Search found 6 matches

by iann
Sun Nov 18, 2012 8:21 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: NGC 6357s Cathedral to Massive Stars (2012 Nov 18)
Replies: 22
Views: 18270

Re: APOD: NGC 6357s Cathedral to Massive Stars (2012 Nov 18)

The blue star embedded in the cloud near the bottom of the picture (north) is Pismis 24-13. It is an O6.5 main sequence star, slightly cooler than the three brightest stars in the photo, but still around 40,000K. The brightest star is the barely resolved double (actually at least triple) Pismis 24-1...
by iann
Mon May 07, 2012 10:15 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: Supermoon Over Paris (2012 May 07)
Replies: 20
Views: 3402

Re: APOD: Supermoon Over Paris (2012 May 07)

Chris, although I agree with the sentiment you express, your calculations are not quite correct. I didn't show any calculations... You didn't have to, but if you'd given the right answers I would have been unable to tell whether your calculations were correct ... or wrong and you just got really lu...
by iann
Mon May 07, 2012 9:10 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: Supermoon Over Paris (2012 May 07)
Replies: 20
Views: 3402

Re: APOD: Supermoon Over Paris (2012 May 07)

Chris, although I agree with the sentiment you express, your calculations are not quite correct. The difference over a very long period between the largest apogee and the smallest perigee is about 14.1%. However it is untrue to say that the May moon diameter was 14% larger than other moons in 2012 s...
by iann
Mon Apr 09, 2012 11:35 am
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: Blue Straggler Stars in Globular M53... (2012 Apr 09)
Replies: 13
Views: 2919

Re: APOD: Blue Straggler Stars in Globular M53... (2012 Apr

As a newby here, are there any theories why these globular clusters haven't formed into galaxies (yet?). Or why all galaxies haven't formed into globular clusters ? Or are they galaxies, and not discernable as such... ? Ron, they're too small. Globular clusters are thought to form as part of larger...
by iann
Mon Apr 09, 2012 9:59 am
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: Blue Straggler Stars in Globular M53... (2012 Apr 09)
Replies: 13
Views: 2919

Re: APOD: Blue Straggler Stars in Globular M53... (2012 Apr

I'm slightly surprised at the statement "astronomers use the abundance of stars like blue stragglers to help determine the age of the globular cluster". Certainly they use the abundance of stars of different colours to determine the age of the cluster, as shown by Ann's diagram and also th...