Am I doing something wrong?

[keef_uk]

HI,

I want to get some good views of the planets - but when I located them and look through my scope all I get is a bright dot (just like a star) in the view finder

How can I acheive the views I see on this forum such as he polar caps on Mars or the strips of Jupiter, even the rings around Saturn are too small to make out clearly

Thanks in advance

[Cornelius Varley]

If you are comparing the view at the eyepiece to photographs taken with webcams remember that the photograph is a combination of several hundred / thousand images processed to get the most detail out of them. The imager will also have used a barlow lens to increase the focal length of the telescope even more ( 2000mm and more).

A Nexstar 102SLT has focal length of 660mm so will always be at a disadvantage to dedicated planetary telescopes (long focal lengths). There is also an art to observing planets, you need to train your eyes to see the fleeting glimpses of detail through the turbulent atmosphere.

You say you see just a bright dot (just as stars). Not true, even at low magnification Mars, Jupiter and Saturn will be seen as discs, stars are always point sources even at high magnifications. The size of the disc depends on the magnification used.

Jupiter is not well placed to see much detail visually because it is low in the sky, the light from Jupiter comes through the thickest part of the atmoshere and gets distorted.

Saturn's rings are almost edge on for now so are not easy to see.

Peter

[yeti monster]

Which scope and EPs are you using? You need some magnification to pull in the planets, and aperture is helpful to catch as much light as possible.

[Paul G. Abel]

Hi keef_UK- DON'T DISPAIR!!!!

My first view of the planets was nothing more than a few vagues streaks and a bright disk! You must not expect to go out on your first few night take a quick peak at Mars and be able to see Olympus Mons, even with a 15 inch 'scope.

You see, seeing the fine details is all about training your eyes and your brain. It's rather like running a 50 mile marathon. You wouldn't on your first training sesison expect to run the full 50 miles would you?! Here's something s that should help.

First, asses the seeing. Have a look at the planet in the sky, if it's twinkling like there's no tomorrow then the air is unsteady and there is absolutely no point in using a high magnification. A general rule of thumb for maximum magnification is that is is twice the diameter of your telescope. So if you have a 150mm (6 inch 'scope) then 2*150=300x, and this is your optimal max mag'n. If seeing isn't good, use half of this, i.e. 150x. It really is important to get a the power right otherwise you'llsee nothing!

Next point, start drawing. You don't need any artistic skill and drawing what you see has an important side effect, your visual system will sharpen up. In the case of Mars, find the right power for the night, then begin asking yourself some simple questions like 'What is the brightest feature on the disk?" "What is the darkest thing I can see?" "What does the North Poalr Cap look like" etc. As you ask yourself these questions your eyes will start to respond and 'search out' these features.

By drawing them, you will crystalize in your mind what you have seen and soon the landscape of Mars and the other planets will become as fimiliar to you as your own home! I also recommend keeping a log book as you will be able to see how you've progressed and keep a record of what eyepieces work best for the different planets etc. It's also nice to compare your drawings with maps and you can see how your accuracy improves!

Remember, the more time you spend at the telescope, the better and more reliable your eyes will become.

Finally, if you have them , try using filters. With Mars, yellow and orange filters can bring out the dark features.

I wish you success, and do let me know how you get on.

All best wishes,

-Paul.

[yeti monster]

Wise words there Paul, my first sketch this evening was way out, so I started a fresh page in my notebook and "looked" where the stars were in the field of view, then tried to remember their colours and brightness (my eyes are too bad for drawing/writing without my specs, and I can use my specs whilst observing).

Once I'd plotted my second sketch I knew that I'd improved it greatly, just by "seeing" what I was looking at. I haven't been able to check how accurate the sketch is, but it looks similar to how I remember the view was.

[kniclander]

if you're just seeing dots are you sure you've got the planet in the e/p? a stange effect that I've noticed is that you need to aim much lower in the sky than you think - something to do with refraction of the atmosphere? sorry if I'm completely off-track.

[derekm]

Go Deep Sky, it's much more mind boggling (IMO)!

Sorry if this comes across as a flippant reply, but I need 10 posts to post my 8" Dob for sale on here!

I want a Revelation 12" ----------------- for Deep Sky.

[John]

...Sorry if this comes across as a flippant reply......

It does. Have you just joined SGL to advertise your scope then

Keef_uk,

As has been said earlier in this thread, seeing details on the planets takes time and practice. I was using a 102mm refractor on Mars last night at 186x magnification and could make out the polar cap and a number of slightly darker markings on the salmon pink disk so smaller scopes can see the details - it just takes time at the eyepiece to tease them out.