HectoSPEC
HectoCHELLE
Positioner
Lives of the Instruments: Hectospec & Hectochelle at the MMT 2003-2026
Health Warning:
Ancient photographs may cause discomfort
At the MMT, the fiber positioner was designed
to feed one of two distinct bench
spectrographs: Hectospec and
Hectochelle.
Builders
Twilight sky,
Oct 19, 2003
First target,
Oct 24, 2003
Prior to the arrival of Hectospec, the MMT instruments such as Blue Channel Spectrograph had been
scheduled and used in a “classical” way. Each PI got specific assigned nights; if the weather was bad,
“try again next time.”
In 2004, Dan decided that data taking for this instrument would be run as a queue, to maximum efficiency.
There was some initial (~2004) resistance to this based on people’s experience at other places (NOAO)
at the time, so we chose to do two things differently from other queues at the time.
A) Try to get everyone something early on, no matter how bad the weather
B) Try to ensure that everyone got the same completion ratio at the end of the period
(first as a trimester, then semester). Thus the scheduling process itself did not favor one project
over another, except for the natural effects of position and moon tolerance.
It was always possible for the TAC to simply give some projects more time,
Operation
Prior to the arrival of Hectospec, the MMT instruments such as Blue Channel Spectrograph had been
scheduled and used in a “classical” way. Each PI got specific assigned nights; if the weather was bad,
“try again next time.”
In 2004, Dan decided that data taking for this instrument would be run as a queue, to maximum efficiency.
There was some initial (~2004) resistance to this based on people’s experience at other places (NOAO)
at the time, so we chose to do two things differently from other queues at the time.
A) Try to get everyone something early on, no matter how bad the weather
B) Try to ensure that everyone got the same completion ratio at the end of the period
(first as a trimester, then semester). Thus the scheduling process itself did not favor one project
over another, except for the natural effects of position and moon tolerance.
It was always possible for the TAC to simply give some projects more time,
After some concern, that scheme was implemented and run for the next 23 years.
Operation
Sample coding for a column of the spreadsheet scheduler:
=IF(ISTEXT(F3);DEGREES(ACOS( (COS(RADIANS(24*$R3))*COS(RADIANS((HOUR($Q3)+MINUTE($Q3)/60)*15))*COS(RADIANS((HOUR($A16)+
MINUTE($A16)/60)*15))*COS(RADIANS(24*$A17)) + COS(RADIANS(24*$R3))*SIN(RADIANS((HOUR($Q3)+MINUTE($Q3)/60)*15))*SIN(RADIANS((HOUR($A16)+
MINUTE($A16)/60)*15))*COS(RADIANS(24*$A17)) +SIN(RADIANS(24*$R3))*SIN(RADIANS(24*$A17))) / SQRT((COS(RADIANS(24*$R3))*COS(RADIANS((HOUR($Q3)+
MINUTE($Q3)/60)*15)))^2+(COS(RADIANS(24*$R3))*SIN(RADIANS((HOUR($Q3)+MINUTE($Q3)/60)*15)))^2+SIN(RADIANS(24*$R3))^2) / SQRT((COS(RADIANS(24*$A17))*
COS(RADIANS((HOUR($A16)+MINUTE($A16)/60)*15)))^2+(COS(RADIANS(24*$A17))*SIN(RADIANS((HOUR($A16)+MINUTE($A16)/60)*15)))^2+SIN(RADIANS(24*$A17))^2) ));" ")
�
Spreadsheet scheduler for nightly observations,
made by hand each night.
Better ?
TCL scheduler, semi-automatic,
Each night was prepared in the afternoon,
but operators used the schedule only as a guide
Names of queue
observers
Perry Berlind
Mike Calkins
Kali Salmas
Ryan Howie
Skyler Self
ShiAnne Kattner…
�Telescope Operators:
Erin Martin
Ben Kunk
Alejandra Milone
Michael Alegria
John McAfee
Brian Pinault
Scott Gotilla
2003
2026
1996
Operators, Fixers
We also initiated the idea that the SAO TDC would reduce the data quickly, and make that available to the PIs. A scheme now considered standard for monolithic projects, but we eventually did it for small projects as well as insuring that scientists didn’t have to waste time learning yet another reduction package.
�
We also initiated the idea that the SAO TDC would reduce the data quickly, and make that available to the PIs. A scheme now considered standard for monolithic projects, but we eventually did it for small projects as well as insuring that scientists didn’t have to waste time learning yet another reduction package.
Knowledge from the operation of Hecto and the running of its queue, to pass onto future generations:
�
And the winner is,
�
Total nights reported from 2004-2026 (not necessarily scheduled):
951 for HectoSPEC
825 for HectoCHELLE
That’s about 15% of the total nights for the active period (11% for Chelle). The most active years used about 1/3 of the time.
Total program completion - hard to say. The worst in a trimester was about 30% , the best was 85%. Typical was probably 70%.
�Total spectra at the end is
866,114 object spectra for Hectospec,
464,303 for Hectochelle (longer exposures).
�
Spec 552 papers, 33099 citations
Favorite topics were
AGN studies (Hickox, Stern, Kochanek, Eisenstein, Murray)
Large Scale Structure and Galaxy Clusters (Geller, Rines, Egami, Sohn, Hwang)
Dwarf Galaxies around larger ones (Weiner, Park, Fang)
Massive stars in nearby galaxies (Massey, Humphreys, Sokal, Drout)
Young Stellar Objects (Kim, Allen, Espaillat, Sicilia-Aguilar, Winston)
Star clusters, integrated and resolved, young and old (Caldwell, M.G. Lee, Chandar, Wright)
Chelle 117 papers, 7481 citations
Topics were:
Individual stars in stellar systems: dwarf galaxies and clusters (Furesz, Olszewski, Walker, Caldwell, Strader, C.Johnson, Meibom)
MW halo structure, streams(Conroy “H3”; Bonaca; Caldwell)
Young Stellar Objects (Allen, Kim, Lim, Espaillat, Hsu, Covey, Curtis)
Highlights of well-cited papers:
Spec (low res)
Mid-Infrared Selection of Active Galaxies, by Stern et al 2005
“find evidence for a large population of optically obscured active galaxies”.
Host Galaxies, Clustering, Eddington Ratios, and Evolution of Radio,
X-Ray, and Infrared-Selected AGNs" Hickox et al 2009
propose a “model of AGN and galaxy evolution, whereby a ‘quasar’ phase and the
growth of the stellar bulge occurs when a galaxy's dark matter halo reaches a critical mass”
"Black Hole Masses and Eddington Ratios at 0.3 < z < 4" Kollmeier et al 2006
“Fueling rates in luminous AGNs are ultimately determined by BH self-regulation of the accretion flow”
"Low-Resolution Spectral Templates for Active Galactic Nuclei and Galaxies
from 0.03 to 30 μm" Asset et al. 2008 –that’s it.
"The Universal Relation of Galactic Chemical Evolution: The Origin of the
Mass-Metallicity Relation" Zahid et al. 2014
“Turnover in the mass–metallicity relation occurs when
the gas-phase oxygen abundance is high enough that the amount of oxygen locked up in low-mass stars is an
appreciable fraction of the amount of oxygen produced by massive stars”
Chelle (high res):
(see Andy S and Matt W’s talks)
Personal Favorites
The Virgo Cluster,
Strader et al.
Peng et al.
M.G. Lee et al.
(more than 1000 GCs)
HGVC-1, aka ”Strader 1”
Vel = -1026 km/s
(note the minus sign)
Globular Clusters in M87 and the Virgo Cluster
Projected distance to M87 is 85 kpc
Caldwell, Strader et al. 2014
JWST time allocated to determine location in Virgo !
Ejected to high velocity via a 3-body encounter with a binary BH ?
M31, The Andromeda Galaxy
M31, The Andromeda Galaxy
M> 13,000 objects of various types with Hectospectra
Caldwell
Humphreys
Huchra
Lada
Massey
MG Lee
Neugent
Young star clusters,
Color represents radial velocity
(red is 0 km/s, blue -550 km/s)
(Caldwell et al, 2007-2016)
Lots of rotation, disk-like
Old star clusters (age > 8 Gyr)
Just a little rotation, mostly in the metal rich group
Some rotation, more than MW clusters
Mg b lines
Unusual H3
Hectochellle Stellar
Spectra
Conroy et al,
2019
(Building up to an anecdote)
Gaseous
Nebulae
in M31
M31 Supernova Remnants
Perhaps similar to Eta Carinae –
high velocity Nitrogen
enriched Circumstellar Material
excited by supernova shocks.
~3000 years old
Caldwell and Raymond, 2024
Ratio of ionizing
Flux to density in a HIIr
Is such that most S is doubly
ionized (hot star), so SII is
Low.
All reduced Spec data in this archive
https://oirsa.cfa.harvard.edu/
Chelle archive coming.
(recall item 3 above about number
of times data needs reducing)
Last Image
March 16, 2026
Last Image
March 16, 2026
Thanks for the memories,
Of little specks of light,
Shining dimly in the night
Those millions of spectra you gave us, with just a little fight.
How lovely it was.