Tips for the visual observation of the Mars opposition 2020
The observations of the Mars channels in the 19th century were made with telescope apertures of 30 to 50 centimeters. Telescopes with similarly large apertures (like the Celestron C14, or the PlaneWave CDK 12.5- and 20 inch) are now well within the reach of amateur astronomers. Perhaps you will succeed in spotting the large Canyon Valles Marineris?
To help you succeed in the hunt for fine details on the Red Planet, we have put together some tips for you.
Telescope and accessories:
- In order to adjust the optics to the outdoor temperatures, bring your telescope outside sufficiently long before the start of the observation to minimize instrumental seeing. At the beginning of October the temperatures around midnight can be quite cool. If your telescope is located in a dome or a retractable roof hut, open it in time.
- If you use reflectors for observing Mars, make sure that the optical system is collimated as perfectly as possible. That the telescope optics should be as clean and dust-free as possible, especially the Schmidt plate f SC telescopes, applies to all kinds of visual observations.
- Also make sure that the eye lenses of your eyepieces are clean and free of grease (streaks). The surface structures on Mars are usually low in contrast and can easily be overlooked by dirt.
- The old rule of thumb for planetary observations is that the normal magnification should be about 1.5 times the telescope aperture. Higher magnification reduces the contrast of the subtle surface structures.
- When observing the planets, make sure you have a comfortable posture when observing them. Balancing on your toes or a twisted head are counterproductive.
- Unlike lunar observations, where the contrasts are very high, the details on the surface of Mars are low in contrast and do not catch the eye at first glance. Start your observation with fainter than the maximum magnification for "looking in". Then observe with your maximum magnification, allow your eyes a regular rest by looking into the distance in a relaxed manner.
- Beginnen Sie mit ihren Beobachtung möglichst früh vor dem eigentlichen Oppositionstermin am 14. Oktober, um sich kontinuierlich in die Beobachtung in einzugewöhnen.
- Begin your observation as early as possible before the actual opposition date on October 14th, in order to get used to the observation.
The American magazine Sky&Telescope offers readers two tools for observing Mars on its website.
At this URL (https://is.gd/Marsprofiler), after entering the date and time, a Mars map with the visible surface structures is shown, as well as some current data such as the central meridian and the apparent diameter. Under this URL (https://is.gd/MarsMoons) the positions of the two Mars moons Phobos and Deimos are calculated after entering the observation data.
In general a telescope should have at least 100mm aperture – more is better, because the planets are small and the highest useful magnification depends on the diameter of the telescope. As a guideline, the highest useful magnification is 1.5 times aperture in millimetres.
Magnifications of 200x to 300x are worthwhile when observing Mars.
If our own Earth's atmosphere allows it, it is also possible to increase the magnification even further. The larger the aperture of a telescope is, the more details can be resolved. No wonder then that Schmidt-Cassegrains are so popular with planetary photographers: They combine a large aperture and focal length with a compact design, so that no extremely heavy and expensive mount is necessary to carry the telescope stably.
Azimuthal mount or equatorial mount
Whether you use an azimuthal mount, which can be set up in no time, or an equatorial mount, which is optimal for photography, remains a matter of taste on Mars – for planetary photography you can even use an azimuthal mount. The only important thing is that it has a tracking system: Then the planet remains in the field of view even at the highest magnification, and you can observe with complete relaxation.
Useful accessories for Mars observation
High magnifications can be achieved with short focal length eyepieces
Orthoscopic eyepieces ("Orthos") are still the first choice for planetary observers because they need just a few lenses to show a bright, high-contrast image; modern wide-angle eyepieces such as the Morpheus eyepieces are not inferior to them and at the same time offer a more comfortable view with a larger field of view – but they also cost much more.
Due to the relatively small apparent field of view of about 50 degrees, the classic orthoscopic eyepieces are relatively inexpensive. Foldable eyecups for shielding from extraneous light are absolutely recommended. With a good Barlow lens, the magnification can be further increased or brought to a value that matches the pixel size of a video module for planetary photography. For highest demands and magnifications you should use the
Fluorite Flatfield Converter (FFC) / 3x-8x (#2458200, € 689,-)
The Baader Q-Turret Eyepiece Set (eyepiece revolver, 4x Classic Ortho, 1x Q-Barlow 2.25x) (#2957000, € 265,-) is a very good choice. The eyepiece turret allows a quick change of magnification.
Especially interesting for the mars observation ist our Planetary-Bundle: the QHY 5-III-462C CMOS planetary camera with the Baader Q-Turret Eyepiece Set. The Q-Turret eyepieces deliver outstandig sharpness and contrast. With one twist you can switch between the three high-quality Classic Ortho eyepieces, which are the first choice of planetary observers because of their image sharpness, and the QHY. Also in the set: A 32mm Classic Plössl and a 2.25x Barlow. The comfort of a zoom eyepiece combined with the quality of fixed focal lengths!
Colour filters help to better highlight low-contrast details
For surface details on Mars, red and orange filters have proven their worth. The red and yellow-orange filters provide a general increase in contrast of the dark surface structures compared to the reddish Mars background. Blue tones in the atmosphere (e.g. clouds and haze) are blocked and the red tones are emphasized. Green filters enhance the contrast of polar caps, CO2 rime and dust storms. Blue and violet filters mainly show structures of the thin Mars atmosphere like haze, clouds and the violet clearing (haze layers on the terminator). Changing the filter is particularly convenient with a filter slider or a filter wheel.
The orange filter ist the classic Baader "Mars-Glass" and provides the best contrast enhancement on the planet Mars. Carl Zeiss coined the name "Mars glass" for this filter over 100 years ago. The Baader Orange filter is optically polished on both sides and has a 7-layer, high-quality multiple coating. It thus delivers the highest achievable brilliance even at the highest magnification
Relaxed observation with binoculars
Relaxed observation is possible with a binoviewer (for example with our Baader MaxBright® II Binoviewer ). We use two eyes during the day, why should we do without them in the night sky?
Remember the Star Diagonal
Often a bad image is not due to the telescope, but to the simple star diagonal that is included. We offer a range of mirror and prism diagonals. There is also an especially interesting option if you are doing both photography and visual observations: With the Baader FlipMirror II Star Diagonal (#2458055, € 215,-) you can switch from eyepiece to camera in seconds, and of course it can be combined with filter sliders / wheels.
For deep-sky and planetary photographers, we have created a high-quality photo bundle with the new – a RGB single shot color camera with high quantum efficiency and high sensitivity in the near infrared spectral range: center a planet in the eyepiece and switch to the QHY for planetary photography with the flip mirror - or connect the QHY to the Off-Axis-Guider and use it as autoguider for deep sky photography with a DSLR or CCD camera! The QHY 5-III 462C camera in a set with Baader FlipMirror II Star Diagonal and Off Axis Guider for Baader FlipMirror II (BFM-OAG) as (DSLR) photo bundle is available.