Astronomy - OBAFGKM

Setting up an ASCOM driver project

What follows is simply a step-by-step guide to setting up an ASCOM driver project with Visual Studio 2019 – mainly so that I don’t forget how to do it myself… Creating from an ASCOM template Install ASCOM and developer components. Start Visual Studio as admin Click on ‘Create a new project’ Search for ‘ascom’ in the search field and choose ‘ASCOM Device Driver (C#)’ Give the project a sensical name and Create… The ASCOM Driver Project Wizard will then appear. Select a driver class and choose another sensical name. Click ‘Create’. The Visual Studio solution should appear with a document to be read. Follow the instructions by trying to build the solution and, if successful, adding a new project. Add a new project by right-clicking on the solution in Solution Explorer and then Add -> New Project… In the new dialog, choose an ‘ASCOM Test Console Application (C#)’ and click ‘Next’ Now, choose a name. Maybe just add ‘Console’ to…

Arduino

Building an inexpensive lux meter for the observatory…

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As part of an environmental monitoring system for an observatory, I wanted to include a measure of ambient light. Ostensibly, this is for safety reasons. However, I must admit that I really just want to see if I can (coarsely) measure sky brightness. There are a number of inexpensive light sensors available from AliExpress/Amazon. The two that I show here are based on the TEMT6000 sensor and the LM393 voltage comparator. Both cost less than $1.50. Hooking up the sensors…

Astronomy

How to find stellar magnitude limit – A bit of a hack

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Finding the stellar magnitude limit in an image is not necessarily as straightforward as it, at first, appears. I needed to come up with some non-hand-wavy numbers and thought, ‘No problem, this is easy.’ It turns out that I was wrong. At least for my imagery and what I wanted to say about it. The ‘proper’ way to calculate the limiting magnitude, it turns out, is to inject synthetic stars of different magnitudes into your imagery and then try to…

3D printing

Cloud monitor MKII (now with POE!)

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After building the Mark I cloud monitor, I realized that I really wanted something with power-over-ethernet (POE). The cheap network adapters that I use typically have an HR911105 (or similar) RJ45 connector which is not compatible with POE. I’ve looked but have yet to find any of these adapters with POE, so I decided to hack my own together. In theory, it should be easy… What you need 2x MLX90614 thermopile sensors 1x Arduino Nano 1x W5500 ethernet adapter (I…

3D printing

Building a network-connected cloud sensor (MKI)

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I’ve wanted to build a cloud sensor for years now, but never actually found the time to do it. So, after seeing IR sensors for something on the order of $5 a piece, I ordered a couple and thought that I’d give it a shot. This has undoubtedly been done by lots of other people, but I thought that I’d share some simple instructions on how to build your own. The theory We could get in to the theory of blackbodies (maybe later), but it is sufficient to say that… Clouds are warmer than a clear sky. The infrared spectrum of an object can tells us something about its temperature. If you can measure the temperature of the sky, you should be able to say something about whether it’s cloud-free or not. To measure the temperature we need some sort of contact-less thermometer that can be pointed at the sky (and ground, more on that later). What you need 2x…

3D printing

A 3D printed Ronchi tester

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The situation was that there were three telescopes. Each with the same 20″ cellular mirrors but one with a slightly different cell than the other two. Two were easy to collimate while the third one could never be fully collimated. It appeared that there was a bit of astigmatism that was preventing easy collimation. So, the problem was how to quickly test a mirror for astigmatism. A Ronchi test was suggested but I didn’t have a grating or even a tester. What to do? Print one? The first step was to find a grating. Since I couldn’t wait for a proper grating to arrive, I decided to try to print a 100 line/inch grating on transparency film with a laser printer. The second step was to make something to hold the grating and a light source. First I cobbled together something out of scrap plywood and, although it worked, it looked like something that the dog dragged in. It was…

3D printing

A cheap, low-light IP finder ‘scope’

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My academic work focuses on meteors. Visual (and sometimes radar) observations of faint meteors. For this, the general requirement is a sensitive video-rate camera with a moderate field-of-view. The traditional solution (after eyes, photograpic plates, vidicon, etc. ) was to use an analogue security camera with low-light sensitivity. For many years, this was the Watec 902 series. They are good with resolutions of 720 lines on an (up to) 1/2″ CCD chip. Their sensitivity is estimated at down to levels…