A NEW STAR CLUSTER IN CAMELOPARDU5?
---------------------------------
John Pazmino
NYSkies Astronomy Inc
www.nyskies.org
nyskies@nyskies.org
1977 November 1 initial
2022 March 22 current
Introduction
----------
Since 1977 Pazmino's Cluster attracts attention when each autumn
it rises into the evening sky of mid north latitudes. It is ushered by
Cassiopeia and Perseus, sitting at the north point of an equilateral
triangle with them.
Some observers begin their annual enjoyment of Pazmino's Cluster
in August under the Perseid meteors. Viewing continues into the next
spring when the Cluster sinks into twilight with Perseus and Auriga.
Altho Pazmino's Cluster is circumpolar, it is typicly hidden by
skyline or shmutz when it is near lower culmination. It is usually
allowed to rest from late spring thru the next Perseid shower.
Pazmino's Cluster is about 6-1/2 magnitude, potentially being a
target for bare-eye when in high sky. I never got a confirmed bare-eye
sighting. All observations are with at least small binoculars.
The constellation is formally 'Camelopardalis', which is
linguisticly the better name. In the 20th century both Camelopardus
and Camelopardalis were in circulation.
Stock 23
------
About two years after discovery, Leif Robinson of Sky & Telescope
came across it in Jurgen Stock's list of open clusters. Stock was
studying certain red stars in open clusters. Pazmino's Cluster has an
obvious orange star in it, altho I don't know if it was suitable for
Stock's investigations. His list was not a catalog as such; it was
just a table of the particular clusters Stock used in his program.
Robinson sent a newsnote about the cluster to Pazmino, appended after
the main artcle here.
Stock simply believed that so bright and prominent a group of
stars was surely already a well-known deepsky object. He moved on with
his program. It is #23 in his list, so you sometimes see it referenced
as 'Stock 23'.
Because deepsky objects do not have adjudicated unique names, you
may freely call this group by either name. Advocates and supporters of
home astronomy use the 'Pazmino's Cluster' name to highlight their
fellow's achievement in our profession. Deepsky litterature calls it
'Pazmino's Cluster' with or without other names.
The cluster may not be a bound gravity unit. From HIPPARCOS data
its principal stars seem to have different proper motions. In this
regard Pazmino's Cluster is like Collindr 399 (Al Sufi's, Brocchi's,
Coathanger Cluster) in Vulpecula. It nay dissipate in a few eons.
Silly stproes
-----------
Silly stories once circulated that somehow I was granted a right
of royalty or something, expecting people who look at my cluster to
send me a fee. The fee varied with the story-teller from 5 US cents to
10 US dollars. Even at the lower value I would by now be able to hire
Donald Trump and Bill Gates as my bootlickers.
Thanks to saner thinking of deepsky observers, I collected exactly
zero money in spite of the myriads upon myriads of spectators that my
cluster attracted.
One situation that, also thanks to sane minds, never came about.
There never was any unbecoming attitude toward Pazmino's Cluster among
astronomers. For a few months after my announcement there were some
claims of finding new clusters that were merely mistakes or omissions
in a particular staratlas but well accounted for in others.
Over the years a couple other home astronomers did find
undocumented deepsky objects, so I'm hardly alone in uncovering new
residents of the cosmos.
About the worst gripe was that my cluster is always up there (with
due regard for season and latitude) for all to enjoy, unlike a comet
that flourishes for a few weeks or months and is then gone or asteroid
that you must chase after thru the stars here and there.
Some facts & figures
------------------
Some facts & figures for Pazmino's CLuster are:
--------------------------------
name | Pazmino's Cluster
other names | Stock 23
Right ascen | 03h 16.3m (2000)
Declination | +60d 02m (2000)
Gal lon | 140.1d
Gal lat | +2.1d
Visual magn | +6.5, should be bare-eye target
Ang diam | 1 arcmin
Stars | 25 estimate
Distance | uncertain, may be in Perseus arm
----------------------------------------------
Discocwey article
---------------
Here's my original account of the discovery, issued in November
1977, with only minor touchup. The diagram I drew back then, HERE, is
cleaned up and a mistake in labeling the stars is fixed.
- - - - -
Donald Trombino and I were stargazing at Don's house in Lake
Mohawk, NJ, on Saturday, 3 September 1977, as part of a Labor Day
retreat from New York. The air was moist and the scattered light from
the City, some 80 kilometers to the southeast, filled nearly the
entire sky. The Milky Way, tho plainly visible, was suffuse.
It was about 11PM [EDST] when I was swinging Don's 110mm, f4.5
refractor down from Cassiopeia to pick up the Double Cluster in
Perseus. With a 40mm eyepiece the field of view was about 6 arcdegrees
and the power was about 13; a finder was unnecessary and starhopping
was rather easy. But I veered too far north, ran thru Camelopardus,
and got temporarily lost.
Backtracking a bit, I stumbled onto a misty patch in southwestern
Camelopardus -- a comet?! No such luck. Close inspection revealed a
neat trapezium of four tiny stars about 10 arcminuutes across --- a
cluster!
The four stars were equibrilliant, of about the 8th magnitude, and
gave a refreshing relief among the otherwise barren plains of the
Giraffe.
I put on a 12.5mm eyepiece, giving me about 40 power, and lo! The
trapezium was sprinkled all over with minute, twinkling stars, about a
dozen in all. All were white except one, a mediocre one at that, which
sent out a distinct orangy tint.
I called Don over. He put down his giant binoculars to take a
squint and aahed: "Yes, it is a very pretty cluster!" When I pointed
out its place among the stars, he was puzzled and reached for Norton's
Atlas to check it out. It wasn't marked on the maps. "Oh, that makes
sense", I explained, "I just discovered it."
We brought out Howard's Atlas and the cluster wasn't there either.
Tho having no other atlases, Don could not believe that there were any
clusters not already well documented and catalogued, specially bright
ones like this one. The overall magnitude of my cluster was 6 or 6-
1/2.
We went back to the refractor and I carefully sketched the fields
shown in Figures 1 and 2. The star designations are from Norton's.
[The original sketch mislabeled the stars. They are correct here.] Don
checked the sketches and agreed with the depictions except that he saw
several minute stars I had left out, bringing the cluster's total
membership to 16 or 18. From the sketches the position of the cluster
is (1950) o RA: 3h 13m, decl: +59 40'.
When I returned to my own home in Brooklyn, I looked up the new
cluster on the Becvar Atlas only to find that it was absent there,
too.
In its place was a solitary star indicated by the faintest
magnitude symbol which I took to be the brightest star of the cluster.
Yet, the SAO Atlas (chart 16), the Verhenberg Atlas (chart 24), and
Menzel's Field Guide (chart 3) all show in the proper place a bright,
well-defined cluster, trapezium and all. The Verhenberg chart is shown
in Figure 3 for comparison with the telescope sketches.
Among the catalogs I have, Becvar's, the RNGC, Revue des
Constellations, and Webb's Celestial Objects make no mention of it.
Indeed, virtually all observing manuals generally disparage
Camelopardus as having no bright deep sky objects for amateurs to
observe.
What cluster is this? Is it really a newly discovered one?
Robinson's letter
---------------
[Newsnote about Pazmino's Cluster sent to John Pazmino by Leif
Robinson of Sky and Telescope in July 1979. 'Eyepiece' was a major
astronomy newsletter of the 20th century issued by Amateur Astronomers
Association, New York.
[Here begins Leif Robinson's findings about the cluster]
PREDISCOVERY REFERENCES TO PAZMINO'S CLUSTER
------------------------------------------
1979 August 1
The large, bright open cluster in Camelopardus discovered by Mr
John Pazmino had been noted in passing by two earlier observers,
according to Mr Dennis DiCicco of Sky and Telescope. The references,
Mr DiCicco emphasized, were obscure and seemed to have been made in
the course of other work, with the two astronomers not realizing that
the cluster had never been openly described and brought to the general
attention of the astronomical community.
The first reference is by Dr Stock, of Cerro Tololo and European
Southern fame, in 1957. He gives an angular diameter of 15 arcminutes,
an integrated spectrum of class B6, and the comment that there are no
red giants.
The second observation was in 1966 by Dr Ruprecht of
Czechoslovakia, carried in the Bulletin of that country's Astronomical
Institute. It gives only the statement that the cluster is large and
coarse.
The publication in Eyepiece [1977 November] of a full substantive
description of this cluster, painting it out to the astronomical
community at large, earned Mr Pazmino credit for its discovery and the
cluster now bears his name.
THE NEW YORK CLUSTER
------------------
By John Pazmino
2007 May 1 in Celestial Observer
2007 June 1 in SAC Newsletter
[Susan Rose, President of Amateur Observers Society, Long Island,
passed along to me a note from one of her members. It related to
Pazmino's Cluster mentioned in the Saguaro Astronomy Club, Arizona,
newsletter of March 2007. She asked for some elaboration about the
cluster, which I sent her. She sent my letter to SAC, where it was
published in the SAC newsletter for June 2007.
[First is Susan's comment]
In the Constellation Highlight column of the March issue of the
Saguaro Astronomy Club newsletter, Dennis Wilde [of AOSNY] spotted a
reference to Pazmino's Cluster. We checked with AOS friend John
Pazmino, a frequent CO contributor and meeting speaker, to see if he
was aware of this. Here is his response:
[Here begins my letter to Susan, with minor editing]
My cluster is up there for anyone to admire. It was one of those
studied by Jorges [actually Jurgen] Stock in the 1950s for certain
types of stars in them. He never realized that this particular one was
as yet unknown. He just assumed it was already in some other catalog
because it was so bright and conspicuous.
I myself found it in 1977 while visiting Don Trombino, who at that
time lived in Sparta NJ. He'd just built an RFT with no finder. I was
using its wide field to aim at the Double Cluster when I veered off
track and ended up in Camelopardalis, a ways north.
A blur skidded through the scope's field of view. I recovered it,
hoping it might be a comet, due to the lack of any obvious nebulae in
Camelopardalis. It was this lovely star cluster!
Among Trombino's books and maps it was missing. On photographs of
that part of the sky the cluster is pretty obvious, almost like a
dimmer version of the Pleiades. On drawn maps it was just not there,
either by label or symbol.
When I got home, I looked in my library of maps. The best I found
was that on the larger scale charts, individual stars of the cluster
were plotted but not otherwise noted, like by a 'cluster' symbol
around them. I bounced this finding off of S&T where Leif Robinson
went nuts trying to find it in any S&T reference.
After a couple weeks, he turned up nothing and allowed that I had
discovered a whole star cluster! Not being all that good at inventing
titles, I called it Pazmino's Cluster.
A year or so later, Leif found the cluster among Stock's work,
with nothing to indicate he recognized it as previously unknown. It's
#23 in his roster, the only cluster there of any significance for home
astronomers. The others are very weak, dilated and sparse.
At one of the Winter Star Parties in Florida I was showing the
cluster to some of the other attendees, most of who didn't know about
the S&T investigation. Most star charts even today still miss it out.
Anyway, I got to bantering about Florida, northerners, snowbirds,
and all that because the WSP attracts a lot of astronomers from
northern frostbite places, like New York and Long Island. So I pointed
out the frozen north regions of Ursa Major and Cassiopeia, and the
sunny warm sections of Orion, Gemini and Auriga.
I pointed out how the snowbirds of the north fly or drive through
Camelopardalis to reach the south and have no waypoint to stop at.
Then I found my cluster. Now the folks traveling between north and
south have this wonderful place to stop over, right in Camelopardalis,
halfway along the way.
There is one feature of Pazmino's Cluster that as yet I have no
confirmation. It SHOULD be a bare-eye target, it being 6 to 6-1/2
magnitude. It's an easy target in binoculars but I never learned of a
positive naked-eye sighting.
Since then I know of two major clusters found by City astronomers.
One is Kimmel's Cluster in Gloria Frederica, found in 1979 by Andrew
Kimmel from his backyard in Juniper Valley while following a comet
with his scope. It's a fainter, but condensed, cluster, about 7-1/2
magnitude.
A third example is Caldwell's Cluster, found AT THE WINTER STAR
PARTY in the mid 1990s by Arlene Caldwell, from Lincoln Square, who
was ticking off star clusters on a star chart as she spotted them in
binoculars. She called me and others over to identify this particular
one in Puppis, there being no item on her map for it.
Other maps, including computer-based ones at setups for imaging,
also missed it. I sketched it and marked it on my own map for checking
out when we got home. Similar to Pazmino's Cluster, it appears in
photographs of the sky but is left off of plotted maps.
It's a large object with about twenty stars in it and could be of
naked-eye visibility. At the WSP, I and others tried to see it, after
inspecting it in binoculars, with no certain success. The Milky Way
passes through this part of Puppis and the cluster may have been
blended into it.
So, 30 years later, my cluster is still doing just fine. Pazmino's
Cluster can be found by going straight north 10 degrees from alpha
Persei. Check out the Millennium Star Atlas plate for this area at
~+60 dec, ~3h [RA].
Who will be the first AOSer to spot it, maybe naked eye?
[The newsletter added a note below my letter]
Ed note:
Shortly after sending out the March [2007] issue, I was contacted
by Sue Rose, one of those nice folks you've never met, except on the
internet. Sue is the president of the Amateur Observers Society of New
York [on Long Island]. I've been exchanging newsletters with Sue & her
club for quite a while now.
Well, anyway, she indicated that AJ's [initials of a SAC member]
reference to this cluster (Stock 23) was noticed by one of her
members. They passed the NL to John Pazmino, who is a friend of the
AOSNY. She told me he was very pleased to see that his reference to it
is known beyond local circles.
The bulk of this article was written by Mr. Pazmino as a
commentary on its history as "Pazmino's Cluster". It was taken from
the May 2007 issue of the Celestial Observer, the information
publication of the Amateur Observers Society of New York. Visit them
at www.aosny.org
= = = = =
[Here are additional details about my CLuster, added on 2019 September
8. They were separately distributed piece-meal over the years but
really belong in this here article. i give each its own section
title.]
Stars in the Cluster
------------------
The Cluster consists of four bright stars in a trapezium. The
trapezium corners are roughly pointed into the cardinal compass
directions. There are 20 or so much dimmer stars sprinkled in and
around the trapezium..
I give here some facts & figures for the trapezium stars, taken
from the SIMBAD database. I use the Henry Draper number as the
principal identifier, with a couple alternate names.
-------------------------------------------------
star | south | east | west | north |
HD num | 20095 | 20134 | 20053 | 20040 |
SAO num | 23918 | 23922 | 23908 | 23906 |
PPM num | 28350 | 14185 | 14174 | 14172 |
BD num | +59:621 | +59:625 | +59:618 +59:616 |
RA 2000 | 03h16m41s | 03h17m00s | 03h16m17s | 03h16m11s |
DE 2000 | +59d59m27s | +60d04m02s | +60h02m07s | +60d06m57s |
AppMagn | +8.12 | +7.47 | +7.64 | +7.54 |
Spect | A0-V | B2.5-IV | O8 | G2-III |
RadiVel | +1.0 | -12.50 | -28.8 | -34.5
ProM RA | +17.58 | -4.13 | -4.39 | -16.12
ProM DE | -17.63 -1.20 | -1.28 | -1.16
-------------------------------------------------
The west star HD20053 is double star STF362 or ADS2426. The data
here are for the primary, but the apparent magnitude is the combined
light from both comites.
Deep photography reveals open nebula Sh2-202 mostly in the east
and south side of the trapezium. Since discovery of the Cluster, the
nebula is usually associated with the Cluster. The region in southwest
Camelopardalis is close to the galactic equator with fields of dark
nebulae. They may cause severe dimming of stars behind them, making
the stars seem farther away then they really are.
Bare-eye sightings?
-----------------
One early determined property of Pazmino's Cluster was its
integrated brightness. This was assessed by several observers, all
yielding the same result, +6.0 to +6.5 magnitude. All estimates I
heard of were made with optical assistance, like a finder scope or
binoculars. Other observers took the brightness from images of the
Cluster.
This brightness is at the threshold of normal bare-eye detection
under an ideal dark sky. At darksky sites, deepsky objects of
magnitude 6 to 6-1/2 are occasionally spotted by eye. Some targets are
offered as eyesight tests. Objects fainter than 6-1/2 magnitude elude
all but the keenest sighted of observers.
Since the Cluster sits only a few degrees from the Perseid meteors
radiant, where the attention of myriads of observers each year is
applied, I initially expected routine reports of bare-eye sightings.
Yet after each Perseid shower I have no positive reports of bare-
eye detection of my cluster. I hear from lots of observers who tried
to see the cluster by eye, even after verifying its location with
binoculars.
Plausible explanation
-------------------
Several observers suggested a reasonable cause for the lack of
bare-eye reports. The stars in Pazmino's Cluster do not blend in the
eye their illumination. They each images on its own retina cell but is
to dim to produce perception.
The four trapezium stars provide almost all of the illumination
from the Cluster. The other stars are much dimmer and add little
additional illumination.
Each star is about 7-1/2 magnitude and sends to us 1/4 of the total
illumination. The Cluster should in total be as bright as 4 stars of
7-1/2 magnitude.
By the magnitude-illumination formula, 4 times ratio of
illumination is quite 1.5 magnitude brighter.
Four 7-1/2 magnitude stars would impress in the eye as a point of
(_+7-1/2)+(-1-1/2) = 6 magnitude. This is within the range of
integrated brightness given by various sources.
Using the actual apparent magnitudes of the stars, the combined
brightness should be 6.16, again consistent with current offered
values.e
Here's the gotcha.
The trapezium stars stand 10 to 12 arcminutes apart, enough to be
angularly resolved by eye. The stars do not merge their illuminations.
Each images on its own retina cell, where its 7-1/2 magnitude worth of
light is too weak to generate vision. The eye is not simulated and the
star's location in the sky is vacant.
This explanation seems plausible for why Pazmino's Cluster escapes
bare-eye sighting. It is not a blend of four stars sending 6th
magnitude of light to us. It's four separate stars, each sending only
7-1/2 magnitude of light too weak to excite the eye to perceive them.
Is it a true cluster?
-------------------
For about 20 years following discovery Pazmino's Cluster had no
firm distance data. Most astronomers treated the Cluster as a real
open cluster. We placed it tentatively in the Perseus arm of the Milky
Way, about 3,000 lightyears away.
We need the distance to determine the linear size of the Cluster
and see if the proper motions and radial velocities of the Cluster
stars are consistent with the Cluster's internal gravity regime.
Distance assessments from the spectral class and distance moduli s of
the the stars was frustrated by poor mapping of interstellar
absorption in front of the Cluster.
Assuming a 3,000 lightyear distance, Pazmino's Cluster, with a 15
arcminute diameter fitting around the trapezium, would be some13
lightyears diameter. This is in line with other known open clusters.
In an open cluster the stars move as a unit thru space and have
radial velocities and proper motions all about 31uql.The RVs and PMs
or the trapezium stars seem to divergent to keep a cluster of this
size together. Pazmino's Cluster should have 'evaporated' eons ago.
It may be more likely that the Cluster is a chance alignment of
dissociated stars with no gravity attachment together. With the
topology of interstellar absorption around the Cluster the stars could
be widely ranging in remoteness from us.
This new finding, of course, does not detract from the cluster's
fame or appeal. it's just that for technical purposes my Cluster like
the Coathanger cluster and Aldebaran-Hyades cluster. = =
Pazminid meteor shower?
----------------------
No, ut the name was bantered about in 2014 for a new meteor
shower. In February 20044 comet 209P/LINEAR was discovered in a 5-year
orbit. It in spring 2014 a dust stream from LINEAR WAS EXPECTED TO
sweep over Earth on 2014 May 24. This stream could possibly produce a
new meteor shower.
The shower's radiant would be in northern Camelopardalis near RA =
8h 00mm, DE = +80d. The shower wold ne brief, lasting only one or two
hours centered on 11h UT on May 24. This would be in strong dawn
twilight in New York.
The expected shower was supposed t be a dash of perhaps 1,000
meteors per hour, making it a potential public spectacle. Astronomy
and general news outlets grandstanded this shower for weeks before
May 24.
What to name this shower? 'May Camelopardalids' would distinguish
this shower from the existing one from same constellation in October.
But this would be a tough name for the public to identify with.
'Polarids' was suggested for the only bright star near the radiant.
This didn't fly because the shower is named for a feature outside its
Same case for Spring Camelopardalids', 'Northern Camelopardalids',
other similar attempt. it's the word 'Camelopardalids' that dampens
public interest in the impending storm of shooting stars.
An other option was to name the shower for the comet itself, like
Bielids and Giacobinids. The LINEAR project found dozens of comets,
all named 'LINEAR.' If other LINEAR comets produce meteor showers,
there would be perpetual confusion between the showers.
How about naming the shower after some feature in Camelopardalis
other than a star? It turns out that Camelopardalis has no bright
object except Pazmino's Cluster. My cluster is some 20 degrees from
the radiant and I had nothing at all to do with predicting this new
shower. On the other hand 'Pazminids' IS a short crisp name, easy to
remember, pronounce, spell..
I am not in the meteor observing circles and knew nothing at all
about this Pazminid proposal. I learned of it only because an
associate asked me about 'this new Pazminid meteors'..
The name as far as I ever knew was never seriously considered by
any meteor observing outfits. In fact, after the shower peak date
passed I didn't hear much about the Pazminids or other shower name. it
seems that on the whole the shower was a weak one, throwing maybe 5 --
not a thousand -- meteors per hour, all dim and easily missed without
diligent attention.
That's how I lost the fame, happily, of having a meteor shower
named after me.