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About Xilman

  • Rank
    Star Forming

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  • Gender
  • Interests
    Almost everything scientific & technical. See web site for astronomical interests.
  • Location
    50% Cambridge, UK 50% El Paso, La Palma

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  1. How long is a piece of string? Seriously: stretch until you can see what you need to see within the limitations of your data and then stop. See https://britastro.org/observations/observation.php?id=20200805_212500_dc7c69e9f34bb551 and http://www.astropalma.com/Projects/Satellites/caliban.html for extreme examples of mine. The former completely destroyed the appearance everything except the target of interest. AFAIK, this is the only amateur image of Thebe ever taken, and I have yet to see a professional one not taken by a probe in Jovian orbit.
  2. I and a number of other people would very much like an INDI driver for the K8055N Velleman USB board. In my case it is used to control the dome. The LesveDome product works well under Windows/ASCOM but it would be nice to be able to use it under Linux/INDI.
  3. Eh? In my experience, 1 GBP is worth more than 1 unit of almost all other currencies. Currently, 1.16EUR, 1.40USD, 102INR, 1.78 AUD, 30.22 CZK, ... On of the very few exceptions is the Kuwaiti Dinar where 1GBP is worth 0.427 KWD, This does not include such as ounces of gold (1 XAU = 1275 GBP) or palladium (1XPD = 1715 GBP) Work your way through www.xe.com if you want to find other exceptions. That is from where I took these figures just now.
  4. Yup. Saving as 32-bit floating point FITS images is a good trade-off between precision and range in my experience.
  5. An outline here and a tarball of the software attached. Give me time to get my act together.
  6. Median stacking is more robust against outliers such as cosmic ray hits or satellite trails, though you should still reject any which pass within the aperture radius around the target and its comparisons. The benefit comes from getting a better sky estimate. Average or summing (almost identical) gives a somewhat better SNR than median for an identical set of subs. I tend to use 30s subs. except for extremely bright stars which saturate the detector at that integration time. For faint objects there could be over a hundred subs. Can give a report about my pipeline going from a s
  7. Seconded. I could well be interested.
  8. Yay, there's a blast from the past! 30 years ago I used to work at robots.ox.ac.uk alongside Andrew Zisserman.
  9. Really nice. Kudos! It took some fiddling to get it to work under Linux but I got there in the end. The stock WINE implementation doesn't cut it because the dotNET framework is not included. To assist others, I followed the instructions at https://www.dedoimedo.com/computers/wine-dotnet-mono.html TL;DR install winetricks and mono-complete, then run "winetricks dotnet45". Wait for ages, accept licensing details and ignore error messages.
  10. There is another difference between our approaches. I don't drive anywhere. Neither, I suspect, would a beginner drive for hundreds of miles.
  11. AARGH! The above got posted somehow before it was complete and I can't find an edit button. What I meant to post was: ... cart around and set-up. IMO, we are both right. Do what works for you and I'll do what works for me.
  12. I use a dim red flashlight. Table: accepted. If you're in an observatory we can assume you have one. If not, a small fold-up table is lightweight and cart around a Your second statement is the real difference between your technique and mine. When observing visually I like to look rather glance at something. "Hundreds a night" --- let's be very conservative and assume only 200 in an 8-hour night which is 2.4 minutes per object, including overheads. In practice I very rarely observe anywhere near 8 hours in a single session.
  13. Yes and no, IMO. Many paper star charts indicate non-stellar DSOs to a much fainter limiting magnitude than the stars depicted. An extreme case might be the interstellarum Deep Sky Atlas. Although its stellar limiting magnitude of 9.5 is about that of a decent pair of binoculars, it shows the positions of objects as faint as the Palomar and Terzan globular clusters and even Balbinot 1. The latter is difficult to image in a 40cm reflector, as its brightest stars are only 18th magnitude. Personally I use often use paper charts: Norton's for wide field preliminary finding and Uranometr
  14. https://web.archive.org/web/20140826115516/http://www.lvastronomy.com/observing-challenge/144-february-theta-1-orionis-the-trapezium is what I used to identify the components.
  15. I am fairly sure you have picked up G as well and there may be a hint of an unresolved H1+H2. Conversion to greyscale followed by sky background removal and aggressive contrast stretching may make the situation clearer, though at the cost of aesthetic appeal.
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