Wednesday 28 February 2018

Orion redux

Here is another go at M42, taken two nights later. In this case I dropped the exposure of the individual frames down to 5 seconds, which has helped reduce the over-exposure in the core of the nebula. However, I would still need to drop it a bit further. Here I took 29 sub-frames and again combined them using Nebulosity. There are still a few bits of electronic noise in the final image. It was a race against clouds again last night, or else I would have taken substantially more sub-frames.


  1. Hi Al,

    Great pics. I really want to get into this type of thing as a hobby I can enjoy with my kids. Would you mind detailing some of the equipment you use?

  2. Hi Mirabel. There are three bits of equipment used here: a telescope, a mount for the scope, and a camera (and laptop). The telescope is a relatively small William Optics 71mm refractor, which cost around 500 pounds when I bought it a few years ago. It's not made now but similar small refractors are easily found. The benefit of this scope is its wide field of view, excellent for extended objects like nebulae and the Moon, nearby galaxies, etc, but no good for planets.

    The scope is in turn mounted on a Sky Watcher GoTo equatorial mount, which cost in the same region as the scope, but which can accept a variety of other telescopes if needed. Importantly, the scope and the mount are not so bulky or heavy that they can't be moved easily, so setting up is very simple and quick - I just carry the entire unit out through a door onto patio decking. My other, larger and heavier scope, the Celestron, is better for planets and distant objects, but can't be carried without disassembly.

    The final element is some kind of digital camera to record the light, and in this case I used a CCD made by a firm called OpticStar, which again cost a few hundred pounds. It goes onto the scope where an objective eyepiece would normally fit, with only the focus needing adjustment, so it's easy to swap between visual and CCD astronomy in just a few seconds. Camera control and image acquisition is done via a USB link to a laptop - in my case a ten year old Toshiba which is pretty useless for anything else, but can still run the control software.

    1. Hey As,

      I Have a question, so I figured I'd ask an astronomer, what would you recommend accessory-wise, if I wanted to view my telescope live on my laptop, is there anything in particular that you would recommend? Great Books, by the way, Clavain and Scorpio need a standalone novel

    2. I can see you eventually building your own observatory. Now that's a toy I'd practically live in.

  3. Hi David - I would like a dome as it would mean I could leave the telescopes permanently aligned (at the moment I have to do a polar alignment each time I set them up, which takes time) but there isn't a suitable site in our garden, which has very obstructed views of the sky in most directions.

    Cory: if you have a CCD camera already (some of which are really just repackaged webcams, from what I can gather, so not expensive) then all you really need is a laptop and a bit of software. Nebulosity allows live-viewing although to get the richness of colours, you need to integrate an image for a few seconds or more. I seem to recall a product being released a year or two ago which allowed true live-viewing, rather than being geared up for image acquisition, but I don't recall the name. It was trying to bridge the gap between visual and digital astronomy, I think.

  4. Hi Al, David,

    The camera that can be used for visual observations is the Mallincam:

    Never used one, but they have a great reputation.

    Al: how large is your Celestron? My current astrophotography rig is also based on a small refractor, but I'm seriously thinking about an SCT...


  5. Have you seen the new edition of Aurora Rising appear to have a typo on the cover... Inspector Drefus

  6. Hi Stephanie - I was aware of that, and told that only a small number of the typo-affected copies had got into circulation. I saw one myself in central London; do you happen to know where yours was purchased?

  7. The scope you're thinking of that was designed to provide true live-viewing may be the eVscope, by Unistellar.

    The scope you're thinking of that was designed to provide true live-viewing may be the eVscope, by Unistellar:

  8. I really enjoyed Pushing Ice and hope you return to this universe soon. The characters and their quirks really set it apart from old-time hard SF. Fishtanks in space! I doubt Clarke or Gentry Lee (even though NASA has in reality done a little aquarium stuff) would have ever had characters fighting over allowing a prisoner their fishtank to make their incarceration more tolerable. When people are upset, they really do have the most absurd disagreements....
    The details of sometimes-but-not-always weightless aquarium plumbing and decor (glued in place, probably pretty minimal?) could be interesting, especially if you spin the tank to give the fish some buoyancy control.

    I'm not sure about tetras or any fish with a swim bladder. They might have trouble moving in weightlessness. I suppose you could really go crazy and spin a cylindrical tank and look at the fish (fishy-up being radially inward) from one end of the cylinder. But maybe some kind of fish without a swim bladder would be simpler, like a not-too-huge species of catfish or loach.

    Tetras are also rather skittish, easily frightened fish; I do not think they have the fishy Right Stuff. Perhaps some ruggedly individualistic, fearless, insanely pugnacious anabantid, like a paradise fish or Betta splendens would cope better even flopping around without buoyancy control. I imagine the last thing a Betta thinks staring down a predator's maw goes something like: "I would sooo eat you, if only you were just a little bit sma--"

    --The Fishman