zola
Cygnus
Posts: 9
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Post by zola on Apr 14, 2017 10:46:30 GMT
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Post by stevie on Apr 14, 2017 21:02:29 GMT
Hi Mark For general observing, and as a beginner, you would struggle to do better than this telescope. This is a slightly smaller version of the scope I had out a couple of weeks ago (the big grey one). Excellent optics, decent eyepiece, good focuser, red dot finder and relatively inexpensive. If you want to learn the sky, and get excellent views of most objects, including planets, then this is the one. There is one eyepiece supplied with the scope, a 25mm plossl, which would give a magnification of 48 times (48x). A 2x barlow would double this magnification. You would probably want a couple of other eyepieces as well. However, this scope would be more or less useless for astrophotography (AP for short), the reason being that it does not track objects in the sky. For AP, the mount is more important than the telescope, and good mounts for AP are not cheap. You may remember the mount on the tripod that Jonathan had the other night, you would need something like that. You might be able to get a snap shot of the Moon at the eyepiece, but that is about all. I know you are a keen photographer, but I would strongly advise you to learn a bit about general observational astronomy first, and think about the AP later. I'll give you a call next time we are heading out and we can talk a bit more then. uk.telescope.com/Telescopes/Dobsonian-Telescopes/Dobsonian-Telescopes-with-Free-Shipping/Orion-SkyQuest-XT8-Classic-Dobsonian-Telescope/pc/1306/c/1316/sc/1351/p/109907.uts?refineByCategoryId=1351#tabs
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zola
Cygnus
Posts: 9
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Post by zola on Apr 19, 2017 10:45:10 GMT
That's great Stevie thanks.
I take it the XT10 version of that product range produces a better / larger image in the scope? I see its a couple hundred quid more in around £500.
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Post by stevie on Apr 19, 2017 21:08:24 GMT
Not necessarily larger or better, but definitely brighter, although not substantially brighter.
Most beginners assume that the purpose of an astronomical telescope is to make an object bigger, so that it can be seen more clearly, but it is better to think of a telescope as a device to make an object brighter. Therefore, the bigger the mirror, (or lens in a refractor), the more light it will take in and direct to the eyepiece. This makes faint objects brighter, and means that the bigger mirror (or lens) can clearly show details of objects which may not be clearly visible in a smaller telescope.
Imagine a telescope mirror as being a square rather than a circle. Therefore, a 6" mirror would have a total light gathering area of 36 square inches. An 8" would have a total light gathering area of 64", a 10" 100 square inches and so on.
A 12" would have 4 times as much light gathering power as a 6", and just over twice as much light gathering power as the 8". The 10" would have approximately 3 times as much light gathering power as a 6", and half as much again light gathering power as compared to the 8".
In reality, this half as much again would not be as immediately obvious as the difference would be between the 6" and the 12". It is usually advised that if you want to increase and upgrade your light gathering capacity, it is best to make a 4" jump rather than a 2" jump
So, the larger the mirror, the more you will see, and the better you will see it. If you felt you could get the 10", then that would be fine, there is no rule to say you must start with something smaller. Many beginners feel that they should start with a "beginner scope", but this often leads to frustration as they cannot see objects as well as they would hope to. The cupboards of the world are filled with 4" and 5" reflectors.
There are a couple of other things to consider. Can you physically manage the scope? (no problem in your case). Can you get it in your car? Have you the space to store it at home? Is it so big that you just can't be bothered to take it out? Will you be able to sell it if you get fed up with it or lose interest in the hobby?
You will also need to budget for accessories. I haven't actually looked at the specs for the scope, but you may need, amongst other things, a red dot finder and a laser collimator. You will soon want more eyepieces to get different magnifications. We can advise you on all these things and you don't have to get them all at once.
One last thing. Compare the price of the 8" intelliscope (xt8i)against the ordinary 10". The intelliscope has a really useful device which finds things in the sky for you after an initial simple setup routine. It could save you a lot of grief and frustration in the longer run.
Next time we are out, if you have not bought anything by then, I'll bring my xt10i and let you have a good long look at it and work it yourself
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zola
Cygnus
Posts: 9
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Post by zola on Apr 20, 2017 10:03:44 GMT
That's really helpful, thanks Stevie!
I wont buy anything until I have been out with you guys again for sure.
Cheers!
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