The Homunculus Nebula (Ignacio Diaz Bobillo)

The Homunculus Nebula

A couple of nights ago, right after dusk, I enjoyed the best seeing ever. Narrow band short subs came in with a FWHM between 0.9" and 1.1" (the lowest was 0.83"). And this hold for more than two hours. As my target for the night was still down, I decided to do some experimentation imaging Eta Carinae and the Homunculus Nebula, using hundreds of short exposures. Ended up collecting 130 x 5 sec on O3, 150 x 2 sec on SII, and 110 x 5 sec, plus 250 x 2 sec, and 150 x 0.5 sec on H-alpha. The image in this post is bicolor (HOO), as I still have to process the sulfur. The presentation is in the form of a GIF animation, comparing the famous 1995 image from the HST. It is amazing how obvious the expansion of the nebula is apparent. I calculated less than an arc second in the last 26 years (which amounts to about 5 pixels at the scale of the image). As usual, I used a 6.6-inch AP apo refractor and a QHY600. Pixel resolution is 0.154", resulting from a native resolution of 0.617"/pixel, processed with drizzle 2x, and later upscaling it 2x.

NOTE: a couple of stars are gone in the field of view of the HST, curious.

NEW VERSION: that includes SII data, in a composition with a HSO lineup (didn´'t like the standard SHO palette). Also, the HST comparison image is from 2018 instead of 1995, so the dimensions are now very comparable. A confirmation that the apparent expansión of the previous presentation is real. Also, I was able to use more stars in the alignment of the two images, for a better match. Finally, note that the blueish streaks of nebulosity in the HST image comes from an UV color channel not present in my image.

Original
Final
C

Astrofotógrafos de Argentina

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