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drjolo last won the day on July 23 2018

drjolo had the most liked content!

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About drjolo

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    Star Forming

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    Nieborowice, Poland
  1. Thanks It was Ha 55x5, Oiii 25x5, RGB 18:12:12x1 minutes for Crab, and Ha 115 minutes in 5 and 2 minute subs for Eagle.
  2. Definitely you need to power stick with regulated voltage. 12V battery with DC converter to 5V is good idea, for powerbank - I do not know if you can draw constantly 2-2.5A, maybe yes. If yes, then it would be more convenient, because you do not need to use DC converter. But power bank contains usually 3.7V battery and boost converter to 5V, so the max current is limited by output converter.
  3. In some extent it depends on the USB ports the stick is equipped with. I have measured power consumption of several sticks and mini PC, and the rated power is usually a sum of stick own power requirements plus USB ports. USB2.0 port should be able to provide 0.5A, and USB3.0 1A (but of course not all USB components will drain that much power from USB port). So now is all up to what you plan to connect to your USB ports. If all USB ports will be loaded with maximum allowed power, then you need as much current as it is stated. Otherwise stick itself requires about 1.5A (at 5V) maximum when CPU is 100% load.
  4. ASI120 mono is not as sensitive as recent CMOS cameras, maybe even less sensitive than 290 color, but with 80/400 scope it will be perfectly ok. You should have no problem with finding guide star. Since this tube have significant chromatic aberrations some filter for mono camera would be advised. IR cur at least, but for my guide setup (80/400 + ASI290 mono) I use Fringe Killer that significantly reduces guide star size.
  5. Maybe you could use the same continuous spectrum source (like halogen lamp) and use second camera with well known QE to do measurement. Take spectra with reference sensor, then with 1600 and you should be able to get proper data. PS - ups, it was already said
  6. I have only compared sensitivity of my QHY163M camera to Atik383 sensor using HaLRGB filters on the same starfield. Here is the result table: It is little bit less sensitive in R (than KAF8300, but then for G and B it becomes more sensitive. No more data
  7. I have shot few color images of the Moon, but I used only RGB filters (the same I use for deep sky imaging - Baader CCD filters). I used G channel for luminance:
  8. You may check what will be the star size when you focus precisely. Your scope is ED, so it is better corrected for chromatic aberrations than achromatic dublet, however you use mono camera without any filter. And that camera is also sensitive in near infrared part of spectrum, so the star may be bloated, because IR focus is in different place than visual focus. It would be good to use at least IR cut filter before camera, or IR/UV cut filter.
  9. I also think flat top may be due to saturating - you may decrease gain or select manually another star. 4.5px HFD means about 10-11" star size for your camera and scope, in my opinion that is little bit too much. Assuming most optimistic theories star centre position will be calculated with 1" accuracy. I would not try to defocus star image, and if it possible to fight for smaller stars. With 50mm achromatic scope, ASI290MM and Fringe Killer filter I was able to get guide stars at 6-7" FWHM diameter.
  10. It is always a hard decision - it somehow depends on your sky quality. If your imaging location provides visible Milky Way and NELM at level 5-5.5mag or better, then OSC camera will do the trick. But if LP is worse, then you probably achieve better results using mono camera with LRGB and narrowband filters. This is my case, I have NELM limited to 5mag during good nights, sometimes it reaches 5.5mag. I have tried with OSC cameras and DSLR few times already, and always got back to mono. However I was pretty happy with having for some time both QHY163M and QHY163C cameras. I used mono for luminance, OSC for colour and it worked pretty well (like here for example https://astrojolo.com/astrophotography/galaxies/m106-after-four-years/ ). I also wrote a post about it at my blog https://astrojolo.com/gears/colour-camera-versus-mono-price-of-comfort/ - at the end you may see sensitivity comparison between OSC and mono cameras.
  11. You may not need to, but for CMOS cameras it is good to calibrate flats with dark flats, then both must be done for the same temperature, gain and offset settings, then it is better to have it cooled at some regulated temperature.
  12. Congratulations on your captures! Here is my five picks: Heart and Soul and comet (with Samyang 135 and QHY163M): Four next were made with Meade ACF 10" and QHY163M.
  13. Here is my shed decorated with snow
  14. How dark sky do you have? Faint galaxy arms can be a challenge under light polluted skies.
  15. Thanks! I tried deconvolution in Pixinsight, but it did not made significant improvement till the moment the image start to become noisy. Overall SNR is probably too low and I would need more subframes (like twice as much) to achieve better result.
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