Target Fun facts
The Horsehead Nebula (also known as Barnard 33 or B33) is a small dark nebula located about 1,375 light-years (422 pc) from Earth in the constellation of Orion. The nebula is located just to the south of Alnitak, the easternmost star of Orion’s Belt, and is part of the much larger Orion molecular cloud complex. It appears within the southern region of the dense dust cloud known as Lynds 1630, along the edge of the much larger, active star-forming HII region called IC 434. It is one of the most identifiable nebulae because of its resemblance to a horse’s head.
The nebula was discovered by Scottish astronomer Williamina Fleming in 1888 on a photographic plate taken at the Harvard College Observatory. One of the first descriptions was made by E. E. Barnard, describing it as: “Dark mass, diam. 4′, on nebulous strip extending south from ζ Orionis”, cataloguing the dark nebula as Barnard 33.
It has an easily recognizable shape which resembles the head of a horse. Heavy concentrations of dust in the Horsehead Nebula region and the neighboring Orion Nebula are localized into interstellar clouds resulting in alternating sections of nearly complete opacity and transparency. The darkness of the Horsehead is caused mostly by thick dust blocking the light of stars behind it. The lower part of the Horsehead’s neck casts a shadow to the left. The visible dark nebula emerging from the gaseous complex is an active site of the formation of “low-mass” stars. Bright spots in the Horsehead Nebula’s base are young stars just in the process of forming.
IC434
The Horsehead Nebula is a dark nebula that is silhouetted against the diffuse background of IC 434. It is protruding from the Orion B molecular cloud, which is part of the Orion molecular cloud complex. IC 434 is a bright emission nebula in the equatorial constellation of Orion. It was discovered on February 1, 1786, by German-British astronomer William Herschel. The nebula is located at approximately 1,260 ly (385 pc) and spans the interior of a neutral hydrogen shell with an angular size of 2° × 4°. At that distance, the dimensions correspond to a projected size of 42 ly × 85 ly (13 pc × 26 pc).
IC434 is an HII region that is being ionized by ultraviolet radiation from the nearby Sigma Orionis (σ Ori) multi-star system. An additional half dozen stars provide further illumination of IC 434. This HII region is one of the youngest to form around members of the Orion OB1 association of hot stars. The region has a radius of about 13 ly (4 pc) and a mass of around ~ 100 M☉. The mass displaced by the advancing ionization front of IC 434 is estimated at 104 M☉. The nebula includes dust with an estimated mass of 2.3 M☉.
IC 434 is surrounded by a shell of neutral hydrogen gas with the identifier GS206-17+13. The primary driving energy behind this expanding shell was likely supplied by the blue supergiant Epsilon Orionis.
NGC2024 Flame Nebula
The Flame Nebula, designated as NGC 2024 and Sh2-277, is an emission nebula in the constellation Orion. It is about 1350 light-years away. At that distance, the Flame Nebula lies within the Orion B cloud of the larger Orion Molecular Cloud Complex.
The bright star Alnitak (ζ Ori), the easternmost star in the Belt of Orion, appears very close to the Flame Nebula in the sky. But the star and nebula are not physically associated with one another. The Flame Nebula contains a young cluster of stars which includes at least one hot, luminous O-type star labeled IRS 2b. The dense gas and dust in the foreground of the nebula heavily obscures the star cluster inside the nebula, making studies at infrared wavelengths most useful.
The energetic ultraviolet light emitted by the central O-type star IRS 2b into the Flame Nebula causes the gas to be excited and heated. The glow of the nebula results from the energy input from this central star. Within the nebula and surrounding the central hot star is a cluster of young, lower-mass stars, 86% of which have circumstellar disks. X-ray observations by the Chandra X-ray Observatory show several hundred young stars, out of an estimated population of 800 stars. X-ray and infrared images indicate that the young stars are concentrated near the center of the cluster.
Other Catalog Designations: Barnard 33, LDN 1630, IC 434
Subtype: Emission nebula (IC434, NGC2024), Dark nebula (B33)
Distance from Earth: ~ 1,375 light-years (422 pc)
Size: IC434: 13 light year radius
Apparent dimensions: IC434: 60′ × 40′
Magnitude: 4.5
Constellation: Orion
{ From: https://en.wikipedia.org/wiki/IC_434, https://en.wikipedia.org/wiki/Horsehead_Nebula, https://en.wikipedia.org/wiki/Flame_Nebula }
Personal Fun Fact
Although I have placed these newer captured images at the front of the gallery, I MUCH prefer the image “below the line” image. The January 2022 version of the Horsehead, captured in the dark skies of the Kiowa National Grasslands, with my very nascent astrophotography skills (approximately 6 months of experience and on the one year anniversary of figuring out how to put Big Bertha together!)
Equipment
Equipment: All equipment controlled by HP Probook (DSO-CTRL1) running Sequence Generator Pro v4.4.1.1441.
- Imaging: (Big Bertha) Orion 8″ f/8 Ritchey-Chretien Astrograph Telescope
- (Mono camera & filter wheel with field flattener) ZWO ASI6200MM Pro Monochrome imaging camera; ZWO – EFW 7×2” Filter Wheel with installed filters (1=SII, 2=Ha, 3=OIII, 4=Lum, 5=Red, 6=Grn, 7=Blue): Svbony SV227 2” Narrow-Band – SII, Ha, OIII; Optolong LRGB Filter Set (2”); Teleskop Service Flattener 1.0x for RC Telescopes (TS-RCFLAT2)
- Mount: Rainbow Astro RST-300 (controlled by iHubo ASCOM driver)
- Polar alignment: QHYCCD camera (controlled by Polemaster for polar alignment)
- Autoguiding: Orion 60mm Multi-Use Guide Scope with Orion StarShoot AutoGuider Pro Mono Astrophotography Camera (controlled by PHD2)
- Auto Focuser: ZWO EAF Electronic Automatic Focuser – Standard (New 5V Version) (EAF-5V-STD)
Capture notes
This image was produced with data captured from four separate sessions during the January 2026 Big Bertha mono camera imaging extravaganza: 17Jan, 19Jan, 26Jan, and 27Jan. Half the sessions (17 & 19Jan) were conducted prior to the ZWO ASI6200MM’s “fix” by ZWO’s Mei on 25Jan2026. The second two sessions (26 & 27Jan2026) were conducted with the new firmware and FPGA software as a part of the “real world validation” of the fix, but with a very bright almost full moon close to this target – that even the narrowband filters struggled to work around.
17 January 2026
Saturday, 17Jan2026, forecast to be clear all night long (which it was), I set up BB for a full night of imaging (CTB1 Garlic Nebula, IC434 Horsehead Nebula, and M65 Leo Triplet). I ran into various issues with each target.
On IC434 Horsehead Nebula, received the data warning after Event#1, Frame#2. So, I paused the collection using SGP to gather 5x1min subframes with ASIImg so I could send the data files to Jose at ZWO, as another example of the issue continuing. Then when I went back to SGP, I again had the data download issue on Event#1, Frame#4. Disconnected (SGP disconnect) all equipment, unplugged/re-plugged in the camera and restarted Frame #6. Received another data download error (23:22:49) and an error sending the dither command (23:23:11). At that point, I paused the sequence disconnected the equipment, rebooted the laptop, unplugged/plugged in all the equipment and restarted the sequence. After that point – every time that I did a target change or a meridian flip, I rebooted the laptop. I sent the ASIImg file to ZWO, submitted a Help Ticket to SGP, and chimed in on Seti Astro Discord Server because the ASIImg files could not be opened by the Seti Blink Comparator!
IC434 Horsehead Nebula: Sequence ran: 17Jan2026, 23:05MST – 18Jan2026, 01:42 hrs (2:37hr). With a pause between 23:11 and 23:19 to capture 5x1min exposures using ASIImg to log the data download issue, to send to ZWO (Jose); and errors/reboot at about 23:20-23:23. Total data capture time: 30x5min subframes = 150min (2:30hrs).
- Blue: 4x1min, 17Jan2026, 23:05MST – 23:24MST (19min elapsed, 4min data: 21%)
- With a pause between 23:11 and 23:19 to capture 5x1min exposures using ASIImg to log the data download issue, to send to ZWO (Jose).
- Red: 10x1min, 17Jan2026, 12:39MST – 23:52MST (13min elapsed, 10min data: 77% efficiency)
- Green: 9x1min, 17Jan2026, 23:56MST – 18Jan2026, 00:09MST (13min elapsed, 9min data: 69%)
- Ha: 12x3min, 18Jan2026, 00:16MST –00:56MST (40min elapsed, 36min data: 90%)
- OIII: 12x3min, 18Jan2026, 01:02MST – 01:42MST (40min elapsed, 36min data: 90% efficiency)
19 January 2026
The last clear night (when I was going to be home before departing for my TDY to Huntsville on 21 Jan 2026) of the New Moon weekend was Monday, 19 Jan2026, forecast to be clear until about 02:00. I set up BB to capture additional data on IC434 Horsehead Nebula (needed Blue and HSO data to round out the data collection on 17Jan2026).
IC434 Horsehead: Sequence ran: 19Jan2026 18:18MST – 20Jan2026 02:04 (7:46 hrs). Total data capture time: 47x1min, 5x30sec, 103x3min = 358.5 min (5:58.5hrs).
- Blue: 19x1min; 19Jan2026, 18:18MST – 18:43MST (25min elapsed, 19min data: 76% efficiency)
- Red: 14x1min; 19Jan2026, 18:48MST – 19:09MST (21min elapsed, 14min data: 67% efficiency)
- Green 14x1min; 19Jan2026, 19:12MST – 19:32MST (20min elapsed, 14min data: 70% efficiency)
- SII: 36x3min; 19Jan2026, 19:39MST – 21:39MST (120min elapsed, 108min data: 90% efficiency)
- Meridian flip at 21:44MST, (Meridian flip actions: plate solve, AG, EAF: 21:39 – 21:50MST)
- Moved 5x30sec Lum up, so used Lum for plate solve
- Lum: 5x30sec; 19Jan2026, 21:50MST – 21:54MST (4min elapsed, 2.5min data: 62.5% efficiency)
- Ha: 30x3min; 19Jan2026, 22:00MST – 23:41MST (101min elapsed, 90min data: 89% efficiency)
- OIII: 37x3min; 19Jan2026, 23:48MST – 20Jan2026, 02:04 (136min elapsed, 111min data: 82% efficiency)
26 January 2026
The following night after Mei “fixed” the camera download issue, the skies were clear affording me the opportunity to test out the fix. I again imaged IC434 Horsehead Nebula using the HSO filters due to the quarter+ moon that was tracking pretty much the same path as IC434.
IC434 Horsehead: Sequence ran: 26Jan2026 18:15MST – 27Jan2026 01:34MST (439min, 7:19hrs). Total data capture time: 5x30sec, 83x3min, 25x5min = 376.5min (6:15.5hr), 86% efficiency.
- Lum: 5x30sec; 26Jan2026, 18:15MST – 18:19MST (4min elapsed, 2.5min data: 62.5% efficiency)
- Ha: 40x3min; 26Jan2026, 18:24MST – 20:36MST (132min elapsed, 120 data: 91% efficiency)
- Meridian flip at 21:18MST, (Meridian flip actions: plate solve, AG, EAF: 21:18 – 21:30 (12min))
- SII: 40x3min; 26Jan2026, 20:42MST – 23:05MST (131min elapsed (-t(flip), 120min data: 91.6%)
- OIII: 3x3min; 26Jan2026, 23:11MST – 23:21MST (10min elapsed, 9min data: 81% efficiency)
- Switched to 5min exposures for OIII because no nebulosity was evident
- OIII: 25x5min; 26Jan26, 23:21MST – 27Jan26, 01:34MST (133min elapsed, 125min data, 95%)
27 January 2026
Another clear night on Tuesday to collect additional data on IC434 Horsehead and validate the “fixed” camera performance. I again imaged IC434 Horsehead Nebula using the HSO filters due to the quarter+ moon that was tracking pretty much the same path as IC434. It looks like the data download, especially the inconsistency is fixed. I need to look at the SGP data download settings – I think I have 8 seconds set for 1×1 binning – that may be causing the inefficiency, especially in the shorter exposure length subframes. Everything went well in the data collect.
When I stacked the data the following morning, the moon reflections, especially on OIII, Lum, and SII were very evident. I sent an email to Ann saying, “now I’ve got the reflections” (she’d had the same issue with her Running Man image the previous week). She reminded me that Telescopius had added a feature (which I’ve been choosing to ignore) that shows when it is recommended to image with which filter based upon moon phase and location relative to the target. IC434, as I’ve noticed, was very close to the increasingly bright moon and wasn’t recommended for any filter.
IC434 Horsehead: Sequence ran: 27Jan2026 18:42MST – 28Jan2026 01:23MST (401min, 6:41hrs). Total data capture time: 46x3min, 43x5min = 353 min (5:53hrs). 88% efficiency.
- Ha: 45x3min; 27Jan2026, 18:42MST – 21:10MST (148min elapsed, 135 data: 91% efficiency)
- Meridian flip at 21:14MST, one subframe into the SII event (Meridian flip actions: plate solve, AG, EAF: 21:17 – 21:30 (13min))
- SII: 1x3min; 24x5min, 26Jan2026, 21:14MST – 23:36MST (131min elapsed (-t(flip), 123min data: 94% efficiency)
- OIII: 19x5min; 26Jan2026, 23:42MST – 28Jan26, 01:23 (101min elapsed, 95min data: 94%)
Processing notes
Processing: Captured in SGP; Image Review using SetiAstroSuite Pro blinking/culling process; stacked in APP producing individual FITS files for each of the R-G-B-S-H-O filters; APP Combine tool: RGB2 for star field, RGBHOO and HSO2 for nebulosity (preferring different results for different portions of the image) – RGBHOO and HSO2 were combined with masks in PS to produce the final nebulosity area. Used Seti Astro Suite’s Palette Picker’s Foraxx palette
Summary
These images represent my nascent mono processing skills, while the image below represents my nascent astrophotography capture and processing skills. While there is likely huge potential in the mono data for extreme creativity – the trade-off of time spent in capture and processing, at least at this point – has me leaning toward spending my precious clear skies time in dark skies with my OSC camera! But, I will keep practicing!
Other Images of B33/IC434 Horsehead & NGC2024 Flame Nebulae
Personal Fun Fact
This image was awarded second prize in the Astronomical League Williamina Fleming Imaging Award in the Deep Space Object category! (https://www.astroleague.org/content/williamina-fleming-imaging-award). Although I followed my normal process of putting newer images on the “top of the stack” the gallery – I still think that this is a much better capture of the Horsehead and Flame nebulae – with my Canon EOS Ra camera and essentially 6 months worth of astrophotography experience!
Equipment
Polar alignment: QHYCCD camera (controlled by Polemaster)
Imaging stream: Orion 8″ f/8 Ritchey-Chretien Astrograph Telescope; Canon EOS Ra with with Teleskop Service Flattener 1.0x for RC Telescopes (TS-RCFLAT2) and Optilong L-Pro light pollution filter
Mount: Sky-Watcher EQ6-R Pro Equatorial Mount (controlled by EQMOD)
Autoguider: Orion 60mm Multi-Use Guide Scope, Orion StarShoot AutoGuider Pro Mono Astrophotography Camera (controlled by PHD2)
All equipment controlled by HP Probook running Sequence Generator Pro v3.2.0.660.
Capture & processing notes
Sequence plan: ISO1600; 40x300sec + 25x30sec (for Alnitak) Notes: Captured, 29Jan2022, 1843MST – 2235MDT. Total exposure time: 3:20 hrs.
Capture: 29 January 2022
Shooting location: Mills Canyon, Kiowa National Grasslands, New Mexico
Processing: Stacked (5min in one stack, 30 sec in another) with Astro Pixel Processor (APP). Processed as layers in Photoshop.