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Tuesday, January 28, 2020

IC 1396 wide field, reprocessed

I reproceed the material for IC 1396 since I noticed a small flaw in the calibration file used.
This was my first light image for my "new" imaging system and first light for the whole winter season 2019 -2020.

Image is now "deeper" and stars are much better resolved. I'm really happy, how well this old second hand Tokina AT-x 300mm f2.8 lens performs. Even the CCD-shell in Apogee Alta U16 camera is very large, over 36x36mm, image from the lens can cover the whole CCD. There are some coma at out most corners of the full frame image but nothing serious.

The imaging system is undersampled, it has a spatial resolution of 6 arc seconds / pixel. This makes the optical system very fast. The same Tokina lens with a small pixel CCD and spatial resolution of 1 arc second / pixel, is 36 times slower to capture light. That's a lot! One hour exposure with my current system is equal to 36 hours exposure with one that has tiny pixels.The lost of resolution is not really an issue, when I want to capture very faint and diffused nebula structures.

Info about my current imaging system can be seen here,

IC 1396
Please, click for a full size photo it's worth it!

Image is in mapped colours, from the emission of ionized elements, R=Sulphur, G=Hydrogen and B=Oxygen. The signal for ionized oxygen. Note, at lower right corner shows a small part of Sharpless 129, Sh2-129. Some images of Sharpless 129 can be seen here,

An experimental starless version
Please, click for a full size photo

The planetary nebula candidate at middle left stands out well in this starless photo of IC 1396 area.

Planetary Nebula?
Please, click for a full size photo

Just left from the IC 1396 seems to be a circular formation with some weak O-III emission. Could this be a planetary nebula? My friend, Sabik Rasool, a planetary nebula enthusiast, Find out that this formation is a HII area discovered in 2015. This doesn't rule out, that this could be an ancient planetary nebula?

A close up and some info
Please, click for a full size photo

IC 1396 spans hundreds of light years at distance of about 3000 light years in constellation Cepheus. The famous formation of glowing gases, the "Elephant's Trunk Nebula" can be seen at four o'clock position.
This is an active star formation region and it has several massive young stars inside it, coursing the ionization of elements of this emission nebula.

The Garnet Star and the suspected planetary nebula PM 1-333. When I published the first version of this image in Facebook, an other friend of mine, Jussi Kantola, pointed out, that near the Garnet Star lays the PM 1-333. More info about this interesting region can be seen here,

Technical details

Processing workflow

Image acquisition, MaxiDL v5.07.
Stacked and calibrated in CCDStack2.
Deconvolution with a CCDStack2 Positive Constraint, 33 iterations, added at 50% weight
Color combine in PS CS3
Levels and curves in PS CS3.

Imaging optics
Tokina AT-x f2.8 camera lens

10-micron 1000

Cameras and filters
Imaging camera Apogee Alta U16 and Apogee seven slot filter wheel
Guider camera, Lodestar x 2 and an old spotting scope of Meade LX200

Astrodon filters,
5nm H-alpha 3nm S-II and 3nm O-III

Total exposure time

H-alpha, 12 x 600 s, binned 1x1 = 2 h
O-III, 6x 600 s, binned 2x2 = 1 h.
S-II, 3 x 600 s. binned 2x2 = 0,5 h

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