SNR G013.3-01.3 (M24, Sh2-41 Region)

SNR G013.3-01.3 (M24, Sh2-41 Region)

CLICK ON IMAGE FOR FULL SIZE VIEW (6220x4144)

Scope: FSQ-106N at f/5, Location: DAA Observatory, Shelter Valley, CA; Dates: 12, 28, 29 June, 2 July, 2024; Camera: ASI2600MM (Astronomik type 2c RGB, 6 nm Ha and OIII filters)

Exposure: Exposure: Ha - 78 x 3.5 min (gain-160 1x1), OIII - 28 x 4 min (gain-200 1x1), OIII - 114 x 6 min (gain-200 1x1), RGB - 32 x 1 min (gain-101 1x1) each RGB exposures.

Processing: Data Collection - N.I.N.A. Sequencer (as FITs). Sub-frame calibration - Pixinsight (WBPP). Sub-frame registration and integration (Average combine - Winsorized sigma clipping) - PixInsight (WBPP). 2x Drizzle of Ha and OIII - PixInsight (WBPP). Both exposure subs of OIII were combined in one integration. Continuum subtraction of OIII -PixInsight (SetiiAstro). Noise reduction - NoiseXTerminator - PixInsight. Non-linear stretching, normalization and gradient removal - PixInsight. Photometric RGB calibration (SPCC) - PixInsight. Deconvolution of Ha, OIII, and RGB stacks - BlurXTerminator. Generation of starless nebulosity Ha, OIII , and RGB images for later processing - Star XTerminator. Curves, Levels, RGB combine - PixInsight. RGB Stars and starless combine - PixInsight. Final finishing - Affinity Photo. Annotation - PixInsight, Aladin (Simbad ), and Affinity Photo. This image is a modified HOO Narrow Band starless composition - with RGB stars added. Image processed at 12496x8352 resolution. Final Image size is approximately 6220x4144.

North is upper-left in this image (37 degree CCW rotation). Central in the image is the blue OIII emission line "sprite" structure of SNR G013.3-01.3. This SNR is in a field of Ha emission identified as Sh2-41 (also LBN 51); the OIII emission is very weak requiring the longer exposure levels . The distance of this SNR has been somewhat elusive with SNRCat indicating anywhere from 6,500 light years to 13,000 light years. The bulk of the red Ha emission of Sh2-41 has a somewhat closer distance of about 7,000 light years. However, the filamentary Ha emission below the blue sprites of the SNR and those to the left are believed to be part of the SNR shell. These filamentary Ha structures appear to be extensions of the dimmer blue OIII emissions .

This is a busy field aside from the main attraction of the SNR. Dark nebulae are LDN 336, LDN 335 (Barn 307), LDN 321 and 328, LDN 327 (Barn 92), LDN 327 (Barn 93) and a string of dark nebulae (Dobashi Catalog) in the lower right. Bright Nebulae seen are LBN 52 and Sh2-39. Open clusters seen are NGC 6613 (M18), NGC 6603 (Collinder 374, Melotte 197), and Biurakan 5. These objects and some of the brighter stars are identified in the annotated image.

Vertical FOV is approximately 2.52 degrees. Full size image scale is about 1.46 arcsec/pix.

Image center is approximately - Equatorial 2000: RA: 18h 19m 11s Dec: -18°10'39"

All images and content remain the property of Jim Thommes - copyright 2003 - 2024

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