Standing on the Slippery Slope of Astrophotography

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Permalink Reply by William George Weller on December 3, 2009 at 10:40pm

Hi Garland. I use a Canon EOS20D, probably not the best for astronomy, but a good allround dslr. The nice thing about it is that there is an aftermarket focussing ring that Laurence put me onto that replaces the autofocus gizmo in the camera. You stick it into the eyepiece holder (sans lens) and rack the telescope focus until the camera beeps. It thinks that is looking through a Canon lens, not your telescoope.
We should all get together some evening to look at the options.

Bill.

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Permalink Reply by Garland Coulson on December 4, 2009 at 9:33am

Thanks Bill,

Yes, it would be nice to get out some night to see everyone else's rig, but I don't think the observer group has been out since I joined in September.

And now of course, we are in the cloudy season.

Garland

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Permalink Reply by Laurence Harry on December 3, 2009 at 10:42pm

Hi Garland, hmmm where to start :-).
First off, the camera.
For planetary images you can use the video function of most point and shoot cameras (if it has one of course) on the Moon, Saturn, Jupiter and Mars. This can be done by getting hold of a bracket that fits around the eye piece or focus tube so that it will hold the camera close to the eye piece ( afocal method ) and then get the planet into focus using video setting. Press the start button and hey presto you have a few seconds or minutes of images that can then be run through some of the freeware programs like Registax and it will sort out the cleanest and sharpest images for stacking.

The end result should be a very nice clean and well detailed image of the planet, ie Moon, Saturn or Jupiter.

For more in depth astro-photography the Canon range of DSLR's are the most popular, the EOS 350D has been seen by most people to be the best for deep sky imaging due to the sensitivity of the CMOS sensor. Of course there has to be a very good eq mount for tracking the object accurately so you wont get star trailing.

You could mount your camera on one of the tube rings if it has the right screw head to do " piggy back " photography.
Obviously a subject for another time maybe.

The basic requirements for shooting with the Canon are as follows.
A decent EQ Mount with GoTo functionality or an EQ Mount with drives on both axis Dec and Alt. Then you need to get a T mount and adaptor for the Canon so you can attach the camera to the telescope and you will also require a remote control cable so you will eliminate and camera or scope movement when depressing the button to take the image.

Once you have these items you should be ready for astrophotography ( a must have is clear skies too ) only kidding, it does help.
Coming back to the main point of your question, Canon EOS DSLR,s are really good for the short exposures needed to image the moon and other planets plus you don't have to worry to much about long exposures. The planets would be washed out by light.
Entry level Canon would be the Rebel 350 which you can still find if you shop around or the next best would be the 400D or 450D with pricing around $500 dollars for the 400D and around 6 to 8 hundred dollars for the 450D. The Live View function on the 450D is very useful for clean sharp focus because you can view the image 5x and 10x magnification. I would still advise you get the remote cable wire just to make sure you will not get camera shake when you press the button to take your photo.

I hope this is of some help to you Garland

Laurence

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Permalink Reply by Garland Coulson on December 4, 2009 at 9:38am

Thanks Laurence,

Very clear and detailed reply. My son owns a Rebel 350, so perhaps I will drag him out one night to just try some tripod shots for short exposures to see how I like how his works.

When I buy for myself, I would look for the live view feature. I did come across a used 40D for about $700US. Would that be a good buy?

Garland

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Permalink Reply by Laurence Harry on December 4, 2009 at 10:33am

Hi Garland....I would seriously look at getting the 40D especially at the price you mention. It is a really good DSLR. With your son's 350D it is a great place to start and you never know...he may get the bug too :-), I have the 300D, 20D and 450D each one has it's good points but they all take great photos.

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Permalink Reply by Garland Coulson on December 4, 2009 at 11:02am

Thanks Laurence,

I'll send a note to the person advertising the 40D to see if they will ship to Canada. My son may take some night sky shots, but he hasn't caught the star gazing bug. I did take him out to look through the telescopes and he was politely interested, but it didn't grab him like it does me,

Garland

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Permalink Reply by Richard Fortier on December 4, 2009 at 11:00pm

Hi Garland. I have spent over $40,000.00 on telescopes and cameras over the years. At the heart of an astroimaging setup is the mount. If you want to take good images you need an equatorial mount that can track. A goto mount will find the object and track it for you. Most goto mounts on the market have a guide port located close to the power button. Guiding the telescope mount rather than simple tracking gives you the ability to compensate for things like wind, mechanical errors inherent in all telescope monts, polar misalignment ...... . A simple web camera or inexpensive guide camera can be connected to a finder scope. This setup would allow you to use any telescope or camera you want within the mounts payload capacity. The images show two setups. The refractor image shows how a camera can be conected directly to the scopes focuser. The newtonian image shows an inexpensive 8" reflector on the same mount. Both scopes normally would have finder scopes mounted on them suitable for guiding. You can also just have your camera mounted directly to the mount with no telescope , just your finder scope for guiding. This mount is inexpensive for a goto mount,retail $ 1,500.00 CAD

. My telescopes don't need a finder scope because I have a camera tha has a self guiding chip inside it. A topic for another time.

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Permalink Reply by Randall (Randy) Krall on December 11, 2009 at 7:44pm

Hi Garland,

What Larry said is basically it in a nutshell. You DO need a tracking mount for most pictures. There are cheap mounts from Ioptron that are go-to. Apart from using either a CCD camera, or a DSLR, you can get a webcam. The best is the Imagaing Source DMK21AU04.AS monochrome (but they do have a colour one as well). They do sell however from about $380 to $ 500 depending on the CDN dollar which is pretty good right now. The other thing to consider is that this camera can also be used as a guide scope camera later when you wish to "move up the ladder". Cheaper webcams can be used. One of the best consumer/astro-adaptable web cams is the Philips ToU Webcam. Check out the websites on this camera. It's hard to track down one of these cameras but they are there and check on E-Bay. These cameras are colour CCD chips ...not CMOS.

For solar sytem photos, nothing beats the webcam. By stacking the resultant frames from their AVI files, you get excellent clarity provided the seeing is good. And you can futher process these images in the renouned freeware program, REGISTAX.

So, a webcam is the choice for the Solar System objects and it can be used as a guidescope camera as well (I use it in this way.) A webcam is NOT good for DSO's yet some people have turned in great shots on The Imaging Source's website. DSLR's are good for wide field shots and CCD's are best for DSO's. The cheapest CCD's are from Orion Telescopes but even they start around $500.00 CDN and they can ONLY be used with a computer. This is a very slective use for an expensive instrument.

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Permalink Reply by Garland Coulson on December 11, 2009 at 8:08pm

One of my reasons for considering it Randy, was that I had found a low priced Canon 40d for sale. Unfortunately this fell through.

I don't think I am ready for astro photography yet. I love to view the night sky through my telescope but I don't think I have the ambition yet to learn all I need to know or the deep desire that makes me ready to commit a larger budget to what I would need for equipment.

I think I will wait a bit. Thought I might watch for DSLR camera boxing day sales... :)

- Garland

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