guide to observing the planets?

[Sunwind]

any out there?

I recently tried to view mars but it was just a small bright dot, I was told on this forum it wouldn't look "proper" until january next year when it will actually look like a planet with a disc and features when it comes closer to us, now i'm thinking, what about the other planets? I'm just looking in Stellarium right now, and Uranus is up, but if I drag my scope out and try and find it, will it just be a small light-dot or will I actually see a greenish disc? where can I find out this stuff?

thanks

[Leegsi]

I think Jupiter is still up there behind the clouds

[George Jones]

According to Stellarium, Mars now has an apparent diameter of 8.7", while the apparent diameter of Uranus is 3.6".

Your 10mm eyepiece gives a magnification of 120x, so Uranus will be (not much, if any, more than) a small dot.

[Lews Therin]

The apparent diameter of Mars is 8.72" at the moment, and Uranus is 3.60"

A 10 inch Dob should have about 0.5" resolving power or better, so assuming you the atmosphere and weather is on your side, with sufficient magnification (do you have a barlow?) you should see a disc

Nathan

[ashenlight]

Hello Sunwind,

Try Jupiter, very satisfying with your size scope - you'll see the great red spot (although it's more salmon pink in colour to me!) significant detail in the bands and the moons.

You might find a Moon filter useful to dull the glare of Jupiter, it can be very bright - the filter will dull the brightness allowing your eye to perceive more detail. if you haven't got a Moon filter, try sunglasses. Worked for me

[Doc]

With a 10" scope you should easily resolve Mars into a disk. I would say you would need at least x200 to fully appreciate it.

[Sunwind]

With a 10" scope you should easily resolve Mars into a disk. I would say you would need at least x200 to fully appreciate it.

so what was that guy on about in the other thread telling me it wont be anything more than a bright light until january?

[Lews Therin]

In Jan, Mars will look approx 50% bigger, but with your size scope you definitely have to ability to see the North polar ice caps, and other features (although not with the 10mm).

[John]

so what was that guy on about in the other thread telling me it wont be anything more than a bright light until january?

I think it's just a question of interpretation. A planetary disk 8.7 seconds of an arc in diameter is a pretty small disk, even with a 10" scope. To some it may seem like little more than a bright light.

To be honest, with the exception of Jupiter and Saturn, the views of planets can be a little dissapointing so there is a tendancy sometimes to try manage down the expections of newcomers to the hobby (appreciate that might not be you).

Even at it's largest, this opposition Mars will only reach around 14 seconds of an arc in diameter. For comparison Jupiter is currently around 40 seconds of an arc in diameter.

John

[Sunwind]

so I need a 5mm ep?

[Doc]

Even if you do resolve it with your 10" scope it will still appear a a point of light but you will see a disk and will be able to tell that it is non stellar.

When it's closer and with more magnification you will be able to make out details such as polar caps.

[John]

so I need a 5mm ep?

1200mm focal length / 5mm eyepiece = 240x - that would be about the max useful magnification on most nights in the UK and would show small planetary disks more easily. The seeing conditions and the accuracy of the collimation of your scope and how cool the tube and the optics are will determine how much planetary detail you can actually see.

John

[Doc]

1200mm focal length / 5mm eyepiece = 240x - that would be about the max useful magnification on most nights in the UK and would show small planetary disks more easily. The seeing conditions and the accuracy of the collimation of your scope and how cool the tube and the optics are will determine how much planetary detail you can actually see.

John

I think John has hit the nail on the head here. Seeing conditions and collimation is so important while trying to see details on planets.

[Jupiter Martin]

Jupiter is quite good and prominent at the moment and is easy to find and there from sunset due south. You will get quite a bit of detail there and the 4 major moons in there various stages of transit. Saturn does'nt rise to early am depending on what your time scale is for viewing my best views are around 4am for saturn

[pvaz]

so what was that guy on about in the other thread telling me it wont be anything more than a bright light until january?

If you are referring to my comment on another thread maybe I didn't explain myself properly. Now Mars haves an apparent size of 8.5". It will "grow" up to 19" or so in late January, so a bit over twice the current diameter and 4x the area.

Anyway it should look like a small disk even now with the 10mm. That's what I see on my 8" with the 10mm. I can't see any detail whatsoever, just a small red disk. With the bad quality barlow I have it just becomes faded and haves some glare, but it gets bigger.

I'm waiting on the 2 Baader Ortho EPs I ordered (9mm and 5mm) hopping to see more detail with them.

[pvaz]

Correction. It won't be that big. I checked on stellarium and the max apparent size will be on Jan 20, and only 14" instead of 19". So thats like 1.5x in diameter and 3x in area.

[iamjulian]

I think I need some help with planets too! Embarrassingly I spend a good while last night convinced that Aldebaran was Mars. Oops. It was only when I went back indoors and tried to view it on Cartes du Ciel that I found Mars was still below the horizon. Good job I didn't take my 7 month pregnant wife out in the cold and have her stand there looking at a bright orange star telling her it was Mars. Ahem.

[Sunwind]

yeah I still need some help with this it's kind of frustrating, I feel a bit like I was conned by pictures of planets and people saying this is what you'll be able to see etc, when all I can ever see are tiny pinpricks of light that are a slightly different colour than the stars around them..

[pvaz]

yeah I still need some help with this it's kind of frustrating, I feel a bit like I was conned by pictures of planets and people saying this is what you'll be able to see etc, when all I can ever see are tiny pinpricks of light that are a slightly different colour than the stars around them..

I just looked at Saturn and Mars at 6am today when it was highest in the sky. Mars was still small but I could see the withe polar cap, the rest was red and had some darker spots on the surface. I used 240x (5mm) for Mars. Still it was small, like 20% of Jupiter's size but definitely not like a star.

Saturn was bigger, about 40% of Jupiter's size. I could see the rings and 2 black lines (one of them really faint) on the surface, parallel to the rings. Also sow 3 moons (those ware tiny dots like stars).

If we could see the planets from the Earth as well as the images captured by the probs sent to space, NASA and ESA wouldn't spend billions of our taxes to make those missions.

I think the secret to like astronomy is to enjoy looking at something with your own eyes.

If you prefer the detailed pictures, NASA and ESA already spend your taxes to bring them to you on their websites without extra cost.

EDIT: Or maybe your just pointing at the wrong target. On my 2nd day observing with a scope I thought I had mars on the EP and spent a good half of an hour till I realized I was watching Betelgeuse, then I moved to another red spot and hit Aldebaran... (those are 2 bright red stars)

[Sunwind]

i'm not talking about images from space telescopes

[pvaz]

i'm not talking about images from space telescopes

My bad then. But what I see on the planets is close in detail to the amateur images here. Just smaller.

And highly dependent on the seeing conditions. Some days nothing is visible, others things are sharp. The only thing that never changes is that the planets always appear smaller in the telescope when compared to most amateur pictures.

[John]

yeah I still need some help with this it's kind of frustrating, I feel a bit like I was conned by pictures of planets and people saying this is what you'll be able to see etc, when all I can ever see are tiny pinpricks of light that are a slightly different colour than the stars around them..

I understand what you are saying but astronomy is not a hobby of "quick wins" really (apart from the moon perhaps). Even with large scopes the details and contrast that we are searching for are ellusive and massively affected by the vagaries of our atmosphere and weather.

One of the 1st pieces of advice that newcomers to the hobby get (from SGL at any rate) is not to expect visual views to look anything like the pictures you see in books and on the web.

As a previous post in this thread said, the real "wow !" factor comes in gaining a little understanding of what you are looking at - the faint fuzzy objects and vague planetary markings at the limit of visual detection take on a whole new meaning when you know a bit more about their significance.

You have some great equipment to view with and your scope has a lot of potential if you give it time and perserverance.

John

[Sunwind]

well I just had my first view of jupiter, it was rather cloudy but for a few seconds every now and then it become crystal clear and I could see the bands and the moons on either side, it was great. it was rather small in my 10mm EP, with a 5mm one would it be twice as big as I just saw it?

edit: just been playing around with this: http://www.skyatnightmagazine.com/interactive/fov/fov.asp if I use a 5.5mm EP and a 2x barlow the size gets rather large

[John]

It would appear twice as big but you would not really see much more detail (maybe less) - Jupiter is rather low down at the moment so we are viewing it through lots of atmosphere which limits the quality of the view. In these circumstances the higher magnfication tends to magnify the poor aspects of the view rather more than the good parts !.

A 5mm might be useful for other objects (eg: double stars, the moon, Mars and Saturn in due course) which are higher in the sky. Saturn in particular seems to take magnification well for some reason.

[robneath]

as has been said its practice that reveals more, strange as that might sound. My first view of Jupiter was an indistinct lemon disk and four moons. Now I can detect the bands plus whichever moons are visible. Same with DSOs - M42 is magnificent, but I've noticed the more you view it the more detail is noticed, even with my puny setup