Montblanc and its Maison Artisan Atelier in Hamburg crafts pens that are valued at prices that often exceed $1 million, but its new line to honor famed astrologer and mathematician Johannes Kepler only improves the reputation of the German luxury brand.

From Montblanc’s High Artistry Homage series, the Johannes Kepler Limited Edition collection is made up of four limited run pens, including a very special one-off example with a seven-figure asking price.

The Johannes Kepler High Pede Serpentari Limited Edition 39 will be restricted to only 39 examples around the globe. Crafted in white gold with a blue lacquer cap and barrel, the pen offers a three-dimensional engraving of the Ophiuchus and Sagittarius constellations. This example is priced at $48,130.

The Johannes Kepler High Artistry Astronomia Nova Limited Edition 9 presents Ophiuchus and Sagittarius on its barrel, but this time it is featured in a skeletonized white-gold overlay that is dotted with diamonds to represent the stars and colored gemstones to symbolize the planets. The nine examples of this stunning pen will each fetch $140,000.

The Johannes Kepler High Artistry Somnium Limited Edition 5 comes with a full moon-phase indicator on its cap. The third Montblanc offering in the line had some help from the brand’s watch manufacture found in Villaret, Switzerland, in order to complete the mechanical complications of incorporating a working lunar movement. Depending on the color choice, this one-of-five pen will sell for $513,000 to $556,000.

The final, one-off piece is the Kepler Stella Nova Limited Edition 1. This singular work of art features 570 diamonds and 5,294 sapphires that have been arranged to evoke the Milky Way. There is also a dazzling 6.2-carat, Montblanc-cut diamond faceted to the pen’s cap; this solar centerpiece is surrounded by three diamond-set rings that represent Kepler’s three laws of planetary motion. The price tag for this extraordinary writing instrument is $1.5 million; that includes a pair of cosmological cuff links emulating Kepler’s vision of the solar system.

All examples are set to go on sale at Montblanc’s boutiques worldwide in April; the Stella Nova Limited Edition will be available through inquiry.