This article is about a new piece of software I developed over the past few years: A telescope focus finder software for Linux (and maybe later Windows).
At the time of publication this project is not even in ALPHA state. However, I feel now is the right time to publish it since it reached a state where at least the source code could be useful to others. You can find the source code on github here.
The software aims to support the amateur astronomer (and especially astrophotographer) with one of the most critical but also most annoying tasks: Finding the best focus position for the camera. The main goal is to provide a free and easy to use software that just does the job – automatically.
With a given configuration it should also be possible to execute “FoFi” from the command-line without requiring any user interaction. This way you can include a call to the Focus Finder into a script. This might be useful if the entire observation process should be automated and you want to re-focus from time to time to compensate the temperature drift.
End of 2018 I visited the new Cherenkov Telescope on La Palma. Actually I planned to write a long article about this visit – but as it happens sometimes, other things are more important… I decided to skip this article since now there is sufficient information out there about this telescope. However, I think the images I took for this article are still worth to see and give an impression from the observation site on the Roque de Los Muchachos on La Palma. The following two links provide more information about the CTA on La Palma:
This article shows how to calculate the 2D signal-to-noise ratio (SNR). Furthermore, it demonstrates how the $SNR$ can be used to decide if there is a potential star in the image.
Long story short – I was looking for a way to detect more or less reliably if a user selected a region which contains a star. I wanted to be able to clearly distinguish between the following two images:
Solution with the CImg library
After a long journey I finally ended up with the following solution. It is based on the CImg library which in a way calculates the Signal-to-noise ratio (SNR):
Some opportunities are very rare to come by. Sightings of certain species of birds are even rarer. For times like these, having a useful magnification tool such as a pair of good binoculars or a telescope can come really handy. In a broader sense, both, telescopes and binoculars serve the same purpose – they make an object that is far away, appear much nearer so you can examine it closely.
When you are observing birds from a safe distance, the birds don’t get nervous or feel threatened. You can enjoy watching the birds going about their activities without scaring them. Regardless if you are a novice or seasoned bird watcher, without a good magnification tool you are quite likely to miss out on priceless moments. Let’s take a look at which of these magnification tools is best suited for bird watching under various conditions.