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drjolo

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Everything posted by drjolo

  1. There is a free software eXcalibrator http://bf-astro.com/eXcalibrator/excalibrator.htm that can assist you in calibration of the image. It analyses stars color in your image, compares it to star color indexes in databases and then calculates the color correction factors.
  2. All my regulated PSUs show rated voltage when measured with multimeter with or without load. Maybe this PSU is rated for 13.8V, but it is actually not regulated.
  3. You can use nova.astrometry.net to do some blind plate solving and check the target, scale and FOV of your setup. I uploaded your image and here are the results http://nova.astrometry.net/user_images/2836462#annotated Center (RA, Dec): (358.887, 56.557) Center (RA, hms): 23h 55m 32.816s Center (Dec, dms): +56° 33' 24.627" Size: 4.35 x 2.67 deg Radius: 2.551 deg Pixel scale: 9.45 arcsec/pixel Orientation: Up is 343 degrees E of N
  4. And I combined image from the first post with some RGB data. 21-22.04.2019, Meade ACF 10" f/10, AP CCDT67, EQ6, QHY163M, L 400x60 s, RGB 80:50:60 x 30 s, gain=100, suburban sky, seeing and transparency good. PS - I do not remember why I made L frames 60s and RGB frames 30s. I probably had a reason, but it was late, and now I do not why
  5. My whole setup (with guider, cameras, etc) is about 15kg. I can balance it with EQ6 standard length rod, two 5kg counterweights at the rod end, and one small 1kg put somewhere in the middle of the rod.
  6. Thanks a lot! SCT are short but pretty heavy, I think 10" ACF is at the limit for EQ6 class mounts - at least for imaging. Also ACF and EdgeHD constructions are little bit heavier than "regular" SCT. I used to have Celestron 11" on EQ6 and it also performed well, but it weighs more less the same as ACF 10" f/10.
  7. I used to have this corrector some time ago with GSO 150/750 newtonian and Atik 383 as well - I think this is the one https://astrojolo.com/gears/pin-point-stars-on-sale/ - it also reduces the focal length a little. It was never easy to have it all collimated and aligned, but should be doable. These are example images I made with that setup (though resolution is small ) https://astrojolo.com/wp-content/uploads/2016/10/2013-09-06-NGC6914.jpg https://astrojolo.com/wp-content/uploads/2016/10/2013-09-27-NGC6888-Ha.jpg
  8. I already imaged M51 four or five times. When spring comes and CdC shows me M51 high in the sky, I just cannot resist This time I wanted to focus on galaxy detail and features, so I needed to wait for good seeing. In the middle of April a few nights happened with decent seeing and also quite good transparency. Unfortunately Moon was also present in the sky for most of the time, so I did not reach as deep as I wanted, and SNR is also not perfect. But if you take a closer look into the left part of image, below these three bright stars triangle you may spot some faint patches of light - I checked them in SDSS and these are galaxies located 3-5 billion light years away. There are a few more also to the right of M51. And AT2019abn (Intermediate Luminosity Red Transient) has also been recorded Meade ACF 10", CCDT67, QHY163M, EQ6, LRGB 400:40:30:30x60 seconds (gain 100), seeing good, transparency good, Moon present. And luminance only:
  9. Nice capture, and many faint fuzzies in the background. Have you used any coma corrector?
  10. Thanks Yes, I use autofocus and it works well. However I have separate crayford focuser attached, so I do not use OTA focusing knob at all. Also temperature compensation works well in this combination.
  11. Uh, this is amazing image. And clusters are well defined there - I have not seen this image before.
  12. In ZWO drivers it looks much more consistent then. In QHY guys are playing with it from one driver version to another. I used to have unity gain at 130 and I had offset set to 50 then to have average bias frame value at 500ADU, and minimum value at 50ADU (more less). With current version I have unity gain again at 13, and even with offset set to 0 I have mean bias frame ADU over 4000 But changing gain in this driver version does not affect much mean bias frame value, so it would confirm the assumption, that offset here is added after gain stage.
  13. Thats quite interesting problem I think. In CCD cameras there is also offset (bias), sometimes also available to set (like in QHY9), but as far as I know it is very low level parameter. It is the charge added to each pixel before exposure starts to avoid negative values read out from AD conversion. But I do not know how it works in CMOS cameras. It may be as in CCD, or it may be added in the driver level, or after conversion. I am also not sure if offset parameter is expressed in electrons. From my observations it is not the case for my QHY163 camera.
  14. Yup, it all depends how dark frame made at these 0/10 settings looks like - ie how many pixels are clipped. If there are 100 or 1000 pixels clipped, then no big deal.
  15. I think you can still calibrate your frames properly. You need darks made with the same settings as your lights (time, temperature, gain, offset, usb traffic). Unless this single dark has many pixels with value 0, you can properly dark calibrate your light frames. As for flats, you can do flat frames with completely different settings. Just use the same settings for flats and dark flats, create master flat and use it to calibrate lights.
  16. I always like to look for distant worlds in the sky, and when I stacked 400 minutes of luminance captured for my new project, I found some faint flocks at the frame edges. It turned out to be distant galaxy clusters located 2600 and 3000 millions light years away: http://simbad.u-strasbg.fr/simbad/sim-id?Ident=%408444694&Name=XMMXCS J0953.7%2B6947 and http://simbad.u-strasbg.fr/simbad/sim-id?Ident=%4010548357&Name=SDSS J095324.38%2B693648.7 . M82 is about 12 million light years away for comparison. There are not much information available about these clusters, just two more among plethora of others. Faintest recorded galaxies in this image are about 22mag. 21-22.04.2019, Meade ACF 10" f/10, AP CCDT67, EQ6, QHY163M, L 400x60 s, gain=100, suburban sky, seeing and transparency good.
  17. Thanks Olly, I am not devoted to this blue, spiral galaxies (especially active ones) have some youngsters that are blue and hot, but actually at my image it may be exaggerated. I looked and found this image from HST, and it actually looks less cyan:
  18. Thanks! I added L channel only to the first post as well. I need to wait for a really good transparency to record some fainter areas under my suburban sky. It is usually about dozen nights over year when sky becomes that clear and NELM is at 5-5.5mag level.
  19. I imaged this nice barred spiral galaxy already 6 years ago with budget 6" newtonian, and it was one of my spring targets for 2019. I managed to gather luminance at the beginning of April, but then I needed to wait three more weeks to collect RGB channels, and unfortunately Moon was already present then All photons collected in my suburban astro shed (NELM about 5-5.5mag at zenith). Meade ACF 10", CCDT67, QHY163M, EQ6, LRGB 290:40:30:30x60 seconds (gain 100), seeing moderate, transparency good. LRGB version and luminance channel only.
  20. 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.
  21. 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.
  22. 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.
  23. 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.
  24. 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
  25. 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
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