Sunday 11 November 2018 — ASTROPHOTOGRAPHY
I have not yet managed to unpack my telescope and CCD camera since we moved here. On the rare occasions that I have had time to think about practical astronomy, the weather has not been helpful. Although the night sky here is much better than it was in our old house, it is not good. THere is a lot of light pollution to the North (from the Fawley oil refinery about a mile and a half away and Southampton city centre and docks about 8 miles away beyond it). To the East there is a light dome from Portsmouth (about the same distance away) and it’s also possible to locate Cowes and Bournemouth clearly by the light they put into the sky. Otherwise, it is genuinely dark to our south and west, but there are trees and a few badly-situated streetlights. Our last house had a very definitely “urban” sky and here it is at the boundary between “suburban” and “rural”. That means we can see the Milky Way on clear nights, and on the very best nights the sky is covered in stars (down to magnitude 5.5). It also means that moonlight turns the sky beautiful subtle shades of blue, unspoilt by artifical light, and a short walk out into the New Forest can find places where the sky is lovely and dark.
I was using astrophotography software I already have— PixInsight— to process some night sky photos I had taken with my DSLR in Ireland and it reminded me how much I enjoyed creating images of deep space. I wondered about using a robotic telescope instead of trying to capture my own images.
First, I tried to log back into the Bradford Robotic Telescope, which I had used some years ago, but I discovered that it has been taken over by the Open Univesity, so my account was no longer there, and I was no longer eligible to register (unless I become an Open University student). Some of the other robotic telescopes I had used before vanished too, or were only available to teachers, schools and colleges.
I signed up for a trial with Slooh, but was able to do nothing for about a week, due to weather and other technical issues, and then found I was signed up, and had paid for, a year’s basic membership. I had a good look at what they offered and it just was not for me. The quality was variable, to say the least, and it looks and feels much more like a mock-up of a telescope than accessing the real thing. I don’t understand, for example, why they present circular images, or the cartoon-like interface that tries to make telescope images look sci-fi. The final straw was their response to my email saying how surprised I was that they had charged my credit card immediately when I thought I was signing up for a short free trial. Basically, they referred to terms and conditions that said they never refund, ever. I told them how poor I thought they were, promised to warn anyone I could to steer clear and will never have anything to do with them again. Fortunately it is not a vast amount of money, but I feel tricked into paying for something I simply do not want.
After more searching, I came across iTelescope. They used to be “Global-Rent-a-Scope”, which I knew about, and they have a professional, solid reputation, but there is a feeling that they are for people who know what they are doing. I have made my own astro-images and have some idea, and after reading their terms and conditions very carefully, I signed up. It’s a pay every 28 day membership, but you can change the level, or cancel, whenever and as often as you like. A membership gives you “points” which you can spend on using their telescopes robotically. Different telescopes use points at different rates (different points per hour) but you only pay for exposure time. You can drive the telescope “live” or set up a plan which will drive the telescope for you. You can reserve time on each telescope to use directly or to run a plan.
There are lots of telescopes, of various sizes, types and roles, spread across five observatories in Australia, Spain and the USA. All the observatories are in areas with pristine skies and dry climates, and at high altitude so there is less air above the telescope to blur the sky.
This is a mosaic of two separate images, both made with an excellent 106mm refractor telescope in New Mexico, USA (ITelescope’s T03). Each images was made with 5 four-minute exposures using a colour astronomical camera. The five images are “integrated” together to reduce background noise. The two images were then stitched to create one larger mosaic and processed to reduce noise further, emphasise and correct the colour and shapes of the stars. It’s far from a pefect image: I am quite out of practice and want to go back and re-make this when I have more time, but it’s still one of the best astrophotos I have made.
Open clusters are groups of stars that are closer together than average, because stars form together in areas that are very rich in gas and dust and then disperse over time. We are seeing stars that are young enough not to have dispersed completely yet. The double cluster is on the borders of the constellations Perseus and Casseiopia and are visible to the naked eye (in any reasonably dark sky) as two fuzzy smudges, close together. The two clusters are thought to be related, and not just in the same line of sight. I have always loved this view. It’s magnificcent in binoculars or almost any telescope, though larger telescopes will struggle to see it all.
I particular like the contrast between the bluish-white, young stars of the clusters and some older, much redder, giant stars dotted nearby.