Planetary Nebula Haro 3-75
In 1953, the Mexican astronomer Guillermo Haro Barraza examined the Taurus-Auriga-Orion region with the 64 cm Schmidt camera at the Tonantzintla Observatory in Mexico. Previously, Alfred Harrison Joy at the Mount Wilson Observatory had discovered numerous stars with strong Hα emission lines, so-called T-Tauri stars. These are young stars that are uneven from a disk of dust. Haro discovered 75 more Hα stars on the photo plates exposed for up to 90 minutes. To number 75 he added the following note: «Strange object. The star is surrounded by a halo that shows emissions in Hα, N1, N2 and possibly other bright lines on images.»  The American astronomer Nicholas Ulrich Mayall finally recognized in 1964 that this was a planetary nebula. 
On Simbad one finds a parallax of 0.2308 mas (milli-arcseconds), which corresponds to a distance of about 4.3 kpc (about 14'000 light years). The apparent brightness in different bands is: B = 14.8 mag, G = 13.8 mag, J = 12.0 mag, H = 11.5 mag, K = 11.3 mag. 
|Designations||PN G193.6-09.5: H 3-75, PK 193-09.1, ARO 218|
|Right Ascension (J2000.0)||05h 40m 44s|
|Declination (J2000.0)||+12° 21' 17"|
|Radial Velocity||+9.5 km/s ± 19.0 km/s|
The planetary nebula Haro 3-75 is located in the constellation Orion. The best observation time is October to February.