first telescope-Meade 70AZ-AR
Posted 04 January 2008 - 10:54 PM
Posted 05 January 2008 - 05:24 AM
Welcome to astronomy. I have not owned one, but I believe the 70mm refractor is a pretty good place to start to get a general introduction to the subject. I do not believe you made a mistake unless you decide that you have. A lot can be see with that size of telescope. However, there is a lot that cannot be seen that requires a much larger scope in terms of diameter. The real issue is simply light gathering power.
That scope will also be good for terrestrial viewing, such as birds and other wildlife. An image erecting diagonal will most likely be needed for that. Assuming that you have a diagonal (turns the image at a right angle) with your scope, it will make right side up. But, left and right are reversed. A terrestrial diagonal generally turns the image 45 degrees instead of the 90, since you will have the scope more or less horizontal instead of looking up into the sky.
With this scope, you will be able to see the moon in detail; Saturn with rings and its largest moon, Titan; Jupiter with its bands (under the right sky) and its four largest moons. You will also be able to see the brightest deep sky objects, such as the Great Orion Nebula (middle "star" in Orion's sword). This scope should also be good a seeing many of the star groups called open clusters. The easiest to see is called the Pleiades. I am not sure if you will be able to see very many of the globular clusters. They will look like round fuzzy balls if you can see them.
There are also, litterally thousands of known double and multiple stars that are out there that you can search out. Many will be too faint or too close together for your scope. But, there are hundreds that you can find. A good example is Polaris, the North Star. It actually has two smaller stars orbiting it. You should be able to see one of them.
A lot of what you can see will be determined by how much light pollution you have in your area and whether or not you can go to a dark site of some kind.
Probably the first upgrade you will need is some astronomy books. You can probably check them out from your local library or request them in from somewhere else. You can also purchase books from places like Amazon.com as well as any book store. Two that I would recommend to you are Turn Left at Orion and Star Watch.
With a 70mm scope like yours, I am not sure if you will need a moon filter or not. If the moon seems too bright, then a filter is in order for your comfort. I do not think any other filter would be to your advantage. Light gathering power is the main limiting factor for your telescope. Filters can only take away light of one kind or another. They cannot add any.
The next part has a little mathematics with it, so bear with me.
Magnification or at least different levels of it is a good way to enhance your experience. However, I would not recommend running out and buying a bunch of eyepieces just yet. Use what you have for a while, figure out what you really like viewing, and go from there. Sometimes, there is a lot of hype about magnification, with a lot of claims. As a general rule, a top flight scope will be able handle about 40X per inch of lens diameter at sea level, about 50X at, lets say, a 1000 feet elevation, and 60X on a mountain top. With your scope, which is not a premium instrument, the limits will be less than that. Depending on where you live, the upper limit with this scope will probably be in the 100X to 125X with good, stable, reasonably clear air. To figure magnification, divide the focal length of your telescope, probably around 700mm by the focal length of your eyepiece. If you have a 25mm eyepiece with a 700mm telescope, the magnification will be about 28X. With a 10mm eyepiece, it would be 70X. With a 6mm eyepiece, the magnification would be about 116X, which I expect would be a realistic limit for your telescope. If you want a wider view to help find things, a 32mm would give you about 22X. The lower limit for most telescopes is somewhere in the 17X to 20X range. A 32mm eyepiece is pretty much a lower limit for you.
Getting a wider view is more important than what you might think. It lets you see things and star groups that you would miss otherwise. Normally, you start out looking for an object with your finder scope and then your longest focal length eyepiece. I happen to be a big fan of a 32mm plossl eyepiece. Plossls generally have a 50 to 52 degree Apparent Field of View (what you see through the eyepiece). In order to know what the True Field of View is (the chunk of sky your are actually seeing), divide the eyepieces Apparent Field of View by the magnification. In a 700mm telescope, a 25mm plossle eyepiece would have a magnification of 28X and a true field of view of 52 divided by 28 or a little over 1.8 degrees, which is really pretty good for finding things. A 32mm plossl would have a true field of view of not quite 2.4 degrees. I would not run out and buy a 32mm just because of this information. I would work with the 25mm you probably have with your telescope first. If you have a lot of trouble finding things, or if you decide you would enjoy a wider view, then save up your money and get one.
Another convenience item is a little red flashlight. You can buy one or do like I do and make one out of another little flashlight. What I did was purchase one of the Maglights that takes two AA batteries. With it, they provide a couple more clear plastic lenses and a hexagonal piece that goes over the lightbulb end of the flashlight to keep if from rolling when you set it down. I took the two extra lenses and put about twelve pieces of red celophane in between them and taped it up with scotch tape. I then put that inside the hexagonal cover and installed that on the flashlight. A little plastic electricians tape over the outside to hold on the cover and the light is ready. I normally put a piece of string through the hole in the back end to hang the flashlight around my neck. I use string just big enough to get the job done, but small enough to break if I hang up on something. I do not want to either tip over my scope or stangle myself.
Well, that is probably enough for now. If you have any further questions, just holler. There are any number of people here that are willing to help out.
The big thing now is to go enjoy the sky and learn about it.
Hope this helps,
Posted 06 January 2008 - 06:36 PM
It was very blurry so I changed the lens and in the process, I lost it. Yes... I was traumatized. I'm pretty sure what I saw indeed Mars, because it looked very similar to the pics I've seen online. But, what do I know? I'm an amateur!
Posted 07 January 2008 - 01:50 AM
Posted 07 January 2008 - 07:34 AM
Images you have seen of mars were captured using very large telescopes.
The 70 mm is a small telescope and can see many things.
Remember this is a beginners telescope.
Limiting factors to get good views depend on seeing conditions and transparency.
Even with a large telescope if conditions arnt right it is very hard to get any details on Mars.
Fife Lake, Mi.
Posted 07 January 2008 - 10:01 AM
What, under good viewing conditions with a 70mm telescope, should I expect to see when I look at Mars?
I wish I could find some images of what different objects look like when viewed with a 70mm scope so I would know if I'm usuing it properly. I've read of people being able to see (with this same telescope) Saturn's rings, Jupters larger moons as well as Mars actually looking like a rust colored planet with darker colored bands. Are these just exagerrations?
Again, the best image I have been able to get essentially looks no different than what I can see with the naked eye.
Posted 07 January 2008 - 10:53 AM
The results are here (but you need to click on each image to get the best view):
In each case, I could see more visually with my "Mak".
I haven't been able to image Mars recently, as I have a bad back and can't carry my Mak out.
YouTube channel: https://www.youtube....jc2Y0j7-UoRD6lg
Amazon Home Page: https://www.amazon.c...56214576&sr=8-5
Posted 07 February 2008 - 08:22 AM
Posted 20 February 2008 - 08:57 PM
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