NGC 246 in Cetus is a reasonably large planetary nebula, about 4 min arc across. Magnitude about 8.5. Slightly brighter in OIII (blue) than in H-alpha (yellow). SII was insignificant, and we have not included any.
We've managed to resolve the mag 12 white dwarf separately from its somewhat brighter binary companion.
For the answer in the back of the book, see the stunning, jaw dropping, Gemini South shot.
According to the Gemini shot docco, the edge at the top of the frame is leading, creating a stronger shock as it hits interstellar medium, and that is why it is noticeably brighter than the bottom edge.
H-alpha 8hrs, OIII 8hrs, both in 1 hour unbinned subs. Field 11 min arc, 0.55 sec arc/pixel. Seeing was just under 2 sec arc.
Cheers,
Mike and Trish
Edit: Trish did a reprocess with H-alpha = red, OIII = turquoise, and slightly less noise reduction. I think it's better.
Mike
That is an interesting looking object. Your resolution is quite similar in many respects to that of the Gemini image. I wonder what difference an AO would make to resolving the finer features with your scope.
That is an interesting looking object. Your resolution is quite similar in many respects to that of the Gemini image. I wonder what difference an AO would make to resolving the finer features with your scope.
Thanks muchly Paul.
AO would be wonderful, but I suspect that finding a guide star would be very difficult at our focal length.
Quote:
Originally Posted by Stevec35
A nice one once again Mike and Trish. I imaged this myself a few years back so perhaps it's time to do another one. Here's my effort:
For the most part Mike, there are enough stars in the field of view to image at 1.7hz. Mag 10 stars can be seen at 0.5" with the 12" at 2430mm. When I imaged NGC253 I had a star which allowed 3.7hz or 0.2" guide exposures. Those so far seem rarer than stars at 0.5". Mind you I have only worked on collecting data on 3 objects so far. I am expecting that your superior light grasp would have a great ability to use dimmer stars despite the smaller field of view. There would be trade offs but I think your system would really benefit from an AO. I take your point though. Long FL has its issues.
For the most part Mike, there are enough stars in the field of view to image at 1.7hz. Mag 10 stars can be seen at 0.5" with the 12" at 2430mm. When I imaged NGC253 I had a star which allowed 3.7hz or 0.2" guide exposures. Those so far seem rarer than stars at 0.5". Mind you I have only worked on collecting data on 3 objects so far. I am expecting that your superior light grasp would have a great ability to use dimmer stars despite the smaller field of view. There would be trade offs but I think your system would really benefit from an AO. I take your point though. Long FL has its issues.
Wow! Thanks Paul. Perhaps it is something to investigate.
Every time I see your images I wonder if I shouldn't cut back my gear collection and funnel a bit of money into itelescope ad get some data from a monster scope. That said I think the data is only a small piece of the puzzle and your superb processing skills make up the rest.
I will second Pauls assertion there. With my setup I was never unable to guide at at least 0.5sec guide exposures and the best I managed was 10hz
Every time I see your images I wonder if I shouldn't cut back my gear collection and funnel a bit of money into itelescope ad get some data from a monster scope. That said I think the data is only a small piece of the puzzle and your superb processing skills make up the rest.
I will second Pauls assertion there. With my setup I was never unable to guide at at least 0.5sec guide exposures and the best I managed was 10hz
Alex, you are too kind. Thanks for the encouragement! I'll certainly think about your and Paul's suggestions regarding adaptive optics.
Regarding hiring time on a big scope, whatever you do, don't stop having fun!
Quote:
Originally Posted by gregbradley
Nice image Mike.
I did a test O111 image and it was very dim. I should look at that again. So you got lots of O111 eh? Maybe my test image had some cloud at the time.
Greg.
Thanks, Greg. Perhaps we should have said brighter in OIII than Ha, rather than bright in OIII. A 15 minute 3x3 binned SII shot showed absolutely nothing. Not a sausage.
Trish did a reprocess mapping H-alpha to red, OIII to turquoise, and slightly less noise reduction. The fine wispy OIII stuff across the centre stands out better now.
I like that also a lot better. Nice and natural Well done Trish.
I took some O111 last night. My original test shot obviously was blocked by cloud and I assumed there was nothing in O111 but as you say its almost as bright as the Ha.
Excellent Mike n Trish. Trish is now official colour balancer . Youve also just given me my next project .
Thanks, Fred. Looking forward to your version.
Quote:
Originally Posted by Paul Haese
Yeah I like that one better. Well done Trish.
Cheers, Paul.
Quote:
Originally Posted by AlexN
Given the field of view the detail in that is simply astonishing.
Thanks, Alex. No two PN's are the same. Would love to understand more about what makes them all so different. Binary companions, dust, actual planets, magnetic fields.
Quote:
Originally Posted by gregbradley
I like that also a lot better. Nice and natural Well done Trish.
I took some O111 last night. My original test shot obviously was blocked by cloud and I assumed there was nothing in O111 but as you say its almost as bright as the Ha.
Greg.
Thanks, Greg. Sounds like cloud was the explanation. Even thin stuff can do it.
Quote:
Originally Posted by rustigsmed
awesome stuff M&T, glad to see that you have put your focal length onto a PN. utterly fascinating stuff.
all the best,
Russ
Thanks Russ. Perhaps our grand theme is "things that go bump in the night", and PN's, WR's, SNR's etc fit that.
Trish's latest rework looks good guys, PN's are all so individual in appearance, like our children...does anyone else see a round headed bloke with a comb-over hair style in this....
Trish's latest rework looks good guys, PN's are all so individual in appearance, like our children...
Mike
Kids and PN's: Agreed! And thanks!
Quote:
Originally Posted by strongmanmike
... does anyone else see a round headed bloke with a comb-over hair style in this.... Mike
Now I'm going to have to try really hard not to think of a cross between Wally from Dilbert and Michael Jackson. We used to see it as more like the face of a baby seal, but this year's data has wrecked that.
. Youve also just given me my next project 
.
