ST-I monochrome Planet Cam and Autoguider


Availability: More on the way

The SBIG ST-iM is a compact high performance monochrome CCD camera that is both an excellent autoguider and a very capable lunar/planetary imager with performance and features that are simply unavailable in any other camera in this size and price range . . .
Our Product #: STI-M

Product Description

Rather than using a low cost/high noise CMOS sensor as other planet cams do, the ST-i monochrome Planet Cam/Autoguider uses a high quality, low noise, Kodak interline progressive scan true CCD sensor. For a discussion of the interline CCD system, click on the "Interline" icon above.

The Kodak KAI-340 CCD sensor in the ST-i monochrome has a 648 x 484 array of 7.4 micron square pixels and a measured read noise of only 9e-. Anti-blooming is standard. The ST-i uses only the Class 1 version of this CCD, with zero column defects, zero cluster defects, zero dead pixels, and zero saturated pixels. On-chip binning is available for 14.8 micron square pixels if desired, and various sub-frame modes may be used to speed-up the focus and download rates.

A full frame high resolution image will update at the rate of approximately 5 frames per second. In addition to full-frame, half-frame, and quarter-frame modes, the user may select a sub-frame region of interest of any size located anywhere on the CCD. In focus mode, using a 20 x 20 pixel box, the update rate is greater than 20 frames per second.

While some inexpensive guiders save cost by using low cost 8 bit or 10 bit electronics, the ST-i uses true high quality 16-bit A/D conversion for superior resolution of the full dynamic range of the CCD, which is greater than 70 dB.

The ST-i monochrome body weighs only 2.2 ounces and is no larger than many 1.25" eyepieces, measuring only 1.25" in diameter and 3.5" in length. The camera receives both control signals and power from the USB 2.0 port of your computer, so only one thin USB cable is required for using the camera as an imager.

The ST-i has an electronic shutter allowing exposure times as short as 0.001 seconds. Unlike most other eyepiece-sized cameras, however, the ST-i also has a built-in mechanical shutter that lets the camera automatically take dark frames. This dramatically improves the performance of the ST-i, particularly when used as an autoguider. The ability to automatically take and subtract a dark frame results in a very smooth background against which detection of dim stars is more reliable.

The ST-i monochrome comes with a front plate that is threaded for standard 1.25" filters; a 15' (4.6 meter) USB cable; a tracking cable; CCDOPS software with PlanetMasterTM, CCDSoftV5 software, and manuals on a CD-ROM.

The Planet Master software will take the sharpest image of the Moon and planets for you automatically. Typically, lunar/planetary imagers take a series of short exposures, knowing that throughout the sequence brief stable periods of seeing will give clear images. The Planet Master takes a sequence of short exposures, grades them for sharpness, and keeps the sharpest one.

Planet Master displays the images it is taking on your computer monitor in a split screen format. The left half of the screen displays the current image. The right side shows the sharpest image taken. The Planet Master command beeps twice each time a sharper image is acquired and updates the right hand image. When you are satisfied with the sharpness of the best image, hit the Done key and the Sharpest image will be shown.

Many planetary imagers like to average several of their best exposures, rather than just accept the single sharpest image. This requires taking a large number of images in a short time and examining each image to determine the best few of the lot. Planet Master makes this easier by automatically examining a series of images for you and assigning a Figure of Merit for sharpness to each one. Then, only the best of the lot can be selected for averaging, without having to tedious examine and judge each image manually.

For guiding purposes, the ST-i can typically guide on a star as faint as the 11th magnitude, using a 60mm guidescope and two second exposures. The guiding output port on the end of the ST-i monochrome is opto-isolated so it can be used with any mount having an autoguider input that conforms to the universally-accepted ST-4 standard.

The ST-i monochrome has both 32 bit and 64 bit drivers and can be used with all Windows versions (including Windows 7) that support USB 2.0, as well as Mac and third Party Linux operating systems.

Tech Details

Pixel Array 648 x 484
Pixel Size 7.4 x 7.4 microns
Warranty 1 year


Review by:
This is a really good little guider. The shutter makes a big difference, because you can get dark frames and significantly reduce noise in the images. Less noise means there's less of a chance of "guiding" on a hot pixel. Make sure to use a good USB cable with this guider because it does draw enough power to need one. Cheap USB cables have power wires too thin for this to be reliable, at least that was a problem for me. The provided cable works fine but if you want a longer one quality matters. Besides guiding, you get can surprisingly good shots using this as a regular camera, again because of the shutter and the capability to get dark frames. (Posted on 10/4/2019)
Review by:
I just sold mine after 7 years of service to get a wider field of view for my telescope. I found that having a shutter was a great advantage - it's easy to make darks on the fly. At the same time the shutter means that the camera draws the maximum possible amount of power - 500 milliamps - so you have to be careful that your computer or hub can supply that much current all night long in hot or cold conditions. (Posted on 11/30/2018)
Review by:
This camera is sensitive enough to use with off axis autoguiding. Some autoguide cameras such as the SSAG may not be sensitive enough to pick up stars when using OAG, but this camera is well capable of doing the job whether or not yous use piggy back scope or OAG. (Posted on 11/5/2018)
Review by:
Small, light and built with the same quality as all SBIG products are. (Posted on 10/31/2018)
Review by:
If you're ready to step up to a really sensitive guide camera, the ST-i would be a perfect choice. After using a couple Orion SSAG's, I went with one of these when I moved to an off-axis guider. I can easily pick up 10th and 11th magnitude stars from my red-zone driveway using 2 second exposures in Phd or Maxim.

Note this if you use this with Phd (as of 1.14.x), you must connect to the ST-i first if you also use another SBIG camera. Once connected, you can then connect to your other camera. Hopefully this will save some time and headaches for someone. (Posted on 8/4/2017)
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