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About David_L

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  1. Bubble Nebula 25 Hours exposure in Sho and Hoo

    Yep - best example of what I always considered a really boring object to image - your work is absolutely exceptional and gives me a new enthusiasm to try to image this object again. David
  2. ASI1600mm cool

    I use 5 minute exposures in narrow band at 139 gain and they haven't failed me yet :-)
  3. ASI1600mm cool

    This thread is a gold mine for the newcomer to this developing equipment so I'm sure people will continue to come to it and any other threads that are created for this camera. Indeed, it may be that the Pro information is lost to the newcomer if it isn't in this thread - so there's potential for missing the opportunity to share your experience. .....and how I wish I could afford the Pro as well LOL! David
  4. NGC7635 Bubble Nebula revisited in HaRGB

    I've found this one of the most unrewarding objects to image but you've made a good attempt at it. David
  5. Show us your set up in action at night.

    Thanks for sharing that. Looks like you had a fantastic opportunity that the rest of us can only dream of. I'm sure you had to work hard to get that opportunity though so well done! Was the altitude a problem? I've always imagined a trip like this would be ruined by the altitude sickness the astronomers in Chile speak about. Does this place do any outreach, is it possible to visit? Edit: I just followed the link in your post :-) Thanks again David
  6. Edge on spiral galaxy C23/NGC891

    Interesting image even with the reflection - I love these edge on galaxies - especially in mono as they look like the images captured in the early days of astrophotography in the 50s As for working with the stars if you're using PixInsight I'd give MorphologicalTranformation a shot - works wonders post stretching and very easy to use. I was looking at the spec for your QHY and it looks almost identical to the ASI1600MM (price too) with the exception of the built in dew heater which sounds good - have you had any issues with dewing? I have a 2nd generation ASI1600MM with the desiccant tablets in the housing. I had to replace them after I started to get dew build up after a year of use. Also I could buy a dew heater for the ASI but the QHY sounds like a good alternative to try even if its just for the sake of variety :-) David
  7. Bubble Nebula LRGB

    That first image is pretty cool - such short exposures I thought you were using an ASI1600MM :-) I've been lucky with focus on the ZWO LRGB filters as they appear to be pretty much parafocal Excellent results, I've only imaged this object once in a quite wide field - so your example is making me want to get a newtonian again :-) David
  8. M31 - ASI1600MM - LRGB - 5hrs

    I've had yet another attempt at this. I've added the DBE, and tutorials from Harry's AstroShed (invaluable PI resource!) What was really interesting is if you "blink" my most recent effort above, with the LRGB version here, you'll see I processed it, quite accidentally, almost exactly the same - but with DBE thrown in I've gotten rid of the gradient. I hadn't used DBE much as I could never get it to work right. My friend Nick encouraged me to revisit it and after watching Harry's AstroShed tutorial on the subject - I did it! :-) ....probably not perfectly but a good improvement I think. I'm happy enough with the LRGB version to park that now, but I didn't get the Ha / red channel combination right and it looks a bit murky :-) Thank you to all who offered guidance, including my bud Nick! David LRGB HaLRGB
  9. M31 with QHY367C stacked with APP!

    This excellent! I'm struggling with this object at the moment. I took 4.75 hours of data in HaLRGB with my ASI1600MM and wish I still had my QHY8 OSC that I won the March 2013 Sky at Night Hot Shot of the month with (LOL! ...my friends know why I mention that with such alarming regularity!) The new mono camera is fine - I just don't know how to process the data from it LOL Again, really well done! David
  10. M31 - ASI1600MM - LRGB - 5hrs

    Thanks - yep you're right and I think it was the SCNR mask I used in the final step - might have had the mask inverted. I've also noticed that, in trying to tame the "stick on patch" galaxy affect seen in the second to last attempt I probably under cooked the processing on the HaLum - I deliberately didn't push the brightness too much - looks like maybe not enough. Also, I didn't use LocalHistrogramEqualisation to bring out the detail on the spiral arms, again to avoid the artificial look these galaxies can get when its not done properly. Just looked at it in the cold light of day and it's amazing how you don't see these things when processing lol I've attempted a few fixes seen below but I think I'll process it again - for practice - then I'm going to create a GIF of all the variants (don't think I can post those here) to see the morph from awful to today LOL. Thanks again David
  11. M31 - ASI1600MM - LRGB - 5hrs

    I think I'm finally happy with this - I just reprocessed it correcting the errors I made earlier - it's amazing how it takes hours each year to remember the nuances of processing, but once I got some practice I was able to totally reprocess this from scratch quite quickly. I'm not sure if this just needs more data but at almost 5hrs its seems like it should have enough :-)
  12. M31 - ASI1600MM - LRGB - 5hrs

    Further to my reprocess above I just realised that I hadn't applied a mask for LocalHistrogramTransformation and it's completely trashed the background - little black dots everywhere - looks like i'll be reprocessing this one again David
  13. M31 - ASI1600MM - LRGB - 5hrs

    I forgot to use SNCR (PixInsight) in the image above Instead of applying it to the whole image (made it a weird shade) I applied a mask, set Protection Method to Additive Mask, the amount to .5 and unticked "Preserve Lightness" (if I didn't it wound up with a magenta haze across the core etc) I'm not used to experimenting with Pixinsight - that was fun ! LOL!
  14. M31 - ASI1600MM - LRGB - 5hrs

    I've integrated an hour of Ha data onto the Luminance sub - I've not done this before so not sure if I'm over cooking the stretch on the Ha / luminance sub I used PixelMath to combine the Ha / Lum channels in their linear state, then stretched them, and then used PixelMath again to combine with the rgb Does that sound right to PixInsight users? Thanks David M31 HaLRGB
  15. M31 - ASI1600MM - LRGB - 5hrs

    I got some more data on this and realised how badly I'd processed it above (saturation hammer lol) Notes below - I'm sure I still don't have this right! David Details Object name Andromeda Galaxy Object ID M31 Date(s) 11, 12 and 15 October 2017 Telescope Altair 115mm Camera ASI1600MM Luminance 89 x 1 min = 89 min Red 16 x 2 min = 32 min Green 24 x 2 min = 48 min Blue 28 x 2 min = 56 min Ha 0 Oiii 0 Sii 0 Total time 3.75 hrs Frames 0 Processing PixInsight / Bias, Flats, Darks / no noise reduction / no masked stretch (manual) Notes This is a reprocess of the image above I also made mistakes in the table regarding sub times – corrected here. Looking at my original process above its clear all I wanted to see was colour and so I hammered the saturation – something I don’t usually do – so for this version I avoided it and I think it looks a little better. I have an hour of Ha data on this but having never combined it with RGB I’ll have to learn about all that now. I think I really need to get more colour data on this too. Hopefully I will before M31 disappears into the West. I accidentally posted the wrong reprocessed image earlier - here's the one I meant to post