Exactly what Kevin says above.
Here's a much longer and
much more waffly version...
Hi Kaye,
Two weeks ago I was in exactly the same position as you - I had a rough idea of what I would like to do, but no understanding of the terminology or the technical stuff. But I did a lot of research and practice and I’m now at least part of the way along the track. So I hope what I can tell you might be useful. Please excuse the length.
Firstly, my goal was very simple (at least I thought it was!) - learn the night sky and take a few pictures. But it turns out that can be anything from pretty easy through to a lifetime’s worth of study - and endless expense…
Here’s what has worked for me so far:
I started by sticking my camera on an ordinary tripod, pointing it upwards and taking some timed exposures. That was pretty simple with a modern DSLR. It’s necessary to use manual settings not auto as the camera can make poor choices when faced with something that consists mostly of blackness, with a few white dots! It’s also good to use a lens with a fairly wide field of vision. Longer zooms will struggle to gather enough light in a short enough time.
Canon do an 18-55mm zoom lens as a “kit” lens and I found it worked very well set at 18. Canon also do an inexpensive 50mm prime lens that worked fine for me too.
I tried different exposure times, and used a remote shutter release cable to reduce blur from wobble (probably not essential but I had one anyway). I set it on Manual (M on the Canon dial), set the ISO for something between 800 and 3200, (1600 worked fine for me) and then set the exposure time at anything from 2 or 3 seconds up to 25 or so. I was also necessary to use manual focus (set to infinity).
For what I wanted (simple wide sky pics) the exposure times wasn’t very critical. Too short (under two seconds) and only the brighter stars showed, and too long (over 20-25 secs) the stars began to show small amounts of movement blur. Anything in between was a compromise between overly light looking sky and varying number of stars. You don’t need a telescope for such photos.
When I attach the camera to the telescope, all I’m after is clear pictures of smaller areas of sky, to help me learn about the skies, although decent moon shots are easy enough too. What I don’t have ambitions to do is take photos of the quality you see in magazines or here at this forum. They require a different league of dedication! I would need to get a better quality scope, some dedicated software, and learn a bunch of new processing skills.
What a telescope does for me, which a regular long lens doesn’t, is gather a heap more light. So it could take pictures of much smaller areas of sky without needing long exposure times. Of course, I’m still only at the very shallowest end of the astrophotography pool, but as I don’t have ambitions to get detailed shots of very far objects, that suits me fine. It’s enough for my needs.
Conclusion: You don’t need tracking equipment to take basic night sky photos. You can leave the shutter open on a regular DSLR for 20 seconds or so before the rotation of the earth will cause noticeable blurring. Longer times can be achieved with a full frame sensor camera (e.g. Canon 5D).
Mounts:
Alt/Az
The Alt/Az style of mount is as simple as it gets. It goes from left to right and it goes up and down. A standard camera tripod can be used in that way. The main requirement of a telescope tripod is that it can carry the weight of the scope and also hold it as steady as possible without tipping or wobbling. Some camera tripods could be a little too flimsy and you wouldn't want to trust anything but light cheap scope on them, but others might be sturdy enough, providing the attachment method was strong enough..
PROS: Easy to use and relatively light to carry about. Requires no special setting up. I can pick up the rig, carry it outside, take the lens caps off, point it upwards and be observing in seconds. Works fine with a camera. It can carry the weight of the camera and scope and hold it steady enough for viewing or basic photography. It can also handle a few seconds of exposure when I put the camera on, which is all I need,
CONS: The light weight that made it easy to carry can make it less steady. I have camera tripods that are actually more solid than the Alt/Az tripod that came with my telescope. But it hasn’t been a problem. Mine has no dials or scales so I can’t read positions off it, but I don’t need to do that so it’s not missed. Tracking is done by twiddling two knobs. After a while I'll run out of twiddling adjustment and have to rewind and realign, but it’s quite a few minutes before I need to readjust, not just a few seconds.
Equatorial
If you like gadgets then an EQ mount is a joy to behold. Bristling with dials and levers, weights and knobs. If you don’t like gadgetry you’d probably hate it.
It’s heavy compared to the Alt/Az. The counterweights alone on mine weight over 5 kilos. It’s awkward to carry, and it requires time to set up. First I needed to set it to the latitude of where I live (mercifully you only do that once). Then it had to be levelled (there was a handy spirit level in the mount) and aligned to the South Celestial Pole. This is an imaginary place in the sky. Unlike the Northern hemsisphere (who get a handy star at the North Celestial Pole) our nearest star is too faint to picked up with the naked eye (and at our house it’s hidden behind a jacarandah tree too….) so an estimate had to be made based on the position of some of the stars in the Southern Cross and imaginary lines drawn from them. It’s suggested that when you get it nearly right you paint some dots on the ground to help putting the tripod back next time. Getting it nearly right isn’t too hard, getting it exactly right is definitely hard.
Unlike the Alt/Az it doesn’t go up and down and left and right in a straightforward manner. It rotates around two axes called right ascension and declination. This is not as easy to get your head around, especially if you want to re-align it quickly.
PROS: Once it’s properly set up you can follow the movement of the target by simply adjusting one knob instead of two. If your alignment is rough it will still work but you will also need to use the other knob, just not nearly so often as the main one. It can be motorised to do the job for you. However, for basic photography purposes, I am unlikely to want to be tracking things. Once it’s set up its weight is now a benefit to stability.
Comes with dials that (in theory) can help you locate objects of interest. Initially I had trouble with this because the instructions were appallingly vague and mostly concerned with the Northern hemisphere. However, once I got the hang of it, they have proved to be useful. In theory you could look up a star’s coordinates and then use the dials to lock onto it. In practice that is unlikely. If the quality of the dials and the accuracy of your setup wasn’t absolutely perfect you can still miss the target by a big margin. What it is useful for is to focus on a known star first - such as something in the Southern Cross, and then set the known coordinates of that star. You can then move across to an unknown different star and get a close enough approximation from the dials to be able to consult a star chart and get a name. Kind of fun if you like that sort of thing. Kind of a mathematical nightmare if you don’t…
CONS: Awkard to move, heavy, and time consuming to set up. Needs setting up again every time you move it outside again. Takes a while to get used to the way it moves.
Finally…. It’s worth remembering that astronomy telescopes generally invert the images so every direction you move the scope appears to do the opposite in the viewfinder. With an Alt/Az mount it’s easier to get used to inversion of up and down. left and right than the more complex movements of the EQ mounts. But all will become OK with enough practice. Which of course you will be doing in the dark. And it’s easier to do simple things blind that complex ones. Although mastering the complex can be fun too.
Good luck with choosing. Once you get going it’s not as bad as it sounds!
Cheers,
Chris.
your neighbour has an interesting mode of travel .. love it!!
