Posts Tagged ‘trius sx694’

How I Currently Take Backyard Astronomical Pictures

Sunday, January 24th, 2016

 

I’ve been asked a few times how I take images that I currently post on Facebook. The process has change substantially since my first attempts in 2005. The biggest changes since my early days are the use of computer controlled telescope mounts with my scopes, open source software to control the mount and the availability of CCD astronomical cameras that have extremely low noise when I try to do long exposures. My favorite objects to photograph are really dim and I image in my backyard in a really light polluted suburb of St. Louis Missouri. It is very possible to take nice photos with all the constraints of backyard imaging, but the process requires extreme patience since everything conspires against the results – bad weather, the full moon, neighbors that leave lights on, a mount that fails for known and often unknown reasons, and the amount of time I have to stay up until 4:00 am in the morning and still do work the next day.

I’ve posted the results of my hobby over the years and the results have gotten better, but the learning process is never ending and I see fairly big faults in almost every image I post. Spending on better hardware has improved the process, but there is always something that that isn’t quite right, or a compromise. A neighbor on the next street over from mine (who I unfortunately have never met) has a dome in his backyard that allows the equipment to be left set up, and his equipment is first rate. In the past he did post an equipment list and results and he rivals the best photographs I’ve ever seen online. However, his equipment cost was the equivalent of a new Nissan Maxima! I don’t have those kind of resources so I make do with cheaper equipment (much of it of Chinese manufacturer) and have all the faults and compromises that choice brings into the hobby.

My main setup has changed over the years and here are photos of my setups since 2005:

 

First attempts and learning – manual telescope control:

Meade LX50 With Meade DSI-Pro CCD Camera

Imaging in 2005 – Meade LX50 with manual fork mount, and Meade Deep Sky Imager

 

 

Globular cluster M13

Photo of M13 From 2005

Changing to a computer controlled mount (2013):

Deforked Meade LX50 With Orion Guide Scope and Orion Computer Controled Mount

Deforked Meade LX50 With Orion Guide Scope and Orion Computer Controlled Mount

Color image of M27 taken in 2013

Color image of M27 taken in 2013

Changing cameras to a modern ultra low noise 6 megapixel CCD in 2015

Current Setup - 2015 Trius SX-694 6 MegaPixel Camera With Color Filter Wheel and Prism Off Axis Guider

Current Setup – 2015 Trius 6 MegaPixel Camera With Color Filter Wheel and Prism Off Axis Guider

M27 Taken with Trius SX-695 Camera 2015

A new telescope (wider angle) with same mount and camera 2015:

Orion 8" Newtonian Astrograph with Trius Camera

Orion 8″ Newtonian Astrograph with Trius SX-694 Camera

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The very center of nebula NGC-2238 The Rosetta Nebula

Here is the list of things I currently use:

1. Computer controlled telescope mount:
This is the mount I currently use:

Orion Atlas Pro AZ/EQ-G Computerized GoTo Telescope Mount

It is very flexible and can mount just about any telescope with the right mounting hardware.  The mount has built in control software that can be used to visually find objects in the sky.  When I image I almost always hook up a laptop to the mount that has much more powerful open source software to guide the telescope, monitor the mount and control the camera and color filters that are attached to it. This allows me to do most of my imaging indoors in the light with a second laptop that connects to the outside laptop. I can watch late night tv in the comfort of air conditioning or heat while the numerous long exposures are taken and saved to disk.

2. Telescopes:

Meade 10″ LX50 Schmidt Cassegrain Optical Tube Assembly

Orion 8″ Newtonian Reflector Astrograph Optical Tube Assembly

I’ve had the LX50 since 2001 when I first used it for visual observing. I now use it for high magnification imaging with my cameras.  It is a heavy tube and has issues with holding focus over my imaging sessions, but also can get the most magnification.  It is comparable to a large telephoto lens in conventional SLR photography. It has an aperture of F10.

The Orion 8″ is a lighter/cheaper telescope that is much faster (aperture is F3.9).  It can image larger objects in the sky with less exposure time, but has to be collimated constantly over the night with a laser collimator to keep the stars and focus sharp. Since it is lighter, tracking accuracy is much better and I can usually get clean longer exposures.

3. Cameras

My main imaging camera now is the Starlight Express Trius SX-694 Monochrome camera.  It has a Sony 6 megapixel CCD sensor with an electronic 2 stage cooling device that can chill the sensor 40 degrees centigrade below the ambient temperature. This reduces the amount of noise in the images I take with it. This camera is fantastic and has changed the detail and resolution of images that I can take. The images can be easily blown up to 16 x 20 inches. Since it is a monochrome camera, I have to use color filters to take color images. The color filters are contained in a color filter wheel that is connected to the laptop. This allows the software to change which color filter is placed in front of the camera CCD while imaging.

Since the Earth’s rotation causes the objects i shoot to move in the sky, I use a smaller second camera that is also getting some of the light from the telescope through a prism arrangement. This camera tracks a star that I choose and sends commands to the telescope mount to keep the star centered over the many hours that I image. The camera is a StarLight Express Lodestar X2 Autoguider camera

Here are images of my cameras and storage case.

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Trius SX-694, Lodestar X2, and USB Color Filter Wheel

Trius SX-694, Lodestar X2, and USB Color Filter Wheel

Here is a closeup of the cameras hooked up to the Astrograph:

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4. Focuser

Since I use the telescope from inside the house, I also used a computer controlled focuser that allows me to automatically focus the camera and telescope over the night as the temperature changes and the telescopes mirror moves.

5. Laptop/Software

The images that I take are actually a series of long exposures from 30 seconds to 15 minutes or more long. The images are stored as data on the computer and are averaged together using software to reduce the image noise that you get from stray lights and the long exposures. A typical image can have 2 hours or more of telescope time to collect the data and then more time the next day to process and expand the detail, merge colors and crop to look good. To do this I use the following packages:

Open Source EQMOD telescope control software – for controlling the telescope mount and autoguiding
Nebulosity Imaging Software
Sequence Generator Pro for controlling the camera, color filters, and autofocus.

Astrotortilla for automatically finding my place in the sky after taking a single image. This helps enormously with aligning the telescope and finding objects to image automatically.

I also use Adobe Photoshop to do final color adjustment, contrast, noise reduction, cropping, etc.

This is a a list of all the stuff I’ve acquired to take sky photos. I made a video a view years ago that shows imaging in action on the laptop during the night. I did not have my current camera, but the process is still very similar.

Taking images with a telescope and CCD camera.

 

Heino Pull January 2016