Perculiar object in Eta Carina

PhotonCollector (Paul) · #1 19-03-2006, 09:35 AM

Hi everyone,

A recent image I did of the Eta Carina nebula shows something perculiar
and I was wondering if anyone knows what it is ? (Perhaps it is nothing
at all and just an interesting arrangement of light and nebula).

The perculiar object that caught my attention is a star which appears to
have a bi-polar searchlight beaming out from it. In other words, the star
appears to be throwing off a beam of light from each side (perhaps from its
polar regions).

At first, I thought it might be an optical reflection but none of the other stars in the image suffer from the effect. The star is catalogued as Tycho 8626-2154-1 Mag. 10.1 (GSC Star 8626-2154) located at R.A. 10h 46m 13s Dec. -59º 59' 51"

Image 1; shows where in the Eta Carina Nebula the star is located.
Image 2; shows a closeup of the general area where the star and its beams of light can be seen at centre-bottom of the image.
Image 3; is a 100% resolution image of the area where the star is located.
Image 4; The final image has drawn on it where the star with searchlights
is located.

Any opinions are welcome, as I said it may be just nothing at all just an
interesting feature.

Paul

JohnG (John) · #2 19-03-2006, 10:17 AM

Interesting, it is almost the same angle as the diffraction pattern on the star to the lower left.

JohnG

Starcrazzy · #3 19-03-2006, 12:06 PM

Hi,
Very interesting...I hope you don't mind but i sved your image and inverted it in photoshop...you can make out the detail alittle better...i am deffinatly no expert but it doesn't appear to be a diffraction spike as it gets wider the further from the star it gets although it is at the same angle as the other spikes in the shot...i think its just interesting nebulous material..it can't be a nutron star as you know as its still glowing..
exellent pic by the way...can you give me some details as to your methods...exposures etc..
cheers

astronut (John) · #4 19-03-2006, 12:14 PM

Could it be the Homunculus?

janoskiss (Steve H) · #5 19-03-2006, 12:44 PM

Homunculus is around the brightest star eta carina in the wide angle pic.

Paul, I had a play with your close-up image in the Gimp. In re-mapped the colour the feature shows up more clearly as part of the surrounding nebulosity.

2020BC (Bill Christie) · #6 19-03-2006, 02:52 PM

Hi Paul.

Here is a cropped 100% resolution image I took of that area on 25Feb06. The unlabelled arrow points at the star in question and the two numbered arrows point at your areas of interest.

PhotonCollector (Paul) · #7 19-03-2006, 03:08 PM

Quote:

Originally Posted by Starcrazzy

Hi,
Very interesting...I hope you don't mind but i sved your image and inverted it in photoshop...you can make out the detail alittle better...i am deffinatly no expert but it doesn't appear to be a diffraction spike as it gets wider the further from the star it gets although it is at the same angle as the other spikes in the shot...i think its just interesting nebulous material..it can't be a nutron star as you know as its still glowing..
exellent pic by the way...can you give me some details as to your methods...exposures etc..
cheers

Hi Starcrazzy,

No I don't mind at all, the inverted image certainly highlights the "object".
Yeah I agree it's probably nothing of consequence - it stood out when I was examining the high resolution version of the image.

The image was done with my 12-inch f/5 GSO dobsonian telescope which is retro-mounted on an old Australian made Samson german equatorial mount. I guide the telescope manually using my 4.5-inch f/18 guidescope and control the main RA drive with a hand held controller (faster and slower buttons). The DEC adjustments are done by hand - since the DEC is not motorised. There's a pic of my setup here http://www.skylab.com.au/pmsa/

With my Canon 300D I have been using ISO200 rather than the faster ISO settings, since ISO200 gives me the best possible result from the camera - smoother images and lower noise. I use IRIS to do image stacking, dark frame subtraction, bias and flat-fielding of the image.

I then normally do final adjustments in Photoshop, and sometimes use Noiseware CE to do further smoothing of the image.

These images of ETA C were 6 x 120 second (12-minutes total) exposure @ ISO200 with dark and bias frames removed and flat-fielded.

Thanks for your comments

Paul Mayo

PhotonCollector (Paul) · #8 19-03-2006, 03:10 PM

Quote:

Originally Posted by janoskiss

Homunculus is around the brightest star eta carina in the wide angle pic.

Paul, I had a play with your close-up image in the Gimp. In re-mapped the colour the feature shows up more clearly as part of the surrounding nebulosity.

janoskiss,

gee, GIMP really made it stand-out.

thanks
Paul

PhotonCollector (Paul) · #9 19-03-2006, 03:13 PM

Quote:

Originally Posted by 2020BC

Hi Paul.

Here is a cropped 100% resolution image I took of that area on 25Feb06. The unlabelled arrow points at the star in question and the two numbered arrows point at your areas of interest.

Hi 2020BC,

That's a relief to see the same effect in your image. I did at one stage think it may of been an optical reflection of sorts - but now I can rule that out, thanks.

Paul Mayo

PhotonCollector (Paul) · #10 19-03-2006, 03:21 PM

Quote:

Originally Posted by astronut

Could it be the Homunculus?

Hi Astronut,

In the first image, there is a bright yellow-orange star just above-left of centre image, which the Homunculus nebula surrounds.

So... good guess but no it isn't the Homunculus nebula.

Paul Mayo

Itchy · #11 19-03-2006, 03:42 PM

Hi Paul

Here is the same area in one of my shots. It shows the same effect. It looks like surrounding nebula to me too.

Cheers

tornado33 · #12 19-03-2006, 05:43 PM

Hi
Heers some of my pics of the area.
1 is 7 Nm Ha image 2x 10 mins ISO 400
2 is 2x10 mins ISO 400 with UHCS filter
3 is 3x200sec shots ISO 1600 with in camera N/R on
All with modded 350D and 10 inch F5.6 scope
The all seem to show the feature.
Scott