alacant Posted February 26, 2020 Share Posted February 26, 2020 Hi everyone Google tells us that this is an old cluster with orange stars. So when I want orange, I get blue. Can't win. Strange sort of all-over-the-place cluster in the middle of nowhere. kstars also gives another cluster in the same fov but I can't see it unless you count the bright-ish stars lower left. Thanks for looking and do post if you've had a go at the same. 700d on 208 f3.9 45min @ ISO 800 ** quite a sight watching scorpio et al rise early hours, carrying the planets with them:) 4 Link to comment Share on other sites More sharing options...
tooth_dr Posted February 26, 2020 Share Posted February 26, 2020 I think that looks good, job well done! 1 Link to comment Share on other sites More sharing options...
bottletopburly Posted February 26, 2020 Share Posted February 26, 2020 Are you using any filters Link to comment Share on other sites More sharing options...
alacant Posted February 26, 2020 Author Share Posted February 26, 2020 19 minutes ago, bottletopburly said: filters Hi. No. No filters. Link to comment Share on other sites More sharing options...
bottletopburly Posted February 26, 2020 Share Posted February 26, 2020 you could reference some of the stars that are aqua and look up what the kelvin colour should roughly be , maybe that is their colour. 1 Link to comment Share on other sites More sharing options...
Martin Meredith Posted February 26, 2020 Share Posted February 26, 2020 Nice shot. Definitely orange and blue! Here's a quick capture from a few nights back in the north of Spain. Martin 1 Link to comment Share on other sites More sharing options...
alacant Posted February 26, 2020 Author Share Posted February 26, 2020 36 minutes ago, Martin Meredith said: quick capture Phew, 6 minutes. Well done. Tremendous! I think we agree on colour. More or less. Thanks for posting. Most useful. 2 Link to comment Share on other sites More sharing options...
ollypenrice Posted February 26, 2020 Share Posted February 26, 2020 As well as the numerical distribution of hotter and cooler stars you have to remember their relative magnitudes. Here's the H-R diagram for M67. (More accurately the colour-magnitude diagram.) The main sequence cutoff is at around B-V 0.58 which is significantly less red than the sun (0.65) There is also a concentration of stars of this colour at around Mag 13, which is mid-range for this cluster. Yes, there are also a great many much redder stars to the lower right but note the decline in their magnitudes. At the high end of the magnitudes there are both blue and red stars. I would say that this was a very good fit with your image. Stars bright enough to show strong colour are red or blue. The bulk of the stars are fairly neutral in colour, as the diagram would lead us to expect. It would be interesting to get an idea of your limiting magnitude in this image and also to see if longer exposures increased the number of faint red stars. I think it probably would. Olly Link to comment Share on other sites More sharing options...
alacant Posted February 26, 2020 Author Share Posted February 26, 2020 1 hour ago, ollypenrice said: longer exposures Thanks. Interesting. This is one minute frames so I'm almost certain there'd be more stars going to two, three... TBH, I ran this through the bd and it turned out almost monochrome. So I went for an "artist's impression"; colour all the way up to eleven. Link to comment Share on other sites More sharing options...
ollypenrice Posted February 26, 2020 Share Posted February 26, 2020 58 minutes ago, alacant said: Thanks. Interesting. This is one minute frames so I'm almost certain there'd be more stars going to two, three... TBH, I ran this through the bd and it turned out almost monochrome. So I went for an "artist's impression"; colour all the way up to eleven. What's 'bd?' If it's a saturation booster it can be set to preserve colour balance or will be set to do so by default. Olly Link to comment Share on other sites More sharing options...
almcl Posted February 26, 2020 Share Posted February 26, 2020 Interesting comparison (I hope!) Here's one I shot 3 years ago (700d, SW200p, no filters, ISO 1600 and six 3 minute exposures). I have not bothered elevating the background levels(!) but the colours seem pretty consistent with yours, at least on my monitor. The lowest magnitude star I've identified is 16 although there may be a 17 lurking nearby... 1 Link to comment Share on other sites More sharing options...
alacant Posted February 26, 2020 Author Share Posted February 26, 2020 18 minutes ago, ollypenrice said: 'bd?' Oh dear... Spanglish: base de datos = database Sorry Link to comment Share on other sites More sharing options...
alacant Posted February 26, 2020 Author Share Posted February 26, 2020 13 minutes ago, almcl said: colours seem pretty consistent Excellent comparison. Yes, I think so too. We're in close agreement. Thanks for posting. Link to comment Share on other sites More sharing options...
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