PDA

View Full Version : Integrated flux nebulae????



akarsh
June 13th, 2014, 07:16 AM
Hi

It seems just ridiculous, but on the first night of TSP, we pointed a Takahashi 5" TOA refractor owned by a friend of mine around M 51. My observing friends noticed some mottling in the background that moved as the telescope moved. At first, I was not going to believe anything of that sort, but when I went and saw it, I did feel some mottling in the background that moved as the telescope moved.

My immediate reaction was "haze in the sky". I told the owner of the TOA that the faint halos around the stars came from haze, not from nebulosity of any sort. But then, he showed me a field saying "here's disproving your halo theory". I said "Wait, the halo on the fainter star is larger than that around the brighter star", and he replied "exactly!". Unfortunately, that was the only instance where we precisely agreed on our observations. We did "kind-of" agree a couple of times, but I don't think we had statistically significant agreement except for that one time.

Given that the region around M 51 does have a lot of integrated flux nebulae, is it even reasonable that we were seeing any? Otherwise, what is the explanation for this mottled moving background? Is it just a trick of the eye-brain complex?

The skies on night 1 of TSP were great. They were terrible until 2 AM or so. Most people had decided to go to bed, having given up hope, but my friend was trying to get his polar alignment, and I was just "playing around trying to image planets" with my dob, in the hope that it might clear eventually. Indeed, it did clear, and those were some very good skies, AFAICT. Also, the contrast in that Takahashi refractor is remarkable, and I was surprised when I could easily see IC 342 through it despite having difficulty in my 18", and later Maffei-I also showed itself (need to double check with my logs, but I do remember seeing Maffei-I in it). So if there is something that could have shown IFNs, it was probably TSP skies and a high-contrast refractor...

Any of your expertise on this matter is deeply appreciated. As you can tell, I'm very skeptical of this observation, just like any observer should be IMO. So please feel free to shoot this down with alternate explanations.

Regards
Akarsh

akarsh
June 13th, 2014, 07:27 AM
Sorry, I just did some more research, and found out that Paul Alsing has seen a lot of these (I did remember a vague report somewhere, so found one here: http://www.cloudynights.com/ubbthreads/showflat.php/Cat/1,2,3,4,5,8/Number/5033212/Main/5032593 )

But most people talk about the IFNs around M81-M82 region. Rogelio Bernal Andreo's image of the big dipper does show some galactic cirrus around M 51 region, but not dense:
http://apod.nasa.gov/apod/image/1106/2011-05Andreo_BigDipper7k.jpg

The IFNs around M81-82 seem to be an interesting project...

Regards
Akarsh