V* V900 Mon, "Thommes Nebula"
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MOUSEOVER IMAGE FOR STARLESS VIEW CLICK
ON IMAGE FOR FULL SIZE VIEW (6454x4526)
Scope:
Celestron 9.25 Edge HD 235 mm at f/7; Location: DAA Observatory, Shelter
Valley, CA; Dates: 4, 5, 30 December, 2024; Camera: ASI294MM (Baader
Ha, LRGB Filters) Exposure:
Exposure: Lum - 193 x 3 min (gain-121 2x2), Ha - 60 x 4 min (gain-180
2x2), RGB - 42/44/47 x 2 min (gain-121 2x2) 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 Lum and
Ha stacks - PixInsight (WBPP). Noise reduction - NoiseXTerminator - PixInsight.
Non-linear stretching, normalization and gradient removal - PixInsight.
Photometric RGB calibration (SPCC) - PixInsight. Deconvolution of Lum, Ha, and
RGB combine -
BlurXTerminator. Generation of starless nebulosity Lum, Ha, and RGB images for later processing - Star XTerminator. Curves, Levels, RGB
combine - PixInsight. Lum starless and Ha starless combine - PixInsight. LRGB
stars screened to starless Lum + Ha - Pixinsight. Final finishing, crop,
and resample -
Affinity Photo. Annotation - PixInsight, Aladin (Simbad),
and Affinity Photo. This image is an LRGB / Ha starless composition -
with RGB stars added. Image processed at 8240x5578 resolution. Final Image size is approximately
6454x4526. North is to the
right in this image. About fifteen years
ago (November 21, 2009), I had the good fortune of pointing my camera in the
direction of the LBN 1022 region in Monoceros and catching an undiscovered nebula
(optical wavelengths) in my image. At first, I thought I had some sort of optical
artifact, but it was persistent in all of my sub frames. I posted my
"mystery nebula" image on the Cloudy Nights astronomy forum. My post
was seen by Sakib Rasool and he put me in touch with a professional astronomer,
Bo Reipurth. His team further studied the star and nebula and hypothesized the nebula was
due to an eruptive FU Orionis variable star. The Astronomical Journal letter was
published March 20, 2012 (Bo Reipurth, Colin Aspin, G.H. Herbig). The star was
classified V* V900 Mon. Their publication has since been cited by 31 other
papers - several of which were about V* V900 Mon exclusively and
referencing the "Thommes
Nebula" . Now fifteen years
later, I have revisited the V* V900 Mon / LBN 1022 region (it is quite a
photogenic region). According to follow up papers, the V* V900 mon eruption /
nebula has brightened steadily until about 2018 when its brightness began to
level off and possibly subside somewhat. V* V900 Mon is embedded/involved
with the nebula (upper left in the image). Its distance is about 4,254 light
years. The small nebula (below and right ) is RNO 78. The larger central
bright nebula is part of LBN 1022; the dark cloud inside LBN 1022 is LDN 1655. The
additional dark nebula and dust in the lower left is LDN 1656. These objects and some of the brighter stars are identified in the annotated image. Horizontal FOV is approximately 0.565 degrees. Full size image scale is about 0.38 arcsec/pix. Image center is approximately - Equatorial 2000: RA: 06h 57m 06s Dec: -08°17'07"
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