telescope question?

Question

i got my 10 inch dob out tonight and looked at mars. what I saw was a small dot that was red. you couldn't distinghish the polar caps or see any detail.

How can I make mars look at it's best?

pathetically weak?
You should be more careful with how you word things, you might come off as a rude person.
Don't do that.

What barlow and eyepiece size do you suggest?

Answer 1

Planetary observing can be challenging, even with a telescope as large (and powerful!) as a 10"

The reason is usually due to atmospheric turbulence, and not the telescope. Even if the atmosphere appears calm and clear, there could be paricles in the air or turbulence at higher altitudes.

And don't forget, Mars has weather too, and at times is covered giant dust storms.

You can get excellent views of Mars in a 10" under the right conditions. Observe on nights when the atmosphere is calm and clear; hope the same is true for Mars. If a planet is on the horizon it will be more difficult to get a clear view of because the atmosphere is thicker in that direction. Some people will sit out for hours watching until a "window" of clarity opens up.

Let the telescope sit outside for a while to reach thermal equailibrium with the surrounding. I usually let mine sit for an hour in temperate climates but if it's particularly cold and the telescope has been indoors then a longer "cooling" period may be warrented. When observing, start with the lowest powered lens and work your way up. Barlows can help you get the best out of your eyepieces but make sure you have a high quality one. You typically will not need anything above a 2x barlow.

You may also want to check to make sure the telescope is collimated properly. I'm assuming it is if it's new and didn't get bumped around too much during shipping. Collimation is a tricky process though so don't touch any screws until you have read up in depth on it.

Answer 2

Mars is very small, about half the size of our planet. So to see it well, you need to look at it when it's at or near opposition. That is where the planet is right now. Secondly, you need a eyepiece or an eyepiece and Barlow lens that will yield about 200X. You also need a night when the atmosphere is not roiled with turbulence from the Jet Stream overhead, a passing weather front or heat rising from buildings and pavement around you. Also, your telescope must be collimated properly, otherwise the view will be disappointing to say the least. Mars is not an easy planet to observe, even people with very large and powerful telescopes had trouble observing it's features, which are often very low contrast. High quality optics that are well collimated help a great deal, along with quality eyepieces. Color filters also can help. A yellow, orange or red filter will make surface features easier to see. Blue and green filters show clouds in the atmosphere. Finally, you need to observe mars for a while and train your eyes to find the faint features across it's small disk. Mars will now start pulling away from us and soon it will be a very tiny disk that will reveal little to nothing in your telescope even at 500X. Now's the time to observe it as often as you can. Before long, you'll start seeing the markings on the surface.

Answer 3

You can see the polar caps and "canals" even with a 6" scope on a clear night, even at 100 power. With your 10", you should be able to use 300 power, and mars will appear to be about 1/4 to 3/8" in diameter. The problem is a dob has a very short focal length, so you need a very small eyepiece to obtain that power.

Answer 4

Mars is quite small, so use the highest magnification you can without making the planet look blurry. For a 10 inch try 300 power or more. This will make pointing and tracking difficult of course. The contrast is EXTREMELY low. Mars has a very bright, washed out look to it. Sometimes a color filter helps, but not much. I think a blue or green filter should bring out the polar cap. The polar cap is usually the easiest thing to make out. It also depends on how much dust is in the air on Mars. Sometimes, planet wide dust storms can hide all the detail on the whole planet.

Answer 5

Hi J -

My experience with Mars has not been terribly rewarding. I have not looked lately, but I've heard that the polar caps are virtually nonexistent recently, so that makes it an even less interesting target. Filters can help - I think a blue one works reasonably well to pull out the contrast with the darker regions. Bottom line is - don't let it frustrate you - there are lots of better things to look at. I had more fun this last fall finding Neptune and Uranus than I ever had with Mars - and they have no detail at all. Wait up for Saturn for sure - you will not be disappointed - Oh and stay warm!

Answer 6

With the 10" Dob I used to have, I used around 250x for Mars. But the most important thing is training your eye to detect faint contrasts on a tiny bright disk. The detail is there; it just takes practice to see it. The best way to train your eye is to make simple drawings of Mars, At first you won't see much but, the longer you stare, the more you'll see. In the source are a couple of articles I wrote recently, one on Mars and one on drawing what you see.

Answer 7

Use a 4.7mm eyepiece, a 9mm eyepiece or something similar.

Answer 8

Increase the magnification, it sounds like your telescope is patheticaly weak, perhaps a more powerful lense?
(or you could try adjusting the focus, but i assume you tried that!)