Accessories

Filters
With many types of filters on the market, the three most important ones to have in your collection would be a solar, lunar (Neutral Density) and Light Pollution Filter.

NEVER LOOK AT THE SUN WITHOUT SUITABLE PROTECTIVE FILTERS!!!! These filters allow only a fraction of sunlight to pass through the telescope, making it entirely safe to observe sunspots, and bright filaments on our nearest star. Depending on aperture and type of material used, solar filters can cost between 30 Euros and 150 Euros.

If you like to look at the moon, a lunar filter is a advantageous. In almost all telescopes, the moon is so bright, that it dazzles the eye into "lunar-blindness." Lucky, it's only temporary, but you can avoid this dazzling experience with a simple, low-cost (less than 20 Euro) filter that screws on to the eyepiece and acts as "sunglasses" for your telescope.

If you want to observe deep-sky objects and you live in or near a city or sub urban area a light-pollution filter can help. LPFs block the kind of light that masks the sky -- specifically that produced by mercury-vapor and high-pressure-sodium street lights, while passing the desirable light from nebulae or galaxies. These filters often produce good results. Deep-sky objects that you think you wouldn't be able to see, increase in high contrast and in detail.

However, there are many types of LPFs (or Nebula Filters) on the market, some specifically for nebulae, others for galaxies, and still others for comets.

Barlow Lens
A Barlow is a negative (diverging) lens that is placed between the objective lens (or primary mirror – or a reflector) and the eyepiece of a telescope. It increases the effective focal length of an objective lens, thereby increasing the magnification. The idea is that 2 eyepieces and a Barlow will give you the flexibility of magnification of 4 eyepieces, and will give higher magnifications with less powerful eyepieces.

For example if you had two eyepieces, one a 20mm and the other a 32mm, with a 2x Barlow, you are now effectively adding 10mm and 16mm eyepieces to your set at a fraction of the price.

For more detailed information about astronomy equipment post your queries on our message board.