Astronomy: Advancements in Astrophotography

Deep Focus: Taken with a Nikon D800 300mm F4 5/30sec at Moonbi. It shows Eta Carina about 7500 light years away in the constellation of Carina. Photos Stuart Goff.
Deep Focus: Taken with a Nikon D800 300mm F4 5/30sec at Moonbi. It shows Eta Carina about 7500 light years away in the constellation of Carina. Photos Stuart Goff.

Digital cameras have come a long way since I started using them.  

The first digital I used was a “CCD cookbook camera”.  

This was a kit you could buy and build yourself.

Today’s modern DSLR as an astro camera is hard to beat.  

You can use them for general photography but at night you can also get some stunning photos.

If you have a DSLR and a tripod you already have system to take wide astro-photos of the sky.  

But in most cases you are limited up to 25-30 seconds per shot.  

Any longer and star-drift becomes noticeable due to the rotation of the Earth.  

Also, if you use a telephoto lens you will need to shorten the exposure time because star-drift becomes even more noticeable.  

In addition, you would find that you have not exposed long enough to get an image.  

This is a problem and how do we overcome this?  

We use a tracking mount for our camera that will track the stars as they slowly move across the sky and keep the stars from drifting in the photo.

There are many tracking mounts on the market.

Lightweight mounts which can handle up to around three to four kilograms through to heavier duty full GoTo mounts for telescopes that can automatically locate objects in the sky using a built in computer.  

The light tracking mounts, or sky-trackers, are great for travelling, such as taking on a camp to a dark sky site, as they don’t take up a lot of room.  

These mounts do have limitations though in which very long exposures will produces star-drift.  But with a 50mm lens you can get up to around two minutes of exposure time.

The next step up is a telescope style mount that has a full GoTo system.

These mounts, once set up, are very accurate.  

They can handle a high payload and if you combine this with a device called an auto-guider the stars will remain sharp.

Taking photos of the night sky with a tracking system can be so rewarding, from photographing planets to comets and galaxies.

You can ether place the camera straight on the mount or attach the camera onto the telescope.  

Placing the camera straight onto the mount and combining it with an auto-guider is the current system I’m using.  

The photos accompanying this article were taken with this system, combining a small guide telescope with an auto-guider and my camera where I can swap the lens on the camera from a wide field fisheye to a telephoto lens depending on what I’m photographing.

Having your camera on a tracking mount can produce fantastic photos.  

Having your camera on a tracking mount can produce fantastic photos.

Stuart Goff

You don’t need a telescope to get photos like these.

Astrophotography with your DSLR is very rewarding and, if you don’t mind not sleeping, you can capture the night sky in all its beauty.

If you would like more information or would like to get involved in astrophotography contact the Tamworth Regional Astronomy Club.

Tracking: The mount setup. An AZ-EQ6 Skywatcher with a 90mm Maksutov Telescope and auto-guider.

Tracking: The mount setup. An AZ-EQ6 Skywatcher with a 90mm Maksutov Telescope and auto-guider.

In the frame: Centre of our galaxy in the constellation of Sagitarius. Taken with Nikon D800 180mm F4 93sec.

In the frame: Centre of our galaxy in the constellation of Sagitarius. Taken with Nikon D800 180mm F4 93sec.