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StuartJPP

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Everything posted by StuartJPP

  1. Even with a DSLR and no inverting of the image (refractor) I still find it a bit tricky when it says "Left xx.x", "Down xx.x". "Left xx.x" means that you need to move the FOV (or NCP) left, which actually means moving the mount right...it comes down to the azimuth bolts that are inverted i.e. using the left bolt moves things right...and vice versa...I can only imagine it getting trickier with a refractor and a CCD... What I do (since I am using Windows XP), is pop live-view on and adjust the bolts by observing a star, then there is no mistaking it. Usually you can hit it within a couple of iterations. I have managed to do a complete polar alignment by being doing it blind, i.e. plonking the mount and scope on the ground roughly pointing north and using PhotoPolarAlign, however I'd recommend using a polar scope at the very least to get it as close as possible to start with.
  2. StuartJPP

    M101

    From the album: Deep Sky Objects

    Canon 5D Mark III Canon 500mm f/4 L IS @ f/4 ISO800 25x 180 second subs AstroTrac TT320X unguided December 24th 2014
  3. One thing I am not sure of is does the quantum efficiency decrease with temperature drop or does it increase? I know that the noise decreases with a decrease in temperature, but does the QE also decrease or any other criteria related to wanted signal? Removing as much unwanted noise is good, removing signal is not good...I accept that we are wanting to improve the S/N ratio which we are doing by decreasing the noise, but sometimes that is not the whole picture. I have seen dark images of 60 minute exposures where there is very little noise...now please point that camera to the stars and show us some results, preferably alongside a stock camera that hasn't been cooled. I am sure that the cooled camera will win hands down, but by how much?
  4. Another tester here...works quite well I find. What I like about it is that there is no DEC slewing like AlignMaster so any potential backlash does not skew results. With some automation this could be made very fast indeed.
  5. StuartJPP

    PhotoPolarAlignment

    Testing PhotoPolarAlignment
  6. From the album: PhotoPolarAlignment

    Canon 650D with Canon 500mm lens.
  7. From the album: PhotoPolarAlignment

    Canon 650D with Canon 500mm lens.
  8. StuartJPP

    Male Stonechat

    From the album: Birds

  9. StuartJPP

    Male Stonechat

    From the album: Birds

  10. Not if you have got the AstroTrac head (or similar). It has RA and DEC "controls"...I would be interested in people in the southern hemisphere trying this out...preferably before March next year
  11. I am assuming that the premise is to take an image in the east then slew in RA only to the west, the error is calculated between the two resolved plates and an adjustment made on alt/azi (based on the arcseconds per pixel of the image)? I was thinking of something similar a while ago...this helps me to not bother about doing it...a stand alone version would be nice albeit a bit large for the off-line plate solving database.
  12. StuartJPP

    output HH78zF

    From the album: Nothing Special

    Canon 5D Mark III coupled with the Canon 500mm f/4 L IS lens mounted on the AstroTrac using 3 minute subs (@ ISO 800). This image shows drift from image to image.
  13. StuartJPP

    BestSub

    From the album: Nothing Special

    Canon 5D Mark III coupled with the Canon 500mm f/4 L IS lens mounted on the AstroTrac using 3 minute subs (@ ISO 800)
  14. StuartJPP

    Mammals

    Various mammals
  15. StuartJPP

    Extending AstroTrac Head Counterweight Bar

    How to Extend the AstroTrac Head Counterweight Bar cheaply. I needed just a bit more weight and found this a cheap alternative to getting more weights...may come in handy for other people.
  16. From the album: Extending AstroTrac Head Counterweight Bar

    This adds about 8cm to the total length of the bar. This allowed me to balance a setup which was just slightly too heavy. Total cost = £1.50 for the stainless steel bolt.
  17. From the album: Extending AstroTrac Head Counterweight Bar

    The large counterweight needs to be used in this position to ensure that it can still be locked into place on the shaft.
  18. From the album: Extending AstroTrac Head Counterweight Bar

    Top = An M10 x 100mm stainless steel dome head bolt. This adds roughly 8 cm to the bar once screwed in. Bottom = Original bolt and washer.
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