Found this picture in my archive, 2017-09-29






Using an ASI camera to image the moon feels lightyears ahead of the Scopium I used to use. It is so much better, versatile, capable – its pricey too, but hey. So I imaged the Moon, taking a total of 12 pieces for a mosaic, each piece being a stack of around 500 frames, all the settings being kept. The stacks were made using AutoStakkert, then sharpening in Registax, using the same settings for all frames. Fortunately the atmosphere did not change much so it was fairly easy to put the pieces together in a fairly large resolution image. A large resolution version of the image below is here. An earlier attempt, from 2015, of mine is here.
Old habits die hard, so I pointed a raspberry pi (an old friend of mine, a model B+ from a few years back, still functioning like a charm) plus some compatible camera with a large field of view (fish eye like) to record. Record what? IDK, just make timelapses and something *will* come out of it.
So I captured the conjunction of the Moon and Mars with a very modest and toy-like MacGyverish, but at the same time very versatile setup. The Raspberry Pi board is „floating” in a drainage tube with tight fittings, with a camera front from a cheap mock camera for weather protection and an ND filter in front (the Sun has a tendency to burn its trail into the sensor, already visible on every image). Since I risked to move the camera, the ND filter stays on for the night which kinda sucks… I know.
I also created a max combination of all the recorded images, function finalPixel(x,y) = max(pixel(frame[0], x,y), pixel(frame[1], x, y) … pixel(frame[n], x, y)) where max compared values of luminance = (rgb24 >> 16) + ((rgb24 >> 8) % 256)*2 + (rgb24 % 256).
After quite a few successful attempts at imaging trails using rudimentary equipment, I decided to put my Raspberry Pi B+ and its camera to work and image a moontrail.
Past attempts include a set of sunrises at both solstices and at equinox, some sunsets, an analemma and some startrails. For these I used a Canon A800 enhanced with CHDK or a FujiFilm HS20EXR unmod. The CHDK was needed to access otherwise unaccessible options like manual focus, manual shutter speed and… well, an intervalometer. But this time a cron job did the work on my little buddy, the pi.
Below I describe the process in detail which lead to the final pictures. If you wish to skip it, click here.
(tovább…)
I had this dilemma: what to use to image the whole disk of the Sun or the Moon? Make full disk pictures with my DSLR – 60 frames tops – or record many little videos with my webcam and put the mosaic pieces together? On one hand it is how much time I am willing to invest and on the other, what output quality I am expecting.
The tech
SCOPE: I used my 150/750 on the motorized EQ3.
DSLR: it is a Canon 1100D (also known as the EOS Rebel T3), unmodified hardware but enhanced by Magic Lantern (thanks guys :) ). The sensor is a 12.20 Megapixels CMOS APS-C (pixel size = 5.2 μm), capable of outputting 14 bits deep raw (cr2).
WEBCAM: it is a Scopium webcam, 640×480 pixels 8 bits sensor, max framerate is 30 fps, video is recorded in raw mode (pixel size = 5.6 μm). (tovább…)
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