Observing the Planets
TIP:
The planets will ALWAYS appear small in a telescope. You will never see any of the planets appear like the size of a dinner plate. The pretty photos that typically come on the box of a telescope are very misleading.
However, despite their small size, a surprising amount of detail can be seen. With your main tool being patience…
I am REALLY hammering this patience thing in these last two posts for a reason. Astronomy is NOT a “smash’n’grab” thing. It requires being calm, concentration, and a keen eye, and it doesn’t matter if it’s with the Moon, Saturn, the Orion Nebula, or the impossibly faint globular cluster Mayall 11 that belongs to the Andromeda Galaxy!
Be patient, and amazing wealth of exquisite details will become visible to you, such as the polar caps on Mars (Yes! Snow on another planet!!!), or like one of my greatest ever thrills, seeing clouds on Mars!!!
FILTERS help with the planets.
While not essential, colour filters can help a great deal with seeing details on the planets. What features and which filters is the subject of this part.
The way I will mention what features are visible will be contained in the following link to astronomical filters. Half way down the following link, you will find a list of the planets, what features are visible, and the best filters to see those features with:
https://www.myastroshop.com.au/guides/filters.asp
CAUTION!
If you do think about getting yourself some colour filters, GET NO MORE THAN THREE OR FOUR.
STUDY that filter guide very carefully, and then compile a list of no more than 4 filters. The reality is YOU WILL NOT USE THESE FILTERS VERY MUCH. So having just a clutch of them is all you will really need.
DO NOT BUY READY MADE FILTER SETS!!!! These are made up of colours that are way too deep and intense, and these filter sets are designed to appeal to novice eyes because of their strong colours. Truth is that these strong colours are not the best options for the planets. Instead, the better/more practical filters are more subtle in hue intensity.
Me, I only have four colour filters, and I use three of these the most, and not very often at that. Only sometimes do I ever bother using filters with the planets. A couple of these really I don’t use all that much, and sometimes I think about getting one or two others to replace them, but I’ve never acted on this as I doubt I would use these filters very much at all too. <sigh>…
Uranus and Neptune.
I will only expressly discuss these two planets because they are particularly challenging in that they really have no discernible disk to make out at all. Instead, the best way to identify these two is by their colour. Uranus has a very distinct bluish-green colour to it, and Neptune is an intense blue that is much too rich to be a star. Because there is no discernible disk with these two planets, don’t worry about using filters with them.
Uranus is actually visible to the naked eye! What you require is a very dark location, good transparency, and an accurate, up to date chart such as one of the astro apps. I’ve been able to see Uranus from up in the Blue Mountains just west of Sydney on many occasions, and I was also able to see fainter stars around Uranus to so I was not confusing things. And of course a quick look through a scope confirmed this too.
Uranus is also VERY EASY to spot with binoculars from under urban skies! At magnitude 6, it is not a challenge for a 7X50 pair of binos. Again I’ve managed this from my home in Sydney.
TIP
You will see more detail on the Moon and planets with a larger telescope due to a larger scope having a greater resolving capacity. But even so, a surprising amount of detail can be seen with smaller apertures. A wee 2” refractor will show the two main equatorial belt of Jupiter and reveal the four Galilean Moons. A good 80mm scope will reveal the Cassini Division in Saturn’s rings. A 14” scope will allow you to spy out the main five moons of Uranus and Neptune’s largest moon Triton.
CHALLENGE
This challenge will be a real test of the quality of your scope. You will also require a scope larger than 6” in aperture for this, and good seeing conditions too.
Saturn’s rings are made up of thousands of individual rings and even gaps. The Cassini Division is the largest of these (roughly 4000km wide). There is another ring division that is visible, the Encke Division. It is much smaller in size (roughly 400km), and to be able to resolve it in any scope over 6” in size is a testament to having a blooming brilliant set of optics in your scope! The Encke Division is a real test of optical quality.
If you would like me to prepare other challenges, such as challenges for smaller scopes, deep sky objects, Moon, planets, whatever, let me know. I’d be only too happy to devise a few!
Alex.