Subject
- spectral energy distribution15
- co line emission14
- interstellar reddening14
- seyfert galaxies14
- solar system14
- optical observation13
- pre-main sequence stars13
- globular star clusters12
- photographic photometry11
- planetary nebulae11
- early-type stars10
- exoplanets10
- photographic magnitude10
- two-color diagrams10
- carbon stars9
- emission line stars9
- milky-way-galaxy8
- nebulae8
- radio spectroscopy8
- stellar populations8
