m67

[alacant]

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:)

[tooth_dr]

I think that looks good, job well done!

[bottletopburly]

Are you using any filters 

[alacant]

19 minutes ago, bottletopburly said:

filters 

Hi. No. No filters.

[bottletopburly]

 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.

[Martin Meredith]

Nice shot. Definitely orange and blue! Here's a quick capture from a few nights back in the north of Spain. 

Martin

 

[alacant]

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.

[ollypenrice]

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

 

[alacant]

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.

[ollypenrice]

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

[almcl]

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...

[alacant]

18 minutes ago, ollypenrice said:

'bd?'

Oh dear...

Spanglish: base de datos = database

Sorry

[alacant]

13 minutes ago, almcl said:

colours seem pretty consistent

Excellent comparison. Yes, I think so too. We're in close agreement.

Thanks for posting.