…continuedObserving Nebulae Season by Season
More Summer Sights
Close to the southern edge of the Big Dipper's Bowl is the remarkable planetary nebula M97, popularly known as the Owl. M97 is no problem for 4-inch telescopes, and I have easily seen it in 15 x 65 binoculars. The two dark spots that form the Owl's "eyes" are more challenging, but under good skies they might be within range of a 4-inch telescope. The nebula measures only 3', and if it isn't seen at once, let your eye wander aimlessly over the field of view until the disk springs into view.
In Ophiuchus is the globular cluster M9. It's near the northeast edge of a remarkable dark nebula, Barnard 64, less than ½° west of it. With my 4-inch Clark refractor or 5-inch Apogee telescope the dark nebula is easily seen. Most dark nebulae are difficult to "see," but here the rich background is rather uniform, and it's interesting to compare the star densities northeast and southeast of M9. Try powers of about 100x. (To discover more dark nebulae, see the article "Seeking Summer's Dark Nebulae.")