James Paulson's roll off roof observatory at the Sunridge Observatory site, taken in the summer of 1986, housing a 10 inch f/5 Cave Astrola Newtonian reflector telescope

Saturday, June 18, 2011

Planetary Observations

One of the simplest things for a beginner to enjoy are the views offered through a telescope of the planets. Jupiter and Saturn are two of the most amazing sights many first timers will ever experience in a telescope, and a quick trip with Google will help you in locating their positions in the night sky. Venus, Mars, Jupiter and Saturn are all fairly easy to spot as they tend to be brighter than the stars around them at various points of their apparitions. Viewing the outer planets is best done when the planet is at opposition (planet rises as the sun sets) as it crosses near the meridian, an imaginary line that transits from due north to due south, directly overhead, which happens generally between midnight and 1 AM.

Planetary viewing requires patience, good seeing, and on those nights of exceptional seeing when you can pour on the magnification, you will be rewarded with amazing details in your observations. Aperture is king here. Telescopes can generally handle up to a maximum of 60 times magnification per inch of aperture in theory, but often the atmosphere will forbid much above 150x on most nights. Still when you hit those special nights of exceptional clarity and pour it on, you will be amazed.

A selection of filters can help in your viewing of details as filters allow transmission of only specific wavelengths and will block others to enhance the contrast of many details like ring divisions, belts, spots and caps. Most any astro retailer will sell a basic set of planetary filters to help get you started, but this chart located at the bottom of the page gives some very good information on specialized filters for specific needs.

As with anything visual, experience will help you a lot here. Getting out and looking at the planets with a variety of instruments helps you to learn to train your eye to see things that most would simply pass over, and it gives you a reference for what to expect during your oberving sessions. Good luck and get out and enjoy, soon Jupiter will be up in the evening and this is an excellent place to begin and learn.

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