October 18, 2017

Astro-Vid Of the Week: The Transit of Deimos

Phobos & Deimos as seen from MSL

Credit: NASA/JPL.

(Click here for full size view).

This past week saw the celebration of the one year anniversary of the landing of the Mars Curiosity rover at Gale crater. In just one year, the SUV-sized rover has revolutionized our understanding of the Red Planet.

And although it’s equipped to be a geologist, the Mars Science laboratory (MSL) has been a surreptitious astronomer on occasion as well. We routinely comb through the MSL camera archive and were recently surprised to find an image of the Martian Moons of Phobos and Deimos in one frame! [Read more...]

AstroChallenge: Spotting NOSS pairs and Martian Moons.

A NOSS satellite pair plus aircraft… (Photos by Author).

By now, satellites drifting silently in the dawn or dusk skies are nothing new to you, the experienced sat-spotter. But every once in a while, you just might catch a glimpse of something truly weird… This week, we’ll take a look at what are known as NOSS pairs… & “stay tuned” for a teaser for the upcoming Mars opposition and a chance to hunt for its elusive moons.

NOSS stands for Naval Ocean Surveillance System. These satellites were launched in sets starting with the first generation of NOSS satellites in 1976 and continuing through to 2007. They generally appear either as a moving triangle “constellation” or more commonly as pairs. There is some thought that further NOSS sets may even comprise more than three sats; we once spotted a row of five evenly spaced satellites from the Chena Flood Channel in Alaska in the 90s’. NOSS satellites are classified and used to track ships at sea, most notably Soviet subs during the Cold War.

A NOSS pass to the north of Astroguyz HQ.

In our experience, spotting these pairings has been an entirely surreptitious affair; we’ve had four positive sightings in 10 years of serious satellite watching. Orbitron currently tracks 63 NOSS sets in Low Earth Orbit. Most have looping elliptical orbits that guarantee drastically different appearances from apparition to apparition. Generally below the naked eye threshold of +5th magnitude, these satellites can be surprisingly bright if you catch them just near perigee. In my experience, I’ve seen NOSS pairs from middle northern latitudes passing within 30 degrees on either side of the zenith. Both photos included were “lucky shots” when I had the camera at the ready to swing into action while photographing other targets. A concerted campaign to catch NOSS pairs would take into account a careful analysis of the perigee times versus the solar angle overhead; Orbitron, Celestrak and Heavens-Above are all good resources. Hey, I’m refining said technique myself! Another technical dissertation on “NOSS-hunting” can be found here. Drop us a line on thoughts, techniques, and any true tales of sat-spotting!

Orientation of the orbit of the Martian moons; (North is up) note the +12 magnitude background star depicted on February 15th! (Created by the Author in Starry Night).

Also this week, we wanted to issue our challenge on the run-up to the 2012 opposition of Mars on March 3rd to try and spot the tiny Martian moons of Deimos and Phobos. We wrote about this challenge as well as tips and tricks to Martian moon-spotting during the last opposition in 2010, and February-March of this year is a good time to try. The featured strip chart depicts greatest elongation for each respective moon in Universal Time in terms of Mars radii.

Ephemeris of the Martian Moons through mid-March; (Credit: Ed Kotapish).

The asute will notice that areas where the two paths cross, a “Martian moon conjunction” will occur, perhaps raising their cumulative brightness a notch. Yes, this opposition is a particularly unfavorable one, although that shouldn’t stop you from trying. This is because Mars reaches aphelion this week on February 15th at a distance of 154.9 million miles from the Sun, its farthest aphelion since 1995. Thus, Mars will grow from a visual diameter this of 13.1” arc seconds in size on February 15th to nearly 14” in early March. Phobos and Deimos are +12 and 13th magnitude respectively, over 63,000 times fainter than bright -1.2 magnitude Mars. So drag out that light bucket and plop in that occulting bar eyepiece for a chance to replicate the epochal 1877 discovery of these elusive moons by Asaph Hall… expect a full post on the 2012 opposition of Mars at the end of February!

 

15.10.11: The Strange New World of Vesta.

Vesta’s south pole region as seen from Dawn’s framing camera. (Credit: NASA/JPL).

NASA’s Dawn spacecraft remains the mission that perhaps you’re not following, but should be… since entering orbit around the main belt asteroid 4 Vesta, the plucky ion-propelled spacecraft is returning some fairly mind-blowing images.  The asteroid/proto-planet/insert-current-favorite-definition is becoming a brave new world before our very eyes, the first dwarf planet we’ve orbited and reconnoitered in detail. What are those ridges? What caused intriguing features such as the overlapping crater doublet dubbed “the Snowman?” [Read more...]

August 2010: Life in the Astro-Blogosphere.

 Summer Lightning as seen from Astroguyz HQ. (Photo by Author).

   Summer lightning as seen from Astroguyz HQ. (Photo by Author). 

   The sultry days of summer are now upon us, in what’s usually the last of the traditional northern hemisphere summer months. You can almost feel the darkness beginning its slow creep back into our daily lives. Although we continue to operate in “stripped down mode” new Astroguyz content will  still continue to be generated on a bi-weekly basis. Here’s what you can expect coming to an astro-blog near you; [Read more...]

12.03.10:Update: A Phobos Flyby/Martian Moons Ephemeris II.

 

(Credit: ESA/DLR/FU Berlin (G. Neukum).

(Credit: ESA/DLR/FU Berlin (G. Neukum).

 Mars Express scouts the proposed landing site(s) for Phobos-Grunt.

    The pictures are in: ESA’s Mars Express has performed two close flybys of Phobos in the past weeks and performed sensitive gravimetric as well as photographic reconnaissance passes of the bizarre moon. Of course, the data reveals more questions than it solves. Is Phobos solid rock, or just a loose rubble pile? Clearly, more is to be learned about this misshapen moon…we’ll have the pics up as soon as they’re in!

   The good news is, it not too late to try and spot these elusive beasties for yourself! Reader Ed Kotapish was good enough to provide us with an extended ephemeris for the eastern elongations of both Deimos and Phobos; note that on early Saturday, the 13th both moons are at their eastern most elongations within 20 minutes of each other! This curious event is favorable for U.S. viewers;

here are the greatest elongations for the Martian moons given in Universal Time through the rest of March;

12 MAR 2010
PHOBOS 2134 W

13 MAR 2010
PHOBOS 0125 E
PHOBOS 0513 W
PHOBOS 0904 E
DEIMOS 0924 E
PHOBOS 1252 W
PHOBOS 1643 E
PHOBOS 2031 W

14 MAR 2010
PHOBOS 0022 E
DEIMOS 0032 W
PHOBOS 0411 W
PHOBOS 0802 E
PHOBOS 1150 W
PHOBOS 1541 E
DEIMOS 1541 E
PHOBOS 1929 W
PHOBOS 2320 E

15 MAR 2010
PHOBOS 0308 W
DEIMOS 0650 W
PHOBOS 0659 E
PHOBOS 1047 W
PHOBOS 1438 E
PHOBOS 1827 W
DEIMOS 2159 E
PHOBOS 2218 E

16 MAR 2010
PHOBOS 0206 W
PHOBOS 0557 E
PHOBOS 0945 W
DEIMOS 1308 W
PHOBOS 1336 E
PHOBOS 1724 W
PHOBOS 2115 E

17 MAR 2010
PHOBOS 0103 W
DEIMOS 0417 E
PHOBOS 0454 E
PHOBOS 0843 W
PHOBOS 1234 E
PHOBOS 1622 W
DEIMOS 1926 W
PHOBOS 2013 E

18 MAR 2010
PHOBOS 0001 W
PHOBOS 0352 E
PHOBOS 0740 W
DEIMOS 1035 E
PHOBOS 1131 E
PHOBOS 1520 W
PHOBOS 1911 E
PHOBOS 2259 W

19 MAR 2010
DEIMOS 0143 W
PHOBOS 0250 E
PHOBOS 0638 W
PHOBOS 1029 E
PHOBOS 1417 W
DEIMOS 1652 E
PHOBOS 1808 E
PHOBOS 2156 W

20 MAR 2010
PHOBOS 0147 E
PHOBOS 0536 W
DEIMOS 0801 W
PHOBOS 0927 E
PHOBOS 1315 W
PHOBOS 1706 E
PHOBOS 2054 W
DEIMOS 2310 E

21 MAR 2010
PHOBOS 0045 E
PHOBOS 0433 W
PHOBOS 0824 E
PHOBOS 1213 W
DEIMOS 1419 W
PHOBOS 1604 E
PHOBOS 1952 W
PHOBOS 2343 E

22 MAR 2010
PHOBOS 0331 W
DEIMOS 0528 E
PHOBOS 0722 E
PHOBOS 1110 W
PHOBOS 1501 E
PHOBOS 1849 W
DEIMOS 2037 W
PHOBOS 2240 E

23 MAR 2010
PHOBOS 0229 W
PHOBOS 0620 E
PHOBOS 1008 W
DEIMOS 1145 E
PHOBOS 1359 E
PHOBOS 1747 W
PHOBOS 2138 E

24 MAR 2010
PHOBOS 0126 W
DEIMOS 0254 W
PHOBOS 0517 E
PHOBOS 0905 W
PHOBOS 1257 E
PHOBOS 1645 W
DEIMOS 1803 E
PHOBOS 2036 E

25 MAR 2010
PHOBOS 0024 W
PHOBOS 0415 E
PHOBOS 0803 W
DEIMOS 0912 W
PHOBOS 1154 E
PHOBOS 1542 W
PHOBOS 1933 E
PHOBOS 2322 W

26 MAR 2010
DEIMOS 0021 E
PHOBOS 0313 E
PHOBOS 0701 W
PHOBOS 1052 E
PHOBOS 1440 W
DEIMOS 1530 W
PHOBOS 1831 E
PHOBOS 2219 W

27 MAR 2010
PHOBOS 0210 E
PHOBOS 0558 W
DEIMOS 0639 E
PHOBOS 0950 E
PHOBOS 1338 W
PHOBOS 1729 E
PHOBOS 2117 W
DEIMOS 2147 W

28 MAR 2010
PHOBOS 0108 E
PHOBOS 0456 W
PHOBOS 0847 E
PHOBOS 1235 W
DEIMOS 1256 E
PHOBOS 1626 E
PHOBOS 2014 W

29 MAR 2010
PHOBOS 0006 E
PHOBOS 0354 W
DEIMOS 0405 W
PHOBOS 0745 E
PHOBOS 1133 W
PHOBOS 1524 E
PHOBOS 1912 W
DEIMOS 1914 E
PHOBOS 2303 E

30 MAR 2010
PHOBOS 0251 W
PHOBOS 0643 E
DEIMOS 1023 W
PHOBOS 1031 W
PHOBOS 1422 E
PHOBOS 1810 W
PHOBOS 2201 E

31 MAR 2010
DEIMOS 0145 E
PHOBOS 0154 W
PHOBOS 0545 E
PHOBOS 0933 W
PHOBOS 1324 E
DEIMOS 1653 W
PHOBOS 1712 W
PHOBOS 2103 E

 Good luck, and again, we’d love to hear of any confirmed sightings!

04.03.10: A Close Flyby of Phobos.

401-20080729-5851-6-na-1b-Phobos-Flyby_H1
Phobos on a pass of Mars Express last July. (Credit: ESA/DLR/FU Berlin/G. Neukum).

  

 The European Space Agencies’ (ESA) Mars Express orbiter completed the closest ever flyby of the misshapen Martian moon, Phobos, but don’t expect to see any mind blowing pictures…yet. Part of a series of 12 flybys, last nights’ pass skimmed to worldlet by 67 km, allowing its feeble gravity to deflect the space probe by a tiny but perceptible amount. This will allow engineers on the ground to get an idea of the internal density and composition of Phobos. But to do so, all instruments must be silent, so scientists can isolate minute oscillations on the probes carrier signal via the Doppler Effect. But take heart; Mars Express will further probe the moon on future passes via its MARIS radar, and will have its cameras switched on during next weeks’ March 7th pass…expect more cool pics soon!

Astro-Challenge: Can You Spot the Moons of Mars?

Mars and its moons as they appeared on the moment of their discovery in 1877. (Credit: Constructed by the Author in Starry Night).

Mars and its moons as they appeared on the moment of their discovery in 1877. (Credit: Constructed by the Author in Starry Night).

This weeks’ challenge is a toughie and not for the faint of eye sight. In 1877, American astronomer Asaph Hall discovered the Martian Moons using the newly installed 26” refracting telescope at the U.S. Naval Observatory. Named appropriately Phobos (fear) and Deimos (terror), the moons were well suited companions for Mars, the god of war. Both moons, however, are tiny; outermost Deimos is 12.6 km in size and orbits Mars once every 30.35 hours, while innermost Phobos is larger, at 22.2 km in size and orbits the Red Planet in only 7.7 hours! In fact, at an orbital radius of only 9,377 km, Phobos orbits its primary closer than any other satellite in the solar system. Both tiny misshapen worlds are believed to be captured asteroids that will, one day millions of years in the future, spiral into Mars. Most of the time, these moons lie out of the range of all but the largest telescopes; but as Mars just passed opposition this past week, however, sighting these elusive moons might just be possible. [Read more...]

An Ephemeris of the Martian Moons.

This is a quick posting of the best apparitions of the moon of Mars, Deimos and Phobos, as promised in the Mars opposition post. The tables run for a week after opposition, and are accurate to about 10 minutes or so. I hand crafted these in Starry Night after I found a lack of info about the web for this data. Obivously, we here at Astroguyz see a definite gap that those looking to spot these ellusive beasties are in need of. With Mars at opposition, the closest Full Moon of the year, and two back to back launches, its going to be a busy last week of January…. we’ll have a larger post out on tips to spy the Martian moons this weekend!

Deimos Date EST
     
Eastern Elongation 29 6:48
Western Elongation   21:33
Eastern Elongation 30 13:01
Western Elongation 31 4:00
Eastern Elongation   19:29
Western Elongation 1 10:42
Eastern Elongation 2 1:36
Western Elongation   16:22
Eastern Elongation 3 8:04
Western Elongation   22:30
Eastern Elongation 4 14:08
Western Elongation 5 5:31
Eastern Elongation   20:07
Western Elongation 6 11:20

 

Phobos

   
   Date  EST
Eastern Elongation 29 2:48
Western Elongation   6:46
Eastern Elongation   10:29
Western Elongation   14:19
Eastern Elongation   18:13
Western Elongation   21:48
Eastern Elongation 30 1:43
Western Elongation   5:37
Eastern Elongation   9:30
Western Elongation   13:10
Eastern Elongation   17:00
Western Elongation   20:55
Eastern Elongation 31 0:49
Western Elongation   4:41
Eastern Elongation   8:30
Western Elongation   12:04
Eastern Elongation   15:56
Western Elongation   19:45
Eastern Elongation   23:42
Western Elongation 1 3:30
Eastern Elongation   7:28
Western Elongation   11:10
Eastern Elongation   14:52
Western Elongation   18:47
Eastern Elongation   22:41
Western Elongation 2 2:34
Eastern Elongation   6:30
Western Elongation   10:19
Eastern Elongation   14:00
Western Elongation   17:45
Eastern Elongation   21:40
Western Elongation 3 1:30
Eastern Elongation   5:24
Western Elongation   9:11
Eastern Elongation   12:56
Western Elongation   16:42
Eastern Elongation   20:31
Western Elongation 4 12:29
Eastern Elongation   4:20
Western Elongation   8:08
Eastern Elongation   11:52
Western Elongation   15:41
Eastern Elongation   19:30
Western Elongation   23:10
Eastern Elongation 5 3:08
Western Elongation   6:58
Eastern Elongation   10:50
Western Elongation   14:40
Eastern Elongation   18:24
Western Elongation   22:10
Eastern Elongation 6 2:05
Western Elongation   6:01
Eastern Elongation   9:42
Western Elongation   13:42
Eastern Elongation   17:26
Western Elongation   21:08

Astro-Event: Mars at Opposition.

Mars during the 2005 opposition. (Photo by Author and Graphic created in Mars Previewer).

Mars during the 2005 opposition. (Photo by Author and graphic created in Mars Previewer).

Contrary to the once-every-August viral emails soon to be clogging your inbox, Mars will not appear as “large as a Full Moon” on this or any other year… but Mars will reach opposition this week on Friday, January 29th. Unfortunately, this apparition isn’t a particularly favorable one; Mars will only reach 14.1” arc seconds in apparent diameter, a far cry from the excellent 2003 opposition where it reached 25.1”, very close to the possible max. This is due to the fact that while Earth reached perihelion earlier this month, Mars is also very close to aphelion in its relatively eccentric orbit. In fact, although Mars approaches us every two years or so, the next really good opposition won’t be until 2018 (24.3”).  Still, any opposition of the Red Planet is worth viewing, as it is rare that Mars reveals any detail at all! Mars is currently in the constellation Cancer, and rises low in the east after sunset. Shining at magnitude -1.2, Mars is unmistakable for its orange-to red glow. Do things look a bit yellowish? A planet wide dust storm could be underway, as it is entering spring on the northern hemisphere of Mars. [Read more...]

Review:Redshift 7: The Ultimate in Astronomy Software.

Desktop-based planetarium programs have really come into their own in the past few years. From their early evolution in the 1980′s with computer programs written in Basic that would show you stick figure constellations, planetarium programs are now full fledged sky simulators that allow you not only to control your telescope and plan your observing sessions more effectively, but allow you to travel through space as well as time.

[Read more...]

Extreme Observing: Challenges on the Edge

Astronomy is a life long pursuit. The universe and time are so vast, I have yet to meet someone who has truly seen it all, even from our sometimes beleaguered vantage point here on Earth. Some targets, like Saturn or the ring nebula, are never tiring to look at. However, as I rack up the years of observing, I find it fun and refreshing to push my skills to the edge. Call it Extreme Astronomy, a sport of sorts. Popular Messier marathons are in this vein. I find that this kind of pursuit can sharpen my skills and hone my knowledge. While I never tire of showing folks Andromeda during public observing, it can be fun to aim at a lesser known object that no one else at the star party has in the eyepiece. Anyhow, below are my top 12… some I’ve seen, some I’ve attempted, and some I know of but have yet try. I’ve tried to keep things as “visual” as possible (i.e. telescope only!), but technology can present is own challenges as well. After all, I’d hate to think I’ve finally seen everything! [Read more...]