Anyone bought a star-tracker for your camera?

[CuriousMike]

I'm saying "star tracker" - a mount you put your DSLR on that tracks the night sky.
Something like this: http://www.amazon.com/iOptron-3302B...tBy=bySubmissionDateDescending#R3RQBV8ZTNOA8P

I've totally not researched this at all, but I have a current hard-on for using my camera to get a nice photo of, say, the Andromeda Galaxy.

My overarching question is this:
1. Is this all I need?

I take this "tracker", plunk it on top of my cheap assed tripod, plop my Nikon with 70-200 on it, and program it to "track Andromeda for 30 minutes" ?

 

[Berliner]

I have not researched very deeply into that stuff as well, mainly for the reason that I would not want to throw thousands at a problem that ESA, NASA and others are throwing Billions at and I can look at their images (and even use some) free of charge.

 

[blastingcap]

The cost of the high end astrophotographer hardware and software is too rich for my blood so I kinda do the same thing you do Berliner, lol.

 

[Spoooon]

You can build one of those barn door tracking mounts.

 

[CuriousMike]

I'm thinking for $299, I can give Hubble a run for the money.

 

[RampantAndroid]

You don't program it to track a star. The scope there is a polar scope; it's marked with other stars so you basically put the crosshair to polar north (or south); You then turn on the motor and it moves at sidereal rate opposite the earth's rotation. Depending on how well you aligned the setup, at 50mm a 20 minute exposure is POSSIBLE. At 300mm you need to stay well below 5 minutes. Ideally, you get some photo stacking software and take a bunch of 60 second exposures (say, an hour of shots) and it stacks them adding the stars together.

Now...as for for you use this? You need a good tripod - sturdy. You need to see how much weight the startracker can hold (I do not for a SECOND believe it'll hold 7.7lbs. The old version was a max of 5lbs. It'll flex a bit.) Mount the camera and everything, then point the scope to polar north, point the camera at what you want to take a photo of, check the polar alignment again and then hit start on the startracker and use a remote to trigger the camera (you'll want a intervalometer to set up the multiple exposures.)

Once you have a final photo, play with it in http://astrometry.net/use.html - the website will figure out WHAT you were looking at and label it. I haven't done this in over a year now (sadly) but this is my first attempt, to give an idea: http://www.flickr.com/photos/99315954@N07/9574307958/

On the right is Andromeda. I clearly didn't have good alignment on polar north, but regardless...I was impressed with my first attempt using a tracker. Using a lens at 300mm I would be able to get a pretty good shot of Andromeda.

I personally use this guy: http://astrotrac.com/

As for everyone saying why bother...well, Van Gogh does a better job painting than most people - so why do people bother trying? It's a hobby. A fun one at that.

 

[RampantAndroid]

And as for the photos you can expect once you get good:

http://www.dpreview.com/forums/thread/3636689

When you look at the SD card and see you've taken a photo of a galaxy...well, the feeling is pretty awesome.

 

[CuriousMike]

You don't program it to track a star. The scope there is a polar scope; it's marked with other stars so you basically put the crosshair to polar north (or south); You then turn on the motor and it moves at sidereal rate opposite the earth's rotation. Depending on how well you aligned the setup, at 50mm a 20 minute exposure is POSSIBLE. At 300mm you need to stay well below 5 minutes. Ideally, you get some photo stacking software and take a bunch of 60 second exposures (say, an hour of shots) and it stacks them adding the stars together.

Thanks for the details - I understand better now.
I've also been looking at telescopes that "auto track", and those actual align to an object you're interested in. ( I wonder if there's a way to retro-fit those to mount your dslr on ? )

With the star tracker for my camera, I'd still have to know where to point the camera - but the tracker will rotate to match the rotation of the night sky.

Got it.

$750 for that AstroTrac looks a bit out of my league for now - but I have something to aspire to.

 

[RampantAndroid]

Thanks for the details - I understand better now.
I've also been looking at telescopes that "auto track", and those actual align to an object you're interested in. ( I wonder if there's a way to retro-fit those to mount your dslr on ? )

With the star tracker for my camera, I'd still have to know where to point the camera - but the tracker will rotate to match the rotation of the night sky.

Got it.

$750 for that AstroTrac looks a bit out of my league for now - but I have something to aspire to.

The problem with those tracking telescopes is they usually only move in alt azimuth - that is to say, up/down, left/right - they don't use an equatorial mount - so photos end up having trails on them anyway. You CAN do it, but I don't advise it - and that assumes the one you buy can handle the weight. The startracker is a fine option, as long as you're not sticking high end 200mm lenses on it. Stick to prime lenses that aren't too heavy and it will work.

The star tracker will rotate at sidereal rate opposite the earth's rotation. When you manually align its axis of rotation perpendicular to polar north, that will zero out any rotation due to the earth's rotation that your camera would see (if that explanation makes any sense. )

 

[tdawg]

I'm loving this thread. The picture I want to create is one of those gorgeous astrophotography shots for my wall; I'm following this thread as I can see there is going to be a good amount of information to glean

Thanks in advance! RampartAndroid, you look to have a wealth of knowledge on this subject (and that shot of Andromeda from dpreview is stunning)!

 

[Spoooon]

What is the cheapest way to get into it without having to build a barn door tracker? $750 is way too much for me to dip my toes. I've seen some as cheap as $300, but there's no sense in spending the money if it's not going to work.

 

[RampantAndroid]

The star tracker is the cheapest, really. It's an odd place to be. Any exposure above 30 seconds at 35mm is going to show trails. Zoom in more and you can't even do 30 seconds. If the equipment isn't moving totally opposite the earth's rotation, it won't work either. There's a lot of precision needed. Both from the equipment AND from the person using it.

Get a Star Tracker, decent tripod and good camera. From there, look up to an Astrotrac and a 1000mm telescope.