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How to observe deep sky objects?
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The deep sky objects are very weak and it is then necessary for the eyes to be acclimated to the dark (stay at least 10 minutes in the dark). Use red lights to avoid glares (for example, cover the lights with red cellophane paper). The lateral part of the retina is most sensible to the light. It is possible to detect very weak objects using the lateral vision. It is fundamental to elaborate an observation plan and to prepare the necessary material (catalogues, maps or computer programs at hand). Note that many objects appear on maps or catalogues that can only be observe with large telescopes. Try to use a smaller magnification as the contrast is higher and the field is greater. In some cases - for galaxies - it is advisable to use a higher magnification. The reason is that the sky background is darkened and it is possible better distinguish the object. The easiest objects to observe are the open clusters. Consider two aspects: magnitude and size to determine if an object is easy or not to observe. Unlike stars, the brightness and magnitude is distributed on all the object's surface of the object. For this reason, if the object covers a large field, it is difficult to see even if, according to its magnitude, it would have to be very bright. The first times that you will observe deep sky objects, you will most likely see a 'milky spot'. With experience, you will see more details such as the form (is it completely round or extended in some direction?), the brightness ( is it uniform or brighter in some areas). In some cases, it is possible to observe colors; for example, many emission nebulae have a greenish color, although in the photographies they appear with red color. The reason is due to the different sensitivity of the eye and the photographic film. In case of globular clusters, applying a higher magnification can in some cases resolve the stars forming it. In other cases complete separation is not possible but a granular aspect is viewable. By using an adapted CCD camera you will be able to produce amazing pictures. Previous topic: |