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The Observing Guide

The Observing Guide means to give hints to the observer on proper preparation and observations at the eyepiece. You may have your own agenda and style of observing, and this is meant only as a introductory guide to successful observing. The guide is divided in the following sections:

• Preparing for an observing session
• Optimizing observing
• Taking notes
• Drawing

Preparing for an observation session

Preparing for an observation session is vital for good results. It also helps on the inspiration to have a plan to follow when the cold is creeping in on you and you will less likely run out of things to point the scope at.

• Have some given, systematic project ready, keeping in mind the particular sky conditions at the time of observing, e.g. daylight for sunspots, bright stars, planets; twilight for other stars and planets while awaiting darkness; moonlight (don't be hasty and write it off!); sky glow and aurora for lunar work, bright clusters and double stars; dark hours - sometimes rather poor conditions and poor seeing may be bad for stars but surprisingly good for some galaxies and extended nebulae. In short, chose a project prepared for almost any condition, barring total overcast.
• Have a list prepared, with appropriate charts and/or current coordinates.
• Have the scope as accurately polar-aligned as possible. Some very faint and elusive objects just cannot be found by sweeping and require use of setting circles. Also have clean optical surfaces! It is also well to have a watch reading UT. And, of course, a good, manageable, dim red flashlight.
• Warm clothing is a must, even in fairly agreeable weather, especially for head and feet. And remember that more layers of clothes is better than thicker layers. Each layer keep some warmth, and therefore increases the isolation effect.
• We need dark-adapted eyes, of course, which takes about half an hour. Beware that bright lights will destroy the dark-adaption in an instance. Try bathing your day-tired eyes with warm, clear water and a drop or two of commercial eye drops such as "Tears Naturale" - and no harsh eye washes.
• Bring out a recommended thermos of tea or coffee, cut the sugar - and NO alcohol. It might make you see a lot of double stars :), but it affects the blood capillaries in the retina.
• A bit of jogging before and deep-breathing exercises while setting up pump some good oxygen into the blood. Tired body and eyes greatly reduce acuity of vision.

Optimizing the observation

• Use a good, low-power eyepiece to locate the desired field. If one's polar alignment has been done properly, or if you are adept at sky-hopping, the object to be seen should be in the field. If it is particularly faint, do not sweep but carefully scan the field. Averted vision will help detect low light levels, as you well know. Your eye probably has a preferential spot, where objects seem brighter. Try also to open your eyes as much as possible. I'm not sure what it is, but in my experience fresh cold air on the eyes make them see better. Once the object is detected, switch to a next higher-power eyepiece, to achieve heightened contrast.
• Slow jiggling of the scope with slow motion RA and Dec controls, moving the object to different areas of vision, is a great help. The reason seems to be that each eye's retina and particulate matter in the eye's liquid create "optical noise".
• Another aid that has proven effective for enhanced viewing is a fine, black, silk cloth over the head and around the eyepiece. It cuts down stray light, moonlight or sky glow, etc.
• Although averted vision for most objects make them seem brighter, some faint galaxies, surprisingly, sometimes seem to be better on direct vision.
• Be very careful not to confuse a single or close double star of similar magnitude for a small, faint, nebulous object. Resolve the confusion by slowly, gently, racking the focus in and out: a dim star on close, attentive observation, will sparkle, sharp and clear, for a brief moment, whereas the true nebular object will remain diffuse.
• Magnitude listings of faint galaxies can differ notoriously from catalogue to catalogue and is often not consistent with the apparent visual brightness. Newer published catalogues of deep-sky objects, using a scale of brightness as well as magnitude, give a truer idea of what to expect at the eyepiece.
• And, above all, observe, observe, OBSERVE. Do not just 'see' and move on. Do not rush. It is surprising how much new detail can be found in even such old faithfuls as M31 and M42. And be prepared for some real surprises, e.g., a night that seems to offer poor seeing may reveal some unexpected good results, and vice versa.

Taking notes

When observing, you'll often find yourself writing down almost the same things for similar objects. Well, it's a fact that most galaxies look alike through the eyepiece. But there are special attributes to an object you can note that make the observation more precise.

General notes

Common for all types of objects is to note things like nearby stars and other objects. You can also describe intricate features specific to that object. The more you can note, the better, but don't be too elaborate! It's good to accompany a good description with a drawing, and vice versa a drawing is better understood when accompanied by a precise description.

Galaxies

• Shape and position angle - Most galaxies are elongated. These galaxies will be oriented in an angle, where 0° is defined as exactly North-South and 90° is exactly East-West. The angle covers the first half of a circle and can be between 0 and 179°. If you have a mount with a fairly good polar alignment, it's fairly easy to note the PA. Just swing the telescope back and forth in East-West direction to indicate where North and East is in the field, and note a rough estimate of the angle.
• Brightness - You can note the brightness of a galaxy with a ratio scale, like Dreyer did with the NGC and IC objects (see Help). You should note though that after having observed a number of faint galaxies (or other object types for that matter), your perception of 'faint' will gradually move to more like 'fairly bright'.
• Structure and other features - Look out for knots in the arms of spiral galaxies and other special features unique to the galaxy. Getting to know the galaxy by studying a DSS image first is often fruitful.

Open Clusters

• Size -
• Brightness range -
• Richness -
• Structure and other features -

Globular Clusters

• Size -
• Brightness -
• Concentration -
• Structure and other features -

Planetary Nebulae

• Size -
• Brightness -
• Shape -
• Colour -
• Structure and other features -

Bright Nebulae

• Size -
• Brightness -
• Definition - Note how well the border of the nebula is defined. Often this is different for different sides of the nebula.
• Structure and other features -

Dark Nebulae

Dark nebulae are probably the least observed objects. Who'd want to observe dark objects in a dark sky? Well, most dark nebulae lie in front of the Milky Way or some bright nebulae, and therefore block out the light. Thus it's possible to see them, and believe me, it's much fun observing them. Most dark nebulae are better for photography, but many of them are in fact very easy to spot.

• Darkness - Rate how well the nebula is standing out from the surrounding field, like 'stands out well' or 'faint darkening'.
• Definition - The same as for bright nebulae.
• Structure and other features - Note specific features like 'comet-like tail' etc. Many dark nebulae will show faint whisks in some directions. Note also foreground stars.

Drawing

The following hints are meant as a guideline only. If you have an other techniques that works fine for you, there's no point in adopting this technique. You might find some hints to improve your drawing, though.

• Requirements: a clip-board with a pad of paper on which are drawn circles and space for notes printed up in advance. By experience, a circle of ~55mm in diameter works best. Too large a circle makes for greater discrepancies in proportion.
• For stars, use a fine, black ballpoint pen, exercising great care in pressure to register varying magnitudes.
• For galaxies, nebulae, etc., use a medium-soft pencil, with not too sharp a point. Go easy. Softly draw in the shape, intensity, etc., and then rub the area with a dry finger tip. Use a sharpened eraser to rub off darkened areas to indicate dust lanes, etc.
• Be sure to indicate directions on your drawing. Exercise great care when drawing objects observed from Zenith to Pole, if you are using a Schmidt-Cassegrain. Some disconcerting reversals, e.g. M81 above M82, may occur, depending on which side of the scope one is observing from. Slow motion of the scope in both RA and Dec will indicate direction of drift.
• In drawing, note carefully positions and proportions, i.e. distance from center-to-edge, a star's or object's "clock" position, patterns such as triangles, ovals, lines, etc. Rack out- of-focus until all but the several brightest stars are apparent; whole relative positions can be quite accurately indicated. These points then serve as a reference skeletal framework for drawing fainter star positions in focus, preserving true overall relationships.
• Keep in mind that drawing experience improves very quickly and greatly perfects one's observing skills. And that, after all, is what this is all about, no?