Near and far, young and old

[John]

I've been having a pleasant relaxed session with my 120mm refractor this evening.

I seem to be interested in observing targets of different extremes currently.

3 of tonights subjects, for example:

- The supernova SN 2023ixf in Messier 101. While the progenitor star was an ancient red dwarf within the 21 light year distant classic spiral galaxy, the immense outpouring of energy (outshining it's host galaxy) that signals it's demise was discovered less than a month ago. Tonight my estimate of brightness for this one is magnitude 11.6 - a little dimmer than my last observation a few days back. Of Messier 101 however, I could see barely the faintest hint.

- The distant globular cluster NGC 6229 in Hercules. I reported on this one a few days ago as well. Then I was comparing it with the much closer Messier 4. The interest tonight was not so much the near-100,000 light years distance that this cluster lies at but rather it's immense age. NGC 6339 has been estimated at 12-13 billion years old so nearly as old as the Universe itself. Compare that with my next target ......

- The famous "blinking" planetary nebula NGC 6826 in Cygnus is around 2000-2200 light years from us but also a very young object compared with many that we observe. Current estimates are that this planetary nebula could be as young as 1000 years old - a tiny baby in cosmic terms. Quite easy to spot at around 50x as a fuzzy star even under the less-than-dark skies but the best view was at around 200x. The magnitude 10 central star shines out from a small cloud of surrounding nebulosity. A UHC filter did not do much for it but an O-III makes it stand out more, albeit at the expense of the central star which becomes very hard to see with this aperture of scope. I think I prefer the unfiltered view with slightly dimmer nebulosity and a nice clear central star. No sign of the "blinking" effect this evening though. 

So even with the skies not really getting properly dark at this time of year, there are some fascinating and rather exotic targets available for the small telescope owner to wonder at 🙂

 

  

 

 

Edited June 13, 2023 by John

[John]

9 hours ago, John said:

- The famous "blinking" planetary nebula NGC 6826 in Cygnus is around 2000-2200 light years from us but also a very young object compared with many that we observe. Current estimates are that this planetary nebula could be as young as 1000 years old...  

 

 

I woke up this morning pondering this. If an event happened 1000 years ago to an object 2000 light years away, how come we can see it ?

I'm going to need to do some more research on this one and "fact check" a bit more ! 🙂

Edited June 14, 2023 by John

[Nik271]

22 minutes ago, John said:

I woke up this morning pondering this. If an event happened 1000 years ago to an object 2000 light years away, how come we can see it ?

I'm going to need to do some more research on this one and "fact check" a bit more ! 🙂

I think the ages given are with respect to our own timeframe: i.e what we see right now is the nebula 1000 years after formation. If we try  relating what is happening to  the nebula 'now in its location' back to our location we run into time paradox: Comparing simultaneous time of events lightyears apart leads to time travel paradoxes because there is no common time frame: Any observer/clock at the nebula location will need to travel 2000 lightyears to get to us. This is one reason that faster than lightspeed travel leads to time travel. Imagine a magic photon arriving to us instantenously after the nebulas formation: they bring us news of a nebula that we can't yet see in ordinary light, and we have to wait thousands of years to see it it properly. From our viewpoint the faster instantenous photon is coming from the future.  

 

 

Edited June 14, 2023 by Nik271
typos

[Paz]

Great report and very interesting. I am one of those observers who probably spends more time thinking about what I am looking at than how it looks. The distances, speeds, temperatures, history and so on are amazing when you think about it.

On the topic of distances I often notice quite a lot of disparity sometimes between different sources about how distant objects are. Some of this might be to do with newer sources tightening the accuracy up but older sources still being in circulation, and some may I guess just be that there are still different assumptions and methods one can take up for measuring and estimating distances.