51 2–22.07, 1990; 3–15.0,1991... 19–11.08,1999 ... 39– 11.09, 2007. The solar eclipse of August 11, 1999 has in this temporal circle the number 21. It must be noted that eclipses within this cycle are not part of the same Saros series since series is formed by eclipses repeated every 18 years, over 12–15 hundred years. In our proposed depiction we chose the place of the month of the year on the circle from right to left, to be in agreement with the direction of the Sun on the ecliptic, as we observe in nature with the sky above our head. When we put each eclipse on the day of the month, we see it alternating every six months in agreement with the seasons of eclipse. Their layout (Figure 2) is not done in a calendar order, but we notice that there are five pairs of families, i.e. A-a, B-b, C-c, D-d, E-e. It appears like an imaginary force is ensuring that each circle should be covered by 39 eclipses. Given this fact we propose that the temporary circle defined by eclipses occurring within a single Saros cycle to be named also “Saros Year” by analogy with the civil year, the Platonic year, the galactic year, etc. THE SPIRAL DIAGRAM. THE ROSETTE OF SOLAR ECLIPSES AND SAROS SERIES Next, we present a novel illustration of the succession of eclipses of Saros series into spirals diagrams who look like a rosette. This is a different approach from den Bergh’s matrix approach (van den Bergh, 1955) and has the advantage of better outlying the major eclipse cycles as depicted next. The creation of the spirals proceeds as follows: First, we trace several concentric temporary circles, each divided in twelve parts for the twelve months of the year and the days. Next, we mark on circles the position of all the eclipses in a Saros cycle by starting from the inner circle. Having completed all the eclipses inside one cycle, we proceed to add the eclipses of the next Saros cycle. As we mark the position of each eclipse on these circles, we observe, in agreement with the idea that eclipses succeed one another at intervals of about six months, that through two consecutive years, approximately in and after the same period of the year, the period of appearance of the eclipses changes. In our presentation (Figure 3), we began by illustrating the eclipse of January 16, 1972, and ended with the eclipse of October 24, 2079. For each eclipse we used data from the Five Millennium Catalog of Solar Eclipse (Espenak and Meeus, 2006). After displaying on the first circle the position of the 39 eclipses within the first Saros cycle, we start again on the second circle, and mark the fortieth eclipse as the first one of the second Saros cycle, which starts on 26 January 1990. Then the first eclipse of the third Saros cycle starts on February 2008, etc. Each eclipse is represented by two numbers: inside the temporary circle is the date of the month and the outside marked with an apostrophe there are the two last digits of the year. For instance, 16/’72 means the 16th day of January 1972, and 11/’99 means August 11, 1999, where the month is visible in the figure. For the four eclipses of 2000, February 5, July 1, July, 31 and December 25 we wrote the full year 2000. For the eclipses of the XXI century, we used the notation /’ 01, /’ 02 . . . /’ 79. It is interesting to observe that, the eclipses of the Fig. 3: The Rosette of spiral diagrams of Saros series of solar eclipse between January 16, 1972 – May 1, 2079
same Saros series are arranged into a spiral. This is because each eclipse in a Saros cycle is 11 days late every 18 years. Finally, all these spiral diagrams look like a rosette. On the outer edge of the rosette are marked the serial numbers of the Saros series; 117, 118, 119 . . . 155. As we already mentioned, the Saros series groups itself in five pair of families: A-a, B-b, C-c, D-d, and E-e, of which the components are “born” in successive diametrical positions during the Saros cycle. We realize that in the time range we use (January 16, 1972 – May 1, 2079) nine of these families have four members, and that the tenth, the family “a” has only three members. The Saros series in each family is as follows: • A (121, 131, 141, 151); a (126, 136, 146) • B (123, 133, 143, 153); b (118, 128, 138, 148) • C (120, 130, 140, 150); c (125, 135, 145, 155) • D (122, 132, 142, 152); d (117, 127, 137, 147) • E (119, 129, 139, 149); e (124, 134, 144, 154) It is interesting to note that in each family the interval between two successive Saros series is 10, for example: 121–131–141–151 etc. Very interesting is the fact that the rosette is a solar symbol. In ethnography, the rosette with curved arms represent the moving Sun (Olenici, 2016). THREE TYPES OF SERIES OF SOLAR ECLIPSES FOUND IN THE ECLIPSE ROSETTE By carefully analyzing the arrangement of the eclipses within the rosette we find that we can distinguish three types of eclipse series (Figure 4): • I-Spiral series (succession according to Saros cycles); • II-Radial series (succession according to Metonic cycle); • III-Circular series (succession according to the lunar year of 354 days). Here, we mention the fact that over time, 82 types of eclipse cycles have been highlighted. They have various timespans and names such as: the Saros (18.0 years), Sar (Half Saros, 9.015 years), Metonic Cycle (19.0 years), Hipparchos Cycle (345 years), Exeglimos (54.1 years), Babilonian Period (441.3 years), Hexon (2.83 years), Hepton (3,315 years), Tzolkinex (7,115 years) etc. (FlatEarth.ws) CORRELATION BETWEEN THE SAROS CYCLE AND MAYA INTERVALS A careful analysis shows us, that, this interval of 354 days is double the duration of the Maya cycle of succession of eclipses at interval of 177 days. This interval was deciphered in The Codex of Dresden, and there was also a shorter interval of 148 days (Innvista). These are average values, in practice there are also values of 176 and 179 days as well as 145, 146, 147, and 149 days. As it can be noticed in Figure 5, these values are repeated according to the Saros cycle. We notice the chaining, after the Mayan cycles (vertically), of the solar eclipses for a period of five years 1981–1985 and their repetition, after the Saros cycle (horizontally), in the years 1999–2003, 2017–2021, and 2035–2039. If we correlate the Maya intervals and the Saros series, we find a shorter Maya cycle of 29 or 30 days. The two intervals of 148 and 29 days (or 147 and 30) together form the interval of 177 days and follow a complete Saros cycle. The calculations show that six lunar months are exactly 52 Fig. 4 (left): Example of the spiral, radial, and circular series into the rosette of spiral diagrams of Saros series of solar eclipse. Fig. 5 (below): The correlation between Saros cycle (horizontally) and Maya intervals (vertically) for the period between February 5, 1981 and December 15, 2039. Fig. 6 – The Maya eclipse intervals between February 15, 1981 – December 15, 2039.
177 days, 6 x 29:5 =177. In fact, every year there are at least two separate solar eclipses of 177 days apart. Therefore, the Maya may have used this fact to chain the seasons of the eclipses. Another interesting aspect is that the Maya intervals of 29 or 30 days are accompanied by intervals of 148 days as seen in Fig. 6. THE SPIRAL DIAGRAM OF SAROS SERIES NUMBER 145 AND THE CYCLE OF 595 YEARS Another advantage of the representation of the Saros series as a rosette is that when we implement a representation of many eclipses, we can observe the start and the end of a Saros series. In Fig. 7 is illustrated the spiral of eclipses of Saros series number 145. This Saros begins on January 4, 1639 and ends on April 17, 3009 and includes the total solar eclipse of August 11, 1999 centered in Romania. If we cross the spiral radially, joining the adjacent spirals, we identify the 595 year cycle of repeating eclipses (exactly 594.99 years or 217315.6 days) around the same calendar date. For instance, after the solar eclipse of February 27, 1729, at the age of 595, the solar eclipse of February 25, 2324 follows, and after another 595 years, the solar eclipse of February 21, 2919 takes place. This cycle of 595 years, is a multiple of 33 Saros cycles and is mentioned as “Unnamed (595) 33 S“ in (van Gent). Interestingly, if we divide 365.25 days by 11.3 days, we find 32.32. If we count the eclipses in a Saros spiral, we find the number 32, e.g.between January 4, 1639 and December 21, 2215. In other words, expressing in units of time the step in the spirals of the Saros series is 595 years, and the angular velocity is 11 days and 8 hours. CONCLUSION In this article we presented for the first time the concept of temporary succession of eclipses in form a rosette of Saros series. By marking the position of eclipses of Saros cycle on a circle on which the months and calendar data are presented, we find that their arrangement is made alternately at intervals of six months in five pairs of families of series of eclipses. The resulting rosette created by a succession of Saros series of eclipses gives us an overview of the occurrence of Saros cycles and series. Within the rosette we can distinguish the arrangement of three cycles of eclipses: spiral (Saros cycle), radial (Metonic cycle) and circular (lunar year). By viewing an entire Saros series, we can easily notice where it begins and ends. Based on this representation we can also identify a cycle of 595 years for the repetition on nearly the same calendar date of the same eclipse in a Saros series. The shared analysis of the Saros cycle and the Maya intervals of repeating eclipses of 148 and 177 days suggests the idea that there are two more Maya intervals of 29 or 30 days and that the Mayans may have included eclipses in their calendar. In the methodology of teaching astronomy, the rosette of the Saros series helps to create a better overview of the time arrangement of Saros cycles and series. n n n Dimitrie Olenici is a senior member of the Romanian Society for Meteors and Astronomy (SARM). 53 Espenak, F., Meeus, J.: 2006, Five millennium catalog of solar eclipses: -1999 to + 3000 (2000 bce to 3000 ce). https://eclipse.gsfc.nasa.gov/SEpubs/5MCSE.html. FlatEarth.ws: The saros cycle and saros series. https://flatearth.ws/saros-series. Fotheringham, J.K.: 1928, The indebtedness of Greek to Chaldean astronomy. The Observatory 51, 301 – 315. Innvista: Maya and eclipses. http://innvista.com/science/astronomy/ancient/ maya-andeclipses/. Neugebauer, O.: 1975, A history of ancient mathematical astronomy. Part 1; Part 2; Part 3. Nickiforov, M.G.: 2011, On the discovery of the saros. Bulgarian Astronomical Journal 16, 72. Odenwald, S.: Did ancient peoples really predict solar eclipses? https://image. gsfc.nasa.gov/poetry/ask/a11846.html. Olenici, D.: 1999, Eclipsele de când lumea, Soarele și Luna, Casa Corpului Didactic. New version in 2015 by Ion Prelipcean Publishing. Olenici, D.: 2016, Semne și simboluri astronomice în ornamentica tradițională din Bucovina, Editura Accent Print. Picke, J.W.: 1837, The past and the present part 3 and 4. The Western Academician and Journal of Education and Science 1. Todoran, I.: 1977, Eclipsele și prevederea lor, Editura Științifică și enciclopedică. van den Bergh, G.: 1955, Periodicity and Variation of Solar (and Lunar) Eclipses, Tjeenk Willink, and Haarlem Edts.. van Gent, R.: A catalogue of eclipse cycles. https://www.staff.science. uu.nl/˜gent0113/eclipse/eclipsecycles.htm. Yeates, T.: 1820, Remarks on ancient eclipses. The Philosophical Magazine and Journal:Comprehending Various 56 (267), p18. References Fig. 7 – The spiral representation of the solar eclipses of Saros series number 145.
54 the art of astronomy Best in Show & First Place Deep Sky Object Category The Explore Alliance recently hosted its first Astrophotography Contest to recognize the excellent work of the imagers in our membership ranks. We were looking for the best of the best in seven imaging categories: Deep Sky Objects, Planetary, Solar, Lunar, Wide Field, Time-Lapse and Terrestrial. In this issue of Sky’s Up, the astrophotography gallery space is dedicated to showcasing some of the top winners in these categories. Heart of the Soul by Steven Siedentop Equipment: Explore Scientific ED127CF FCD100 telescope; Explore Scientific PMC-Eight G11 Mount; Astro-Tech 60mm Guide Scope; Orion SSAG Guide Camera; ZWO ASI-1600MMCool imaging camera Processing: Lights: 40, 300 seconds, Unity Gain; Darks: 15, 300 seconds; Acquisition Software: Sequence Generator Pro, PHD2; Processing Software: PixInsight with scripts from the DarkArchon repository
the art of astronomy Second Place Deep Sky Object Category Thor’s Helmet by Christopher Sullivan Equipment: Explore Scientific f/3.9 N208-CF Newtonian Astrograph; Explore Scientific HR Coma Corrector; EQ6-R Pro; ZWO 1600 MM-Cool; ZWO RGB; Chroma OIII 3 nm; Optolong Ha 6.5 nm; ZWO OAG; Lodestar X2 guide camera Processing: Chroma OIII: 156x300”; Optolong H-alpha: 173x300”; ZWO Red: 73x150”; ZWO Green: 181x150”; ZWO Blue: 155x150”; 40 darks for 300”; 40 darks for 150”; 25 flats for each filter, stacked in DSS, processed in Photoshop and PixInsight Discover how optics work & explore the night sky with the iconic Galileoscope build-your-own refractor kit! Now available at explorescientificusa.com 55
56 the art of astronomy First Place Timelapse Category Star Trails by James Hubbard Equipment: Explore Scientific EXOS2 PMC-Eight mount; Nikon D3400 and 18-55mm kit lens Processing: Single 15min exposure at Headlands Beach State Park. Third Place Deep Sky Object Category Equipment: Bresser N20839; Asi533; Asi120mini; Idas Ngs1 zf filter; Bresser 8in Newtonian; Eq6-R Pro; Asiair Pro Processing: 285 lights at 120sec; -14c; 0 gain; 20 darks; 100 bias; no flats; processed in Pixinsight and lightroom from Bortle 8 Los Angeles Bubble Nebula by Craig Weston
57 the art of astronomy First Place Wide Field Category Equipment: Explore Scientific ED102 Apo Triplet Refractor; Orion Sirius Eq-g Mount; Canon EOS T2i 550D DSLR; Orion 60mm Guidescope; ZWO ASI120mm Mini Guide Camera Processing: 20 x 180 second subs; ISO 800; 10 Dark Frames; 25 Bias Frames; 25 Flat Frames; Total Integration Time : 1 hour Andromeda Galaxy by Larry Byrge Second Place Wide Field Category Tadpole, Spider & Fly nebulae by John Bellisario Equipment: Explore Scientific ED80CF; ZWO ASI1600MM-Pro; Chroma Sii, Ha, & Oiii; TeleVue TRF-2008 .8x FF/FR; Orion Atlas EQ-G Processing: Sii, Ha, & Oiii 16x600 sec @ unity gain each (-20 degrees cooled, offset 10); Dark: 36; Flat: 36 each; Bias:300; Adobe PS 2019
58 the art of astronomy Third Place Wide Field Category First Place Solar Category Equipment: Explore Scientific David H Levy Comet Hunter; Zwo 183; Baader film; CG-4 hand tracked Processing: Single frame processed in Windows photo Mercury Transit by Richard Grace NGC2264 by Marko Pola Equipment: Explore Scientific EXOS2-GT PMC-Eight Mount; Canon 300mm F/4 Lens; ZWO Canon EOS filter drawer adapter; Optolong L-enhance filter; 30mm/120mm guidescope with ASI120MM-Mini guide camera; ZWO ASI294MC-Pro Camera Processing: 20 x 300 second subexposures with darks, flats, bias frames. Live stacked in the ASIAIR Pro and processed in Siril and Photoshop
59 the art of astronomy Second Place Solar Category Our Star by Jim Norwood Equipment: Explore Scientific iXOS-100 mount; Nikon D7500 DSLR; Nikon 200-500 lens at 480mm (720mm equivalent) Processing: 1/800 sec at f5.6; mylar-type solar filter repurposed from the Great American Eclipse of 2017 Equipment: Explore Scientific ED80CF; Canon T6 Processing: Single Raw frame edited in Windows photo Day Moon by Richard Grace First Place Lunar Category
60 the art of astronomy Second Place Lunar Category Third Place Lunar Category Second Place Planetary Category Equipment: Explore Scientific 152ED APO Refractor; Explore Scientific 82° 14mm eyepiece; Explore Scientific EXOS2-GT PMC-Eight Mount; ExploreStars set to “lunar” tracking speed, iPhone XR Processing: Nightcap app; GIMP Moon by Andrew Corkill The Moon by Stefan Dal Pra Equipment: Explore Scientific 2” 2X Focal Extender; William Optics Z61; Skywatcher Star Adventurer Pro; ZWO ASI224MC Processing: AutoStakker 3; Photoshop Equipment: Explore Scientific EXOS2- GT PMC-Eight Mount; Meade 8” ACF Telescope; GSO 2” Linear Bearing Crayford Focuser; Imaging at 2175mm effective focal length; ZWO ASI294MC-Pro Camera; ZWO Canon EOS filter drawer adapter; ZWO UV/IR Cut filter; ASIAIR Pro Processing: Composite image created by taking 60 second videos of Jupiter and Saturn and processing in Autostakkert and Registax; processed images of the planets were then over laid onto an wide field overexposed image to reveal the moons Great Conjunction — December 21, 2020 by Marko Pola
61 the art of astronomy First Place Planetary Category Third Place Planetary Category Comet Neowise over Lake Erie by James Hubbard Equipment: Explore Scientific iXOS-100 PMCEight mount; Nikon D3400; William Optics Zenithstar 80edll Processing: Single 13s shot, touched up with Lightroom free app Equipment: Explore Scientific EXOS2-GT with PMC-Eight Mount; Skywatcher 100ED; ASI1600 ME Cool; with L-Pro Filter; EAF Focuser Processing: This was a reduced pixel image of about 3000 frames from an AVI File Mars by Tim Myers
the art of nature First Place Terrestrial Category Second Place Terrestrial Category 62 Pelican by Jim Norwood Equipment: Explore Scientific iXOS-100 mount; Nikon D7500 DSLR; Nikon 200-500 lens at 500mm Equipment: Bresser Bird Feeder Camera Processing: Lightroom Carolina Chickadee by Jennifer Shelly
the art of nature Third Place Terrestrial Category PMC UNiVeRSAL POWeR FOR eXPlORATiON Learn more at explorescientific.com Questions/Comments? 866.252.3811 + 8300 mAh Capacity + Rechargeable DC 12V and 5V USB 8300 mAh USB Power Bank with Red LED Flashlight FirstLight 80mm & iEXOS-100 Tracker Combo Kit + Wireless Control or Wired Control via serial + PMC-Eight GoTo System + AR80/640mm Refractor FirstLight 80mm Wireless Control or Wired Control via serial 2020 ASY_Holiday_7.25x3_AD_2020.indd 1 9/25/20 4:56 PM Bee in the Holly by James Hubbard Equipment: Explore Scientific EXOS2 PMCEight mount; Nikon D3400 with 300mm kit lens mounted on top of scope Processing: Minimal touch up with Lightroom free app.
64 The International Dark-Sky Association (IDA) is the recognized authority on light pollution. We work to protect and restore the natural nighttime environment through outreach, public policy, conservation, and the certification of environmentally responsible outdoor lighting. INTERNATIONAL DARK SKY PLACES IDA works to preserve the natural nighttime environment on public and private lands. So far we have designated 87 International Dark Sky Places. Dark Sky Places are committed to night sky conservation and dark sky education. IDA CHAPTERS We support more than 60 IDA Chapters around the world in their efforts to influence their local communities, leading to better lights, increased public awareness and an ever-increasing curiosity about the night sky. FIXTURE SEAL OF APPROVAL PROGRAM We have certified more than 1,000 Dark Sky Approved lighting products for residential, commercial, and municipal use, making it easy for the public to find lighting products that use less energy and have minimal impact on nocturnal wildlife and our night skies. “The nitrogen in our DNA, the calcium in our teeth, the iron in our blood, the carbon in our apple pies were made in the interiors of collapsing stars. We are made of starstuff.” --Carl Sagan Join the Fight to Protect the Night www.darksky.org
January 15 February 1 February 15 March 1 March 15 April 1 April 15 May 1 May 15 June 1 June 15 July 1 July 15 August 1 August 15 September 1 September 15 October 1 October 15 November 1 November 15 December 1 December 15 January 1 DST Local Time A B B C C D D B C D B C D B C D B C D B C D A B C D A B C D A B C D A B C D A B C D A B C D A C D A C D A B A B A A A A 5 p.m. 6 p.m. 7 p.m. 8 p.m. 9 p.m. 10 p.m. 11 p.m. Midnight 1 a.m. 2 a.m. 3 a.m. 4 a.m. 5 a.m. 6 a.m. 7 a.m. 6 7 8 9 10 11 M 1 2 3 4 5 6 7 8 65 With a universe of options to explore, it can be difficult to track what awe-inspiring treasures are visible in your sky each month. To help guide your explorations throughout the year, Sky’s Up is providing the following collection of seasonal star maps created by noted celestial cartographer Wil Tirion. Based in The Netherlands, Tirion has been crafting stars maps since the 1970s and became a professional uranographer shortly after the publication of his highly regarded Sky Atlas 2000.0 in 1981. To learn more about Tirion and his work, click here. the key to your sky created by Wil Tirion
E C L I P T I C Horizon 10°N Horizon 20°N Horizon 30°N nozir oH N°03 zir oH 2 no N°0 zir oH no °01 N SOUTH WEST EAST NORTH WINTER SKY For observers at 10° to 30° northern latitudes A ANDROMEDA ANTLIA ARIES AURIGA CAELUM CAMELOPARDALIS CANCER CANES VENATICI CANIS MAJOR CANIS MINOR CARINA CASSIOPEIA CEPHEUS CETUS COLUMBA COMA BERENICES CRATER DORADO DRACO ERIDANUS FORNAX GEMINI HOROLOGIUM HYDRA HYDRUS LACERTA LEO LEO MINOR LEPUS LYNX MENSA MONOCEROS ORION PEGASUS PERSEUS PHOENIX PICTOR PISCES PUPPIS PYXIS RETICULUM SCULPTOR SEXTANS TAURUS TRIANGULUM URSA MAJOR URSA MINOR VELA VOLANS Adhara Achernar Alphard Betelgeuse Canopus Capella Castor Pollux Polaris Procyon Regulus Rigel Sirius Algol Mira M31 M42 M41 Tarantula Nebula M35 M44 Hyades Pleiades Double Cluster LMC 66 the key to your sky created by Wil Tirion
E C L I P T I C Horizon 40°N Horizon 50°N Horizon 60°N 06 nozir oH N° 5 nozir oH N°0 nozir oH N°04 SOUTH WEST EAST NORTH WINTER SKY For observers at 40° to 60° northern latitudes A BOOTES ANDROMEDA ANTLIA ARIES AURIGA CAELUM CAMELOPARDALIS CANCER CANES VENATICI CANIS MAJOR CANIS MINOR CASSIOPEIA CEPHEUS CETUS COLUMBA COMA BERENICES CORONA BOREALIS CYGNUS DRACO ERIDANUS FORNAX GEMINI HERCULES HOROLOGIUM HYDRA LACERTA LEO LEO MINOR LEPUS LYNX LYRA MONOCEROS ORION PEGASUS PERSEUS PISCES PUPPIS PYXIS SEXTANS TAURUS TRIANGULUM URSA MAJOR URSA MINOR Adhara Alphard Aldebaran Betelgeuse Capella Castor Pollux Deneb Polaris Procyon Regulus Rigel Sirius Vega Algol Mira M31 Double Cluster M42 M35 M41 M44 M13 Hyades Pleiades 67 the key to your sky created by Wil Tirion
E C L I P T I C Horizon 10°N Horizon 20°N Horizon 30°N nozir oH N°03 nozir oH N°02 ozir oH N°01 n SOUTH WEST EAST NORTH SPRING SKY For observers at 10° to 30° northern latitudes B BOOTES ANTLIA AURIGA CAMELOPARDALIS CANCER CANES VENATICI CANIS MAJOR CANIS MINOR CARINA CASSIOPEIA CENTAURUS CEPHEUS CHAMAELEON CIRCINUS COLUMBA COMA BERENICES CORONA BOREALIS CORVUS CRATER CRUX CYGNUS DRACO GEMINI HERCULES HYDRA LEO LEO MINOR LIBRA LUPUS LEPUS LYNX LYRA MONOCEROS MUSCA NORMA OPHIUCHUS ORION PERSEUS PUPPIS PYXIS SCORPIUS SER SERPENS CAPUT SEXTANS TAURUS TRIANGULUM AUSTRALE URSA MAJOR URSA MINOR VELA VIRGO VOLANS Adhara Alphard Antares Hadar Acrux Arcturus Betelgeuse Capella Castor Pollux Polaris Procyon Regulus Rigil Kent Sirius Vega Spica Mimosa Double Cluster M35 M44 M41 M13 Southern Pleiades Eta Carinae Nebula Omega Centauri Jewel Box 68 the key to your sky created by Wil Tirion
B Horizon 40°N Horizon 50°N Horizon 60°N 6 nozir oH N°0 5 nozir oH N°0 04 nozir oH N° SOUTH WEST EAST NORTH SPRING SKY For observers at 40° to 60° northern latitudes BOOTES ANDROMEDA ANTLIA AQUILA ARIES AURIGA CAMELOPARDALIS CANCER CANES VENATICI CANIS MAJOR CANIS MINOR CASSIOPEIA CENTAURUS CEPHEUS COMA BERENICES CORONA BOREALIS CORVUS CRATER CYGNUS DRACO GEMINI HERCULES HYDRA LACERTA LEO LEO MINOR LIBRA LYNX LYRA MONOCEROS OPHIUCHUS ORION PEGASUS PERSEUS PUPPIS PYXIS SAGITTA SCORPIUS SERPENS CAPUT SEXTANS TAURUS TRIANGULUM URSA MAJOR URSA MINOR VELA VIRGO VULPECULA Alphard Aldebaran Arcturus Betelgeuse Capella Castor Pollux Deneb Polaris Procyon Regulus Sirius Vega Spica Algol M31 Double Cluster M35 M44 M13 Hyades Pleiades 69 the key to your sky created by Wil Tirion
E C L I P T I C Horizon 10°N Horizon 20°N Horizon 30°N zir oH N°03 no zir oH N°02 no ozir oH N°01 n SOUTH WEST EAST NORTH SUMMER SKY For observers at 10° to 30° northern latitudes C BOOTES ANDROMEDA APUS AQUARIUS AQUILA ARA CAMELOPARDALIS CANES VENATICI CAPRICORNUS CASSIOPEIA CENTAURUS CEPHEUS CIRCINUS COMA BERENICES CORONA AUSTRALIS CORONA BOREALIS CORVUS CYGNUS DELPHINUS DRACO EQUULEUS GRUS HERCULES HYDRA INDUS LACERTA LEO LEO MINOR LIBRA LUPUS LYRA MICROSCOPIUM NORMA OPHIUCHUS PAVO PEGASUS PERSEUS PISCES PISCIS AUSTRINUS SAGITTA SAGITTARIUS SCORPIUS SCUTUM SERPENS CAUDA SERPENS CAPUT TELESCOPIUM TRIANGULUM AUSTRALE TUCANA URSA MAJOR URSA MINOR VIRGO VULPECULA Altair Antares Hadar Arcturus Fomalhaut Polaris Rigil Kent Vega Spica Deneb M31 Double Cluster M13 M7 M8 M22 Omega Centauri 70 the key to your sky created by Wil Tirion
E C L I P T I C C Horizon 40°N Horizon 50°N Horizon 60°N oH zir no N°06 r oH nozi N°05 zir oH N°04 no SOUTH WEST EAST NORTH SUMMER SKY For observers at 40° to 60° northern latitudes BOOTES ANDROMEDA AQUARIUS AQUILA ARA ARIES AURIGA CAMELOPARDALIS CANCER CANES VENATICI CAPRICORNUS CASSIOPEIA CEPHEUS COMA BERENICES CORONA AUSTRALIS CORONA BOREALIS CYGNUS DELPHINUS DRACO EQUULEUS GEMINI HERCULES HYDRA LACERTA LEO LEO MINOR LIBRA LUPUS LYNX LYRA MICROSCOPIUM NORMA OPHIUCHUS PEGASUS PERSEUS PISCES PISCES SAGITTA SAGITTARIUS SCORPIUS SCUTUM SERPENS CAUDA SERPENS CAPUT TELESCOPIUM TRIANGULUM URSA MAJOR URSA MINOR VIRGO VULPECULA Altair Antares Arcturus Capella Castor Pollux Deneb Polaris Vega Spica Algol M31 Double Cluster M13 M7 M8 M22 71 the key to your sky created by Wil Tirion
E C L I P T I C Horizon 10°N Horizon 20°N Horizon 30°N Hor zi on 30 N° Hor zi on 2 °0 N Hor zi no 01 N° SOUTH WEST EAST NORTH AUTUMN SKY For observers at 10° to 30° northern latitudes D ANDROMEDA AQUARIUS AQUILA ARIES AURIGA CAMELOPARDALIS CAPRICORNUS CASSIOPEIA CEPHEUS CETUS CORONA AUSTRALIS CYGNUS DELPHINUS DORADO DRACO EQUULEUS ERIDANUS FORNAX GEMINI GRUS HERCULES HOROLOGIUM CAELUM HYDRUS INDUS LACERTA LEPUS LYNX LYRA MICROSCOPIUM OCTANS OPHIUCHUS ORION PAVO PEGASUS PERSEUS PHOENIX PISCES PISCIS AUSTRINUS RETICULUM SAGITTA SAGITTARIUS SCULPTOR SCUTUM SERPENS TAURUS CAUDA TELESCOPIUM TRIANGULUM TUCANA URSA MAJOR URSA MINOR VULPECULA Achernar Aldebaran Altair Betelgeuse Capella Deneb Fomalhaut Polaris Rigel Vega Algol Mira M31 Double Cluster M42 M35 M13 M8 M22 SMC 47 Tuc Hyades Pleiades 72 the key to your sky created by Wil Tirion
E C L I P T I C Horizon 40°N Horizon 50°N Horizon 60°N oH ir oz n 06 N° oH ir oz n 05 N° oH ir oz n 04 N° SOUTH WEST EAST NORTH AUTUMN SKY For observers at 40° to 60° northern latitudes D BOOTES ANDROMEDA AQUARIUS AQUILA ARIES AURIGA CAMELOPARDALIS CANCER CANES VENATICI CAPRICORNUS CASSIOPEIA CEPHEUS CETUS CORONA BOREALIS CYGNUS DELPHINUS DRACO EQUULEUS ERIDANUS FORNAX GEMINI GRUS HERCULES LACERTA LEO MINOR LYNX LYRA MICROSCOPIUM OPHIUCHUS ORION PEGASUS PERSEUS PHOENIX PISCES PISCIS AUSTRINUS SAGITTA SAGITTARIUS SCULPTOR SCUTUM SERPENS CAUDA TAURUS TRIANGULUM URSA MAJOR URSA MINOR VULPECULA Aldebaran Altair Betelgeuse Capella Castor Pollux Deneb Fomalhaut Polaris Vega Algol Mira M31 Double Cluster M35 M13 Hyades Pleiades 73 the key to your sky created by Wil Tirion
all images and captions are courtesy of NASA/JPL-Caltech/University of Arizona Released June 3, 2015: This impact crater appears relatively recent as it has a sharp rim and well-preserved ejecta, the material thrown out of the crater when a meteorite hit Mars. The steep inner slopes are carved by gullies and include possible recurring slope lineae (known as RSL) on the equator-facing slopes. RSL could be a sign that water, its freezing point lowered by a high concentration of salt, could be seeping down these steep slopes. MRO has seen RSL appear in warmer seasons and disappear in cooler seasons in a few locations on Mars, indicating a planet with plenty of active processes. Released April 1, 2012: From a distance, the floor of this crater looks like a giant honeycomb or spider web. The intersecting shapes, or polygons, commonly occur in the northern lowlands of Mars. The polygons in this “patterned ground” are easy to see because their edges are bound by troughs or ridges covered by bright frost relative to their darker, frost-free interiors. Patterned ground on Mars is thought to form as the result of cyclic thermal contraction cracking in the permanently frozen ground. Mars orbiter’s views are out of this world Since arriving at the Red Planet on March 10, 2006, the Mars Reconnaissance Orbiter has kept a constant eye on the Martian landscape and returned revealing images of the forces at work there. Launched Aug. 12, 2005, the MRO is outfitted with six instruments that aid in its mission to “gain better knowledge of the distribution and history of Mars’ water” through detailed observation, atmosphere monitoring and underground probing using radar. Among those instruments is the powerful High Resolution Imaging Science Experiment (HiRISE) telescopic camera. HiRISE is designed to reveal features as small as 1 meter (3 feet) across. This gallery is a glimpse of some of the stunning images that have been captured by the MRO and HiRISE. For more images gathered by the orbiters and rovers exploring Mars, click here. 74
Released May 20, 2015: The South Polar residual cap (the part that lasts through the summer) is composed of carbon dioxide ice. Although the cap survives each warm summer season, it is constantly changing its shape due to sublimation of carbon dioxide from steep slopes and deposition onto flat areas. This observation was acquired on March 23, 2015, in the summer of Mars Year 32. Released March 9, 2016: NASA’s Mars Reconnaissance Orbiter, nearing the 10th anniversary of its arrival at Mars, used its High Resolution Imaging Science Experiment (HiRISE) camera to obtain this view of an area with unusual texture on the southern floor of Gale Crater. This area shown hosts many distinctive landforms in a different part of Gale Crater from where NASA’s Curiosity rover is working. This view spans about half a mile or one kilometer across, with north toward the top. It shows about half of the floor area of a small crater lying within Gale Crater, which is 96 miles (154 kilometers) in diameter. An enigmatic deposit appears to have flowed into the small crater from the south. 75
Released Sept. 30, 2015: This cliff is the site of the most frequent frost avalanches seen by HiRISE. In this area in northern spring, frost avalanches are common and HiRISE monitors this cliff, or scarp, to learn more about the timing and frequency of the avalanches, and their relationship to the evolution of frost on the flat ground above and below the scarp. The small white cloud in front of the brick red cliff is likely carbon dioxide frost dislodged from the layers above, caught in the act of cascading down the cliff. It is larger than it looks, more than 20 meters across, and it probably kicked up clouds of dust when it hit the ground. The avalanches tend to take place when the North Polar region is warming, suggesting that the avalanches may be triggered by thermal expansion. Released Sept. 7, 2011: Mars has extremely large temperature changes from winter to summer compared to the Earth. It gets cold enough to freeze carbon dioxide out of the atmosphere during the winter, but this ice is unstable when the warmer summer arrives and forces it to sublimate (transform directly back into a gas) away. Near the South pole though, it stays cold enough for some of this seasonal ice to stick around all year and even accumulate from year to year. This slab of ice is a few meters (about 10 feet) thick and is penetrated by the flat-floored pits shown here. The quasi-circular pits in the center of the scene are about 60 meters (200 feet) across. The distinct color of the pit walls may be due to dust mixed into the ice. For most of the year these walls are covered with bright frost, but they defrost and show their true colors at the end of the summer. 76
Released Feb. 22, 2012: These barchan (crescent-shaped) sand dunes are found within the North Polar erg of Mars. This type of dune provides a great record of the wind environment when they formed and moved: barchan dunes’ horns point downwind. Although the question of present-day sand motion is still open, it appears possible that these dunes are active (when not covered in frost) as their crestlines are very sharp and their slipfaces (the inner curved region between the horns/downwind surface) appear very smooth and steep. In this image, taken during the northern spring season, the dunes and ground are still covered in seasonal frost. The speckled appearance is due to the warming of the area -- as the carbon dioxide frost and ice on the dunes warm, small areas warm and sublimate (turn from solid to gas) faster, creating small jets that expose/deposit dark sand and dust onto the surface. Released April 1, 2012: This observation shows a portion of the wall (light-toned material) and floor of a trough in the Acheron Fossae region of Mars. Many dark and light-toned slope streaks are visible on the wall of the trough surrounded by dunes. Slope streak formation is among the few known processes currently active on Mars. While the mechanism of formation and triggering is debated, they are most commonly believed to form by downslope movement of extremely dry sand or very fine-grained dust in an almost fluidlike manner (analogous to a terrestrial snow avalanche) exposing darker underlying material. Some of the slope streaks show evidence that downslope movement is being diverted around obstacles, such as large boulders, and a few appear to originate at boulders or clumps of rocky material. These slope streaks, as well as others on the planet, do not have deposits of displaced material at their downslope ends. The darkest slope streaks are youngest and can be seen to cross cut and lie on top of the older and lighter-toned streaks. The lighter-toned streaks are believed to be dark streaks that are lightening with time as new dust is deposited on their surface. 77
Released April 1, 2012: A towering dust devil casts a serpentine shadow over the Martian surface. The scene is a late-spring afternoon in the Amazonis Planitia region of northern Mars. The view covers an area about four-tenths of a mile (644 meters) across. North is toward the top. The length of the dusty whirlwind’s shadow indicates that the dust plume reaches more than half a mile (800 meters) in height. The plume is about 30 yards or meters in diameter. A westerly breeze partway up the height of the dust devil produced a delicate arc in the plume. The image was taken during the time of the Martian year when the planet is farthest from the sun. Just as on Earth, winds on Mars are powered by solar heating. Exposure to the sun’s rays declines during this season, yet even now, dust devils act relentlessly to clean the surface of freshly deposited dust, a little at a time. Released Oct. 20, 2010: This image shows blocks of bright, layered rock embedded in darker material that are thought to have been deposited by a giant flood that occurred when Uzboi Valles breached the rim of Holden Crater. The magnitude of this ancient flood is indicated by the large size of the blocks (up to 100 meters across). The blocks do not appear to have been moved very far by the flood, as they are not rounded. Holden Crater was one of the last four landing sites considered for the Mars Science Laboratory rover which has been exploring Mars since August 2012. The bright layered rock in this image probably contain a record of a wetter, warmer period early in Martian history, and are therefore a prime target for exploration. 78
Released Feb. 29, 2012: This scene shows dark sand dunes marching over the ridges created by an alluvial (waterdeposited) fan in an impact crater. These dunes may be active today, but we haven’t yet observed them at significantly different times to measure the movement. The dunes are moving from northwest (upper left) to southeast, with the steep slope facing downwind. Released Feb. 10, 2016: Wind is one of the most active forces shaping Mars’ surface in today’s climate. Wind-carved features such as these, called “yardangs,” are common on the Red Planet. Wind has also deposited fine sand on the floor of shallow channels between the yardangs. On the sand, the wind forms ripples and small dunes. In Mars’ thin atmosphere, light is not scattered much, so the shadows cast by the yardangs are sharp and dark. 79
parting shot 74 COURTESY OF NASA/JPL-Caltech Above, this high-resolution still image is part of a video taken by several cameras as NASA’s Perseverance rover touched down on Mars on Feb. 18, 2021. A camera aboard the descent stage captured this shot. Right, this first image of NASA’s Perseverance Rover on the surface of Mars from the High Resolution Imaging Experiment (HiRISE) camera aboard NASA’s Mars Reconnaissance Orbiter (MRO) shows the many parts of the Mars 2020 mission landing system that got the rover safely on the ground. The image was taken on Feb. 19, 2021. This annotated version of the image points out the locations of the parachute and back shell, the descent stage, the Perseverance rover, and the heat shield. Each inset shows an area about 650 feet (200 meters) across. COURTESY OF NASA/JPL-Caltech/University of Arizona