EAA and Outreach
Viewing night sky objects directly through a telescope's eyepiece can be a deeply satisfying experience. But there is no doubt that using electronically assisted on-screen viewing using a camera instead of using an eyepiece has many practical benefits. The signal boost that the camera can deliver means that objects that are typically seen only faintly when viewed through the eyepiece of a typical amateur's telescope now become much brighter and better defined. Not only that, but a camera offers the possibility of delivering views in colour whereas eyepiece views are generally only seen in monochrome. Add in the camera's capability of recording its views to image files and you have the added bonus that your viewing session can be enjoyed over and again long after it has ended. And, as an extra benefit, those of us with poor eyesight and who have trouble using an eyepiece mostly have no difficulty when viewing the target objects as displayed on-screen. In the early days this technique was commonly called "video astronomy" because only video cameras were then used. But as technology advanced and camera design became ever more sophisticated the distinction between video and conventional cameras has become quite blurry to the point where a better name was needed for the camera-viewing technique and presently it seems that "electronically assisted astronomy" (EAA) has been adopted.
There is no reason why EAA cannot be enjoyed alone and indeed it often is, particularly in recent times when the global Covid-19 pandemic has mostly put an end to public viewing events. But in principle EAA is ideally suited to outreach work which offers simultaneous group viewing where displayed objects are always in focus for all viewers regardless of their eyesight differences.
Taking this EAA approach to outreach work generally means having readily transportable equipment that is easily manhandled and does not take forever to set up on site. Because visitors like novelty it is usually advisable to view a number of different objects in a single night's session. For that reason auto-guiding is not realistic since it would necessitate recallibrating the auto-guiding software after each move and that would be quite time consuming. But, provided that the telescope mount is quite precisely polar aligned, on-screen images of up to quite a few minutes are possible by simply relying on the mount's clock drive to follow targets across the sky. When conducting a solo session (i.e. not in company with other telescopes) it is preferable to stick to bright, easily imaged objects (typically open and globular star clusters and very bright emmision nebulae) that require only short exposures so that visitors do not have to wait too long between the display of each object. Only when in company with other telescopes is it realistic to show fainter objects that require longer exposures. Visitors can then attend those other 'scopes while waiting for the fainter objects to display properly on screen.
There is no reason why EAA cannot be enjoyed alone and indeed it often is, particularly in recent times when the global Covid-19 pandemic has mostly put an end to public viewing events. But in principle EAA is ideally suited to outreach work which offers simultaneous group viewing where displayed objects are always in focus for all viewers regardless of their eyesight differences.
Taking this EAA approach to outreach work generally means having readily transportable equipment that is easily manhandled and does not take forever to set up on site. Because visitors like novelty it is usually advisable to view a number of different objects in a single night's session. For that reason auto-guiding is not realistic since it would necessitate recallibrating the auto-guiding software after each move and that would be quite time consuming. But, provided that the telescope mount is quite precisely polar aligned, on-screen images of up to quite a few minutes are possible by simply relying on the mount's clock drive to follow targets across the sky. When conducting a solo session (i.e. not in company with other telescopes) it is preferable to stick to bright, easily imaged objects (typically open and globular star clusters and very bright emmision nebulae) that require only short exposures so that visitors do not have to wait too long between the display of each object. Only when in company with other telescopes is it realistic to show fainter objects that require longer exposures. Visitors can then attend those other 'scopes while waiting for the fainter objects to display properly on screen.
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So far, four "video" cameras have been used. The first was the GStar-Ex mono video camera. Then came the LP-Guide CMOS colour camera followed by the GStar-Ex3 CMOS colour camera. Recently (in 2020) the ZWO ASI294MC Pro colour CMOS was added. The three CMOS cameras have a video imaging mode in which they can record video files for frame exposures ranging from micro-seconds up to 5 seconds long. But they also have a "still" imaging mode in which the exposure setting can be extended out to many minutes in duration.
As to telescopes : initially, the Meade ETX 90EC was used with the GStar-Ex mono camera but it was superseded by the Vixen R130sf and the cameras progressed to the LP-Guide colour camera and then to the GStar-Ex3 colour CMOS camera . As from May 2018 the Sky-Watcher PDS 150mm has taken over duty for outreach purposes. And from late 2020 it has been used with the ASI294MC Pro. The ASI294MC Pro camera has also been teamed up with the observatory mounted Vixen R200SS 8 inch Newtonian telescope for personal enjoyment. In June 2022 the Western Sydney Amateur Astronomy Group was kind enough to include an article that I wrote in its Tutorials section. You can see the article by clicking the button to the right.
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