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StuartJPP last won the day on December 18 2017

StuartJPP had the most liked content!

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About StuartJPP

  • Rank
    Brown Dwarf

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  • Gender
  • Interests
    Birding and now a bit of astrophotography.
  • Location
    Leeds, UK
  1. If your OAG and main camera are now rigidly mounted then I am sure your issue will disappear. I used to have similar star trailing with my refractor and it turned out to be flexure of the lens (OTA) foot. The flex was undetectable by feel/naked eye. My trailing would happen if I guided or not and was eventually eliminated by securing my OTA in a much more secure manner at both the front and back of the dovetail. Your flexing will still happen of course but the guiding using the OAG will correct for it. See this thread for animation showing the star trailing I used to have before the issue was solved. Hope your new setup works out for you and you are able to find the source of your problem.
  2. Complete opposite to me, since I started dithering my subs I have completely eliminated taking or using dark calibration frames. If you can get it working reliably/consistently then I deem it well worth it. No longer do I need to match darks and temperatures and run the risk of losing signal due to darks. For reference I use APT and PHD2 along with a Canon DSLR (either 650D or 6D) and QHY5-L-II guide camera.
  3. It definitely does make a difference if there is light hitting the viewfinder, say from a street light as I have experienced it myself. As a consequence I always cover the optical viewfinder to eliminate this.
  4. The thing is that we are living in a topsy-turvy world these days. I don't trust institutions like the BBC as they always put some PC slant on everything they spew, to a lesser degree than some of the other rags, but they still wind me up. So if that drivel is to believed why not flat Earth theories? No more ridiculous then some of the current gender theories floating around to someone who believes in science, not feelings.
  5. Did this I once and heated the front objective of my refractor (lens) a tiny bit too much and dew formed on the inside of the lens.....so be careful It completely dissipated but was quite worrying when I first saw it. These days I just use some low wattage DIY dew heater strips which keeps dew and frost at bay.
  6. There's definitely benefit to using "decent" cables regardless of their origin. There are a few things that do make a difference, the wire gauge used should be correct (to be able to carry the current), the data lines should be twisted to eliminate cross-talk and shielded and the connectors should be decent quality, preferably gold plated. Anything more is more than likely snake oil. A cable with an integrated ferrite can also help interference issues. I keep all the cables I get from various equipment, in that way I have all manner of USB cables, with different connectors (Micro, Mini, A-B etc and also some right-angled ones) and lengths...comes in handy as they are effectively "free". There's also a difference between setups where the cables are left plugged in indefinitely or plugged in every session...plugged in indefinitely can have issues with dissimilar contact platings causing contact issues over time whereas being plugged in each session can have a self cleaning action. I have thrown rubbish cables away before as they were definitely the cause of my issues but I certainly wouldn't pay crazy money for a USB cable.
  7. It is quite strange that Roger's image looks like no other image of that region of sky, both from OSC or mono cameras. Perhaps everyone else is doing it wrong? I am an advocate of having a DSLR modified if you can so that it's spectral response is similar/closer to that of a dedicated astro OSC camera. It all depends on your own personal preference. Do you have to modify your camera? No, of course not but I will stick with my modified Canon 6D, my Canon 5D Mark III however will remain unmodified...
  8. I did a back-to-back test of SharpCap and Polemaster a while ago, both produced very similar results which is not surprising as they use very similar methods. SharpCap's method is based upon PhotoPolarAlign which itself is based upon another that escapes me. SharpCap has the potential of more accuracy since it can use much longer focal lengths than the 25mm of the Polemaster. Here were my findings:
  9. What is the reason for not wanting to continue using the Canon lens? Poor corner stars, coma etc? I have been imaging with a Canon 500mm F/4 L IS lens from day one and will continue to do so until I stop doing astrophotography. The reason being is that it costs nothing as I already own it. The only real benefit of going with a dedicated OTA for me is focus, since on the Canon lenses the travel near infinity focus is very short. Additionally for me, it is next to impossible to get anything close to f/4 at 500mm. However since I intend to stick with my Canon 6D for imaging I also get free remote focus...
  10. Have you got any USB cables with integrated ferrite beads in them, they can help reduce EMI with tightly bundled cables? Use them on the camera USB cable. Like this: Or ferrite clamshells on existing cables if you have got any:
  11. StuartJPP

    Easy PCBs

    I have used Eagle before and found its user interface extremely infuriating, however for the price of the freeware version you can't complain too much.....
  12. I am surprised that the title of this movie managed to get approval these days and the lack of the planting of the flag to me was purely politically motivated. Me, I'll give it a skip, perhaps it is just me getting older that makes me detest most Hollywood tripe these days, especially with hidden agendas.
  13. I used 3 minute subs on an f/4 scope (lens) using an unmodified canon 5D Mark 3 a while ago and found that was the sweet spot for me. The sweet spot being able to get enough data on each sub, not losing too much time on lost subs and getting enough subs for stacking algorithms to do their job (>25 or so). I was also unguided at the time and felt going longer than 3 minutes would have introduced too much drift. F/7 is nearly 4x as slow as f/4 so personally I would stick with longer subs. Of course it also depends on the ISO you are using...don't want to oversaturate the stars. This was imaged in a fairly dark area in Scotland.
  14. You definitely need to book outside of the "rainy" season.......I went to SA in 2015 in March to attend a combined wedding and birthday anniversary and it rained during the night most of the time I was there....last time I go on holiday for an anniversary/birthday etc! At Namibian latitudes astronomical darkness doesn't vary too much between summer and winter so best bet is to find what is best placed in the sky for beginning or the end of the "drier" season. I did see and briefly image the LMC.....very awesome to see visually, like a mini Milky Way, about fist size at arm's length.
  15. Much like everything else reported by The Guardian, pure rubbish.
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