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lensman57

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Everything posted by lensman57

  1. The majority of the imagers using DSLR will have all those settings disabled. The so called " RAW " data is not really RAW as a lot of manipulation of data is carried out inside the camera using the ever more powerful processors but you do not want to make matters worst by applying daytime photography NR algorithms to AP data. The only real raw comes from cooled CCDs. A.G
  2. Hi, Had a chance earlier on to take 11X900s subs of M27 in Oiii before clouding over and anyway it was getting very light so I just used 9 subs and discarded the other two. It was quite hazy as well and not as clear as last night. The Oiii was processed in PI but I did the combine with the OSC data of a last night in PS and it took a long time, well beyond my patience. Now I have to see if I could get a night to add the Ha. OSC data: 7 X 900s subs, Atik 428EXC, IDAS D1 and SW 150PDS with the 0.9X CC. Oiii Data : 9 x 900s subs, Atik 314L+, Baader 8.5 nm Oiii, SW 150PDs with 0.9 X CC. Hope you like it and thanks for looking. Regards, A.G
  3. Very nice capture. I would give much longer exposure if I were you. % minutes subs will make a huge difference. Here is the FOV with an 8" SCT with 0.63 FF/FR. A.G
  4. I am surprised to hear you say that the AVX struggles with 200 PDS. Anyhow as you are on a budget perhaps consider the 130 PDS . It is a decent imaging scope if not so hot for planetary. A.G
  5. I am not sure if his site can get any darker in practical terms. SQM 21~22 is pretty dark already. He is also a master of processing faint stuff. The truth is that given a site as dark as his and a 6nm Oiii on top of a cooled CCD the OU4 can probably be imaged at around 8 hours of exposure with 30 minute subs. Still pretty good for a DSLR I'd say. A.G
  6. As well as the eBay Dell-XP that I use for capture I also have a Dell i5 with 8 gig of memory and Windows 7 Pro which I believe is 64 bit. It will soon take over from Dell XP and it has 4 USB sockets. I think that they are about £150.00 or thereabouts on eBay. Win 7-64 is properly stable and doesn't seem to have any issues with the drivers or the software. A.G
  7. I totally agree. Longer exposures are pre requisite for extraction of faint objects by selective stretching to raise above the noise level. With a star field shorter exposures are at times preferable. Many great DSO images that I seen have been processed by removing the star fields first to allow heavy stretching of the faint targets. I am no expert on any of this but I would have thought that the test would have been better carried out using mono sensors to remove the effect of the Bayer Matrix. As far as DSLRs are concerned all the so called raw data is molested internally to reduce noise. This is a very interesting comparison none the less. A.G
  8. Hi, This was collected earlier on tonight before it got clouded over. It is the start of a project which should hopefully result in an Ha, Oiii, RGB image. 7 X 900s, SW 150PDS with SW CC, Atik 428 OSC, IDAS D1, all on HEQ5. Processed in PI and PS. Thanks for looking, Regards, A.G
  9. This is a lovely image full of detail. Interestingly I was reading about the Nii filter on Astrodon Forum and the discussion was about the effect of the Nii with the same target, M27. Apparently most of the detail in the core and the surround comes from the Nii and not Ha. If a narrow enough Ha filter is used there is very little sharp detail evident but apparently since most Ha filters are relatively quite wide they also pick up the very close by Nii signal as well. Now I wonder how much Hb signal is there? Regards, A.G
  10. It will be a squid covered in black ink. But joking aside have a look at this, 45 hours exposure in Ha, Oiii and RGB @ F3.5, that is a years imaging time for me but the result is unbelievable and he has brought the squid out with a 6nm Oiii Astronomik clip filter.http://www.astronomersdoitinthedark.com/index.php?c=110&p=525, my only observation is that he has an extremely dark sky with SQM figures in the 21 and 22s. Regards, A.G
  11. Nice image but I am afraid that I have to quote Mark Twain who said " the reports of my death have been exaggerated " in relation to CCDs. A.G
  12. If you have used APT in the Av mode to take the flat then the chances are that it is correct, however the way the flat is displayed has nothing to do with it being correct or not, Flats have no colour BTW as it is the Luminance that is important for correction. To judge it without looking at the end Master Light you have to stretch the Master Flat and have a good look at it. There must be vignetting present with a DSLR size sensor even with a TAK FSQ and the usual dirt traces on the sensor, the dirt on the optical surfaces shows up as doughnuts as they are further away from the sensor. I have also read somewhere that with a DSLR it is better to expose at +1 stop over in Av Mode. The easiest way of doing this is to set the exposure compensation to +1. Take two sets of flats at 0Ev and +1Ev and see which one gets you better results in the final stack. A.G
  13. This is lovely. Like a lot of southern beauties this one is also out of our reach up here. A.G
  14. Excellent work. Your 460 is in another universe compared to your DSLR as far as sensitivity goes. Enjoy it. A.G
  15. This is shaping up to be an epic project. Framing and the colours are spot on. A.G
  16. Very good effort. You are lucky that you can see Sagitarius and Carina from where you are. It is just too low for us mortals up north. A.G
  17. Thank you Guy and Ajay. Much appreciated. Ajay, the Tarantula nebula in your set of images is stunning. Regards, A.G
  18. Thanks to all of you gentlemen for your kind words. I have now added 6 more subs of the same duration with the same set up from the night before. On their own they were a right off but together they make 14 X 900s which has brought down the noise a bit and allowed me to stretch just a little more aggressively without upping the noise too much. Hope that like it. Regards, A.G
  19. With a camera using the very quiet Sony ICX sensor the gains achieved in thermal noise below -10C over -20C is about marginal. You may get down to -15C during a cool summer evening but there is no point in pushing the camera if it is not required, set the temp to -10C and given that you use a very large number of Bias and Flats in calibration you don't even need darks. A.G
  20. Hi, Took advantage of a clear evening last night. It is nearly dark at 12.00am till about 2.00am now so 2 hours is all that I could give this, 900s subs stacked and processed in PI and PS. I also used my 150 PDS that has been a problem for me since day one, the focuser still needs to be sorted out and set square to the tube but I think that I am 80% there. Atik 428EXC with SW CC, IDAS D1 on HEQ5. Thanks for looking, A.G
  21. Forget the calculators, one minute sub is a total none sense. If you had asked me whether to go for LRGB imaging with significant LP I would have said not to go there but here we are. First of all you need a decent LP filter in front of all your filters, if you are using the ACF @ native F8 you need much longer subs than 5 minutes. For RGB a lot of 5 minute subs might be OK if you can build the detail with 15 minute or longer subs for L. The other way is to for get the L and give RGB as long as you can guide. Looking at the image guiding long subs might be an issue as you have misshaped stars at 5 minute exposure. A.G
  22. I too have this problem. I live less than 20 Meters away from a main road out of the city what we call a dual carriage way here in the UK. When heavy lorries usually carrying construction waste pass by and hit the drain grids or the pot holes I feel the house shakes. Mercifully they do not pass very often in the late evening while imaging is happening but they do pass at times and this has an effect on the guiding if the scope is set up on the tarmac. It is not so bad when I set up on the grass as it cushions the vibration to some extent. The other problem that I have noticed recently is the flashing blue lights of the police or emergency vehicles that seem to light up the night sky for a considerable period. A.G
  23. Toughbooks are meant to be used in harsh environments such as garages and so on. Mostly they are used for engine fault diagnostics and tune ups. It should be fine outside but if you have dewing problems you can make a cardboard box to house it with the screen side open( I usually fold the screen over as I don't want the bright screen lighting the sky up ) . Normally the heat of the screen and the processor is enough to keep the dew away but keyboards do get damp, however a Toughbook should be able to cope with this. My over riding concern would be to make sure that the power supply is protected from damp and best to use an RCD in the power train. A.G
  24. before spending any money ask around to make sure that your scope can achieve focus with a DSLR. If it has the 0.96" EP fitting chances are that it was never meant for imaging. A Nikon DSLR has 46.5mm of back focus that need to be taken into account when focusing. You may find that the scope can probably reach focus with a Planetary webcam and not a DSLR. A.G
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