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What am I supposed to see......

Started by lloe, 10/19/2009 07:16PM
Posted 10/19/2009 07:16PM Opening Post
When I Aim my 12" scope at Jupiter? Even with 8mm EP I can barely make put the bands. I cannot see the red spot at all as I can just barely see the bands.

Would a properly collimated scope see better?

all I can guess is that collination is bad.

Posted 10/19/2009 07:39PM #1
Hi Lawrence,

Several possibilities, improper collimation is certainly one. Non-thermally equilibrated optics and generally poor seeing are others. Start by making sure that your scope is properly collimated. Take the scope outside at least an hour before you intend to use it and start with low/medium power oculars.


Posted 10/19/2009 09:16PM #2
Lawrence Loe said:

When I Aim my 12" scope at Jupiter? Even with 8mm EP I can barely make put the bands. I cannot see the red spot at all as I can just barely see the bands.

Would a properly collimated scope see better?

all I can guess is that collination is bad.



Jeff pretty much hit the nail on the head. To get a good view with a Newtonian, it takes good seeing, a scope that is properly collimated and a scope that has thermally equilibrated. It takes all three.

The seeing is the most important factor, that's the steadiness of the atmosphere, not much you can about it except be aware of it and try to gauge how good the seeing is. Make sure you are not looking over houses or trees if you can and try to wait until Jupiter is as high as possible, right now it is poorly positioned for those of us in the northern Hemisphere.

If the stars are twinkling, that is a sign the seeing is not stable.

Make sure you scope is cooled down, you can do something about this... Best is a smooth fan that is properly mounted so that it does not cause the scope to vibrate. Floyd Blue makes some nice custom fan assemblies. Then put the scope out at least an hour before you plan to observe and let it cool down with the fan running.

And finally collimation, I am not sure what tools you have but if you are using a laser, make sure the laser itself is collimated, most arrive out of collimation so first you need to collimate the collimator. Collimation requires good tools... If you are going the laser route, I suggest the Howie Glatter units, he makes them himself and they are accurately machined, arrive in alignment and stay aligned...

So, if the seeing is good, the scope is cooled and collimated, then you should have some enjoyable views. As far as the Great Red Spot goes, of course it's not there all the time (it might be around the back side of Jupiter) but it's really not a big red spot but rather an outline in the cloud bands...

Get that scope ready and one day, you will say, Ahh... So that's what it looks like when the seeing is top notch.

Posted 10/20/2009 04:46AM #3
Jeff and Jon both have good advice for you. I would just add this small thought: Practise! Observing is a skill that is developed. The more time you spend looking the more you will see.That would be true on a nightly basis, where those fleeting moments of good seeing are the reward for time spent at the ep. It will also be true over time, as your eye develops the capacity for pulling fine low-contrast detail out of the planetary image. I've often had a wonderful view of Jupiter where I see multiple bands, festoons, barges, etc., then invite a friend over to the ep who only sees "a couple of belts". Keep practising, and you'll see more and more!
Posted 10/20/2009 05:37AM #4
All the observing advice you are getting will help.....

However, the first thing you should do is adjust your expectations. You may be thinking that the Great Red Spot is indeed a great red spot. In fact visually it is most often a slightly tan interruption in a generally tan stripe on the planet. The stripes with all the whorls and twists are (visually) kinda a strip of light brown against a strip of tan.

In other words, what you see in the Hubble and other pictures is not what you will get at the eyepiece. Under exceptional conditions you may get glimpses of the detail, but it takes patience.

Posted 10/20/2009 06:10AM #5
I see the two equatorial bands, and slight darkening at the poles on my 10" dob. I can barely make out the red spot, if I am sure that it is facing me that night.

I usually don't go beyond 150x when viewing Jupiter. The view is just better between 100x and 150x. Enjoy the moons, sometimes over the course of an hour or two you can watch one disappear or reappear from behind the planet.

Posted 10/20/2009 12:37PM #6
what eyepiece type are you using? and are they clean? where are you viewing from?all factor in to what and how good you can see.I dont care how big the scope is ,if you use a $15 plossl you'll get $15 views and light polution and smog will ruin any planet hunt,for sure!! Remember too,that the image will be inverted or upside down so the red spot won't be where you think and the pics you see in magazines are from usb snapshots on excelent nights,they get 25 shot in one second of perfect viewing and stack then photoshop.Keep trying it only gets better with practice