Light pollution

This is really a problem in the Netherlands. Ambient sky light makes it really hard to look at the skies sometimes. Nevertheless, a bit of planning, patience and a special filter really make a difference.

As far as planning goes, unless you’re going to look at the Moon, it helps to observe during the times when the moon is new or below the horizon. You can find a gazillion moon calendars on the internet or your mobile phone, so there’s really no excuse when you don’t know the current phase of the moon.

There’s also the patience thing again. Allow your eyes to get used to the dark. In a mere matter of minutes, you will see more details, fainter objects and objects of higher magnitudes. Buy yourself a red lantern. If you go outside, make sure there are no light sources blinding you. Sometimes moving your telescope a few inches will hide the light of your neighbor behind a tree. If you go outside with your notebook computer, check out if your software has a special “red” mode. Lots of software does this, like Voyager from Carinasoft which I’m using. Everything to help you get used to the dark.

And the third thing you need is a deep sky or light pollution filter. I got myself a LF3010 from a company called Lumicon. Sure, it sets you back another $140 or so, but it blocks all high and low pressure mercury and sodium vapor lamp light, neon lights and airglow, while transmitting the rest of the visible spectrum.

You must get one that has the same diameter as the rest of your lenses and filters, so in the case of the NexStar 5SE that’s 1.25″. That’s the common standard for just about every amateur telescope. The filter screws onto the zenith prism so you can switch eyepieces while always having the deep sky filter in place.