Altair Hypercam 183M V2 mono astronomy imaging camera
A deep-sky specialist that’s especially impressive with narrowband objects
Having previously reviewed the colour Altair Hypercam 183 (see issue 147), here we’re reviewing its updated, monochrome brother. The compact Hypercam 183M is a great match for short focal length refractors or camera lenses. We chose our trusty 3-inch (75mm), f/6.7 telescope which would give a nice flat field across the camera sensor. To take colour pictures with a monochrome camera requires separate colour filters; standard 1.25-inch models easily cover the sensor. The camera itself does have a built-in filter which blocks infrared and ultraviolet wavelengths.
Set-up was simple: download and install the driver package and plug in the camera. We operated it with the AltairCapture software, but it’s also compatible with the popular SharpCap. Once the camera’s selected in the software, the built-in cooling fan turns on and a red LED lights up.
The mono Hypercam 183M is geared towards deep-sky imaging, although with user-defined Region of Interest (ROI) settings, taking lunar, solar or even planetary pictures is possible, as the camera will also record video files that can be processed and stacked into a final image. The smaller the ROI chosen, the faster the frame rate and smaller the eventual file size. However, given the low position of the major planets at the time of the test and the apparent reluctance of the Moon to put in an appearance, we opted to test the camera on a variety of much fainter, deep-sky targets.
Our first was the popular pairing of M81 and M82 – Bode’s Galaxy and the Cigar Galaxy – as these two offered the camera a chance to show what it could do on faint swirling galaxy arms along with bright galactic cores and dust lanes. For these exposures we selected the 12-bit operating mode, rather than 8-bit, adjusted the gain setting to five, and took a series of exposures, each of five minutes.
Trial and error
We found it took quite a bit of trial and error at first to settle on the most useful gain setting for each target, although after a few nights’ practice it was getting easier. Generally speaking, lower gain settings resulted in smoother, cleaner images, but the increased sensitivity of higher gain offered an acceptable compromise on certain targets. The
resulting image showed impressive detail in both the faint outer arms of M81 and within the bright glowing core of M82.
Moving onto globular clusters, we were pleased that the camera achieved sharp captures of the bright cores of clusters like M13 in Hercules, without losing the much fainter outer stars. For this we used the lowest gain setting. A test on M3 in the same area revealed that a higher gain and shorter exposures wasn’t the best option for globular clusters, as some of the central stars blurred into each other.
We were particularly interested to see how the camera performed on objects requiring special narrowband filters and – normally – exposures of over 20 minutes. The best available target for this proved to be the Crescent Nebula, NGC 6888, and we went after it with our 7nm H-alpha filter. This type of target can be more suited to higher gain settings, so we nudged gain up to 20 and captured some seven-minute exposures. The results did produce some unwanted artefacts, notably a bright glow on the middle edge of the image, so taking calibration frames is a must. The resulting stacked image demonstrated good sensitivity to faint emission nebulosity, and the calibration frames helped negate the unwanted artefacts.
Attractively priced and easy to use, this mono Hypercam opens the door to deep-sky imaging, including spectacular narrowband objects.