New answers tagged telescope
As mentioned previously, to be certain you need to record the day and time of the picture and compare to a program or table of moon positions. Short of doing that, the far right & left ones appear to be the smaller moons (IO & Europa) while the middle two appear to be Callisto & Ganymede (I base this upon apparent size of the moons). If you ...
In-the-Sky.org has a dedicated calendar for the Galilean moons. I can't seem to reconcile your picture with the plot for the last day or two, though!
Use an orrery that will let you specify a specific epoch and vantage point. There are some quite fancy ones online, for example this Solar System Scope: What you do in this particular tool is click on the calendar bar below and enter date and time of your observation (if you forgot that, there's a good chance your photograph has a time stamp, either of ...
The easiest way is to look it up, e.g. here: http://www.skyandtelescope.com/observing/a-jupiter-almanac/ Because the moons' positions change, and they are too small to distinguish in a small telescope, there are no general rules.
On Murdoch's Mysteries, the technophile detective at the end of the Victorian era made, in one episode, night vision goggles that used mirrors surrounding the eyes, essentially a pair of reflecting telescopes with no magnification. It would not cover the same angle, though: just straight ahead. The naive design you might throw together would handle light ...
The closest I've seen to what you mention in your question are wide-angle binoculars, the like of Vixen SG 2.1x42. There are other similar instruments available, often of Russian or Chinese (like this one) production. They have low magnifications and are examples of Galilean binoculars. They don't have a fixed-size exit pupil and you can gain about 1.8 ...
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