View allAll Photos Tagged Subframing
You can see from the little machine marks that the subframe did get pushed backward a little in the collision.
3 Nov 2025, 02:00 UT; Spotsylvania, Virginia USA. Bortle 4.5 zone.
WO Redcat51 telescope, ZWO AM5 mount and ASI2600MC camera, autoguiding, calibration frames, exp 60s, gain 0, bin 1x1, sensor -20°C, autofocus, 95 subframes. Data acquired in ASIAir. Processed in PixInsight. Image scale: xx arcsec/pixel.
Clouds: partly cloudy
Transparency (AL): 5
Seeing (AL): F
Moon: illuminated xx%, age xx days
Apparent magnitude 5.6
Apparent size 6x3 arcmin
Appearance: Small dim reflection nebula with six bright stars in core. Other notable objects in the FOV include blue star HD 21402 (mag 5.7) at 10:00 position, orange star HD 21110 (mag 7.3) at 11:30, small blue reflection nebula vdB16 at 02:30, and several dark nebulae including Barnard 1, 2, and 202-205. Objective for this image is to appreciate wide FOV, although the image scale does not emphasize the most prominent objects.
Note: Calibration frames (bias, dark, flats, flat darks) were necessary to pull the dim nebulae out of the background haze. This image might benefit from adding StarX to the workflow and stretching the background independent of the stars.
From Wikipedia
NGC 1333 is a reflection nebula located in the northern constellation Perseus, positioned next to the southern constellation border with Taurus and Aries. It was first discovered by German astronomer Eduard Schönfeld in 1855. The nebula is visible as a hazy patch in a small telescope, while a larger aperture will show a pair of dark nebulae designated Barnard 1 and Barnard 2. It is associated with a dark cloud L1450 (Barnard 205). Estimates of the distance to this nebula range from 980–1,140 ly (300–350 pc).
This nebula is in the western part of the Perseus molecular cloud and is a young region of very active star formation, being one of the best-studied objects of its type. It contains a fairly typical hierarchy of star clusters that are still embedded in the molecular cloud in which they formed, which are split into two main sub-groups to the north and south. Most of the infrared emission is happening in the southern part of the nebula. A significant portion of the stars seen in the infrared are in the pre-main sequence stage of their evolution.
The nebula region has a combined mass of approximately 450 M☉, while the cluster contains around 150 stars with a median age of a million years and a combined mass of 100 M☉. The average star formation rate is 1×10−4 M☉ yr–1. Within the nebula are 20 young stellar objects producing outflows, including Herbig–Haro objects, and a total of 95 X-ray sources that are associated with known members of embedded star clusters. In 2011 researchers reported finding 30 to 40 brown dwarf objects in the cloud and in the Rho Ophiuchi cloud complex.
15 objects with a spectral type of M9 or later were discovered in NGC 1333. This spectral type corresponds to a mass of a planetary-mass object (PMO) at the age of NGC 1333. About 42% of the PMO are surrounded by a circumstellar disk, but only one out of six objects with a spectral type of L0 (about 10 MJ) or later has a disk. Scholz et al. argues that this indicates that very low mass PMOs form like planets (aka ejected planets) and not like stars (also called sub-brown dwarfs). Parker & Alves de Oliveira on the other hand argue that the distribution of PMOs in NGC 1333 follows N-body simulations of objects that form like stars and that none of the PMOs has a peculiar motion, which is predicted for ejected planets. They also note that ejected planets are hiding in this and other star-forming regions. Additional PMOs were discovered by Scholz et al. 2012 with Subaru (e.g. SONYC-NGC1333-36 with estimated 6 MJ) and by Langeveld et al. 2024 with JWST (6 objects and one JuMBO candidate). Langeveld et al. did not find any object below 4 MJ, despite JWST being sensitive enough to detect these objects. This could mean that star-formation does not occur below 4 MJ, which is consistent with previous observations in most star-forming regions and the nearby stellar population. One source, called NIRISS-NGC1333-5 (NN5), shows infrared excess, which is an indication of a disk around the object. With a mass of 5 MJ, this object could be one of the lowest mass object with a disk known so far.
Just a couple of sketches of the stock subframe to give me ideas on how I can simplify my subframe design. This is mainly just for my own reference.
24 Jan 2026, 03:07 UT; Spotsylvania, Virginia USA. Bortle 4.5 zone.
Stellarvue SV80/9D achromat telescope, ZWO AM5 mount and ASI533MM Pro camera, autoguiding, no calibration frames, SVBony 5nm narrowband filters, exp 240s, gain 100, bin 1x1, 15 subframes each filter (S, H, and O), sensor -10°C, autofocus. Data acquired in ASIAir and processed in Pixinsight. Image scale: 1"/pixel.
Clouds: scattered clouds
Transparency (AL): 5
Seeing (AL): F
Moon: illuminated 28%, age 5.3 days
Apparent magnitude - very dim
Apparent size 50 arcmin
Notes: False color -- narrowband SHO data processed in the Hubble palette to differentiate areas of Sulfur II, Hydrogen alpha, and Oxygen III emission.
Appearance: Significant portions of target cutoff at right and bottom of frame. Use longer test exposure (without filter) when framing dim targets. Redcat51 with ASI533 would provide better FOV for framing this target.
From Wikipedia
IC 443 (also known as the Jellyfish Nebula and Sharpless 248 (Sh2-248)) is a galactic supernova remnant (SNR) in the constellation Gemini. On the plane of the sky, it is located near the star Eta Geminorum. Its distance is roughly 5,000 light years from Earth.
IC 443 may be the remains of a supernova that occurred 30,000 - 35,000 years ago. The same supernova event likely created the neutron star CXOU J061705.3+222127, the collapsed remnant of the stellar core. IC 443 is one of the best-studied cases of supernova remnants interacting with surrounding molecular clouds.
The SNR optical and radio morphology is shell-like (e.g. a prototypical shell-like SNR is SN 1006), consisting of two connected sub-shells with different centers and radii. A third, larger sub-shell—initially attributed to IC 443—is now recognized as a different and older (100,000 years) SNR, called G189.6+3.3.
Notably, IC 443 X-ray morphology is centrally peaked and a very soft X-ray shell is barely visible. Unlike plerion remnants, e.g. the Crab Nebula, the inner X-ray emission is not dominated by the central pulsar wind nebula. It has indeed a thermal origin. IC 443 shows very similar features to the class of mixed morphology SNRs. Both optical and X-ray emission are heavily absorbed by a giant molecular cloud in the foreground, crossing the whole remnant body from northwest to southeast.
The remnant's age is still uncertain. There is some agreement that the progenitor supernova happened between 3,000 and 30,000 years ago. Recent Chandra and XMM-Newton observations identified a plerion nebula, close to the remnant southern rim. The point source near the apex of the nebula is a neutron star, relic of a SN explosion. The location in a star forming region and the presence of a neutron star favor a Type II supernova, the ultimate fate of a massive star, as the progenitor explosion.
The SNR IC 443 is located in the galactic anticenter direction (l=189.1°), close to the galactic plane (b=+3.0°). Many objects lie in the same region of sky: the HII region S249, several young stars (members of the GEM OB1 association), and an older SNR (G189.6+3.3).
The remnant is evolving in a rich and complex environment, which strongly affects its morphology. Multi-wavelength observations show the presence of sharp density gradients and different cloud geometries in the surroundings of IC 443. Massive stars are known to be short lived (roughly 30 million years), ending their life when they are still embedded within the progenitor cloud. The more massive stars (O-type) probably clear the circum-stellar environment by powerful stellar winds or photoionizing radiation. Early B-type stars, with a typical mass between 8 and 12 solar masses, are not capable of this, and they likely interact with the primordial molecular cloud when they explode. Thus, it is not surprising that the SNR IC 443, which is thought to be the aftermath of a stellar explosion, evolved in such a complex environment. For instance, an appreciable fraction of supernova remnants lies close to dense molecular clouds (~50 out of 265 in the Green catalogue), and most of them (~60%) show clear signs of interaction with the adjacent cloud.
X-ray and the optical images are characterized by a dark lane, crossing IC 443 from northwest to southeast. Emission from quiescent molecular gas has been observed toward the same direction,[9] and it is likely due to a giant molecular cloud, located between the remnant and the observer. This is the main source of extinction of the low energy SNR emission.
In the southeast the blast wave is interacting with a very dense (~10,000 cm−3) and clumpy molecular cloud, such that the emitting shocked gas has a ring-like shape. The blast wave has been strongly decelerated by the cloud and is moving with an estimated velocity of roughly 30–40 km s−1. OH (1720 MHz) maser emission, which is a robust tracer of interaction between SNRs and dense molecular clouds, has been detected in this region.[11] A source of gamma-ray radiation is spatially coincident with IC 443 and the maser emission region, though is not well understood whether it is physically associated with the remnant or not.
In the northeast, where the brightest optical filaments are located, the SNR is interacting with a very different environment. The forward shock has encountered a wall of neutral hydrogen (HI), and is propagating into a less dense medium (~10-1,000 cm−3) with a much higher velocity (80–100 km s−1) than in the southern ridge.
In the western region, the shock wave breaks out into a more homogeneous and rarefied medium.