The Geometry of the Helix - Faint Halo Struktures in NGC 7293

[Atlas]

Hello everybody,

my name is Johannes and I am new to this forum. I live in southwest Germany. I have been in amateur astronomy for 12 years. My main instrument is a 25" f 4 home built Dobsonian (Obsession style), equipped with Argo Navis and ServoCat. I have been reading along for a while in this forum, which is very stimulating and informative, and I would like to thank the organizers for providing such a great chance of interchange and conversation.

I would like to draw your attention to a new observing project (#3) that I posted on my private astronomy website. The topic is the visual observation of the faint halo structures in the Helix nebula. It contains a drawing, images and further materials about the true geometrical shape of this object. This project would also be suitable as a deep sky challenge.

My website is mainly in German, but there is an English version of observing project #3 as well.

If you are interested, please follow this link:

http://homepages.uni-tuebingen.de/johannes.brachtendorf/Beobachtungsprojekt3.html

If you prefer English over German, click "English version" in the top right corner of the page.


Thank you very much
Johannes

[Jimi Lowrey]

Welcome to Deep Sky Forum Johannes.

I enjoyed reading you're observing report of the Helix. Good Job!

[Uwe Glahn]

Hi Johannes,

thanks for the detailed article.

The observation of the halo sounds very interesting. Can you tell us some more about the visual observation of the halo, especially how difficult the main structures were and if you could hold it steadily? How were your sky conditions and did you try a Hß filter? - the arcs seem to be very red.

I tried the halo years ago with my 16" under alpine skies and could not detect anything. A quick and dirty view with my 27", also under alpine skies did not bring out much more. But the arcs looks bright enough within reach. Especially interesting the "NE object".

[Bill Weir]

Johannes , that looks like a challenging project. I'm curious where you observed this from. Germany is similar to Canada in that from our latitude the Helix is always low in the sky. I think I might need to add this to my challenge list for a late summer high altitude star party for next year.

One comment I have is that the APOD image is rotated about 180º off the sketch you've supplied. It makes toggling back and forth between the two a bit awkward but then again maybe it's just me.

Bill

[Atlas]

Hi Uwe and Bill,

I observed under dark rural skies at about 950 Meters (ca. 3000 ft) elevation. My location is at 48° N, which seems to be very similar to Vancouver Island, only without the ocean nearby. I did not try H beta, just UHC and OIII, but primarily UHC. Bill, you are right, I should have rotated the APOD to make it easier to compare to the two sketches. Sorry for the glitch.

Johannes

[Howard B]

Hi Johannes, excellent observations and a really cool project! You've inspired me to try this for myself next year.