Equatorial Mounts For Budget Astrophotography? 85
Posted
by
timothy
from the rubber-band-and-hope dept.
from the rubber-band-and-hope dept.
Timoris writes "With the Perseids approaching rapidly, I am looking for a good beginner's motorized equatorial mount for astrophotography. I have seen a few for $150 to $200, but apparently the motor vibrations make for poor photographs. Orion makes good mounts, but are out of my price range ($350) and the motor is sold separately, adding to the price half over again. Does anyone have any good experience with any low- or mid-priced mounts?"
In that budget range just buy used commercial (Score:4, Interesting)
In that budget range, just buy a used commercial drive base from a broken small equatorial telescope like a Meade ETX-70 or ETX-90 that are typically sold in Wal-Mart at Chirstmas time. It is common to find them on ebay cheap with broken optical components. Another option is an old B&L 4000, the optics on most of these were junk, but they had a decent AC powered drive base, and since everyone knows the optics were junk, just ask google, they tend to sell cheap ($100 or so) on ebay.
Ike
I too wonder... (Score:2, Interesting)
I've been thinking about this for a while as I have built myself an 8" scope from the ground up, including the mount. And it all works well, except that it doesn't track. And everytime I look for a clock drive to put on there I end up only seeing options somewhere between $300-$30k. All I need is a big worm gear setup and a slow enough constant speed motor, but it seems gears are a lot more expensive than I think they should be. The weight of my scope is about 13lbs, with counterweights as it is now, closer to 15lbs... anyone know of an astrophotographic worthy clock drive and where to get it? I wouldn't mind spending $200-$300 if I knew it was going to work flawlessly, but it seems all the low end prices are flimsy replacment mounts, and all the clock drives sold separately are expensive professional grade setups.
For Meteors? Just a tripod (Score:4, Interesting)
To shoot a meteor shower, you need nothing more than a tripod, a camera with a ~50mm lens, warm clothes and patience.
You don't want to take real long exposures to get meteors, too long and light pollution/sky glow will likely mess up your pictures.
Just point near the radiant (I try for framing a nice constellation nearby), and using a cable release take 20-30 second exposures while watching the area of sky that the camera sees. Most exposures obviously won't have meteors, but when you do catch one, take note of which exposure for later when you delete the (many) exposures that didn't have a meteor. When you do capture a meteor, start a new exposure because keeping the shutter open longer won't likely gain you anything.
If you're looking at doing further astrophotography beyond a meteor shower, then you will need some form of tracking. Making a barn-door tracker can be a cheap option to get started (YMMV, depending on how good you are at making stuff and your level of patience!).
As with the rest of astronomy, you can start out spending a bunch of money on stuff you don't really need or use, so it's always good to start cheap and see if you are really into it. If your interest holds, you will find a way to buy up.
Re:Just a DSLR (Score:3, Interesting)
Stuff like this makes me think that we're really missing some opportunities in amateur astronomy. Computers and software have the potential ability to revolutionize how much of it is done.
Why do you need an equatorial mount in the first place, when a computer can do the math to emulate this with an azimuthal mount? Why futz with calibration and guide scopes, when the computer can just analyze every shot from the main scope and calculate drift in near-realtime?
It seems like much of the equipment is optimized to gain the most benefit from doing things the old way, where there might be opportunity to reach a better optimum if you aim for a different way. Maybe sensors should be optimized to take thousands of fast exposures rather than a few noise-free long ones, etc?
Capella? (Score:2, Interesting)
You can always try the Capella plans from the link below. I built it and it works fairly well. I find the friction required to get a proper static/stable lock on anything insufficient. Could be my implementation of the plans. I'm modifying the concept to use a couple of worm gears to stabilize everything. I've purchased some worm gears for garage door openers with 0.5" shafts. They are sturdy enough to keep a lock on an object. Probably not accurate enough to track an object over an extended period of time but, this is just for fun right?
have a look see: http://solar.physics.montana.edu/larson/Capella/index.html
Re:Just a DSLR (Score:2, Interesting)