Astrophotography Equipment
This page details the current inventory of my astrophotography hardware. Utilizing the equipment shown below plus several key pieces of software, I am able to acquire all images (light and calibration) with little or no operator intervention. This process includes the ability to suspend imaging at prescribed intervals, slew to a nearby bright star, refocus the scope (to account for focus drift due to temperature changes, filter change, etc.), then return to the object to continue imaging. In addition, using my local area network and a remote administrator software package, I have the ability to sit at my indoor computer and view the status and progress of the laptop computer that is controlling the imaging run. This ability to automatically acquire images also allows me to sleep while the system continues imaging during what is usually the best part of the night (12am thru 5am).
Functional Block Diagram:
The following chart displays the details of my current imaging system. The large block titled "Scope/Camera/Mount Assembly" is, obviously, the heart of the system. This assembly consists of the Takahashi TSA-102S 4" f/8 refracting telescope which is rigidly mounted to the Takashashi EM-200 German equatorial mount. In turn, the imaging train is rigidly attached to the scope and consists of the SBIG ST-8XME CCD camera and the SBIG CFW-10 filter wheel. Riding piggyback on top of the main imaging scope is the SBIG ST-402ME CCD camera and SBIG E-finder 100mm lens that serves as the system's guide scope and camera. Finally, the Robo-Focus stepper motor is attached to the shaft of the scope's focus wheel and a dew strip heater is wrapped around the front-end of the imaging scope at the base of the retractable lens shade. Each black line in the block diagram represents a cable or connection that must be made to complete assembly of the system.
Astrophotography Imaging System Photos:
Mount:
Arguably, the most important piece of equipment for astrophotography is the mount which carries and moves the telescope and any attached equipment such as camera, finder scope, guide scope, filter wheel, etc. Whether images are guided or unguided, the ability of the mount to smoothly and accurately track across the sky at the sidereal (star) rate is paramount.
My current mount is a Takashashi EM-200 Temma II with the Takahashi SE-L wooden tripod. This German Equatorial Mount (GEM) has tracking errors of +/- 5 to 10 arc seconds of periodic and random errors and is capable of handling loads up to 35 lbs. My setup includes three 5kg counterweights and features an integrated polar alignment scope capable of getting within 2 arcminutes of the celestial pole. A sales photo of this mount is shown below:
Camera:
Probably the next most important piece of equipment is the camera. My camera is the ST-8XME manufactured by Santa Barbara Instrument Group (SBIG). This is the fifth generation of SBIG CCD cameras and is based on Kodak's KAF1602E blue enhanced E series CCD. The CCD array is 1530 x 1020 pixels in size with a pixel size of 9 microns by 9 microns. The CCD is cooled with a solid-state thermoelectric cooler and is enclosed inside a windowed hermetic chamber sealed with an o-ring. A rechargeable dessicant in the chamber keeps the humidity low, forcing the dew point below the cold stage temperature. This camera employs a non-antiblooming gate (NABG) CCD that is prone to "blooming" from a strong light source. The ST-8XME interfaces with the imaging computer and software via a high speed USB interface. A sales photo of this camera is shown below:
The ST-8XME also features a separate built-in tracking CCD that is based on the Texas Instruments TC-237 CCD. In my setup, I use the SBIG ST-402ME camera attached to a SBIG E-finder 100mm f/4 "scope" as my guide scope/camera assembly. A cable from the ST-402 to the mount activates mechanical relays that drives the EM-200 to maintain a guide star in the same spot on the camera CCD for extended exposures.
Filter Wheel:
Since the SBIG ST-8XME is strictly a monochrome camera, images must be captured through Red, Green, and Blue filters to collect the data needed to generate color pictures. The hardware that I use to place the correct filter in front of the CCD detector is the SBIG CFW-10 Color Filter Wheel. This device is a 10-position filter wheel that is controlled and powered by the ST-8XME camera. It attaches directly to the front (scope-side) of the camera and adds about 0.60" of length to the optical train. A photo of the CFW-10 mounted to the front of a camera is shown below:
Color Filters:
The filters mounted into the CFW-10 include the Astrodon 1.25" (27mm) Tru-Balance E-Series LRGB filters. All filters feature near-infrared (NIR) blocking and all filters are parfocal with each other meaning refocusing is theoretically not required between filter changes. (However, I always refocus after a filter change.) The response curve of the E-series filters is shown below:
Also mounted into the CFW-10 filter wheel is the Astrodon hydrogen-alpha filter. This narrow band filter has a bandpass centered near 656nm with the bandwidth (measured at the full-width, half-maximum point) approximately 6nm. This filter is also parfocal with the LRGB filters. The response curve of the Hydrogen-Alpha filter is shown below:
Telescope:
My main telescope is a Takahashi TSA-102S 4" refractor telescope with retractable lens shade. This scope features an 4" (102mm) apeture and a focal length of 814 mm (f/8). This scope features triplet apochromatic optics with very high color correction and knife edge baffles and over sized tube that produce very high contrast images. A photo of the Takahashi TSA-102 telescope is shown below:
Robo-Focus:
In order to achieve accurate and repeatable focusing, I use the Robo-Focus system manufactured by Technical Innovations. In conjuction with the free software, FocusMax, the important job of focusing is completely automated. As shown in the photo below, the Robo-Focus stepper motor is attached directly to the shaft of the scope's focuser. Also, as shown in the photo, I use the stock mounting plate that comes with Robo-Focus to rigidly mount the stepper motor.
Imaging Computer:
The laptop computer that I use for all my imaging is a Toshiba Satellite model A105-S1014. This computer has a 1.50 GHz Celeron M processor with 512MB of RAM. The operating system is Windows XP Home edition with service pack 2 installed. The computer features four USB ports which are all used during imaging (one port for imaging camera data, one port for guide camera data, one port for mount communications [with serial-to-USB converter], and one port for Robo-Focus controller communications [with serial-to-USB converter]). A sales photo of the A105-S1014 is shown below:
Imaging/Processing Software:
The following table lists the major pieces of software that I use for astrophotography. The table is arranged by title of the software, latest version, author, phase of use (Aquis. = Image Aquisition, Proc. = Image Processing, Pres.= Image Presentation), and the purpose or use of the software.
| Software | Version | Author | Phase | Purpose |
| The Sky6 | 6.0.0.55 | Software Bisque | Aquis. | Planetarium and Telescope Control |
| CCDSoft | 5.00.186 | Software Bisque | Aquis. | Camera Control |
| RoboFocus Control | 3.2.3 | Technical Innov. | Aquis. | RoboFocus Control |
| FocusMax | 3.14 | Weber/Brady | Aquis. | Automatic Focusing |
| PoleAlignMax | 2.0.39 | Weber/Brady | Aquis. | Polar Alignment Tool |
| CCD Commander | 1.4.57 | Matt Thomas | Aquis. | Executive Image Aqusition Control |
| CCD Inspector | 1.3.2 | CCDWare | Aquis./Proc. | Sub-Frame Evaluation |
| CCD Stack | 1.3.2 | CCDWare | Proc. | Calibrate, Pixel Rejection, Stack, RGB Gen. |
| Registar | 1.0.7 | Auriga Imaging | Proc. | Sub-Frame Alignment/Registration |
| NewAstro DeBloomer | 1.3.22 | newastro.com | Proc. | Sub-Frame Deblooming Tool |
| CCDOps | 5.47 | SBIG | Proc. | Sub-Frame Micro-Lens Artifact Removal |
| CCDSharp | 1.14 | SBIG | Proc. | Image Deconvolution (Sharpening) |
| Photoshop | CS3 | Adobe | Proc./Pres. | Final Image Processing/Presentation |
| HTML Editor | 2007 | Coffecup SW | Pres. | Website HTML Editor |