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lensman57

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Everything posted by lensman57

  1. Electronic filter wheel is useful if you have robotic remote set up with an auto focuser otherwise a manual filter wheel will be more than adequate. The trick is to try and avoid the usual crop of the cheap Chinese made ones with little mechanical integrity, filters not indexing in the correct position and being loose and light leaks are the usual culprits. I have one from Modern Astronomy which is mostly metal and is not bad but I still had to do a bit mods inside and outside to stop the light leaks. You will also find that the Parfocal filters that you paid an arm and a leg for are not exactly parfocal as this depends to a great deal on the level of correction of your scope so refocusing in between filter changes is rather mandatory therefore a manual filter wheel is not such a bad idea. A.G
  2. Hi, Can't help you much with your query but the mention of Tech Pan brought back fond memories for me. I think that I still have a few sachets of Technidol LC developer powder somewhere in the house. Hope you get a satisfactory answer soon. Regards, A.G
  3. This is a lovely wide field of the Iris and the surrounding dust. Lovely tight stars with great colour. Regards, A.G
  4. Hi, EQ5 can handle a 200p but the combination of the scope, camera etc will be right on the edge of EQ5s capacity. If you can house the scope and the mount so that they are sheltered from the gusts of wind and the likes then both observing and imaging are a possibility. I used to have an EQ5 Pro and I even managed to image once or twice using a twin rig set up but balancing the whole thing was nightmare. As for the trade off of the aperture I can't be specific as I am no observer but as they say in observing the size of the aperture is the king. If I have a reservation with regards to your choice it would be with the 200p and not EQ5 as it is not exactly the easiest scope for imaging due to a multitude of reasons the long FL and the bulk are only two that springs to my mind and before anyone accuses me of being biased against the 200p I do own a Quattro 8s and a 150 PDS and I find that my HEQ5 Pro really struggles with the Quattro 8s and this is less bulky and shorter scope than the 200p. Regards, A.G
  5. You need a 3 star align to build an accurate picture of the sky within triangle of the 3 alignment star. Also choose the alignment stars so that the last star is the nearest to your target. If this is not possible then after a 3 star align slew to a star nearest to the target and do a PAE, Pointing Alignment Error or something like that. the mount will then apply the correction to a radius of about 10 degrees from the star then slew to the target and it will be bang in the middle of the FOV. Budget mounts with their less than perfect mechanics are not capable of centring targets without a bit of help from the operator. A.G
  6. HI, This is the result of my endeavours from last night. 15 X 900s subs stacked in PI and processed in PI and PS. Ascension 80mm Apo @ F4.8, Atik 428 EXC, IDAS D1 and HEQ5. The subs were taken with extreme Dither in Neb 3 and then Drizzled in PI. Hope you like it and thanks for looking. Regards, A.G
  7. Cheap is good if you could get it to work properly but it can also put you off imaging for good. A.G
  8. HI and welcome, You need a planetary camera/ " webcam". The faster and more sensitive the better. With your budget two names come to mind. ZWO ASI 120 either MM or MC and the QHYLII either Mono or Colour this is the same for the ASI 120 MM is the mono one and MC is the colour camera. The compatibility of the drivers with Mac OS is a problem though as most imagers are on the Windows OS. There is also the Celestron NexImage camera that is well within your budget but not very popular judging by the amount of images that I have seen taken by it, there are very few. So you have some decisions to make, which camera first, then Mono or Colour and then you need to think of the operating system compatibility. Most of the image capture and processing are free but again these are by far for the Windows OS. A.G PS: You will soon find that your choice of target is realistically limited to the Sun, Moon, Jupiter , Saturn and Mars depending on the time of the year and their relative positions to earth.
  9. Good first attempt. You have to be congratulated for finding 1/2 hour of clear sky up here. Keep at it. A.G
  10. Thank you all, Here is a version with HLVG applied, the original doesn't look green on my monitor but then again the display leaves a lot to be desired. Regards, A.G
  11. Hi, Taken last night after a few weeks of inactivity due to the weather. Ascesion 80mm Apo @F4.8, Atik 428 EXC with IDAS D1 and HEQ5 pro. 14 X 600s subs stacked and processed in PI. Thanks for looking, A.G
  12. Atik 420 is not the best choice for a CCD camera. The sensor is very quiet and clean but the sensitivity leaves a lot to be desired compared to the latest offerings. You can use 1.25" filters up to and including Atik 460. A.G
  13. Sensor size has nothing to do with the size of the M104. it remains the same size regardless of what equipment the human being uses to observe or image it. If you use the same scope or rather more accurately the same FL to image it with different size sensors then the size of the sensor is irrelevant but what changes is the apparent FOV. The larger the sensor the more of the target will appear on the chip. larger sensor of the DSLR can not make the galaxy larger or smaller but your FL will alter your FOV. A.G
  14. Unless your sky is pristine and truly dark there is no point of collecting Lum without the use of an LP filter. The amount of noise also indicates that the data is really short. Use an LP filter, increase the sub length to 900s and collect a minimum of 16~20 with dithering and use as Olly has suggested, Sigma Clipping to get rid of a lot of the nasties. A.G
  15. Your subs are not Flat fielded. You can easily tell this by the appearance of the image which shows severe vignetting. what ever DSS has done appears to be concentrated around the central ring. A.G
  16. Good Feeling, isn't it. Well done very nice image. A.G
  17. Your best bet is to download Ron Wodaski's CCD calculator plus the catalogue of the images of the popular DSOs. Load the particular's of your scope and camera and then choose a target and it will show you how much of the target will fit in the FOV. It is very accurate and easy to use. Your sensor is on the small size and with the FL of your scope you will find that a lot of the DSOs will just not fit on your sensor. A.G
  18. Hi Pete, I am so glad that you cleared the " confusion " of the OP. With regret I do not believe that a Delta T of 10 C is going to do your Dark subtraction any favours. I would strongly advise every one imaging with a DSLR to read the article in the following link. As for one our friends claiming that uncooled DSLR has less noise than an uncooled CCD I am afraid that this is not true yet again as simply the two can not be compared. The output of an Astronomical imaging CCD is linear even those with Anti Blooming Gates, at least extremely close to linear, which simply encompasses all the cameras that are manufactured for hobby purposes and do not have a scientific grade sensor. As far back as 2012 Craig Stark ( author of PHD guiding and nebulosity ) in an article written for CN forums, discovered that at least Canon were applying on chip noise manipulation to long exposure data before these were written to file. This simply means that the data extracted from a CR2 file is not really " RAW ". I strongly believe that at least Nikon and most probably others are following suit. The point that I am trying to make is that these cameras are not really manufactured for AP but can be used quite successfully if their limitations are kept in check but there is absolutely no point in people constantly trying to compare them to cooled CCDs and trying to challenge them. These are completely different animals to each other and can not be compared, the same goes for Mono CCD V OSC CCDs IMHO. Regards, A.G http://www.mirametrics.com/tech_note_tempvar.htm http://www.stark-labs.com/craig/resources/Articles-&-Reviews/CanonLinearity.pdf
  19. The blue NGC 7023 Nebula itself is relatively bright and easy but to record the dust lanes you really do need long exposure and very dark skies. A.G
  20. " DARKS About 150 very bright pixels, these, I guess, are the 'hot' ones. Rather more 'warm' pixels, but the bayer pattern remains distinct, indeed the histogram looks almost identical to the bias one, which suggests that the sensor isn't a bad one. No sign of 'amplifier glow' no matter how hard I push the histogram." You seem to be fixated on the Darks. These are the least important of the calibration frames and I say again that with any imaging device without set point cooling Darks are irrelevant. Darks are highly temperature dependant and your camera as fine as it maybe has no set point cooling so the darks taken and applied at any stage unless are a match in temperature to the Lights, will cause all sorts of problems. If hot pixels are your problem the best way of dealing with them is to use High Dithering during capture and applying Cosmetic Correction and Sigma Clipping during the stacking stage this will get rid of a lot of other nasties that your stretching may not show. DSS is capable of doing this but needs a minimum of 16 subs for it to work properly and you also need to be careful about setting the Threshold level for cosmetic correction so it wouldn't over correct. As for calibration procedure and unless the mathematics have somehow changed the procedure starts with Bias then Master Bias and then the Flats are Master Bias subtracted and then it goes on. I suggest that if you have not done so already do some reading about the Stacking. Regards, A.G
  21. Looks excellent. I also am a bit surprised that with such a fast F ratio such long integration time was required but the image looks excellent and the level of detail is very high. Regards, A.G
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