![]() Taking the actual photos of the sun is not too different from lunar or planetary imaging – you need the shortest (ideal) exposures possible for the best chance of capturing a sharp frame, and you need a lot of them. This is in part what makes solar astrophotography the oft-forgotten middle-child of photographing the “night sky ” while almost anyone with a camera can attempt to capture some stars (something even modern cell phones can accomplish with long-exposure camera apps), solar imaging can require the photographer to pursue expensive and specialized equipment before even attempting to take a photo. These dedicated solar telescopes can easily reach several thousand dollars for smaller models in fact, many higher-end models rival the entire cost of my deep sky imaging setup – and as they are only useful for observing one object, it is not an expense I have so far pursued (but it is something I would like to further explore in the future). Ca-K filters show large-scale surface features often associated with magnetic activity. The Calcium-K line, shown in purple in the image above, displays a slightly cooler region using a wavelength near enough to UV that many people are unable to use these filters visually, instead relying on cameras to pick up the details missed by our limited organic eyes. These specialized optics can show the “sexier” details on the sun such as prominences and filaments of ionized hydrogen which form the chromosphere (an area above the photosphere). Probably the most popular wavelength used by dedicated solar telescopes is Hydrogen-Alpha, which centers on a deep-red wavelength of 656nm. While white light filters reduce the sun to a grainy white-ish ball, narrowband solar telescopes reveal the sun to be a seething furnace of nuclear fire. We all know the sun is bright, but what can you see on the sun? Solar filters, depending on the specific nature of the filter and wavelength they target, can capture various layers of the sun’s atmosphere and “surface” (as much as a plasma ball can have a surface).ĭedicated solar telescopes allow observation and photography of more interesting aspects of the sun. Using proper filters, then, is of upmost importance – each time I set up for solar observing, I am attentive and mindful on applying the filter before the telescope is pointed anywhere upwards, and the filter is always checked for pinholes before and after every use. If I pointed my telescope at the sun and looked into the eyepiece, I would be immediately blinded in that eye faster than my brain could compel me to look away. ![]() Most people understand you shouldn’t stare at the sun, and this is especially true when using a telescope. In the mid-2020’s the Sun will likely have more frequent sunspots of even larger sizes than this one, but for now I will take what I can get.Ī Brief Overview of Solar AstrophotographyĪstronomy is a fairly benign pursuit as far as danger and injury is concerned – except for some fairly persistent sleep deprivation, the worst we may ever deal with is frostbitten fingers on a cold night stargazing outdoors, but solar observing is a different game altogether. The sun is currently in what we call a Solar Minimum, meaning sunspot activity is near the low of an 11 year-long cycle. Sunspots of sizeable proportions are currently rare. The smallest of these are around 1500km wide and they sometimes only last several minutes before disappearing. The uneven background mottling is called granulation – each granule is a region of hot plasma rising or cooler plasma descending (which makes the edges of each granule). ![]() This sunspot also featured a small line (which was ~800km wide) across its center – this appeared for about 2 days, indicating the sunspot may have been in the process of splitting, before the line disappeared. Some smaller spots can be seen around AR2738 and likely many more than what I could capture - sunspots can be a small as 16km wide, but these are invisible next to AR2738’s impressive ~50,000km diameter. They appear darker because, due to magnetic activity, they are cooler than the rest of the sun’s surface – while most of the sun’s surface is a scorching 5600C, sunspots can be a much more pleasant 3500C. Sunspots are regions of intense magnetic activity on the sun and can change in size and shape over the course of several hours. This sunspot was about 3-4 times the diameter of Earth, at least at the time I captured it.
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