# Does the Sun Dagger also mark the 18.6-year lunar standstill cycle? · Great houses of Chaco Canyon > Three answers have been proposed. The lunar shadow positions are by-products of the slabs' shape; the site was not used to follow the… leads, with… Source: https://mysteriesdept.com/mysteries/chaco-canyon/questions/QST0D9KV4KG0K3Y/does-the-sun-dagger-also-mark-the-18-6-year-lunar-standstill Publisher: Mysteries Department Licence: CC BY 4.0 (credit Mysteries Department and link the page) Updated: 2026-10-26T16:39:42+00:00 --- **0** # Does the Sun Dagger also mark the 18.6-year lunar standstill cycle? Asked 26 Oct 2026 by [**apollo** ](https://mysteriesdept.com/u/apollo)·Part of [Was the Fajada Butte spiral made and used as a solar calendar?](https://mysteriesdept.com/mysteries/chaco-canyon/questions/QST0D9KV4BP04RM/was-the-fajada-butte-spiral-made-and-used-as-a-solar)·3 answers·0·0 following **Most likely: the lunar shadow positions are by-products of the slabs' shape; the site was not used to follow the…** Ahead on the evidence, not yet confirmed. It needs two reviews to be accepted. ## Where it stands Three answers have been proposed. The lunar shadow positions are by-products of the slabs' shape; the site was not used to follow the… leads, with evidence 2 for: partly supported by its tests. Two are still possible. ## Why it matters If it does, the builders followed a cycle that takes 18.6 years to complete, which would put their astronomy well beyond sun-watching; the claim rests on slab shadows at moonrise and has no counterpart in Pueblo ethnography⁠[[1]](https://mysteriesdept.com/sources/SRC0D9KTB7030KR/lunar-markings-on-fajada-butte-chaco-canyon-new-mexico)⁠[[2]](https://mysteriesdept.com/sources/SRC0D9KT6JJ6MNC/the-fajada-butte-solar-marker-a-reevaluation). ## Answers 3 [**The lunar shadow positions are by-products of the slabs' shape; the site was not used to follow the…** ](https://mysteriesdept.com/mysteries/chaco-canyon/answers/ANS0D9KVP601RTM/the-lunar-shadow-positions-are-by-products-of-the-slabs) Partly supported by its tests Evidence: 2 for Most likely [**At moonrise the eastern slab's shadow marks the moon's minor and major standstills on the large spiral, and…** ](https://mysteriesdept.com/mysteries/chaco-canyon/answers/ANS0D9KVMYY1XT5/at-moonrise-the-eastern-slabs-shadow-marks-the-moons-minor) Tested, but the results don't decide it Evidence: 2 for, 2 against Disputed [**None of these.** ](https://mysteriesdept.com/mysteries/chaco-canyon/answers/ANS0D9KVPXE08XN/none-of-these) Not tested enough to call either way Evidence: none yet Still possible ## History 1. 1982[Sofaer et al. puts forward: at moonrise the eastern slab's shadow marks the moon's minor and major standstills on the large spiral, and…](https://mysteriesdept.com/sources/SRC0D9KTB7030KR/lunar-markings-on-fajada-butte-chaco-canyon-new-mexico) 1. 1982[Sofaer et al.: at sunrise at declination +18.4°, standing in for the moon at its northern minor standstill, the eastern…](https://mysteriesdept.com/sources/SRC0D9KTB7030KR/lunar-markings-on-fajada-butte-chaco-canyon-new-mexico)For: At moonrise the eastern slab's shadow marks the moon's minor and major standstills on the large spiral, and… 1. 1985[Zeilik puts forward: the lunar shadow positions are by-products of the slabs' shape; the site was not used to follow the…](https://mysteriesdept.com/sources/SRC0D9KT6JJ6MNC/the-fajada-butte-solar-marker-a-reevaluation) 1. 1985[Zeilik: there is no ethnographic evidence that historic Pueblos attended to the lunar standstill cycle.](https://mysteriesdept.com/sources/SRC0D9KT6JJ6MNC/the-fajada-butte-solar-marker-a-reevaluation)Against: At moonrise the eastern slab's shadow marks the moon's minor and major standstills on the large spiral, and… 1. 1985[Zeilik: historic Pueblo practice records sun-watching but not tracking of the lunar standstills.](https://mysteriesdept.com/sources/SRC0D9KT6JJ6MNC/the-fajada-butte-solar-marker-a-reevaluation)For: The lunar shadow positions are by-products of the slabs' shape; the site was not used to follow the… 1. 2011[Sofaer et al.: in November 1987, at the major standstill, the project photographed the moonrise shadow of the eastern slab…](https://mysteriesdept.com/sources/SRC0D9KTBET0V0D/the-sun-dagger-interactive-computer-graphics-model-a-digital)For: At moonrise the eastern slab's shadow marks the moon's minor and major standstills on the large spiral, and… 1. 2020[Schaefer & Stamm: one spiral designed to mark three or four separate dates is very unlikely; the extra dates are most likely…](https://mysteriesdept.com/sources/SRC0D9KTCE25TNP/a-case-study-of-the-picture-rocks-sun-dagger-plus-a-review)Against: At moonrise the eastern slab's shadow marks the moon's minor and major standstills on the large spiral, and… 1. 2020[Schaefer & Stamm: the probability that a single spiral was designed to mark four dates is very small.](https://mysteriesdept.com/sources/SRC0D9KTCE25TNP/a-case-study-of-the-picture-rocks-sun-dagger-plus-a-review)For: The lunar shadow positions are by-products of the slabs' shape; the site was not used to follow the… 1. 26 Oct 2026Asked on this site ## Discussion 0 [Add to the discussion](https://mysteriesdept.com/signin?next=/mysteries/chaco-canyon/questions/QST0D9KV4KG0K3Y/does-the-sun-dagger-also-mark-the-18-6-year-lunar-standstill%23discussion) Help with this question [ **Propose an answer** Something the evidence could support or rule out ] [ **Propose an answer** Something the evidence could support or rule out ](https://mysteriesdept.com/signin?next=/mysteries/chaco-canyon/questions/QST0D9KV4KG0K3Y/does-the-sun-dagger-also-mark-the-18-6-year-lunar-standstill%23add-answer) [ **Add evidence** A result for or against an answer ] [ **Add evidence** A result for or against an answer ](https://mysteriesdept.com/signin?next=/mysteries/chaco-canyon/questions/QST0D9KV4KG0K3Y/does-the-sun-dagger-also-mark-the-18-6-year-lunar-standstill%23add-evidence) [ **Ask a sub-question** A smaller question that would help settle this one ] [ **Ask a sub-question** A smaller question that would help settle this one ](https://mysteriesdept.com/signin?next=/mysteries/chaco-canyon/questions/QST0D9KV4KG0K3Y/does-the-sun-dagger-also-mark-the-18-6-year-lunar-standstill%23add-question) [ **Add a source** A paper, archive record or image ] [ **Add a source** A paper, archive record or image ](https://mysteriesdept.com/signin?next=/mysteries/chaco-canyon/questions/QST0D9KV4KG0K3Y/does-the-sun-dagger-also-mark-the-18-6-year-lunar-standstill%23add-source) Where it fits Great houses of Chaco Canyon [**Was the Fajada Butte spiral made and used as a solar calendar?** ](https://mysteriesdept.com/mysteries/chaco-canyon/questions/QST0D9KV4BP04RM/was-the-fajada-butte-spiral-made-and-used-as-a-solar)most likely the site was a sun shrine where the solstices and equinoxes were watched and honoured, not a calendar for… **Does the Sun Dagger also mark the 18.6-year lunar standstill cycle?** You're here · the lunar shadow positions are by-products of the slabs' shape; the site was not used to follow the… [ Ask a question under this one ]