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PhotoGav

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PhotoGav last won the day on February 16

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About PhotoGav

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    Astroholic

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  1. Argh...! I am in conversation with Support now and am just waiting for them to say ‘please can you send it in’. I just removed the fan screws, eased out the fans and had a look. There was a bit of general detritus in there, but not too bad. However, I did see that one of the fans has the red wire disconnected. That can’t be good. It seemed a bit corroded at the joint. Hopefully it’s quick, easy and cheap to fix. Yeah right, and we’ll have clear skies for two months straight too, starting tonight...
  2. Oh dear, I hope they sort yours out. How long have they had it for? I hate the idea of being without a camera for any length of time!
  3. Thanks Dave, interesting idea... I hope it’s that simple... I’m off to investigate...
  4. I noticed yesterday that the two fans on the back of my QSI 683 are not working. The cooling seems to work normally, but no fans. I have contacted QSI / Atik and await their response, but wonder if anyone on here has had a similar problem? I have tried turning everything off and on again and have played with turning the fan on and off through the driver, but all with no joy. Any other thoughts about how to get the darn thing working properly again? Thanks, Gav.
  5. Good stuff. Thank you for pushing me to the reprocess. That’s what I love about this forum, there is such a wealth of experience and great suggestions. Good luck with the Starnet experiments - definitely worth pursuing.
  6. Thanks Geof. I ended up using the Screen Mask Invert method that I know from I know not where, but it’s certainly not my invention! I gave Olly’s Equalise Method a go, but I need advice from the Master himself to understand how to make it work successfully.
  7. Thank you Olly. I know what you mean about the NR / Noise equation! I particularly like your comment that this rendition '...feels very true to the object...' - that is completely my approach to astrophotography, so I am happy that perhaps I'm somewhere close to my goal! However, inspired by Göran, I couldn't resist giving it a tweak. I'm not one for going mad, so I have just turned up the outer shell by a stop or so. I think I prefer it, but I'm now getting dangerously close to not being able to objectively assess the screen anymore - I've stared at this one too much now...
  8. Thank you Göran, I will have a go at teasing out more from the outer shell with the Equalize method. In fact, you make me think of the Screen Mask Invert technique that I forgot to try - I was so engrossed in the Starnet thing! As for how to get the standalone Starnet version to work on the Mac, here's the method I used: 1. Download the latest version of Starnet for Mac OS from here: https://sourceforge.net/projects/starnet/files/v1.1/StarNet_MacOS.zip/download 2. Unzip the folder and place it on your Desktop 3. Save the image that you want to make starless as a 16 bit mono or RGB .tif file 4. Place the file in the Starnet folder on your desktop 5. Open Terminal and navigate to the Starnet folder (you can do this by pasting - cd ~/Desktop/StarNet_MacOS - into Terminal and hitting Enter) 6. Open in Text Editor either the file 'run_mono_starnet.sh' or 'run_rgb_starnet.sh' depending on whether you are working with a mono or RGB file and edit the filenames in there to be the filename of the file that you want to make starless 7. Drag either 'run_mono_starnet.sh' or 'run_rgb_starnet.sh' onto the Terminal window and you should see the path of the the file appear 8. Make sure that Terminal is the uppermost window and hit enter - Program will run (this can take a while!) 9. When it's finished doing its magic, go to the Starnet folder, open up the _s version of your file and be amazed at the results! Hope that's useful
  9. Thanks Richard. I ended up with the Nebula on the layer above the stars so used Screen mode. If the layers were the other way round I guess Lighten mode would bring the stars in. I wonder which works better?
  10. Thanks Dave. The technique allows a good stretch of the Nebula without killing the stars. It’s basically what the Finnish guy, JP Metsavainio (aka AstroAnarchy), was doing years ago, I just could never suss out how he was doing it! Starnet seems to be an easy solution. It’s not perfect by any means and I needed to tidy up some of the brighter star removal areas to avoid weird artefacts. Definitely worth a play though.
  11. This data set has been sitting on my laptop since capture back in July last year, waiting patiently for me to pluck up the courage and find the time to try and turn it into a presentable image. Well, that has finally happened over the last few days and here is my latest rendition of that popular planetary nebula astrophotography target some 1,400 light years away in Vulpecula. I know, it's a bit odd posting a summer target in the depths of winter, but at least it helps to remind us that the sky can be clear sometimes! Technical Details Celestron EdgeHD 8" on a Mesu 200 and QSI 683-WSG8 with 31mm Astrodon Filters (5nm narrowband) RGB = 18 x 300s each Ha = 26 x 1800s OIII = 28 x 1800s Total Integration = 31 hours 30 minutes I changed my usual processing workflow with this image and gave Starnet++ a try. All the calibration and stacking was done in Astro Pixel Processor, along with the RGB combination. I saved out the RGB, Ha and OIII stacks, each with the Digital Development from APP. (I do love APP ever more, especially having had a long, detailed and generally wonderful chat with its creator, Mabula Haverkamp, at AstroFest this year - what a totally lovely chap!). I took everything into PhotoShop and did a few bits and bobs. I struggled to successfully combine the narrowband and broadband data - it just wouldn't fit together nicely. So, a brainwave struck me and I wondered whether that Starnet thing I had read about might just be the answer. Once I had sussed out how the heck to get it to work (thanks to a post from Andy on IceInSpace for the very useful notes!) I let it strip away the stars from the Ha and OIII images. I then combined the two starless images as a bi-colour Ha/OIII/OIII in PhotoShop and tried adding that to the RGB starfield using Screen blending mode. Wow, that was far more the kind of thing that I was looking for! I then did the few polishing techniques to arrive at this final version. I am a bit disappointed that there isn't more of the outer halo of material visible in the image, but I've pushed the data as far as I am happy to go and that is as much as it is willing to yield to me. It has a mysterious outer glow and that is OK, but all in all, an insufficiently dark sky coupled with a slow (f10) telescope has left that glowing material hidden in space. Nevermind, there's always next time... if we ever get to see the night sky again that is - this incessant cloud is now really getting tedious. It's scuppering my current attempt at a four pane mosaic of the Spaghetti Nebula! (If I ever get enought data for that one I will definitely be trying this starless narrowband processing approach with it). Clear skies to you all and I hope you like this image.
  12. Good, that’s where I’ve got too. As far as I can see the expected output from a just-pre-supernova star would be constant and would brighten as the collapse starts to occur and core temperature and pressure rise significantly. Dimming is all to do with expansion, increasing surface area, decreasing surface brightness and increasing material in the star’s atmosphere. Giant stars can shed their outer envelopes in the latter stages of evolution, but would this cause significant dimming? I can’t see why. Yup, it’s a good story for the media. However, Betelgeuse is about to explode as a supernova. It’s just that ‘about’ in astronomical terms can take many many thousands of years!!
  13. This might be a silly question, but I’ve been trying to work it out in my head and haven’t so far... why would a star dim before it exploded as a supernova anyway?!
  14. I was out observing last night and it is definitely on a magnitude par with Bellatrix (+1.6) rather than Rigel (+0.3) in the visible part of the spectrum. Still waiting for it to brighten (or explode ). My all sky cam (which is mono and responsive to longer wavelengths) shows it more on a brightness par with Procyon and Rigel than Bellatrix... Obscuration!
  15. In my experience, a younger audience is less likely to enjoy sitting patiently just listening to your expert delivery, as an adult audience normally would. That will work for about 10 to 15 minutes and then the 'less focussed' amongst them will start to fidget and wander 'off topic'. I would suggest adding plenty of interactivity to your session - that can be in the form of things to hand round, but absolutely key to keeping their attention is to ask them questions. Don't just put a picture of the Moon up (for example) and tell them it's the Moon and how you made the image, ask them what it is (yes, an easy one to start!) and what they know about it already, guess some answers, etc. Give them plenty of opportunities to talk, that will keep them listening. Gauge their ability to answer as you go along and pose questions of a suitable level. You will undoubtedly find that there will be one or two amongst them who love anything space related and will want to answer / comment on everything. Spread it out and make sure you pick others with their hands up to give answers too! Good luck, I'm sure you will enjoy the experience and will find it very rewarding.
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