Normalized Messier Catalogue

Charles Messier was a french astronomer in the 18th century. During his hunt for comets, he regularily came across similar looking yet stationary (in relation to the stars) objects, which could not be classified further in that era. To exclude these faster, he finally created a list which contains 110 such objects,  known as the Messier Catalog. In that time probably nobody realized, that they just observed various nebulae, star clusters and distant galaxies.

All Messier Objects can be observed visually with even smal telescopes, since they are quite bright. As classic entry level objects they may even be observed under less optimal conditions or even at full moon. But, similar to Charles Messier, when observing visually you will not see much more than a bright spot in the dark sky.

For taking an image of a Messier Object, a somewhat longer focal range (above 1000mm) will be required. The galaxies in particular are rather small. Only few objects, like the nebula in Orion (M42), the Plejades (M45) or our neighboring galaxie Andromeda (M31) require a shorter focal length and can already be spotted with binoculars.

Several Messier Catalogs may be found in the internet with many great images. This catalog has a different approach. It does not target the best possible image for each object but a normalized representation of each object regarding exposure time, image processing and field of view. Each image was created from one hour exposure time (30x 30s L, 3x15x 60s R/G/B) and show a field of 30 arcminutes (0.5 degrees) squared.

All images were taken with the ASI2600MM Pro at the TSQ-100ED APO (580mm f/5.8). The images are a 1:1 crop of 1346x1346 pixels, just 15% of the pixels provided by the sensor. To avoid loss of details, only little denoise was applied. The slight variations in background are probably caused by different observing conditions which could not be compensated properly with this unified workflow.

This catalog was completed in December 2022, some targets will be updated with better versions, eventually.

March 2023: At the moment I am completing the abstracts for the objects and for many targets I already added the complete frame as a reference (580mm, APS-C). For more detailed information I still recommend reading the linked page on Wikipedia.