Image 1 Caption: "Engraved portrait of Simon Marius (1573--1625) from his book Mundus Iovialis (1614)." (Slightly edited.) Note Renaissance astronomers had a tendency to look like Faust who is immortalized in Doctor Faustus (play c.1592). Maybe it was a professional requirement to assure customers that they were really topnotch astrologers.

Simon Marius was the first to telescopically observe and describe the Andromeda nebula (i.e., the Andromeda galaxy) which he did 1612 (see Wikipedia: Simon Marius: Discoveries; Wikipedia: Andromeda Galaxy: Observation history; No-402). The references do NOT make it clear if Simon Marius discovered the Andromeda nebula relative to Renaissance astronomy (see discussion below).

Note Simon Marius could only see the Andromeda nebula as fuzzy cloud with his small primitive telescope. He probably could NOT see its fiducial modern size on the sky: ∼ 3° x 1° (see AstroPixels.com: M31 - Andromeda Galaxy). The spiral arms (i.e., spiral structure) of the Andromeda nebula was discovered by Lord Rosse (1800-1867) in 1850 using the largest reflector telescope of that time, Lord Rosse's own Leviathan of Parsonstown (1.83 m primary, operational 1845--c.1890) (see Wikipedia: Andromeda Galaxy: Observation history).

The early history of the observation of the Andromeda galaxy:

1. As a naked-eye astromomical object, the Andromeda galaxy was observed casually as a "cloudy star" without comment by myriads going back into indefinitely into prehistory. The "cloudy stars" were eventually called nebulae (used in the historical sense here). "Nebula" is just Latin for cloud (see nebula (Latin)).

2. Ptolemy (c.100--c.170 CE) listed 6 or 7 nebulae in his 2nd century CE catalog of 1022 stars in 48 constellations (see No-113,402; Wikipedia: Almagest: The star catalog). Tycho Brahe (1546--1601) listed 6 nebulae in his catalog of stars (see Wikipedia: Tycho Brahe: Observational astronomy). Surprisingly, both of these astronomers (Ancient and Renaissance) missed the Andromeda nebula (No-402).

3. Medieval Islamic astronomer al-Sufi (903--986, in Europe AKA Azophi Arabus) in his Book of the Fixed Stars (circa 964) is the first to put the Andromeda nebula in the historical record as a nebula (historical sense) (see No-188,402; Wikipedia: Andromeda Galaxy: Observation history; Wikipedia: Book of the Fixed Stars: Influence). Al-Sufi seems to attribute the recognition of the Andromeda nebula as a nebula (historical sense) to Medieval Islamic astronomers in Isfahan very probably before 905.

4. Al-Sufi's work was known in Europe by the 14th century (see Astronomical atlas by al Sufi, Middle of the XIVth century, north of Italy; Biography of al-Sufi; Duerer's hemispheres of 1515 - the first European printed star charts). However, the references do NOT state if Simon Marius or other Renaissance astronomers were aware that the Andromeda nebula had been recognized as a nebula (historical sense) before Simon Marius in 1612.

   

5. Image 2 Caption: A woodcut sky map of the nothern celestial sphere by Albrecht Duerer (1471--1528), circa 1515.

   The constellation Andromeda (with an overlaid portrayal of the mythical Andromeda) is to the left of constellation Pegasus near the top of the sky map.

   Decorative imaginative portraits of astronomers are shown in the corners clockwise from the upper left: Aratus (c.315--c.240 BCE), Ptolemy (c.100--c.170 CE), al-Sufi (903--986, in Europe AKA Azophi Arabus), Marcus Manilius (fl. 1st century CE).

Images:

1. Credit/Permission: Anonymous artist, 1614 (uploaded to Wikimedia Commons by User:Rob_at_Houghton, 2014) / Public domain.
   Source: GC6 M4552 614m, Houghton Library, Harvard.
   Image link: Wikimedia Commons: https://commons.wikimedia.org/wiki/File:Houghton_GC6_M4552_614m_-_Simon_Marius.jpg.
   
2. Credit/Permission: Albrecht Duerer (1471--1528), circa 1515 (uploaded to Wikimedia Commons by User:JarektUploadBot, 2011) / Public domain.
   Image link: Wikimedia Commons: File:Albrecht Dürer - The Northern Hemisphere of the Celestial Globe - WGA7195.jpg.