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The NASA websites for the Solar and Heliospheric Observatory (aka SOHO) spacecraft and the Solar Dynamics Observatory (aka SDO) publish a massive amount of data, but of particular interest to amateur astronomers is the daily sunspots image which gives a indication of what to expect when solar observing/imaging. I downloaded the full set of published sunspot images dating back to 2006. I felt it could be interesting to see how the intensity and number of sunspots evolved over the course of the solar cycle, so I set about animating them into a video. A solar cycle is 11 years, so with 16 years of data we’re coming up to having 1 & ½ solar cycles worth of sunspot images.

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When talking to visitors at the Baker Street Irregular Astronomers events in London, there is often discussion about useful / interesting applications that people might have on their phone. This blog lists the various applications that I currently have on an Android phone that are useful for astronomers. There are many others available beyond this list, some of which may be better; these just happen to be the ones I currently use. Some are available for iOS too, or have equivalent options available.

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I recently had cause to digitize a type written book from the 60′s running to 250 dense pages of text. Re-typing the text was out of the question, so attention turned to using OCR software to automate the process. It was quickly apparent that image quality was the most important factor controlling the quality of OCR results. Building a wooden rig to hold the book partially open made it easier to capture the pages using a DSLR without the pages distorting or having uneven lighting.

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Maia is a camera inspired by the compound eyes found in some insects such as flies. The idea is to have multiple film canisters arranged in a grid, each capturing the scene from a slightly different point of view. Using orthochromatic 35mm film, the camera can be loaded in the darkroom under red light conditions, and film pieces later tray developed.

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The key to getting good results from any tracking mount is to take care when doing the initial setup and alignment. The Star Adventurer comes with an illuminated polar scope to make this process easier. The polar alignment pattern orientation needs to be set using the date / time graduation circles. The explanation of how to use the graduation circles in the manual is not as clear as it should be though, so this post attempts to walk through the process with some pictures along the way.

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With the long awaited GIMP 2.10 offering 16-bit and 32-bit colour channel support, it is now a viable option for astrophotography image processing. In fact I've been using development snapshot pre-releases for 2+ years now for the high bit depth support! For lunar surface videos, I first stack with AutoStakkert2, then would use Registax for RGB align & wavelet sharpening. I decided to investigate if it was practical to do equivalent processing using GIMP. I eventually figured out that combined with the G'MIC plugin it is indeed practical to replace Registax with GIMP for post stacking image processing tasks

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Arcturus is a custom build digital pinhole camera that is constructed using a cheap USB HD webcam, controlled from a Raspberry Pi Zero board. The Pi runs a dedicated application that shoots images continuously with a short delay between each shot, saving images to a micro-SD card. The two circuit boards are hidden inside a ladies’ powder compact and powered from an external USB powerbank.

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The cyanotype and lumen printing processes are two of the more frequently practiced alternative photographic processes, because of their overall simplicity and the fact there is little-to-no need for equipment. Most people will do their exposures outside in the Sun initially, but if you want to work with these processes on a regular basis it can be frustrating to have ideas ready to try, but be delayed by lack of a sunny day. Working with the sun it is also difficult to figure out predictable exposure times as the intensity varies according to the daily weather, time of day and time of year.

The solution is to switch to an artificial UV light source which can be used any time of day or year, whatever the weather, always giving the same exposure time. With recent developments of LED lighting, it is possible to cheaply build high intensity UV exposure units from strips of 300 UV LEDs which are capable of exposing a cyanotype in just a few minutes

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This is talking about my involvement in the Obsolete & Discontinued project which has just had its first exhibition at the Releva-T analogue photography festival in Spain. The project involves a group of photographic artists, many part of the London Alternative Photography Collective, working with a wide variety of outdated / expired photographic paper (and some film) to demonstrate the potential of materials that most would consider throwing straight in the bin.

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Over the past year or two I’ve done a bunch of experiments with the Chemigram process and even combined it with the Lumen process. In the work so far I’ve used various different substances as resists to control the action of the developer and fixer on the paper, thus influencing the pattern of the light & dark regions. Meanwhile for film processing at home I have been using my Caffenol-C-H-UK recipe almost exclusively as the developer. Caffenol is not just for film, it can be used for developing paper too and it occurred to me one day that instead of mixing up the caffenol in a jug, it might be interesting to just let the caffenol ingredients mix and react directly on the paper. So began a new series of chemigram experiments without using any kind of resist at all.

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In recent weeks I’ve been experimenting with a some old Kodak Autopositive paper and been amazed by the colour produced. When initially exposed it goes an intense crimson red colour, while this colour is lost during fixing, it is replaced by a fairly intense orangey-yellow colour which is almost as attractive. It started me wondering what on earth is going on to form such colours from the POV of the chemistry. In order to figure out what might be happening during the Lumen process, it is important to first understand the chemical processes by which normal silver gelatin images are formed…

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When learning how to create Lumens, the intent was always to figure out how to then combine the technique with the chemigrams process to form hybrid works. The idea is that chemigrams excel at producing abstract images, while Lumens can produce some very detailed reproductions of objects being imaged. Combining the two techniques would hopefully allow the appealing aspects of both techniques to be presented in a single print.

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I have an interest in traditional photographic techniques which can be performed under normal interior or exterior light conditions....Continuing with this theme, the time came to try out the Lumen printing process

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Following on from the previous post, the results of more experiments with different resists and image making techniques

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This post covers some of the initial exploration and experimentation I have done with the chemigram process. It looks at the results of a couple of different resists and illustrates the usage of stencils when applying the chemicals.

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The chemigram process is an artistic technique that involves the use of photographic materials and chemicals, but counter-intuitively will not generally be classified as a photographic process.

Photo credit: the story of nine dots, by Balazs Sprenc, licensed CC BY-NC-ND

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At the start of May, the Wellcome Collection organized a festival, On Light, exploring the relationship to light, which naturally included a number of events related to photography and photographic processes. I went along on Saturday 2nd for “Ultraviolet: World Record Cyanotype”, an attempt to create the world’s largest ever cyanotype print covering approx 110 square meters (actual dimensions 7.5m x 15m). I took along my ZeroImage 2000 camera to document the event...