of it. This effort was prompted by a Bob King article at Sky & Telescope online suggesting readers should try to observe this star, which hosts an earth-sized exoplanet, Ross 128b, that's in the habitable zone of its host star and has recently been in the news. I succeeded on both counts. The image above was captured at 5:01 am EST (18 minutes before the start of astronomical twilight) with a Canon 6D digital SLR camera and a Canon 200 mm f/2.8L telephoto lens on a fixed tripod. It was exposed 2 seconds at f/2.8, ISO 12,800 in monochrome mode. It was cropped to about 34% of the original size, yielding a field nominally 3.5 wide x 2.3 high. Mouseover for labels.

Then, using the image on the camera's viewing screen as a guide to the star field near Zavijah (or Zavijava, Beta Virginis), augmenting my SkyTools and AAVSO finder charts, I found Ross 128 visually at 5:20 am with my 85 mm spotting scope at 60x, 1.2 from Zavijah. It was dim, but not that difficult to see. No reddish color was noticed (probably need a bigger scope for that). Rather than star hopping from Zavijah, the "mini-Scorpius" asterism near Zavijah drew my attention at 27x, then I zoomed to 60x to get a solid view of Ross 128, which was in the "Dschubba (Delta Scorpii)" position of the asterism. According to the Telescope Calculator at Sky & Telescope online, an 85 mm scope can reach magnitude +11.4 at 27x and +12.3 at 60x under clear dark skies. Consequently, the four stars in a diagonal row labeled with magnitudes (including Ross 128) were unambiguously seen.

 

 

Mercury, Saturn and the Crescent Moon
November 20, 2017

On November 20, 2017, the 2.45-day-old, 5.5% illuminated, waxing Crescent Moon was grouped with the planets Mercury and Saturn in evening twilight. This picture of them was captured from Swede Run in Moorestown, NJ, at 5:27 pm EST, 47 minutes after sunset at 4:40 pm EST, when the moon was at 10.0 altitude, Saturn was at 9.1 altitude and Mercury was at 2.7 altitude (mouseover for labels). At the time, Mercury was at magnitude -0.34 and Saturn was at magnitude +0.53, so Mercury was 2.2x brighter than Saturn, but more difficult to see because of its lower altitude, which means it suffered greater atmospheric absorption and had a brighter twilight background. This is the third sighting of the sixth (and final) elongation for 2017. Taken with a Canon 6D digital SLR camera and a Canon 100 mm f/2.8L macro lens on a fixed tripod, then lightly cropped producing a field about 15 wide x 11 high. Exposed 1/4 second at f/2.8, ISO 400, daylight white balance.

 

 

Click here for the previous page.

Click here for an index to previous SJAstro pages.

 

 

 

 

 

 

West Jersey Astronomical Society

Rittenhouse Astronomical Society

South Jersey Astronomy Club

S*T*A*R Astronomy

 

 

Last Update: Wednesday, December 13, 2017 at 08:17 PM Eastern Time