Red Dot Rifle Sight as a Finder

One of my RDFs died recently. It seems to be something they do. Anyhow, I had a red dot rifle sight sitting around doing nothing, so I removed the mount from the RDF and cut a plate from a bit of aluminium sheet to fit the mounting on the sight. That screwed to the top of the RDF mount and presto! A new RDF!

In use it seems to work fairly well. The LED is variable brightness red or green and the fact that there are two layers of glass doesn’t seem to dim the image too much. It does suffer a little from dew though, so I need to make up a proper hood for it.

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A Short “Great Red Spot” Animation

From the same night (just a little later) as my previous Io transit images, watch the GRS as Jupiter rotates:

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Io’s Transit of Jupiter, 11 December 2012

Ganymede and Europa are “in the bag”. Catching Io here means there’s only Callisto left. Of course I didn’t catch the whole transit for the first two so I shall be revisiting that next apparition.

And an animation of the entire event. Spot the jump in the middle when I had to do a meridian flip because I was running out of clearance on the EQ3-2:

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Europa’s Transit of Jupiter, 29 November 2012

Having managed to catch some of Ganymede’s transit the previous day, it was then Europa’s moment of fame, though again I didn’t manage the entire transit:

And an animation of the end of the transit:

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Ganymede’s Transit of Jupiter, 28 November 2012

On the 28th November I (pretty much accidentally) caught the transit of Jupiter by Ganymede. Here’s one of the better stills from that night:

And an animated sequence of first half of the transit:

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It’s Raining Again…

It seems to have rained here for almost all of December and the Met Office says that it’s already been the wettest year in England since records began in 1910 and stands a good chance of being the wettest year for the UK as well. So, stuck indoors because most of the things I want to do are outside and I don’t fancy getting soaked and being up to my elbows in mud, I grabbed some of the Met Office rainfall statistics for the UK since 1910. Here are a few interesting/depressing items I pulled out:

Three of the ten wettest years occurred this century (2000 to 2011)
Six of the twenty wettest years occurred this century
Eight of the thirty wettest years occurred this century

So two thirds of the this century thus far is represented in less than the top third of the rainfall figures. It doesn’t look that much better if you increase the window to the last twenty years either:

Half of the top ten wettest years occurred in the last twenty years
Half of the top twenty wettest years occurred in the last twenty years
Thirteen of the top thirty wettest years occurred in the last twenty years

To find any earlier over-representation you have to go back to the 1920s, and this century so far beats the 1920s into a cocked hat (only four years in that decade in the top thirty).

And on the assumption that 2012 turns out to be a chart-topper it looks even worse, as then fully three quarters of this century so far will be in less than the top third of the data.

Regrettably I’m rather clueless when it comes to statistics so I can’t work out how likely these outcomes would be if rainfall patterns were truly random, but intuitively (and intuition is often no better than chance) it doesn’t look good. There are times when I’m tempted to start gathering together pairs of animals and drawing up plans for an ark…

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SPC900 vs. PS2 Eye camera

When I posted images from the Xbox, Lifecam and SPC900 for comparison, someone asked about the PS2 Eye camera (not the Eye Toy). Last night whilst I was imaging Jupiter and Europa I had a go with it. Control is very awkward compared with the other cameras and whilst I found it to be quite sensitive it also appeared to be astonishingly noisy which meant I had to wind back the gain and exposure times to try to keep it under control. Even then I struggled and it has resulted in artefacts around the edge of the planet as well as washed out colours. Here are some examples of processed images:

There’s good detail there, certainly, and in terms of sensitivity I think it’s done as well the SPC900 at picking out Europa but the noise just ruins it all.

For comparison, here are three from the SPC900 that I took just prior to the above:

In my opinion, the PS2 camera just doesn’t have what it takes. I shan’t be using it again.

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Our own little deluge

I feel desperately sorry for those people in the south west and Wales caught in the recent flooding. The pictures from the news are shocking. We didn’t suffer quite so badly, merely having the road past the end of our drive flood to the point where it was too deep to drive through. A number of car drivers found this out the hard way and both I and the neighbouring farmer towed several cars out using tractors.

This is what it looked like on the morning of Saturday 24th November, when it had been raining pretty much non-stop for a couple of days. Our drive is the first right in the first image.

And the following morning, when it was far too deep to wade down to the far end to take a photo from there…

By the Monday and Tuesday it had risen even further, mostly I think from rainwater running off the surrounding fields.

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Registax v6 vs. Autostakkert!2

I’ve had some discussion with a few people about using Autostakkert!2 instead of Registax for stacking planetary images, and potentially using AS!2’s drizzle function as well so I decided to reprocess some of my recent Jupiter images

So, here are the results for three images from mid-November with three different processing treatments. I’ve processed them entirely within Registax v6, stacked in AS!2 and used wavelets in Registax v6, and stacked with 1.5x drizzle in AS!2, used wavelets in Registax v6 and downscaled to match the size of the originals.

In each of the three sets the last image is the drizzled one and I think it’s rubbish compared to the other two. Where the non-drizzled images are concerned, I think it’s a very close call. I’d go with the first image by a gnat’s whisker in the first two sets after a fairly microscopic examination and I’d go with the second image in the last set.

I’ve since had an email from someone who knows rather more about AS!2 than me making some suggestions about the application of drizzle and stacking, so I probably need to go back and have another go.

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SPC900 webcam brightness setting

It has been said that the brightness setting for the SPC900 camera affects only what appears on the screen and not what appears in the capture file. Having read the code for the Linux SPC900 driver I wasn’t at all convinced of this and so created three images from captures from the camera at minimum (0), mid (63) and maximum settings (127) in SharCap. Here are the results:

I think it’s quite clear from those that the brightness setting does indeed affect what appears in the capture file. The question that now springs to mind is “What is the best brightness setting?”. I’ve no idea about that, so I leave my brightness control at the mid-point of the range.

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