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About AlistairW

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    Proto Star

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    Chromatic Free Base Accordion, Chess, Astronomy, Boxing.
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  1. Do people image during astronomical twilight ? - I decided not too, but am now wondering if i should have. What issues are there associated when imagining when not dark - more gradients(?). I am guessing these can be processed out though. Alistair
  2. Learning chess
  3. AlistairW

    M51 Whirlpool

    Hello, Took the chance to image M51 for the first time, seen as we have had a few clearer nights. This was about 6 hours each of RGB and L. Combined in PixInsight and Photoshop. Thanks Alistair
  4. AlistairW

    Sometimes you get some luck

    So i forgot to put my counterweights in the correct "balanced" position last night for my imaging session. Only realised my mistake in the morning. Looked at the guide graph - any it was my best ever! There's a morale in this story - but for the life of me i dont know what it is
  5. AlistairW


    Hello, The other night I was imaging near the Zenith, with poor transparency. My Dec graph in PHD2 was flicking back and forth and producing a very saw tooth affair. Now, this it not usually the case as my Dec is well aligned and I normally have a fairly flat graph. I decided to tun off Dec guiding, and the result was a flat line again. So I was wondering, is this down to the star PHD2 selected and that fact that transparency was not good. The guide star seemed to be moving around a lot, presumably because of the transparency. I was just surprised I was getting better tracking with doing no guiding! (The only other thought was that it is more difficult to image at the Zenith, and the saw tooth was simply due to backlash - which I admit is a possibility). Thanks AListair
  6. AlistairW


    Hello, My imagining train is static and I rarely have to take it apart. So, I tend to take a set of flats and use them for a few months. However, I was wondering, - if I were to clean my Objective lens (whilst leaving everything else - as is), - do I then need to take a new set of Flats. Or put another way, does the dust on the Objective make any difference to Flats (as I though the dust particles nearer the sensor were the only contaninents of concern) ? Thanks Alistair
  7. AlistairW

    M81 - First Play with PixInsight

    Thanks for all the comments :-) Wim - I have added in the Lum the best I know how, and looked at Colour Saturation with the Hue Shift to boost the red. Might have gone too far, but can definitely see the jets in M82 better. Thanks for the suggestion. I feel I have taken a step forward today Alistair
  8. Hello, This is my first foray in to PI - so far enjoying it. M81 below 4 hours each of RGB combined. I have 4 hours of Lum I need to figure out how to work in. Thanks Alistair
  9. Hello, I have RGB calibrated images, which I am trying to combine with the ChannelCombine tool. I have come up with the following though - eeek !! - What am I doing wrong ? Thanks Alistair
  10. AlistairW

    Dark vertical stripes on AstroArt stack

    Hi, Thanks for the reply. I found what i was doing wrong - i was playing around with master bias for flat darks. But was putting the master in the wrong section - think i ended up subtracting the bias twice - hence introducing the noise. I will put it down to the learning curve and avoiding using darks at all. Next is to learn how to create a defect map Thanks Alistair
  11. AlistairW

    Dark vertical stripes on AstroArt stack

    Should a stacked bias of 30 frames look like this ?
  12. Hello, I have been using AstroArt 6 to stack a red channel. Using Flats, Bias as Darks, and Bias as Flat Frame for Darks. I seem to be getting a lot of vertical banding after the stack, that does not exist on the subs. Any ideas, as I am using the default options apart from having Sigma (Average) as the Result Image. Thanks Alistair
  13. AlistairW

    InfraRed pass for Glass

    Not thought of that - thanks
  14. AlistairW

    InfraRed pass for Glass

    Thanks for this I will give it a try - it appears the band I am trying to pass is .... (The 1045 Phidget Temperature Sensor IR uses long wavelength infrared (5.5 to 14 µm).
  15. AlistairW

    InfraRed pass for Glass

    Hello, I am in the process of building a cloud sensor, and have managed to get one of these sensors working: https://www.robotshop.com/uk/phidgettemperaturesensor-usb-ir-temperature-sensor.html?gclid=EAIaIQobChMIqOqCr4Pa2AIV5grTCh3UwgbBEAQYASABEgJP2PD_BwE I have housed it in an acrylic case, but the issue I have is the sensor is at the bottom of a barrel, and is open to the atmosphere. I was thinking of using a microscope slide cover to place over the top to protect it from rain etc., but then I read that glass blocks IR. Ultimately I guess I need to experiment to see what works, but anyone have any ideas on materials that allow IR to be transmitted ? Thanks Alistair

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