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Equatorial Mounts For Budget Astrophotography?
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?"
It depends on how you are wanting to do your astrophotography. If it is a camera alone then you might consider making and/or getting a barn door mount.
http://en.wikipedia.org/wiki/Barn_door_tracker
They are simple and work well.
If you are considering astrophotography through a telescope then you'll have to have some sort of eq mount for the scope and then the prices do rise. But since you seem to be interested in photographing the Perseids then I doubt this is the case. The wide field available with just a camera would be the way to go.
If you're on a tight budget, but want to capture the Perseids, put a DSLR on a standard tripod. Wide shots, say 18-55mm lens, you can expose for 30 seconds or so without noticing any earth rotation in your field. Take a bunch of exposures, and use a program like the free Deep Sky Stacker to align them into a final image with total exposure time equal to all the shots combines. I haven't taken any like this for meteor showers yet, but you can get some stunning shots of the Milky Way, and some of the bigger objects in the night sky. If you use a narrower field lens, like 100mm, then you might only get 10-15sec exposures, but just take several hundred and let the stacker program turn them into awesome.
If you want a motorized mount for astroimaging you get what you pay for.. A cheap one will have poor periodic error and vibration. I got a now discontinued LXD75, but due to the cheap plastic gears it's made with, I wish now I went with a more expensive EQ6 to get more accurate guiding.
I hope you are not intending on photographing a meteor from a telescope.
The most common thing to when photographing meteor showers is to point to the pole star and set your SLR (hopefully manual, film based on a tripod with a cable for the shutter) to a B setting and take a shot for a couple of hours. This produces really nice star trails and the occasional meteor.
If you are piggybacking the camera to a telescope you should not have any issues with the motor vibration, but you will need to beware of wind.
Save up your money and buy a Meade LX200, you can now get the older models (I personally think are better) for around 2000$US, combine that with a wedge and reticle eyepiece and you are ready to go. The thing really is a light bucket and something you will be happy with, with a little training you can even work out the periodic error correction with the scope so you can do astrophotography with the camera for the eyepiece.
If that is not satisfactory, build an adjustable wedge and buy a motor that rotates at 15 deg/hour and attach the motor to the top of the wedge with a camera on it.
GO BLUE!
Check this out:
http://members.cox.net/tfangrow/hissdrive.html
Otherwise, barn door mounts:
http://www.mikeoates.org/mas/projects/scotch/
http://www.astunit.com/tonkinsastro/atm/projects/scotch.htm
http://www.davetrott.com/DoubleArmBarnDoor.html
Equatorial platforms:
http://tech.groups.yahoo.com/group/eqplatforms/
Lots of other links:
http://members.ziggo.nl/jhm.vangastel/Astronomy/links.htm
I mean, for a meteor shower you would need a wide field, right? Probably under 150mm? Then small tracking errors such as minor vibrations would not really show up in the photo. I remember when I was in school, I was piggybacking on my manual equatorial mount telescope and I could manage crisp photos tracking manually - I doubt the inexpensive mounts are worse. ;)
I am assuming you have already tried fixed-mount photographing techniques for meteors, such as star-trail exposures or shooting repeatedly at exposures just before the stars start to trail (which of course depends on your lens & what dec. you are pointing at), and are considering advancing to something else. Otherwise try that first, budget astrophotography can start VERY cheap
Violence is the last refuge of the incompetent. Polar Scope Align for iOS
Point to the pole star?
I'm in the southern hemisphere, you insensitive clod!
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'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.
I'm not trying to troll or be mean spirited, but take it for me, any EQ mount that is in the price range you are looking for is going to drive you absolutely bonkers...at least in the 'motorized' category. You can get close to the upper price range on a manual EQ but it would only be good enough to piggyback a camera. I have been in the hobby (astrophotography) for about 10 years now and have lived through the pain of the cheaper mounts. Unfortunally, cheap mounts are only good for one thing...making you so fed up with them that you eventually get tired of trying and give up....and keep you from actually watching the shower since you will be constantly messing with the mount.
:
For what you seem to what to do from the summary above you could accomplish with the following
1. Stick the camera on a normal tripod and aim where the meteors are originating from with the widest angle lens you have.
2. Take 10 sec shots after ten second shots with an ISO of at least 800, while adjusting for position every 10 or so minutes so that you keep the general area of the sky in view.
3. The next day, use an astrophoto stacking program RegiStax to 'stitch' together your images made the previous night.
You would be surprised how good the pictures will actually come out...and for the price of a $50 tripod.
Now, barring that you are dead set on an EQ mount for this, I have only one piece of advice. In the land of EQ mounts, the heavier the better (less shaking, better stepping motors). And the heavier it is, the more expensive it is. There is just no getting around it. I currently have this mount and it required a complete tear down, polishing, and rebuild before it was even capable of astrophotography...and that's at $600!!
an equatorial mount will give you photos of meteor showers like this:
http://www.medanku.com/wp-content/uploads/2009/08/perseid-meteor-shower.jpg
instead of this:
http://celeb-news.net/wp-content/uploads/2009/08/meteor_shower_san_diego-8369.jpg
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.
A house divided against itself cannot stand.
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
In astrophotography you will find cheap is not the way to go, you are best off buying a mount! I own a Celestron CG-5 (new version) mount which does both fine for short-focal length (50mm-to200mm) piggyback DSLR, and at prime focus with my C8-SCT. - You can shoot with out a mount, make sure you use the smallest focal-length lens you got. gives you 1-30+ seconds (depending on make, will will need to stop it down to reduce bloating of starts and abrations (Decrease F number)) - Buy a good mount. If you want it bad but dont have the money get the CG-5. - invest in a remote shooting device, your hand/ or vibrations will kill your pictures! (wireless, or build your own with a 2.5mm stereo plug and a switch) I use my computer + USB remote shooting to my camera for quick feedback of the pictures (Canon rebel XS)