Astronomy every Thursday
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There were 255 meteors captured in October 2020 from 30 showers including 49 from the Orionids. The media hype about the Orionids amounts to nothing however we did record double the number of Orionids as last year so in some ways it was special - although it could have just been cloudy last year...
The video below documents all the meteors we captured in the month.
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If like me you have had problems guiding but you can't identify any problems with the guiding stats then the problem might be flexure between your guide set-up and the main imaging telescope. My guiding is generally ok, but I have had nights when the telescope in certain positions, but not always repeatable, simply fails, by this I mean the guide stats show really good guiding, but the main telescope shows trailed stars. The most likely cause of this is flexure between the guide telescope and the imaging telescope.
So in this video I tackle this problem by fitting an Off Axis Guider (OAG), this is a small piece of kit that uses a prism to divert some of the light from the telescope imaging train to a guide camera. This ensures that the imaging camera and guide camera are always aligned as they are using the same optics, thus minimising flexure problems between the two systems.
Two criticisms I've heard about OAG's
I didn't find any issues at all, the key is to be methodical, the video below takes you through how I did this.
I've used the OAG for 3 nights now (~21Hrs of imaging a dozen objects) and so far I've always had multiple stars to choose from, I generally guide with 5s exposures but experimented with shorter exposures and was still able to find stars, that said I need more experience with the OAG to completely conclude this isn't a problem, but I'd like to offer a possible reason for this criticism, back in the early days of CCD the sensors were tiny and the guide cameras even smaller, they were also very inefficient, However modern guide cameras are efficient and much larger - my guide camera is a QHY5L II - this has a sensor that is 4.8mm x 3.6mm, giving a field of view of on a 1000mm focal length telescope of 16' x 12' (about half the size of the full moon) and a quantum efficiency of 74% (for 100 photons hitting the sensor 74 electrons are produced) .
The full guide on how to set-up an Off-Axis Guider is in the video below.
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7 members of the society attended the Kelling Heath Autumn Equinox Star Party, some booking camping pitches and others static caravans. The weather was overcast with showers with long dry spells and whilst the astronomical observations were very limited between clouds it was still a great event which I'd recommend any keen observers try to book.
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This is the meteor report for the automated meteor camera operated by the Crayford manor house astronomical society Dartford, for the month of September 2020
This month we detected a total of 269 meteors, well over half were sporadic meteors, meteors from known showers only making a minor contribution to the total, the largest identified shower came from the September Perseids but contributed only 22 meteors to the months total
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This this article i demo how I use Simon Telescopium's free Astro Actions to process my astro-images.
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You can get the free actions (macro's) for Photoshop here
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In this article I'll show you how to improve the contrast in dust lanes in galaxies and dark features in nebulae. The article uses an image of the Pacman nebula taken from a Bortle 8 sky (very light polluted) I explain the process in a way that can be applied to most image processing packages.
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Link to download Simon Telescopium Astro Actions [STAA]
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The below video is a report for the perseid meteor shower, based on meteors captured by the semi-automated meteor camera operated by the society members.
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In this video I'll take you through the steps to reduce noise from your images, I demo the approach in Photoshop but the approach should also work in GIMP.
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In this guide I'll show you how to remove sky gradients from astro-images. The process can be applied using most imaging software, I'll talk through the theory of the approach and then demo it in photoshop, I have created a free photoshop action (macro) which can be used to automate the process, this can be downloaded here
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