The NGC410 group of Galaxies in the constellation Pisces

 

NGC410 Group 
PIRATE robotic telescope. Data Credit: telescope.org, Open Observatories, Open University. Image Credit: Pip Stakkert Jodrell Plank Observatory.  

First Crop of the NGC410 Group

Second Crop of the NGC410 Group

Annotated version of the second crop image.
Credits: astrometry. net and Stellarium +

" When you have a large aperture telescope, located high on a dormant volcano, above the clouds, peering through less of the Earth's dynamic and murky atmosphere and away from light pollution, you can obtain excellent data which can be processed to show distant and faint astronomical objects. The PIRATE and COAST robotic telescopes on Mount Teide, Tenerife certainly fit this bill. The above images show what can be seen as the original footprint of the night sky on the Pisces, Cygnus border, captured with the PIRATE telescope, has been cropped once and then twice by Pip Stakkert at the Jodrell Plank Observatory. The image shows many galaxies and galaxy groups just on the edge of visibility in the final crop. In particular PGC 4234 is just the largest of a group of galaxies which have magnitudes of 15 or more. What is obvious from this image of just a tiny part of the sky, is how mind boggling huge the cosmos is and how many galaxies and stars abound. Our good friend, Prof G.P.T Chat, estimates that in the Galaxies shown in the above image (NGC 407, NGC 408, NGC 410, NGC 414A, NGC 414B, PGC 4234, and PGC 4206  ) there are some 650 to 700 billion stars. Of this total, there are probably some 450 billion stars in NGC 410 alone "! - Kurt Thrust current Director of the Jodrell Plank Observatory.

Comparative Study of Galaxies in the Constellation Pisces by Professor G.P.T Chat (visiting astrophysicist) and Kurt Thrust

This report presents a comparative analysis of seven galaxies located in the constellation Pisces: NGC 407, NGC 408, NGC 410, NGC 414A, NGC 414B, PGC 4234, and PGC 4206. The study examines their morphological type, apparent size, distance, luminosity, spectral characteristics, and stellar population age, with the goal of identifying similarities and differences in their evolutionary status and galactic environments.

Morphological Classification and Structure

The sample includes a range of morphological types, from elliptical and lenticular to actively star-forming spiral galaxies. NGC 410, the most prominent member of this group, is classified as a large elliptical galaxy (E), possibly cD-type, typical of galaxies found at the centers of groups or clusters. It exhibits a smooth, rounded structure with an extended halo.

In contrast, NGC 407 is an edge-on lenticular or early-type spiral galaxy (S0/a), characterized by a thin disk and little to no visible spiral structure. Similarly, NGC 414A and NGC 414B form a compact galactic pair, both classified as lenticular (S0) or elliptical/lenticular hybrids (E/S0). These galaxies show minimal disk structure and are likely passively evolving.

NGC 408 is somewhat of an outlier in this group. Though not as well-characterized morphologically, it appears to be a late-type spiral galaxy, likely of Sc-type or later, due to its ongoing star formation and detection of an ultraluminous X-ray source (ULX). This implies the presence of massive, young stellar populations.

Size and Scale

In terms of angular size, NGC 410 is the largest in the group, spanning approximately 2.4 arcminutes by 1.3 arcminutes, which corresponds to a physical size of about 170,000 light-years at its estimated distance. NGC 407 is slightly smaller, measuring about 1.7 by 0.4 arcminutes, with a thinner, disk-like appearance due to its edge-on orientation. The NGC 414 pair is more compact, with each component contributing to a combined angular size of approximately 0.8 arcminutes, translating to a physical size of roughly 50,000 light-years.

While NGC 408 lacks detailed size measurements, its star-forming nature suggests it is a moderately sized spiral galaxy, possibly comparable to the Milky Way in extent.

Distance and Redshift

The galaxies in this study lie at similar redshifts, ranging from z ≈ 0.01578 to z ≈ 0.01859, corresponding to distances of approximately 210 to 250 million light-years (or 64 to 77 Mpc). Specifically, NGC 414A/B are the closest, at around 210 million light-years, followed by NGC 410 at 240 million light-years, and NGC 407 slightly farther at 250 million light-years. Although a precise redshift for NGC 408 is not readily available, it is likely to be at a comparable distance, given its spatial proximity and grouping.

It is worth noting that PGC 4234 and PGC 4206 are catalog designations equivalent to NGC 410 and NGC 407, respectively, and therefore share identical properties.

Luminosity and Spectral Properties

NGC 410 is the brightest galaxy in this group, with an apparent visual magnitude of 12.5. Spectral studies reveal it to be a composite LINER/H II galaxy, indicating low-level nuclear activity possibly powered by weak AGN processes, as well as localized star formation. Its spectral profile includes weak emission lines typical of low-ionization nuclear emission-line regions (LINERs) and ionized gas from H II regions.

NGC 407, with a visual magnitude of 14.3, also exhibits features consistent with a low-activity galactic nucleus, possibly LINER-like, although detailed spectral data are limited. NGC 414A and 414B are slightly fainter, with a combined magnitude around 14.5, and show little evidence of active star formation or nuclear activity, consistent with their lenticular morphology.

NGC 408, while less luminous in optical bands, is notable for hosting a ULX (ultraluminous X-ray) source emitting at approximately 3.4 × 10³⁹ erg/s. This is indicative of high-mass X-ray binaries or possible intermediate-mass black holes, commonly found in regions of intense star formation. The galaxy’s star formation rate is estimated at about 4.5 solar masses per year, supporting the presence of a younger, actively evolving stellar population.

Stellar Population and Age

Stellar age estimates across this group generally reflect the galaxies’ morphological types. NGC 410, as a massive elliptical galaxy, is dominated by an old stellar population, with most stars likely formed over 10 billion years ago, although the presence of weak H II emission suggests some intermediate-age components (~1–3 billion years) in the nucleus.

NGC 407 and NGC 414A/B, being lenticular galaxies, also contain predominantly older stars, consistent with passive evolution and little to no ongoing star formation. These systems likely ceased significant star formation several billion years ago and now exhibit red, evolved stellar populations.

NGC 408, by contrast, contains young stellar populations, particularly in regions associated with the observed ULX. The age of these populations is likely less than 100 million years, indicating that the galaxy is still actively forming stars, unlike the others in this sample.

Conclusions and Scientific Context

This comparative study highlights the diversity of galactic properties within a relatively small section of the Pisces constellation. NGC 410 stands out as a giant elliptical galaxy with modest nuclear activity and a dominant old stellar population. NGC 407 and the NGC 414 pair represent passively evolving lenticular systems, consistent with aging stellar populations and little gas content. In contrast, NGC 408 displays signs of active galactic evolution, with high star formation rates and energetic X-ray sources that set it apart from the rest.

Although all galaxies lie at similar distances, suggesting they may belong to related local structures or loose groups, their internal dynamics and star formation histories vary significantly. Further high-resolution imaging and spectroscopic surveys would help refine stellar age distributions, gas content, and environmental interactions—particularly for less studied systems like NGC 408 and the 414 pair.

In summary, this group of Pisces galaxies exemplifies the range of evolutionary pathways observed in the local universe, from quiescent elliptical systems to actively star-forming spirals, offering valuable insight into the lifecycle of galaxies across cosmic time.

Summary Table

Galaxy	Type	Apparent Size (′)	Redshift / Velocity	Distance (ly)	Luminosity & Spectra	Age Estimate (stellar pop.)
NGC 407	S0/a (edge‑on lenticular/spiral) Wikipedia+4Wikipedia+4Wikipedia+4	1.7′ × 0.4′	z ≈ 0.01859; 5,573 km/s Wikipedia	≈ 250 million ly (≈75 Mpc)	m_V ≈ 14.3; intermediate activity, likely LINER-like	Intermediate to old bulge (~1–10 Gyr typical)
NGC 408	Spiral (likely Sc‑type) (limited data)	—	(No direct redshift found)	Poorly characterized; likely similar distance (z0.015–0.020)	Host of ULX X‑ray source; star‑forming (~4.5 M_⊙/yr) arXiv	Active star formation implies young (<100 Myr) populations in parts
NGC 410	Elliptical (E), cD/LINER‑H II composite de.wikipedia.orgWikipedia	2.4′ × 1.3′	z ≈ 0.01766; ~5,294 km/s WikipediaGo-Astronomy.com	~240 million ly (~73 Mpc) de.wikipedia.org	m_V ≈ 12.5; contains LINER/H II regions, some star formation regions de.wikipedia.orgGo-Astronomy.com	Dominated by old stellar populations, though nuclear region may include ~10⁸–10⁹ yr intermediate populations
NGC 414A / 414B	A: S0, B: E/S0 within NGC 414 pair Wikipedia	Combined ~0.8′ – likely individual ~0.4′	z ≈ 0.01578; 4,730 km/s Wikipedia	≈ 210 million ly (~64 Mpc)	m_V ≈ 14.5; typical lenticular spectra, likely no strong emission lines	Generally old (~few Gyr), low ongoing star formation
PGC 4234	Equivalent to NGC 410 (PGC 4224) de.wikipedia.orgWikipedia	same as above	same as NGC 410	same ~240 million ly	same	same
PGC 4206	Equivalent to NGC 407 (PGC 4190) Wikipedia	same as NGC 407	same as NGC 407	~250 million ly	same	same

In the words of Southend's Ian - " Getting there"! - 'Seestar S30 Objective lens filter Spectrometer'.

 

1 - Tack bonding the 80 lines/mm. holographic printed
transmission grating film to the 3d printed holder

2- The film holding ring fixed to the grating holder
and gripping the grating firm and flat between them.

 

3 - The magnetic Seestar fixing ring being filled
with epoxy resin doped with iron filings.

" Putting together the separate elements is relatively simple using super-glue gel and two part epoxy resin putty. The grating was obtained from China via the internet. Whether an 80 lines/mm. grating was the right choice remains to be seen when we try it out on the Seestar.The lines per millimetre determine the angle of dispersion, the spread of the spectrum on the camera sensor and the resolution of the spectral profile. Currently, in the JPO stores, we have 100 lines/mm. and 500 lines/mm grating film awaiting future projects. 

1 - This image shows the grating film, which we had previously cut to size, having been tack glued to the 3d printed grating holder. You will note that the grating covers 50% of the full aperture. This was done to help the Seestar's goto, guidance and stacking algorithms, which might otherwise struggle if the full aperture was 100% covered by the grating.

2 - This image shows Kurt Thrust holding the spectrometer, the fixing ring having been bonded to the grating holder, gripping the film flat and firmly between the two. If you look closely, you can see the light from the lamps in the clean room displaying spectra after passing through the grating.

3 - Unfortunately, we did not possess any magnetic fibre for our 3d printer. As the rolls available on the Internet were much larger than our requirements and quite expensive, we decided to try to incorporate iron filings into the design, which might allow the spectrometer to be affixed, when required, to the Seestar using its integral magnets. Joel Cairo runs a fiscally tight ship! The image shows the fixing ring with its central groove now filled with a mixture of epoxy resin and iron filings. If this does not work, we will have to think again and Joel might have to get his wallet out!! The resin takes 24 hours to fully dry, so we shall have to be patient. If the ring does fix to the Seestar magnets, when we  try it tomorrow, we will stick it permanently, to the underside of the spectrometer, using super-glue gel.

The team at the Jodrell Plank Observatory are all getting rather excited as to whether this device will work with the little Seestar S30. Clearly, this spectrometer will not provide spectral profiles to the higher resolution we regularly achieve with our other 500 lines/mm QHY5-11 mono cam- spectrometer attached to the 127mm and 66mm telescopes at the JPO. It will however; benefit from being easy to set up and use, be full mobile and have accurate 'goto' and 'tracking-stacking' software, 

Once we have trialled the spectrometer and obtained satisfactory test spectral profiles for stars, we will be happy to freely share 3d printer STL files for the constituent parts of the 'Seestar S30 Objective lens filter Spectrometer'. - Karl Segin community out-reach coordinator at the Jodrell Plank Observatory.

All the staff at the JPO wish to congratulate Professor Michele Dougherty on being appointed as the new Astronomer Royal !!!!

Calibration, 3d printing, design development and the final print prototype rings for the Seestar S30 stellar spectrometer.

 

"  Busy - busy in the Jodrell Plank Observatory Clean Room today! The first prints made by Jolene had to be scrapped for two reasons; the first being, the printer configuration files and the print bed levelling had both been corrupted, whilst the 3d printer had been in storage and the second being, fabrication problems associated with the spectrometer design.

When she tried to fit the first prints together and on to the Seestar S30, the parts clearly didn't fit even though she applied some force. Kurt had to intervene by shouting " Jolene, Jolene, Jolene, Jolene......, please don't break it, just because you can" !

Several hours were spent, configuring the printer parameters and levelling the print bed to ensure the printer was working at its best. Several more hours were used re visiting and changing the design for the better.

The above plans show the three redesigned parts of the spectrometer, which interlock to hold 50% of the transmission grating in front of the Seestar's 30mm objective lens system and fix the spectrometer unit magnetically to the Seestar S30's housing.

Tomorrow our instrumentation engineer, Jolene McSquint- Fleming, will be combining and fixing all of the parts and completing the prototype spectrometer. We then just need a clear night in Lowestoft, so we can try it out"! - Joel Cairo CEO of the Jodrell Plank Observatory.

The three printed components shown on the 3d Printer Bed

A close up of the three components

The 3 components loosely put together to check the fit
and as seen from the bottom and Seestar end.
The transmission diffraction grating will be
sandwiched between the two upper components.

Dedicated transmission spectrometer grating for the Seestar S30

 

OpenScad designs for interlocking 3d printed holders
for an 80 lines/mm. holographic printed film grating

" Our instrumentation engineer at the JPO, Jolene Mc Squint-Fleming, has finally got around to designing a transmission grating holder for the Seestar S30. We have had the holographic printed film available for some time but have been thinking through the issues involved before finalising the design of the proto-type holder. 

The Seestar is a little bit of a 'black box' to us at the JPO but the general consensus was that a grating which covered only 50% of the little scope's objective lens was less likely to interfere with the on board 'goto' and 'guidance' software and subroutines. With all prototypes there is an element of try it and see.

The next stage is to refurbish, reset and program the 3d printer in the JPO 'clean room' and have Jolene print the two interlocking elements of the objective lens grating holder. Completing the prototype Seestar S30 stellar spectrometer will then be a straight forward and easy build.

A first light project for the spectrometer prototype is the variable star Cygni34 or P Cygni, which has an interesting spectral profile with a strong H-alpha emission peak.

P Cygni (34 Cygni) is a variable star in the constellation Cygnus. The designation "P" was originally assigned by Johann Bayer in Uranometria as a nova. Located about 5,300 light-years (1,560 parsecs) from Earth, it is a hypergiant luminous blue variable (LBV) star of spectral type B1-2 Ia-0ep that is one of the most luminous stars in the Milky Way". - Kurt Thrust current Director of the Jodrell Plank Observatory.

The variable star P Cygni - data captured some time ago at the JPO using the 66mm Altair Lightwave  ED Doublet on the Star Adventurer EQ mount but reprocessed using SIRIL and Affinity Photo 2.

Messier 51 and NGC 5195 revisited with the COAST robotic telescope.

 

Interacting Galaxies M51(NGC 5194) and NGC 5195
- Data Credit:telescope.org, Open Observatories, Open University.
Image Credit: Kurt Thrust at the JPO. 

"With time on his hands, Kurt Thrust found data captured from Tenerife with the COAST robotic telescope and BVR filters in 2024. He worked on the data to emphasise the bright spiral arms in Messier 51 where star formation is evident". - Joel Cairo CEO of the Jodrell Plank Observatory.

Tidal Encounters and Star Formation in the M51 System: A Case Study of NGC 5194 and NGC 5195

A high-resolution optical image of the M51 system. NGC 5194 (left) displays grand-design spiral arms that wrap around the smaller, lenticular companion NGC 5195 (right). This iconic view shows the tidal bridge of stars and gas connecting the two galaxies—a clear signature of their ongoing gravitational interaction.

                    Optical Image of the M51 System (NGC 5194 and NGC 5195)

Source: Hubble Space Telescope / NASA, ESA

Authors: Professor G.P.T Chat, visiting astrophysicist at the Jodrell Plank Observatory and Kurt Thrust current Director of the Jodrell Plank Observatory.

The M51 system, composed of the grand-design spiral galaxy NGC 5194 and its smaller companion NGC 5195, represents one of the most well-studied examples of galaxy interaction in the nearby universe. Their ongoing gravitational interaction provides a compelling laboratory for investigating the dynamical processes that drive morphological transformations and star formation. In this report, we examine the tidal influence of NGC 5194 on NGC 5195 and explore the implications of their interaction on recent star formation activity within the system, particularly focusing on the peculiar case of NGC 5195, which exhibits signs of both past and suppressed star formation.

1. Introduction

Interacting galaxies provide critical insights into the dynamical evolution of galactic systems. The Whirlpool Galaxy (M51), comprising the spiral galaxy NGC 5194 and its lenticular companion NGC 5195, lies approximately 23 million light-years away in the constellation Canes Venatici. This pair is a prototypical example of a tidal encounter between a massive spiral and a smaller companion. The interaction, first modeled numerically by Toomre & Toomre (1972), is responsible for M51’s prominent spiral structure and continues to be a benchmark for simulations of galaxy interactions.

2. Gravitational Interaction Dynamics

NGC 5195 is currently located just beyond the plane of NGC 5194 and is moving away after a recent close passage through the disk of the larger spiral. This gravitational encounter has triggered large-scale tidal perturbations in both galaxies. The most conspicuous result of this interaction is the grand-design spiral arms of NGC 5194, which have been amplified and maintained by the torque induced by NGC 5195’s gravitational pull.

Simulations and observations suggest that NGC 5195 passed through the disk of NGC 5194 roughly 100–300 million years ago. This close passage induced strong tidal forces, generating density waves in the disk of NGC 5194, enhancing gas compression and leading to significant episodes of star formation. Tidal bridges and tails, seen in H I and optical imaging, confirm this interaction and show material being exchanged between the galaxies.

3. Star Formation in NGC 5195

While NGC 5194 exhibits intense star-forming regions along its spiral arms, NGC 5195 presents a more complex and nuanced case. Classified as an SB0-type lenticular galaxy, NGC 5195 possesses limited cold gas reserves and lacks the large-scale disk structure typically conducive to starburst activity. However, recent multiwavelength observations (e.g., Hubble Space Telescope, Spitzer, and Chandra) have revealed signs of localized star formation and nuclear activity, suggesting the interaction has not been entirely passive for the companion.

                                   Multiwavelength View of Star Formation in the M51 System

Data: Hubble (optical), Spitzer (IR), GALEX (UV), and Chandra (X-ray). Composite credit: NASA / ESA / JPL-Caltech / CXC

Notably, UV and H α imaging reveal faint emission in the central and circumnuclear regions of NGC 5195, indicative of recent, though limited, star formation. The triggering mechanism is likely tidal compression from the interaction, which funneled residual gas into the inner regions. Despite this, the overall star formation rate (SFR) in NGC 5195 remains significantly lower than that of NGC 5194, suggesting either a depletion of star-forming gas or the presence of feedback mechanisms (e.g., AGN activity or supernova-driven outflows) inhibiting widespread star formation.

4. Gas Dynamics and Feedback Processes

CO and H I mapping have shown that while some interstellar medium (ISM) exists in NGC 5195, it is largely confined to its central regions. The lack of extensive molecular gas may explain the subdued star formation. Furthermore, X-ray observations reveal hot gas bubbles and shock-heated regions, implying that energy injection from past starburst episodes or AGN feedback could have disrupted the ISM, suppressing further star formation.

The interface region between NGC 5194 and NGC 5195 shows tidal tails and ionized gas streams, suggesting that the gravitational encounter has facilitated gas exchange. Whether this material will reignite star formation in NGC 5195 remains an open question, dependent on future accretion and cooling timescales.

5. Conclusion

The M51 system exemplifies how tidal interactions shape galaxy morphology and star formation. While NGC 5194 responds to the interaction with a classic spiral arm starburst, NGC 5195 shows only limited, localized star formation, constrained by morphological type, gas availability, and possible feedback mechanisms. The gravitational dance of these two galaxies continues to sculpt their evolution, offering astronomers a vivid example of the complex interplay between dynamics and star formation in interacting systems.

References:

Toomre, A., & Toomre, J. (1972). Galactic Bridges and Tails. ApJ, 178, 623.

Smith, B. J., et al. (2010). Triggered Star Formation in Interacting Galaxies. AJ, 139(3), 1212.

Dumas, G., et al. (2011). Gas Kinematics and Feedback in M51’s Companion. A&A, 528, A10.

Mentuch Cooper, E., et al. (2012). Star Formation in Interacting Galaxies. MNRAS, 419(2), 1409.

Messiers: 99 and 83, Spiral Galaxies

 

Messier 99 - PIRATE robotic telescope, Tenerife, BVR filters
- data  credit: telescope.org, Open Observatories, Open University.
Image credit: Pip Stakkert - Jodrell Plank Observatory.

Messier 83 - PIRATE robotic telescope, Tenerife, BVR filters
- data  credit: telescope.org, Open Observatories, Open University.
Image credit: Kurt Thrust - Jodrell Plank Observatory.

" On recent nights the weather in Lowestoft has prevented any astro-data collection. This is a great pity as the team was enthusiastic about using our Seestar S30 to capture 60 second light subs for the first time. We purchased the Seestar just under a year ago and in that time ZWO, the robotic scopes manufacturer, has upgraded the software app and firmware for free, to enable use on an EQ mount, mosaic mode and now extended subs. The Seestar S30 is excellent value for money!

As we have been unable to capture our own photons, we have been relying on the Open Observatories robotic telescope, PIRATE, to provide them for us. We have just programmed it to take some images of the galaxy NGC 7331 where there has been a recent supernova". - Joel Cairo CEO the Jodrell Plank Observatory.

Galactic Twins Across the Cosmos: A Comparative Look at Spiral Galaxies M99 and M83

By Professor G.P.T. Chat, for the Jodrell Plank Observatory Blog

In the vast tapestry of the universe, spiral galaxies unfurl like celestial pinwheels, each with a unique character shaped by millions—sometimes billions—of years of cosmic evolution. Among these stellar masterpieces, Messier 99 (M99) and Messier 83 (M83) stand out not only for their striking beauty but also for the scientific insight they offer into the life cycle and structure of spiral galaxies. Though separated by millions of light-years, these two galaxies reveal a tale of similarity and contrast, hinting at the forces that sculpt the universe.

The Galactic Players: M99 and M83

M99, located in the constellation Coma Berenices about 50 million light-years from Earth, is a prime example of a grand design spiral galaxy. It is classified as SA(s)c, indicating a loosely wound spiral structure with well-defined arms. Discovered in 1781 by Pierre Méchain, M99 forms part of the Virgo Cluster, a bustling galactic metropolis where interactions are frequent and often dramatic.

In contrast, M83—often referred to as the "Southern Pinwheel"—resides a mere 15 million light-years away in the constellation Hydra. It is categorized as SAB(s)c, suggesting a weak central bar and open spiral arms. Unlike M99, M83 sits on the outskirts of the Centaurus A/M83 Group, a smaller galactic neighborhood. Despite its relative isolation, M83 is anything but quiet.

Structure and Symmetry

Visually, both galaxies exhibit a stunning spiral symmetry, yet their internal structures tell different stories. M99’s arms are elegant but asymmetrical—a clue to its recent turbulent past. Astronomers believe that M99’s lopsided appearance is due to gravitational interactions, likely with nearby galaxies or the intracluster medium of the Virgo Cluster. These interactions may have sparked bursts of star formation and slightly distorted the galaxy’s spiral arms, giving M99 a distinctive "tilted" visage.

M83, on the other hand, shows near-perfect symmetry with six prominent spiral arms radiating from its central bar. Its arms are dust-rich and laced with regions of intense star formation—evident in ultraviolet and H-alpha imaging. The presence of a central bar hints at internal dynamics that funnel gas inward, fueling both starbursts and the possible growth of a central black hole. M83’s smooth, organized spiral structure contrasts with M99’s more chaotic appearance, pointing to a relatively undisturbed evolutionary path.

Starbirth and Stellar Populations

Both M99 and M83 are prolific stellar nurseries, but the scale and intensity of their star formation vary. M99’s star-forming activity is concentrated in its spiral arms and outer disk. Its location within a cluster and the presence of hydrogen gas suggest ongoing accretion and interaction-induced starbursts.

M83, however, is in a league of its own. It is one of the closest and most studied starburst galaxies. Its central region is a hotbed of star formation, with hundreds of young clusters and supernova remnants dotting its inner spiral arms. Since 1923, astronomers have recorded at least six supernovae in M83—an unusually high number that underscores its vigorous star-forming processes.

Infrared and X-ray observations have also revealed a dense, turbulent core where massive stars are born and die in rapid succession. M83’s central starburst activity contrasts sharply with M99’s more evenly distributed stellar generation, offering a compelling case for how environment and internal dynamics shape galactic evolution.

Galactic Narratives

In many ways, M99 and M83 offer a comparative window into two archetypes of spiral galaxies—one shaped by external pressures, the other by internal dynamism.

M99’s story is one of interaction and adaptation. Nestled within the Virgo Cluster, it is subject to tidal forces and intergalactic encounters. These interactions, while disruptive, also stimulate growth and transformation. Its asymmetry and off-center star formation reflect a galaxy in flux—a portrait of evolution in motion.

M83, in contrast, illustrates what happens when a spiral galaxy is largely left to its own devices. With fewer gravitational disruptions, M83 has had the opportunity to develop a strong internal structure and maintain a stable star-forming regime. Its intense central starburst activity, fueled by its bar, speaks to an inward-focused evolution—driven not by external collisions, but by a well-regulated internal engine.

Conclusion

Though they are separated by tens of millions of light-years and shaped by different cosmic environments, M99 and M83 both exemplify the richness and diversity of spiral galaxies. Their comparative analysis allows astronomers to decode the influence of environment, structure, and internal dynamics on galactic evolution.

In the grand chronicle of the universe, galaxies like M99 and M83 are more than just distant pinwheels of stars—they are dynamic ecosystems, each with a history written in gas, dust, and light. By studying them side by side, we begin to unravel the universal threads that bind all spiral galaxies, including our own Milky Way, to the cosmic story.

References

NASA/IPAC Extragalactic Database (NED)

Hubble Space Telescope Imaging Archives

Chandra X-ray Observatory

de Vaucouleurs, G. et al., The Third Reference Catalogue of Bright Galaxies

The Great Globular Star Cluster in the constellation Hercules

 

Two views of the Globular Star Cluster M13.
On the left: a widefield combination of data from our Seestar S30 in Suffolk and the PIRATE robotic telescope on Teneriffe. On the right: an enlarged view of the cluster captured with the PIRATE robotic telescope. Data credits: telescope org, Open Observatories, Open University and the Jodrell Plank Observatory. Image credit: Kurt Thrust.

"The Great Globular Star Cluster, M13, in the constellation Hercules is one of the Northern Hemisphere's 'show stopping' astronomical sights. It can be seen in binoculars from a dark site and is aa go to target for the Jodrell Planks 80x11mm tripod mounted binoculars" - Joel Cairo CEO of the Jodrell Plank Observatory.

Messier 13 in all its glory. Data credit: PIRATE robotic telescope Mount Teide, Teneriffe. Image credit: Pip Stakkert at the JPO.

"What is M13?

Messier 13 is a globular star cluster, which is essentially a spherical collection of hundreds of thousands of stars, all gravitationally bound together and orbiting the halo of our galaxy. It's one of the brightest and best-known globular clusters visible from the Northern Hemisphere, located about 22,200 light-years from Earth in the constellation Hercules.

Stellar Composition and Evolution

Globular clusters like M13 are ancient—roughly 11.65 billion years old, formed not long after the Big Bang. This means almost all the stars within M13 are Population II stars—old, metal-poor, and long-lived.

Most of these stars are low-mass, mainly around 0.8 solar masses, since more massive stars have already evolved off the main sequence. The more massive ones that once existed would have become white dwarfs, neutron stars, or possibly black holes by now.

You can see this reflected in M13’s Hertzsprung-Russell (H-R) diagram: the main sequence ends fairly early, and there’s a prominent red giant branch, with stars in post-main-sequence stages of evolution. Many of these stars are currently in the helium-burning phase, having already exhausted hydrogen in their cores.

Structure and Dynamics

M13 is about 145 light-years in diameter and contains around 300,000 stars. The cluster has a high stellar density, especially toward its core. In the center, stars are separated by just 0.1 light-years or less, compared to around 4 light-years between stars in our solar neighborhood.

Despite this density, stars rarely collide directly due to their small sizes relative to the vast distances between them. However, gravitational interactions are frequent and important. These close encounters can:

Cause mass segregation: heavier stars sink toward the core, while lighter ones migrate outward.

Create binary systems or disrupt existing ones.

Lead to blue straggler stars—stars that appear younger and hotter, likely formed via stellar mergers or mass transfer in binary systems.

Pip Stakkert asked Copilot AI to create a night view of M13 as seen from a rocky airless planet orbiting a star within the Globular cluster. If the star was located towards the the centre of M13 the sky would be awash with light from  thousands of stars and as bright as day.

Orbital Mechanics and Galactic Role

M13 orbits the Milky Way’s galactic center in a roughly elliptical path. Its motion is governed by the galaxy’s gravitational potential. As it orbits, it experiences tidal forces from the Milky Way, which can strip stars from the outer regions—a process called tidal stripping.

Over billions of years, some stars are pulled into tidal streams that trail behind the cluster. These streams are important to astronomers because they help trace the mass distribution and dark matter content of the Milky Way.

Metallicity and Formation Clues

M13 has a metallicity ([Fe/H]) of about –1.5, meaning its stars contain only about 1/30th the iron content of the Sun. This tells us they formed at a time when the universe hadn’t yet produced much heavy element enrichment via supernovae.

Interestingly, while globular clusters were once thought to be composed of stars with a single age and composition, we now know that clusters like M13 show evidence of multiple stellar populations. This means they might have gone through more complex formation histories than originally believed, possibly involving early bursts of star formation or enrichment from earlier generations of stars.

Why Is M13 Special?

Besides being one of the brightest globular clusters, M13 has served as a kind of cosmic message board. In 1974, astronomers sent the Arecibo message toward M13—an interstellar radio message designed to demonstrate human technological achievement. Of course, M13 will have moved by the time the message arrives in 25,000 years, but the symbolism still stands.

Final Thoughts

M13 is a stunning example of gravitational physics in action. It's a self-contained stellar ecosystem where stars evolve, interact, and sometimes collide. Its dynamics help us understand everything from stellar evolution and galactic structure to the early conditions of the universe.

Despite its beauty, M13 is a harsh environment—dense, old, and metallically poor. Yet, within that ancient crucible, the dance of gravity continues, slowly shaping the fates of hundreds of thousands of stars across billions of years". - Professor G.P.T Chat visiting astrophysicist at the Jodrell Plank Observatory

Messier 20- The Trifid Nebula

 

Messier 20 data credit: PIRATE robotic telescope, Teneriffe.
telescope.org, Open Observatories, Open University.
Processing credit: Pip Stakkert the Jodrell Plank Observatory.

" Pip Stakkert has been reading MasterClass in Astronomy Now and decided to experiment with data captured with the PIRATE robotic telescope, using BVR, SHO, H-alpha and clear filters. The image shows lots of very faint nebulosity around the main areas of emission (red) and reflection (blue) nebulae. Even cursory inspection reveals dark nebulae (clouds of dust) that permeate he brighter nebulae. What a shame that this interesting  target does not rize above the Jodrell Plank Observatory's southern horizon". - Kurt Thrust current Director of the Jodrell Plank Observatory.

"Messier 20 (M20), also known as the Trifid Nebula, is a visually striking object in the constellation Sagittarius, approximately 4,100–5,200 light-years away from Earth. It’s an active star-forming region and a rare combination of three distinct types of nebulae.

 The Three Types of Nebulae in M20:

1. Emission Nebula (H II Region)

 Location: Central and red-pink regions of M20.

 Appearance: Glows with a reddish hue due to hydrogen-alpha emission.

Physical Process: Ultraviolet radiation from young, massive stars (especially an O7-type star near the core) ionizes the surrounding hydrogen gas. When electrons recombine with protons, they emit photons, most prominently in the Hα line at 656.3 nm.

Temperature: \~10,000 K.

Size: The ionized region spans several light-years in diameter.

2. Reflection Nebula

Location: Blue-hued regions, mostly in the northern part of M20.

Appearance: Blue due to scattered starlight by dust grains.

Physical Process: Unlike emission nebulae, reflection nebulae do not emit their own light. Instead, they reflect the light of nearby stars, often appearing blue because shorter wavelengths are scattered more efficiently.

Material: Fine dust particles, likely remnants of the same molecular cloud from which stars are forming.

3. Dark Nebula (Barnard 85)

Location: The dark lanes that appear to divide M20 into three lobes (hence “Trifid”).

Appearance: Opaque, dust-rich filaments silhouetted against the brighter emission background.

Physical Process: These are dense molecular clouds that obscure light from behind. The dust absorbs and blocks visible light but may emit infrared radiation.

Role: These regions often harbor the earliest phases of star formation—protostars hidden deep within.

Arrangement and Structure of M20:

M20 spans roughly 50 light-years across (angular diameter ~28 arcminutes) and is dominated by its trifurcated structure, with three main lobes formed by the dark dust lanes radiating outward from the central emission core. The central ionizing star system (dominated by HD 164492) is embedded within the emission nebula, energizing the gas and influencing star formation in the surrounding regions.

Stellar and Nebular Evolution in M20:

Birth: Star Formation

M20 lies in the Sagittarius Arm of the Milky Way, part of the larger Lagoon Nebula complex.

Star formation occurs as gravitational instabilities within dense parts of the molecular cloud cause it to collapse.

The resulting protostars accrete matter from surrounding disks and, once nuclear fusion begins, they ionize their surroundings.

Jets and outflows from these protostars can be seen in infrared and radio observations.

Life: H II Region Expansion:

The massive O and B-type stars live short lives (millions of years), continually ionizing the surrounding hydrogen and carving out expanding bubbles of hot gas.

UV radiation and stellar winds erode and compress nearby molecular clouds, potentially triggering sequential star formation (a process called radiation-driven implosion).

Over time, the surrounding gas becomes ionized and dispersed.

Death: Supernova and Nebula Dispersal:

The most massive stars will end their lives in core-collapse supernovae, enriching the interstellar medium with heavy elements.

These explosions can further compress nearby regions, initiating new waves of star formation.

Lower-mass stars become white dwarfs, and as the ionizing sources fade, the H II region will dissipate, leaving behind open star clusters.

In time, the dark nebulae will be consumed or dispersed, and M20 will fade as an active star-forming region

Scientific Significance:

M20 is a benchmark region for studying the interplay of different nebular types.

It showcases the feedback loop between star formation and cloud erosion.

It contains multiple Herbig-Haro objects (jets from young stars colliding with nearby gas) and proplyds (protoplanetary disks), making it crucial for understanding the early solar system’s analogs." - Professor G.P.T Chat visiting Astrophysicist at the Jodrell Plank Observatory.

 Summary Table:

| Feature                        | Description                                               

| Distance                      |~4,100–5,200 light-years                                

| Size                             |~50 light-years across                                   

| Main Nebula Types     | Emission, Reflection, Dark                                

| Dominant Star Type    | O7-type star (HD 164492A)                                

| Star Formation            | Active, with embedded protostars                          

| Long-Term Evolution   | Cluster + remnant dust after gas dispersal                                                                  and supernovae 

Markarian's Chain of Galaxies in the constellation Virgo

 

Markarian's Chain of Galaxies. Seestar S30 in EQ and Mosaic modes.
Credit: Pip Stakkert.

" Earlier in the year, Pip Stakkert was experimenting with the Seestar S30 and captured this rather poorly centred and under sampled mosaic of Markarian's Chain of Galaxies in the constellation Virgo. We will however return to this target next year when, once again, Virgo is high above our southern horizon in Lowestoft. Given more and longer sub exposures, the Seestar App now allows for 1-minute subs in EQ mode and mosaic format, we should be able to improve upon the image published above". - Kurt Thrust current Director of the Jodrell Plank Observatory.

"Markarian's Chain is a visually striking group of galaxies in the Virgo Cluster, named after Benjamin Markarian, who studied galaxy alignments and UV-active galaxies.While not all physically connected, several of the galaxies in the chain are interacting, providing valuable insights into galaxy evolution and cluster dynamics.

Notable members of the chain include:

• M84 (NGC 4374) – a giant elliptical galaxy.
• M86 (NGC 4406) – another bright elliptical galaxy.
• NGC 4435 and NGC 4438, often referred to as “The Eyes” because of their close pairing.
• Other galaxies such as NGC 4477, NGC 4461, and NGC 4458 are also part of the chain.

Some of the galaxies in the chain are gravitationally interacting, suggesting they are not just aligned by chance."  - Prof G.P.T. Chat visiting astrophysicist at the Jodrell Plank Observatory.

Altair and Tarazed in the constellation Aquila the Eagle.

 

The Summer Triangle above the Jodrell Plank Observatory.

"This time of year in the Northern Hemisphere, Altair and the less bright Tarazed are visible to the naked eye on clear transparent nights in Suffolk. Altair is one of the three bright stars which make up the 'Summer Triangle' asterism.  Altair is the alpha star in the constellation Aquila the Eagle. Tarazed a red giant and nearby Altair, is also in Aquila and is designated Gamma Aquilae.

This part of the summer night sky is awash with stars and dark nebulae (clouds of obscuring dust). Barnards 'E' can be seen in Kurt's image just above and to the right of Tarazed.

 

Kurt is very fond of using the spectrometer, designed and manufactured by our resident engineer, Jolene McSquint-Fleming, to create stellar spectral profiles". - Joel Cairo CEO of the Jodrell Plank Observatory.

Comparative Analysis of Low-Resolution Spectral Profiles of Altair and Tarazed

Prepared by: Prof G.P.T Chat, visiting astrophysicist at the Jodrell Plank Observatory

Date: July 5, 2025

This informal report presents a comparative analysis of the low-resolution spectral profiles of two nearby stars: Altair (α Aquilae) and Tarazed (γ Aquilae). Although they lie close together in the sky within the constellation Aquila, these stars differ significantly in spectral type, temperature, and luminosity class, which become evident when analyzing their spectral features.

Stellar Data Overview

Property Altair Tarazed

Spectral Type A7 V K3 II-III

Effective Temp. ~7,600 K ~4,300 K

Luminosity Class Main Sequence (V) Bright Giant (II-III)

Dominant Color White Orange-red

Spectral Profile Differences

1. Continuum Shape

Altair: Displays a blue-white continuum with a strong rise toward the shorter (bluer) wavelengths. This indicates a hotter surface temperature, consistent with its A-type classification.

Tarazed: Shows a redder continuum, peaking more in the longer (redder) wavelengths due to its significantly cooler surface temperature (~4300 K).

Interpretation: The blackbody radiation curves are shifted—Altair peaks in the UV-visible, Tarazed in the visible-red to near-infrared.

2. Balmer Line Strength

Altair: Prominent and broad hydrogen Balmer lines (especially Hα, Hβ, Hγ). This is typical of A-type stars where the hydrogen absorption is at its strongest due to optimal excitation conditions in the photosphere.

Tarazed: Very weak or absent Balmer lines. Cooler atmospheres do not excite hydrogen sufficiently to produce strong Balmer absorption features.

Interpretation: Balmer line strength peaks in mid-A spectral types and decreases sharply toward both hotter and cooler temperatures.

3. Metallic Lines and Molecular Bands

Altair: Metallic lines are present but not as strong, and molecular bands are virtually absent due to the high temperature preventing molecule formation.

Tarazed: Strong absorption lines of neutral metals such as Ca I, Fe I, and especially the Ca II infrared triplet. Also displays TiO molecular bands, common in cooler K and M-type giants.

Interpretation: Lower temperatures in Tarazed allow molecule formation and enhanced low-ionization metallic absorption. Molecular bands serve as clear markers of late-type stars.

4. Line Broadening

Altair: Broader spectral lines, especially in hydrogen and metal lines. This broadening is primarily due to rapid rotation (~250 km/s), which causes Doppler broadening across the stellar disk.

Tarazed: Narrower absorption lines. As a giant star, Tarazed rotates more slowly, and the lower surface gravity leads to less pressure broadening.

Interpretation: Rotation and gravity play key roles in line profile shape; Altair's fast spin contrasts strongly with Tarazed's more "settled" atmosphere.

Conclusion

In low-resolution spectra, Altair exhibits features typical of a hot, fast-rotating, hydrogen-rich main sequence star, dominated by strong Balmer lines and a blue continuum. In contrast, Tarazed, a cool and evolved bright giant, displays a redder spectrum dominated by metal lines and molecular absorption bands with relatively weak hydrogen features.

The differences in spectral profiles reflect underlying physical contrasts in temperature, gravity, chemical composition visibility, and rotational velocity, making these two stars a textbook example of spectral diversity across the HR diagram.