Controlling an SBIG STF-8300M astronomy camera in Windows and Linux
Part 1: Setup and Installation
Right = full-size crop (1.85% of original area) of a single 10-minute frame of the Horsehead Nebula shot through a 50-mm camera lens, showing the remarkable smoothness of the images from a cooled CCD camera (7 nm Hα filter, color added).
The SBIG STF-8300M is a mid-range 16-bit monochrome USB camera popular with amateur astronomers. It is highly sensitive in near infrared and near ultraviolet. There's no aperture control or autofocus, and its minimum exposure time is 0.09 seconds, which means it's not much good as a regular camera. But the pixels have a full well capacity of 25,500 electrons, and it cools to 40°C below ambient, so the dark current is a remarkably low 0.002e-/pixel/sec, which makes it incredibly useful for astronomers. It's also useful in the lab for imaging low-light phenomena like chemiluminescence.
Although the camera is highly regarded, the manufacturer has not paid as much attention to software. This article describes some of the troubleshooting steps that may be necessary in getting the software to work.
SBIG provides a basic control program called CCDOps5. I installed this on my laptop, which was running 64-bit Windows 7, but it would not run.
The program cannot start because MSVCR110.dll is missing from your computer. Try re-installing the program.
vcredist_x86.exe = 32-bit version
vcredist_x64.exe = 64-bit version
This is not related to whether your OS is 32 or 64 bits. It must match the version the software was compiled with.
File format problems
By default, CCDOps5 saves images in SBIG format or 8-bit TIFF format, with no option for 16-bit TIFF, so you have trick it. In the menus, set the default format to FITS. The next time you change it back to TIFF, a dialog box comes up asking whether you want 8 or 16 bits. If you select 16, the setting is remembered and you get 16 from then on.
SBIG also includes a utility that can convert their proprietary SBIG format to TIFF or FITS. There's a Python utility on the Internet that's also supposed to work, but it just crashed on my system.
File "sbig2fits.py", line 42, in <module> sbig = PySBIG(infile) File "/usr/local/lib64/python2.7/site-packages/PySBIG.py", line 74, in __init__ buf = struct.unpack('<H', line[at+1:at+3]) struct.error: unpack requires a string argument of length 2
CCDOps5 is nice, but it's only useful for testing whether the camera works. To capture a series of frames, you need something like Bisque's CCDSoft. Unfortunately, CCDSoft version 5.00.210, which is provided with the camera, does not work for the STF-8300. No matter which camera you select, it says "Device not supported, Error code 220 0xDC".
It seems that this software is obsolete, and Bisque wants you to buy their very expensive TheSkyX software, which tries to do everything, including control your telescope, be a planetarium, and for 200 bucks more, maybe control your camera. For those of us who don't need no steenkin' planetarium, this creates another challenge: navigating Bisque's website.
To control the STF-8300, you must download CCDSoft Version 5.00.217 from www.bisque.com/sc/media/g/ccdsoft/default.aspx. There is no link to this page on their website. The only way I found it was from a mention by one poster in their Forum page.
Before you can download it, you must register and enter the Serial Number of your copy from the CD. Bisque will then email you a password, enabling you to log in. The web site is extremely disorganized—it took me a long time to find the correct page.
Getting rid of the giant advertisement
The new version of CCDSoft works, but it also pastes a giant ad for TheSkyX on the screen. On my computer, it filled up the entire screen, making it impossible to use the program. Normally in Windows if a window gets too big you would hit Alt-Space. A menu would pop up with options for minimize, resize, and restore. But this only works if the window has a border around it, which the ad does not.
To get rid of the big ad, do the following:
- Right click on the bottom taskbar (which contains the Start button) and uncheck "lock taskbar."
- Drag the taskbar to right. It is now vertical on the right side of the screen.
- A Close button should now be visible on the ad. Click Close. If your screen is too small for this to work, you're out of luck. Even the Task Mangler can't get rid of it. Your only recourse is to edit the program with a hex editor.
Focusing in CCDSoft is much slower than in CCDOps5, and CCDSoft sometimes gets itself into a screwed-up state where it captures useless truncated files. But it's easy to use, and so far I have not had it crash. It's convenient, but the advertisement problem and the slowness of its focusing caused me to switch to Nebulosity instead.
Be sure to turn off Microsoft Windows Update. Otherwise, your laptop may decide that it needs to reboot while you're in the middle of an exposure, which happened to me the first day. You also have to change the power settings so the computer doesn't go to sleep while you're taking exposures.
Linux CCD controller software problems
There are many advantages to controlling the camera in Linux. For example, you could take advantage of Linux's better networking and use a pair of USB-Ethernet adapters or hubs to control the camera from a remote location. While Linux software is not as easy to set up as Windows software, it is generally easier to troubleshoot. I was hoping to modify the Linux Imal scientific imaging program to control the camera directly. However, so far I have not been able to get any of these other Linux camera control programs to work.
Xmccd is a graphics-mode program that requires Motif, Motif developer libraries, FITS libraries, FITS utilities, ds9 image display software, XPA communications library, Fxload, and the SBIG library (libsbig). All these components have to be downloaded and installed, so the overall process is very complicated. The authors recommend Suse 12.2 or 12.3.
The xmccd documentation says that they are discontinuing support for SBIG cameras, because SBIG no longer plans to release their Linux library. This is a big deal, because the library has to upload camera-specific firmware to the camera whenever it is connected and powered on. Thus, it wouldn't make sense to start using xmccd with an SBIG camera if you're just starting out.
Nightview is a little simpler. The documentation says it doesn't need the SBIG libraries, and it can be run from the command line. However, when I tried to compile it, it still insisted on the wxwidgets graphics library.
Wxwidgets installed flawlessly. The following commands got nightview to compile.
./configure --without-sbigudrv --without-xnightview --without-xmove
This program seems to create a Web server and a number of CGI scripts, but the documentation is a little vague.
Remote control options
Remote control eliminates the risks of keeping a computer outside, where it can fall into the snow or have weird things done to it by bugs and animals. SBIG's STT series cameras with Ethernet built-in are the easiest solution for remote control. But if you have an extra laptop lying around, you can use VNC to control an STF camera remotely. It doesn't eliminate the need for keeping a laptop outside, but at least you don't have to be out there in the snow with it.
However, an STT costs about $1500 more than an STF, so if the software doesn't work, it's a bigger loss. But network software is a little easier to write than USB software, so if you're a programmer the STT might still be a good choice.
- It is much heavier than a DSLR, so with a camera lens attached you need a small counterweight to balance it, unlike with a regular camera.
- The 12V power connector is shorter than normal. This means standard 12 volt battery cables don't attach securely. I had to make a special adapter by soldering a 5.5×2.1 mm DC power connector with a locking ring to a Celestron Car Battery Adapter cable.
- There is no on/off switch. The manual warns that unplugging it at the power connector will damage the camera. I might just install a switch on it myself, but it's not clear what could be causing an inductive surge in a camera.
It produces outstanding images. The image quality blows away a DSLR, but it also
has lots more hot pixels. Here is a full-size crop of a 10-min exposure. At least
30 hot pixels are visible. You have to use dark frames with this camera.
- The image above also showed astigmatism in the edges (as shown by distorted star shapes around the edge), which means that the lens adapter distance is a little bit off.
Update (Nov 04, 2014) Another SBIG camera controller is Ekos, which is said to be a complete astrophotography stack for Linux that supports all of SBIG CCD/Filter wheel features. The author says you can even use SBIG CCD hooked to a raspberry PI. It's oriented toward Ubuntu users, but source code is provided.