Last updated: 30 August 2003
Keep in mind that Mars is now getting further from the Earth and so will be getting smaller in apparent size. But for the next several weeks it will still make a fine object to view.
A common new-user error is to turn the focus knob until the image of Mars is as "large as possible". This is incorrect; when properly focused, Mars will actually be as "small as possible" for that particular eyepiece. If the Moon is in the sky, turn your telescope on that first and focus. If the Moon is not visible, focus on an easily seen star, which will be a pinpoint of light when in focus. Then swing over to Mars; the focus should remain essentially the change (although some fine adjustment may be necessary as the telescope orientation changes). With small telescopes you will not get an infocus view of Mars that fills the entire eyepiece field-of-view so don't try to use the focus knob as a "magnification knob".
OK, what can you see with the ETX-60AT and ETX-70AT?
I used my standard ETX-70AT with the supplied 25mm and 9mm eyepieces. I also used a Scopetronix Moon Filter and a Meade #126 2X Barlow Lens. ETX-60 and -70 users should invest in a Moon Filter if they plan to view the Moon; the filter reduces the brightness of the Moon, making it less painful to view it, especially near Full Moon. A Barlow Lens is also a useful addition if you have a limited set of eyepieces. So, I decided to test with these since I hope that many users have these accessories.
25mm (14X) - The disk of Mars was "pinhead" sized with no details visible. It was overwhelmingly bright (at Magnitude -2.9 at this point in its approach). But there was a definite disk visible; it was not the same size as seen with my naked eye (which showed no disk) nor the same as in my 7x50 binoculars (which also showed no visible disk).
25mm + Moon Filter (14X) - Adding the Moon Filter helped reduce the glare from the bright image of Mars but there was still no detail visible.
9mm (39X) - Mars showed a larger disk. The South Polar Ice Cap was readily visible and a large expanse of dark area (a faint gray) was also visible.
9mm + Moon Filter (39X) - There was not really much change when adding the filter from the view without the filter.
9mm + 2X Barlow Lens (78X) - Now the view was really getting good. Both the dark area and the Ice Cap were easily seen. But Mars was still fairly bright to the eye and so it was hard to just "stare" at it (which you shouldn't do anyway but people do).
9mm + Moon Filter + 2X Barlow Lens (78X) - This presented the best view of all with the ETX-70. By using the Moon Filter, the brightness was reduced to where it was easy to just look at Mars without being overwhelmed. With the brightness reduced, there was an apparent increase in contrast that brought out the dark area and Ice Cap.
I didn't try any higher magnifications as most new users don't have additional eyepieces yet. But using higher magnifications (up to around 100-120X) will yield even nicer views. Remember that as you get closer to the theoretical maximum usable magnification (twice the aperture in millimeters, or 140X for the ETX-70), the image gets fainter and fuzzier, reducing the details that can be seen. However, with good seeing and good optics, you can exceed the max on brighter objects (like the Moon and brighter planets; just don't expect a crystal clear view).
What can you see with the ETX-90?
I used my seven year-old ETX-90RA with the supplied 26mm eyepiece and the 9.7mm eyepiece that came with the Meade $99 eyepiece deal. I also used a Scopetronix Moon Filter and a Meade #126 Barlow Lens. ETX-90 users should invest in a Moon Filter if they plan to view the Moon; the filter reduces the brightness of the Moon, making it less painful to view it, especially near Full Moon. A Barlow Lens is also a useful addition if you have a limited set of eyepieces. So, I decided to test with these since I hope that many users have these accessories.
26mm (48X) - Note that in moving from the ETX-70 to the ETX-90, the magnification has already increased due to the longer focal length of the ETX-90 (1250mm) vs the ETX-70 (350mm). Basically I started with a little more magnification with the ETX-90 than where I left off with the ETX-70. This eyepiece presented a nice view with the dark area and the South Polar Ice Cap easily seen.
26mm + Moon Filter (48X) - Adding the Moon Filter reduced the glare making it easier to just look at Mars. The dark area and Ice Cap were still easily seen.
26mm + 2X Barlow Lens (96X) - Doubled the size of the disk of Mars with the dark area and Ice Cap even more visible. It was getting easier to see more shape to the dark area, which still appeared grayish.
26mm + Moon Filter + 2X Barlow Lens (96X) - Wow! This was a very nice view.
9.7mm (129X) - More shape could be seen to the dark area. Of course, the Ice Cap remained readily visible.
9.7mm + 2X Barlow Lens (258X) - Very nice! You notice that I have now exceeded the max theoretical magnification for the ETX-90 (180X). But Mars was bright enough (right now) to make this possible.
9.7mm + Moon Filter + 2X Barlow Lens (258X) - Again, adding the Moon Filter reduced the overall brightness of Mars, increasing the contrast and bringing out the dark areas. Lots of detail was seen, especially during moments of really good seeing.
Bottom Line Even these small telescopes can currently show Mars. If you are expecting to see canals or cities or craters, won't happen. They don't exist (the cities; there is a large "canal" but it is a natural canyon) or they are too small to be seen from the Earth. But you can see the Polar Ice Cap and some dark areas on the surface. If you are lucky you might even see some clouds (as a bright band) along the limb (they can form at sunrise at that location).
So don't expect too much and you will be amazed at what you can see with the ETX-60, ETX-70, and ETX-90. I didn't set up my ETX-125 but with its larger aperture and longer focal length, the views would be even better than I've reported on here. Same for the ETX-105.
For its size, the ETX-90 continues to deserve my name for it: "The Mighty ETX".
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