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Comet C/2017 O1 (ASASSN)
October 20, 2017

This image of Comet C/2017 O1 (ASASSN) was captured on October 20, 2017, from Carranza Field in Wharton State Forest, NJ. This comet has been described as a binocular object in a number of places (e.g., the APOD of 23-Sept-2017 and Joe Rao's Space.com article of 06-Oct-2017). However, these seem to be armchair astronomer reports since I've failed to see it a number of times with 16x70 binoculars from the NJ Pines. I first saw it (just barely) on September 29, 2017, from Carranza with an 85 mm spotting scope at 60x. My best view so far was on October 18, 2017, from the Pit in Wharton State Forest with an excellent 12.5-inch, f/6 Newtonian (not mine) on a night of fine transparency and good seeing (magnitude 5.7 Uranus wasn't difficult with unaided eyes; in the scope, NGC 206 in M31 was easy and we saw six stars in the Trapezium). The comet was just an amorphous patch of haze with no color apparent. The November 2017 issue of Sky & Telescope magazine also has a two-page article on this comet, including finder charts (pages 48 and 49). Here's an S&T PDF finder chart.

Back to this morning. I could not find even a hint of the comet in 10x50 binoculars, but I did manage to capture a smudge with my camera. Can't find it? Mouseover for labels. This picture was taken at 4:27 am EDT with a Canon 6D digital SLR camera on a fixed tripod and a Canon 200 mm f/2.8L lens, then cropped to a 4:3 ratio and roughly 35% of the original size to a field about 3.4 wide x 2.5 high. It's a single frame exposed 4 seconds at f/2.8, ISO 6400 and 4200K white balance (but saturation reduced to zero on processing, so it's now monochrome).


One of my primary purposes this morning was to see the Zodiacal Light, since it was new moon and the morning ecliptic in the east presents a steep angle to the horizon this time of the year. However, as shown in the picture below, high thin clouds produced less-than-ideal transparency, although the sky overhead near the comet seemed good. Note that it's somewhat overexposed to emphasize the clouds. I wonder if there isn't some airglow involved here, and I also wonder if some of the vague, whitish brightening along the body of Leo isn't ZL? Mouseover for labels.

This picture was taken on October 20 at 4:49 am EDT with a Canon 6D digital SLR camera on a fixed tripod and an Irix 15 mm f/2.4 Firefly lens, then cropped slightly to level the horizon, yielding a field about 97 wide x 74 high. It was exposed 10 seconds at f/2.8, ISO 3200 and 4200K white balance.



Venus, Mars and the
Earthshine-Filled Crescent Moon
October 17, 2017

The 6% illuminated, waning Crescent Moon was 1.3 (center-to-center) from the planet Mars on the morning of October 17, 2017. The bulk of the Moon's disc is filled with earthshine, sunlight reflected back to the Moon by the nearly "full" earth (as viewed from the Moon). The crescent here, directly illuminated by the sun, is greatly overexposed to better see the earthshine. This image was captured at 5:44 am EDT (2 minutes after the start of astronomical twilight) from Swede Run in Moorestown, NJ, with a Canon 6D digital SLR camera and a Tamron 150 to 600 mm f/5-6.3 zoom lens (on a fixed tripod) set to 483 mm focal length, providing a field about 4.2 high x 2.8 wide. It was exposed 1.6 seconds at f/8, ISO 800 and auto white balance. At the time the Moon and Mars were a little over 9 altitude. Mouseover for labels.


This wider-angle view was captured 20 minutes later, at 6:04 am, after the planet Venus had cleared the tree tops at Swede Run and reached 6 altitude. The Moon and Mars are now 1.4 apart and about 13 altitude. Taken with a Canon 6D digital SLR camera (on a fixed tripod) and a Canon 24 to 105 mm f/4L zoom lens set to 70 mm focal length, then cropped to 85% of the original frame size, yielding a field about 24 wide x 16 high. Exposed 2.5 seconds at f/5.6, ISO 1600 and auto white balance. Mouseover for labels.



ISS Lunar Transit
October 7, 2017

On October 7, 2017, the International Space Station (ISS) transited the moon along a line from the 10 o'clock limb position to the 4 o'clock limb position at 8:51 pm EDT. The centerline of visibility from the earth's surface ran very nearly west to east in our area, passing just north of the intersection of 40N-75W, and about 1.5 km north of my local observing site, Swede Run in Moorestown, NJ, where this image was captured. This transit was somewhat unusual in that the moon, about two and a quarter days past full, was only 7 altitude at the time, 42 minutes after it rose and 49 minutes after the end of astronomical twilight. The low altitude meant that atmospheric degradation of the image was inevitable. It also meant that the ISS was far away (more than 1,500 km) and therefore small in angular size, around 16 arc seconds, roughly the apparent diameter of Saturn's disc (sans rings). However, the great distance also caused the apparent motion of the ISS to be relatively slow, taking 3.4 seconds to cross the lunar disc.

I was just going to watch the transit visually through my 85 mm spotting scope, but decided at the last minute to try taking some pictures too. The spotting scope was placed on a fixed tripod and set to 50x. Next to it, I set up the camera on a fixed tripod close enough that I could operate the cable release while looking through the scope. I used my Canon 7D Mark II digital SLR camera and a Canon 400 mm f/5.6L telephoto lens. After a few test frames to get a suitable exposure (1/400 second at f/8, ISO 800, daylight white balance), I set the camera to high speed continuous shooting mode (up to 10 frames per second) and as the time of transit approached, turned on live view to lock the mirror up.

Initially, I saw the illuminated ISS with unaided eyes low in the northwest at 8:45 pm as it rose heading north (moving left to right) and then ultimately entered the bowl of the Big Dipper, where it disappeared into the earth's shadow. I had the NIST web clock on my smartphone's screen (holding the phone below the eyepiece so I could see both at the same time) and planned to begin taking pictures at 8:51:00 pm, about three seconds before the predicted start of transit as calculated by the ISS Transit Finder for Swede Run. Taking only full-resolution JPEG images, the 7DII can capture almost 10 frames/second indefinitely. At the last minute, I fiddled with the aim of the camera and didn't start the imaging run until 8:51:01 or :02.

Looking into the eyepiece, I never saw the dark spot of the ISS moving across the lunar disc, so I kept the camera running for 20+ seconds hoping to catch something in case I actually started early or the pass was a bit later than predicted. A total of 215 "transit" frames were captured. A quick look at the images on the camera's rear screen didn't show anything either, and when I checked the time stamps of the images, they started at 8:51:22 and ended at 8:51:45 pm (the camera's GPS was turned on for setting its internal clock). So, it did indeed look like some sort of timing error occurred and I ended up with no visual sighting or any pictures of the ISS. I then compared the camera and smartphone times directly and it did look like the camera was 20 seconds or so fast, but it was set to 15-second updates, so it difficult to get a good comparison. After switching the camera to a 1-second update, the two clocks were essentially identical, so I don't really know what happened. Next time, I'll make sure to check the clock synchronization before the event!

 Anyway, when I returned home and looked at the images on my laptop, I did find a series of faint dark spots moving across the lunar disc along the expected track starting near the 10 o'clock limb position, so I had captured the transit after all, and the NIST clock on the smartphone must have been accurate. However, the dark spots of the ISS were much less prominent than those in typical ISS transit pictures. The ISS in the image above is the most distinct one I could find in the set. It's in the upper-left quadrant, at the upper vertex of an isosceles triangle formed with the craters Aristarchus and Copernicus (mouseover for a magnifying, highly cropped image with labels).

So, circumstances weren't ideal for an ISS transit and the results weren't outstanding, but it was interesting nevertheless. And it was definitely a learning experience.



Venus and Mars
October 7, 2017

Venus and Mars were just a degree apart on the morning of October 7, 2017, after Venus passed a quarter of a degree from Mars on the morning of October 5 as it heads east towards superior conjunction with the sun on January 9, 2018, so it's rising later on successive mornings. Mars is also moving east at this time, but at a lesser rate than Venus and the sun, so it's rising a little earlier every morning after solar conjunction on July 26, 2017, and towards a perihelic opposition on July 27, 2018. Bright Venus, at magnitude -3.9, was easily visible with unaided eyes once it cleared the tree tops shortly after arrival at 5:15 am EDT. Mars, at magnitude +1.8 (5.7 magnitudes or 190 times dimmer than Venus), was first seen with difficulty at 5:30 am, but from 5:45 am until 6:15 am when I left, it was relatively easy to see. When I arrived home at 6:30 am, some effort was needed to pick out Mars with unaided eyes in the brightening twilight it would have been impossible to spot without nearby Venus as a guide.

This image was captured at 5:57 am EDT (65 minutes before sunrise) from Swede Run in Moorestown, NJ, with a Canon 6D digital SLR camera (on a fixed tripod) and a Tamron 45 mm f/1.8 lens. It was exposed 2 seconds at f/4, ISO 1000 and 4500K white balance. It was mildly cropped to a 16:9 ratio. In the foreground, some ground fog can be seen above the recently-harvested soybean field. Mouseover for labels.



Geostationary Satellites
September 29, 2017

Inspired by Bob King's article at Sky & Telescope online, and the cool, clear fall weather, I went to Carranza Field on the morning of September 29, 2017, to try and capture an image of some geostationary satellites. I also wanted to spot comet C/2017 O1 (ASASSN) for the first time, which I did at 2:14 am EDT with my 85 mm spotting scope. It was just a dim patch of haze, without a tail, about 12 northeast of the Pleiades (about a degree from 55 & 56 Persei).

Back to the picture. It was taken at 2:52 am EDT with a Canon 6D digital SLR camera (on a fixed tripod) and a Canon 200 mm f/2.8L II USM lens, then cropped to roughly 60% of the original size (and to a 16:9 ratio), yielding a field about 6.6 wide x 3.7 high. It's a single frame exposed 180 seconds (3 minutes) at f/4, ISO 400 with 3800K white balance. Long exposure noise reduction was manually turned on, so a 3 minute dark frame was automatically taken and processed by the camera (otherwise, a number of random colored specks were present). Among the numerous star streaks generated by the long exposure, there are nine white point-like objects, presumably geostationary satellites. Given the three-minute exposure near the celestial equator, the streaks are about three-quarters of a degree long (3 min / 60 min/hr x 15/hr).

 I'm not vey good at figuring out star-trail fields, but since I knew the approximate area where the camera was pointed, about 10 below and slightly left of Alrisha (Alpha Piscium, the knot joining the Ropes of Pisces), I believe the field is centered near 67 Ceti, a magnitude 5.6 star at -6.3 declination (which was at 43 altitude, 169 azimuth at the time). Since geostationary satellites are nominally 22,300 miles above the equator, parallax from viewing them here at 40N latitude makes them appear to be about 6.3 south of the celestial equator. I did not attempt to identify the specific satellites, but they have been marked on mouseover. Six of the nine labeled satellites are in a horizontal line with 67 Ceti, while three are up to a few degrees below below it. I'm not sure why that is.



Mercury, Regulus and Mars
September 9, 2017

Mercury was near Regulus and Mars before sunrise on September 9, 2017. This picture of the trio was captured at 5:41 am EDT from Carranza Field in Wharton State Forest, NJ, 40 minutes after the start of astronomical twilight (5:01 am) and 53 minutes before sunrise (6:34 am). Mercury was 1.0 southwest (to the right) of Regulus (Alpha Leonis) and Mars was 2.5 east (below-left) of Regulus, which was 5.3 altitude at the time. Mouseover for labels. Mercury had  brightened significantly to magnitude +0.1, from +1.7 when observed on September 4, and was easily seen with unaided eyes once it cleared the trees at 5:30 am. It was still visible at 6 am when I left the field. Regulus (magnitude +1.4) and Mars (magnitude +1.8) were also seen with unaided eyes at the time of the picture. Taken with a Canon 6D digital SLR camera and a Canon 200 mm f/2.8L lens (on a fixed tripod), then cropped to about 70% of the original size, yielding a frame about 7.8 wide x 4.4 high. Exposed 1 second at f/5.6, ISO 800.


While waiting for Mercury and its companions to rise and clear the trees on September 9, 2017, I took this picture of Venus at 4:55 am. The moon, three days past full and still 89% illuminated, was high in the sky behind my right shoulder, so the field itself is illuminated in this long exposure. Venus, of course, is the brilliant object in the bottom-left quadrant at 9 altitude. It's in Cancer, just west (above) the border with Leo. Above, and slightly right of Venus, is Messier 44, the Beehive Cluster in Cancer. Towards the upper-right corner is the first magnitude star Procyon, and above it, Gomeisa. This pair forms the single-line stick figure of Canis Minor. Mouseover for labels. Taken at 4:55 am EDT with a Canon 6D digital SLR camera (on a fixed tripod) and a Tamron 45 mm f/1.8 lens, producing a field about 43 wide x 30 high. Exposed 6 seconds at f/4, ISO 1600 (that's about 4.5 stops more exposure than the Mercury-Regulus-Mars twilight image above).



The Nearly-Full Moon
September 4, 2017

Here's the waxing gibbous moon at 10:02 pm EDT on September 4, 2017, about 29 hours before new at 3:03 am on September 6. Taken with a Canon 7D Mark II digital SLR camera and a Tamron 150-600 mm f/5-6.3 zoom lens on a fixed tripod, set to 600 mm focal length then cropped to a little more than 50% of the original frame (yielding a field about 1.1 wide x 0.8 high). Exposed 1/800 second at f/8, ISO 800. Mouseover for labels. Click here for a larger, unlabeled version.



Large Sunspots
September 4, 2017

Here's the sun at 1:33 pm EDT on September 4, 2017, showing a couple of prominent sunspot groups. The spots could also be seen with unaided eyes (using proper solar filtration of course). For most of this year, sunspots have been weak or nonexistent as we head to an expected deep solar minimum. Taken with a Canon 7D Mark II digital SLR camera and a Tamron 150-600 mm f/5-6.3 zoom lens on a fixed tripod, set to 600 mm focal length then moderately cropped. Exposed 1/3200 second at f/22, ISO 1600, through an ND5 filter, which yields a natural white color, but the sun was colorized with Corel PaintShop Pro. Focus and exposure settings are not optimum as I still need to improve camera technique in bright sunlight. Mouseover for active region labels.



Mercury Update - September 2017

Mercury has six elongations in 2017. The initial sighting for each of these is tabulated below:


Initial Sighting Date (2017)

Observing Location

Greatest Elongation (2017)


January 5, 6:15 am EST Old Mart Site, Pennsauken, NJ

January 19, western (morning)


March 16, 7:16 pm EDT Baseball Fields, Maple Shade, NJ

April 1, eastern (evening)


May 14, 5:05 am EDT Old Mart Site, Pennsauken, NJ

May 17, western (morning)


June 26, 8:33 pm EDT New Albany Rd, Moorestown, NJ

July 29, eastern (evening)


September 4, 5:50 am EDT Swede Run, Moorestown, NJ

September 12, western (morning)



November 23, eastern (evening)

Click here for the sighting details of each elongation this year. The current sighting streak is now 43 elongations in a row, starting in January 2011, which includes six complete calendar years of six or seven elongations each (click here for sightings from last year's elongations). This demonstrates that locating and seeing Mercury is not nearly as difficult as many suppose. It just takes some planning and a little effort.



Partial Solar Eclipse
August 21, 2017

Clouds developed early in the afternoon of August 21, 2017, the day of the total solar eclipse, although it was only a partial eclipse in the Philadelphia area, including Maple Shade, NJ, where this picture was taken at 2:25 pm EDT, 20 minutes before the maximum 75% obscuration. It's the only usable shot of the few captured during brief gaps in the clouds, streaks of which can be seen in the picture. Taken with a Canon 6D digital SLR camera and a Tamron SP 150-600 mm f/5-6.3 zoom lens (on a fixed tripod) set to 600 mm focal length. It was exposed 0.6 seconds at f/11, ISO 400 through an ND5 filter (ND5 = neutral density, 10^5 or 100,000x attenuation, about 16.6 photo stops). Update, September 7, 2017: The image was re-cropped to about 57% of the original size, and re-centered, yielding a field about 2.0 x 1.3. The solar crescent was also colorized from its natural white with Corel PaintShop Pro.

For a collection of superb eclipse images, check out Jerry Lodriguss' site.



The Crescent Moon Nears the Eclipse
August 20, 2017

On August 20, 2017, the crescent Moon rose at 4:40 am EDT, 14 minutes after the start of astronomical twilight and 85 minutes before sunrise. This picture of it was captured at 5:16 am when it was 2.3% illuminated and 4 altitude as viewed from Carranza Field in Wharton State Forest, NJ. That morning's crescent Moon had a solar elongation of 17.5 and it was the last time it would be readily visible before the solar eclipse on August 21. It was 33 hr 14 min before new when the picture was taken with a Canon 6D digital SLR camera and a Tamron SP 150 to 600 mm f/5-6.3 zoom lens (on a fixed tripod) set to 600 mm focal length (not cropped). It was exposed 1 second at f/8, ISO 12,800 and  3600K white balance. The moon was last seen with unaided eyes, after first locating it with 10x50 binoculars, at 6:05 am from the side of a field next to Seneca High School on Carranza Rd. At 6:10 am, the thin crescent was still fairly easy in the 10x50s, but it could no longer be seen with unaided eyes. The moon was 32 hr 20 min before new when last viewed at 6:10 am. Click here for additional pictures from August 20 at 300 mm and 150 mm focal lengths.



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Last Update: Friday, October 20, 2017 at 08:15 PM Eastern Time