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About andrewluck

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    Star Forming

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    Member of Breckland Astronomical Society.
    Ex-RAF electronics engineer. Now a consultant with a computer system integrator.
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  1. This is a two panel mosaic of Sh2-155 comprising a lot of 20 minute red, green and blue sub-frames for 28 hours total integration time. Taken with my FSQ-85 with 1.01x flattener and Moravian G3-16200. Processed in Pixinsight. Andrew
  2. No dispute there, you're absolutely correct. Finger trouble with the calculator here. Apologies for the confusion. Andrew
  3. From the specs on Takahashi America I see that the 130d has a 44mm image circle. The diagonal of a full frame sensor exceeds this at 49.5mm. I've no experience with this scope but with my FSQ-85 (same image circle specification), when I switched to a 16200 chipped camera the stars in the corners were very poor. This sensor is considerably smaller than a full frame. Now I've fitted the new flattener this has made a considerable difference. I'd seek the advise of either Takahashi Europe or America and see what they recommend. Andrew
  4. The flattener has now arrived and been installed. As I already had an adapter for the front of the filter wheel to connect to a CA-35 all I had to do was include some M54 extenders between the flattener and the adapter. The ones I used were these: https://www.aliexpress.com/store/product/A-set-of-M54-Extension-Tube-4-9MM/1371081_32819456658.html?spm=2114.12010612.8148356.4.73733ccaSiki3y Originally, I intended ordering a new custom adapter once I'd determined the back focus requirement but I don't think this is essential. The results are interesting. I was previously aware that these FSQ scopes are extremely sensitive to focus position and this hasn't changed with the flattener. Apparent tilt swings pretty wildly either side of focus and on my last trip to Namibia I was manually focusing an FSQ-106 by focusing for minimum tilt (completely ignoring the usual FWHM metric) and achieved good reults with this. Incidentally, using this method the direction of tilt indicates which way to turn the focuser which makes the process quicker. With the Lakeside auto-focuser at home, I'm focusing on a star in the centre of the field and then offsetting 20 steps out. This has the effect of reducing the FWHM of the focus star from 6 to about 4 and reduces the indicated curvature from 30% to around 10%. Some further fine tuning is probably possible here and should yield a small improvement. As CCD Inspector doesn't distinguish between FWHM and eccentricity I also measured the image using Pixinsight with these results: The stars in the corners of the test image look like this: In summary, I'm very pleased and looking forward to the next clear night. If anyone is interested in the 3D plots either side of focus then ask and I'll post them. Andrew
  5. Hi Julian I haven't got a flattener yet but I'll be pressing the buy button very soon. I'll also need a new adapter to connect it to the filter wheel. <Edit> Button pressed. Also a set of M54 extenders </Edit> Andrew
  6. I use one of these: http://www.auroraeurotech.com/CloudSensor.php Works well with CCD Commander to open and close the roof. No wind speed measurement though. Andrew
  7. Filter is the Baader 4.5nM Ha. There's a thread here somewhere detailing some of the work I had to do getting acceptable (to me) results. I've ended up with some tape under one corner of the camera / filter wheel connection and, having focussed on a star in the centre of the field I then step out an additional 10 steps (about 50 micron). There's still some elongation top left, bottom right but I can live with that for the moment. Hint: machined adapters are never orthogonal and sometimes the tolerances will add up the wrong way and bite you! After noise reduction in the linear phase (TGV & MMT) I used a histogram stretch rather than a masked stretch to preserve what contrast there was. Then there's 3 iterations of LocalHistogramEqualisation at scales of 64, 128 and 256 (decreasing amounts each time) to boost the contrast and then some S curves to finish. More noise reduction etc etc etc Andrew
  8. This is the result of 16x 20 minute Ha frames taken over the two clear nights earlier this week with my FSQ85 / Moravian 16200 combination. Processing in Pixinsight and resampled to 45% of the original size. Andrew
  9. That's my Moravian G3-16200 on the back of an FSQ-85.
  10. I think I've finished NGC1333 for the year. I've added some data to what I collected last winter and it's now up to a total of 36 hours in 20 minute RGB frames, no luminance. Processed in Pixinsight. I had to discard quite a few hours of blue frames as they were quite badly affected by thin cloud / humidity which tends to produce blue halos around the brighter stars when the image is stretched this far. Andrew
  11. No plans to add OIII, there's just not enough clear nights in the year and there are other objects that are a lot more rewarding. You could run up 40 hours and it would still be just a fuzzy blob. Good luck with the mosaic Steve. I look forward to seeing the results. Andrew
  12. I finally got around to adding a few more 60 minute Ha frames to my collection for Sh2-216 taking the total to 10. There's a paper that includes this object measuring the distances of the central stars using parallax: http://iopscience.iop.org/article/10.1086/510348 Andrew
  13. ...or the Aurora Cloud Sensor http://www.auroraeurotech.com/CloudSensor.php Totally automated here. It's the only way I can take full advantage of my investment in telescope/mount/camera. The image quality is also improved by the much longer integration times I can achieve by being able to image all night on the rare nights that it's clear and still drive to work in the morning. Tinkering, no, that's not for me. Boring, never. The satisfaction for me is running a well maintained system that just works when it has to and delivers the raw sub frames ready for processing. One proviso; if the forecast is for rain later then as a general rule I won't open up. Andrew
  14. Well, thanks, I'm pleased you like it. Always more to do though...
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