The Hubble Space Telescope - Home | STScI€“ 2 – 1. Introduction About 3000 orbits of Hubble Space Telescope (HST) time are allocated each year by the Space Telescope Science

Instrument Science Report ACS/WFC 2017-12

The Hubble Space Telescope

“Program of Last Resort”

A. Bellini, N. A. Grogin, N. Hathi, T. M. Brown

Updated version: September 12, 2017

Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218

AbstractEvery year, the Space Telescope Science Institute allocates over 3000 orbits of Hubble time to

approved Guest Observer, Snapshot, and Director’s Discretionary programs. The ensemble

of targets among all these programs are not distributed uniformly around the celestial

sphere, and most targets have observational constraints that limit their schedulability to

something less than the entire year. Despite the best efforts of the Hubble schedulers to

allocate every last orbit, a small but persistent fraction (∼ 2–3%) of the orbits go unused.

Salvaging this unused observing time presents an opportunity for the Institute to benefit the

astronomy community. The Institute’s Hubble Mission Office has initiated a pilot, ultra-low

priority SNAP program (14840, PI: Bellini) in Cycle 24, with the goal of taking useful

data in Hubble orbits that absolutely no other program is able to use. The initial target list

comprises ∼ 500 moderately large, bright NGC/IC galaxies that were not priviously imaged

by HST in V -like filters. As of Septemer 2017, over 100 galaxies have been observed as

part of this program (∼> 2 galaxies per week). This document focuses on the data quality of

the first 10 months of observations. All data taken through the SNAP-14840 program are

intended for legacy science only, and STScI strongly encourage the astronomical community

to use these data for science purposes.

1Copyright c© 2003 The Association of Universities for Research in Astronomy, Inc. All Rights Reserved.

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1. Introduction

About 3000 orbits of Hubble Space Telescope (HST ) time are allocated each year by

the Space Telescope Science Institute (STScI) to approved Guest Observer (GO), Snapshot

(SNAP), and Director’s Discretionary (DD) programs. Currently, HST takes 96 minutes

to complete one orbit around the Earth. Given the limited slew rate of approximately 6◦

per minute of time, HST needs about one hour to go full circle in pitch, yaw, or roll. After

the telescope arrives at a new target, attitude updates and guide-star acquisitions require

an additional ∼13 minutes before observing can begin. As a result, large maneuvers are

costly in time and are generally scheduled during Earth occultation or while HST crosses

the South Atlantic Anomaly (SAA).

The large population of targets among a given Cycle’s programs are not distributed

uniformly around the celestial sphere, and many targets have observational constraints

(e.g., HST orientation requirements) that limit their schedulability to significantly less than

the entire year. Despite the best efforts of the HST schedulers to allocate every last orbit, a

small but persistent fraction (∼2–3%) of the orbits go unused, because the time necessary

for HST to slew and settle from a previously-observed target to the nearest available one

is larger than the SAA transit time and/or the Earth occultation time. As a result, the

available target visibility once HST has settled is too short to schedule all the planned

observation in a visit2, and the telescope is forced to wait until the target is again visible in

the next HST orbit.

Salvaging this ∼2–3% of unused HST observing time presents an opportunity for

STScI to benefit the entire astronomy community. Toward the end of Cycle 23, the

Institute’s HST Mission Office (HSTMO) requested the Advanced Camera for Surveys

(ACS) Instrument Team to establish an ultra-low priority SNAP program as a solution to

fill the gaps in the HST scheduling calendar. With this mandate from the HSTMO, a pilot

superSNAP “program of last resort” (SNAP-14840, PI: Bellini) commenced observations

at the beginning of Cycle 24, with the goal of taking useful data in HST ’s orbits that

absolutely no other program is able to use. All images taken through the SNAP-14840

program are immediately public and are intended solely for legacy science.

2Visits are typically 60-minutes long for GO programs, and 20–30 minutes long for SNAP programs.

– 3 –

Fig. 1.— Time allocation of each SNAP-14840 visit, as rendered by the Orbit Planner

module of the Astronomer’s Proposal Tools (APT).

2. SNAP design

In order to provide enough candidate targets to fill the scheduling gaps, 500 HST

provisional orbits were assigned to the SNAP-14840 program in Cycle 24. The program

is designed as follows. All observations use the ACS Wide Field Channel (WFC) as the

prime instrument, with no parallel observations allowed. Each target is allocated a single

orbit in a single visit. Each visit consists of two 337-second exposures, both taken through

the ACS/WFC F606W filter. This particular exposure time is the minimum allowing two

consecutive ACS/WFC exposures with parallel data-buffer dumping, thereby maximizing

the efficiency of scheduling. A minimal dither is applied between the first and the second

exposure (POS-TARG X=0.′′247, Y=0.′′267) for: (1) minimizing the impact of detector defects

(bad columns, hot pixels, etc.); (2) allowing a stacked image largely free of cosmic-ray

artifacts; and (3) mitigating pixel-phase errors for a more uniform point-spread function

(PSF) among the dataset. Single guide-star mode is also specified as an implementation

requirement, to further increase schedulability. There are no other configuration constraints

allowed for the observations (e.g., specification of HST roll-angle), again allowing for

maximal schedulability.

As illustrated in Fig. 1, each target-visibility window is consumed by 241 seconds to

complete guide-star acquisition, 20 seconds to dither the telescope between the first and

the second exposure, and 2×337 seconds of exposure (plus image-acquisition overheads) to

observe the target. The total visit time is 1315 seconds (21.9 minutes), not inclusive of the

terminal data-buffer dump.

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3. Sample selection

Appropriate targets for the SNAP-14840 must satisfy specifically defined characteristics.

To start, targets need to be sufficiently faint to avoid CCD full-well saturation in a 337-

second F606W exposure, and also need to be bright enough to guarantee a meaningful

signal-to-noise per pixel. The target size should be large enough to fill nearly the short

axis of a WFC CCD (2048 pixels of 50 mas each, for a total of 102.′′4). Larger targets

could in principle still fit within a WFC CCD if elliptical in shape and oriented along

the WFC CCD long axis (4096 pixels, 204.′′8). Because no constraints are allowed on the

telescope orientation, however, targets must always fit within the shortest dimension of the

WFC CCD. Furthermore, targets have to be near-homogeneously distributed across the

sky, such that HST can always slew to an available target regardless of any prior orbit’s

pointing. Given these constraints, the initial choice for the target list was unobserved,

∼<100′′ diameter, NGC/IC galaxies.

The initial target list was drawn from the Revised New General Catalog and

Index Catalog, actively maintained by W. Steinicke3. After the non-galaxies (NGC/IC

classification code 6= 1) were excluded, the catalog was culled on galaxy size. To fit within

the short WFC CCD axis, galaxies were selected with diameters 0.′9–1.′6, and were placed

at the CCD center (the ‘WFC1’ aperture position). To obtain a suitably large number of

galaxies (∼500) for a full Cycle of observations, the sample was further restricted to the

magnitude range 11.4 ≤ V ≤ 12.6.

This target list was further culled to remove previously observed sources using HST in

F606W (or with the other V -like filters: F555W and F625W) with either the ACS/WFC or

the Ultraviolet-VISible channel (UVIS) of the Wide-Field Camera 3 (WFC3).

Milky Way obscuration naturally results in an uneven distribution of magnitude-limited

NGC/IC galaxies across the sky. We created a histogram of the distribution of targets

in both R.A. and Decl., binned every 0.h5 and 7.◦5, respectively (48 total divisions for

both). A uniform R.A. distribution of 500 targets results in 10–11 targets in each bin, but

the initial list overpopulated some bins (i.e., those coindicent with the Virgo and Fornax

clusters), and underpopulated other bins (particularly at low Galactic latitudes). To obtain

an even distribution of targets, we removed from the initial list the faintest targets in the

overpopulated bins, and added NGC/IC galaxies up to 0.9 mag fainter (V ≤ 13.5) where the

Milky Way obscuration was stronger. The leveraging of the R.A. distribution maintained,

to the best extent possible, a uniform distribution of targets across Declination.

3http://www.klima-luft.de/steinicke/ngcic/ngcic_e.htm

http://www.klima-luft.de/steinicke/ngcic/ngcic_e.htm

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Fig. 2.— (Top:) Mollweide projection of the celestial sphere. The grey-scaled background

illustrates the local density of stars in the 2MASS catalog. The final list of 491 NGC/IC

targets of the SNAP-14840 program are in azure. Targets that have already been observed

(as of August 26, 2017) are in green, while targets scheduled to be observed in the following

week are in red. (Bottom:) histograms of the distribution of targets in R.A. (left), Decl.

(middle), and V magnitude (right), color-coded as on the top panel. The red line in the

R.A., Decl. histograms indicates a perfectly uniform distribution on the sky.

– 6 –

The final target list comprises 491 objects. The top panel of Figure. 2 shows a

Mollweide projection of the sky in which the grey-shaded background illustrates the local

density of 2MASS sources (Skrutskie et al., 2006). The location of the Milky Way center

(MWC) is shown in white. Targets in the final list are shown with azure crosses. Targets

that have already been observed (as of August 26, 2017) are marked by green diamonds,

while scheduled targets to be observed in the following week are represented by red

diamonds. The three histograms at the bottom of the figure show the distribution of all

(azure), already-observed (green) and scheduled (red) targets in R.A. (left), Decl. (middle),

and V magnitude (right). The red lines in the R.A. and Decl. histograms represent a

perfectly homogeneous distribution on the celestial sphere.

As of August 26, 2017, 106 NGC/IC galaxies have been already observed by HST since

October 2016, averaging 2.3 targets per week.

4. Data reduction

As soon as a new visit is completed, we download from the MAST archive its associated

two ACS/WFC flc-type images4 and visually inspect them.

Then, we use the python package ASTRODRIZZLE5 to create a resampled, combined

image of the scene. ASTRODRIZZLE is executed with the following parameters:

• driz sep bits=’256,2048,64,32’

• final scale=0.05

• final rot=0

• skysub=False

• driz cr=True.

The parameter driz sep bits tells ASTRODRIZZLE which values of the data-quality

4 flc images are dark, bias, flat-field, and CTE-corrected by the standard CALACS reduction pipeline, but

are not combined together nor resampled.

5http://drizzlepac.stsci.edu/.

http://drizzlepac.stsci.edu/

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extentions (DQ; one per WFC chip) of the flc file are considered usable.6 The other

parameters tell ASTRODRIZZLE to create the output image ( drc sci type) with a pixel scale

of 50 mas per pixel and with the axes parallel to the R.A. and Decl. directions. The sky

background is not subtracted, and cosmic rays are flagged, masked, and rejected.

As part of our daily monitor of the program, we generate a 1-slide summary of each

visit, containing basic information concerning the observed galaxy (e.g., V -band magnitude,

R.A. and Decl. positions, and date of observation), an image of the entire ACS/WFC field

of view (FoV), and a zoom-in of the galaxy itself (see Fig. 3 for an example).

5. Data quality

Saturation. Most of the galaxies in the target list have never been observed by HST, and

none of them were observed in a filter similar to the F606W. As a consequence, we could

not examine in detail how cuspy the core of these galaxies are at HST resolution, or what

would be the expected central surface brightness in the F606W filter. Despite the great

effort spent during the preparation of the target list in making sure that targets would not

saturate in our exposures, saturation of a small percentage of target cores is anticipated.

If we consider a pixel to be saturated in the flc exposure if it has more than 75, 000

electrons7, then we found that 11 out the 106 galaxies observed so far have a few pixels in

their very center that are saturated (in four cases, only the very central pixel is saturated).

Saturation is not necessarily a problem for ACS/WFC photometry, since the ACS detector

conserves electrons even when full-well saturation causes them to bleed from the place

where they were generated (see, e.g., Gilliland 2004). The 11 galaxies with known saturated

cores are: IC 2200 (V = 12.7), NGC 2601 (V = 12.5), IC 4312 (V = 12.3), NGC 1222

(V = 12.5), NGC 2891 (V = 12.6), NGC 3636 (V = 12.4), NGC 3796 (V = 12.6), NGC 4283

(V = 13.0), NGC 5799 (V = 12.9), NGC 6701 (V = 12.1), and NGC 6970 (V = 12.6).

Among the 106 targets observed so far, 43 are brighter than V = 12.5, but saturation

occurs in the core of only three of these.

6The DQ value associated to each pixel can be found in the third and sixth extension of the multi-

extension flc fits file. For more information about the DQ values, see Table 3.4 of the ACS data handbook:

http://www.stsci.edu/hst/acs/documents/handbooks/currentDHB/acs_cover.html.

7The ACS/WFC full well varies across the FoV from ∼ 80, 000–88, 000, with an average of ∼82, 000 (see

Gilliland 2004). Here we have adopted a more conservative value of 75,000 electrons, to take into account

for deviation from linearity near the saturation regime.

http://www.stsci.edu/hst/acs/documents/handbooks/currentDHB/acs_cover.html

– 8 –

IC 520

V mag: 11.7

Trgt ID: 182

R.A.: 08:53:42.1

Dec.: -73:29:27.0

Obs.: 2017-08-20

Fig. 3.— Example of a summary slide. The observed target is the galaxy IC 520. Basic

information about the visit is reported on the top-left corner of the slide. On the bottom

left, there is a full-frame view of the drc sci combined image. The right-hand side of the

slide is dominated by a zoomed-in view of the central regions of the galaxy.

Cosmic-Rays impact. The left panel of Fig. 4 shows a histogram of the number of flc

exposures as a function of the amount of their pixels that are flagged as affected by cosmic

rays according to their associated DQ value.8

The average number of pixels affected by cosmic rays is found to be ∼253, 000, with a

rms of ∼76, 000. This means that, on average, some 750 ACS/WFC pixels are affected by

cosmic rays every second. The top axis of the left panel of Fig. 4 shows the percentage of

8The specific DQ value for cosmic rays is 4096, but pixels can be flagged for multiple reasons (e.g., a

cosmic ray that hits a bad pixel). When transformed into binary numbers, pixels affected by cosmic rays

can be easily found when the associated DQ value has a “1” in the 12th digit.

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Fig. 4.— (Left:) Histogram of the number of pixels affected by cosmic rays in each exposure

(212 single exposures are analyzed in this figure.) Histogram bins are 20,000 pixels wide.

Note that a cosmic-ray event usually affects more than one pixel. The axis on top shows

the percentage of full-frame ACS/WFC FoV affected by cosmic-rays. Three outliers stand

out: the two images of NGC 940 were taken during an anomalously high solar activity, the

other outlier is the second of the two images of NGC 6945. (Right) On top, the flc WFC1

chip of NGC 6945, which is the one with the high amount of flagged pixels. A prominent

dragon-breath is present on the image. The middle figure shows the corresponding DQ

values associated with cosmic-ray events (in white). The bottom figure shows the DQ values

associated with cosmic-ray events of the slightly dithered other image of NGC 6945.

the full-frame FoV affected by cosmic rays. The average is 1.5%. There are three significant

outliers: both exposures of NGC 940 and the second exposure of NGC 6945. Images of

NGC 940 were taken on May 16, 2016: a day of high solar activity with several recorded

– 10 –

solar flares that might explain the excess of cosmic radiation.9

The high amount of pixels flagged as cosmic rays in the image of NGC 6945 are instead

due to the effects of the so-called “dragon breath”: a “tongue of flame”-like anomaly caused

by light reflections of a star just outside the FoV, and involving the knife-edged mask in

front of the CCD detector (see Porterfield et al. 2016). The affected chip (WFC1 of exposure

jdbabyqsq flc.fits can be seen on the top right of Fig. 4. All pixels of this chip that

were flagged as cosmic rays are shown in white in the middle panel of the figure. It is clear

that the reduction pipeliene has been tricked by the dragon breath profile into mistakenly

flagging most of the dragon-breath-affected pixels as affected by cosmic rays. The other

image taken within the same visit (jdbabyqrq flc.fits shows much less overflagging of

cosmic rays (bottom right panel in the figure). The impact of the dragon-breath effects can

vary substantially with very small offsets (∼0.′′1) of the offending star outside the FoV.

The bright star causing the dragon-breath effects in the images of NGC 6945 was

situated in a very narrow glint-region just outside the ACS/WFC FoV (illustrated in

Porterfield et al. 2016), so that the small dither between the two exposures of the visit was

enough to dramatically change the way the DQ flags are determined.

With only two exposures per galaxy, the resampled and combined drc sci images are

expected to have — on average — a fraction 0.0152 = 0.000225 of their FoV affected by

irremovable cosmic rays (or ∼0.02%).

Surface-Brightness limit. To estimate the limiting surface brightness (SB) — defined

as the surface brightness corresponding to the 1σ sky-subtraction uncertainty — for

these V-band (F606W) images of nearby galaxies, we follow the method outlined in

Hathi et al. (2008). First, we estimate the sky SB using the original sky-background

values subtracted during the image reduction process. The sky-background level was

obtained from the flat-fielded (flc.fits) images because the final co-added data products are

sky-subtracted. The header parameters MDRIZSKY (sky value, in electrons, computed

by the AstroDrizzle code) and EXPTIME (exposure time, in seconds) were used to obtain

the observed sky-background value in electrons sec−1 from each flc.fits image. The average

sky-background value can then be expressed as the V-band sky SB as follows:

µV = 26.498− 2.5 · log(average sky-background value/(0.05 · 0.05))

where 0.05 corresponds to arcseconds per ACS/WFC pixel, and 26.498 is the ACS/WFC

9https://www.solarmonitor.org/?date=20160516.

https://www.solarmonitor.org/?date=20160516

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21 22 23 24Sky SB (mag arcsec−2)

0

5

10

15

20

Num

ber

Mean: 22.42SD: 0.36Median: 22.44

Sky Surface Brightness

23.5 24.0 24.5 25.0 25.5Limiting SB (mag arcsec−2)

0

10

20

30

40

50

60

Num

ber

Mean: 24.59SD: 0.12Median: 24.61

Limiting Surface Brightness

Fig. 5.— (Left:) Distribution of sky surface brightness in units of mag arcsec−2. (Right:)

Distribution of limiting surface brightness in units of mag arcsec−2.

V-band AB zero-point. The average V-band sky SB for the current sample of galaxies is

22.42 mag arcsec−2 with a 1σ scatter of 0.36 mag.

Next, we use drizzled (drc sci.fits) images to estimate the 1σ sky subtraction

uncertainty. The python ‘photutils’ package was used to estimate the background and

background noise levels in these drizzled images. It uses the combination of sigma-clipped

statistics and source masking to estimate these quantities. The output of this process

includes an estimate of the background noise, which corresponds to the 1σ sky subtraction

uncertainty. We estimate the relative (random) sky-subtraction error as the ratio between

the background noise and the actual sky-background value. The V-band SB corresponding

to the 1σ sky subtraction uncertainty is given as:

µV − 2.5 · log(relative sky-subtraction error)

The average SB corresponding to the 1σ sky subtraction uncertainty for the current

sample of galaxies is 24.60 mag arcsec−2, with a range of values between 24 and 25 mag

arcsec−2 (see Figure 5).

Stellar magnitude limit. Although the objects of interest in our images are relatively

bright NGC/IC galaxies, these images also contain 102–103 Milky Way stars. In order to

estimate the stellar magnitude limit of the superSNAP program, we proceeded as follows.

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Fig. 6.— Histogram of the stellar magnitude limit (see the text for details).

First, we define the limiting magnitude as the total stellar flux that corresponds to a 5σ

detection of the central (brightest) pixel above the local sky background.

Instrumental stellar magnitudes10 were measured using the publicly available

10The instrumental magnitude is defined as minstr. = −2.5 × log(∑

(flux)), where∑

(flux) indicates the

total amount of flux under the fitted PSF.

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img2xym WFC.09x10 software package and the state-of-the-art, spatially varying empirical

PSF models described in details in Anderson & King (2006). To account for the small PSF

variations due to the so-called “telescope breathing”11, we perturbed the library PSFs to

closely match the particular focus status of each exposure. Instrumental magnitudes were

then transformed into the VEGA-mag flight system using the improved aperture corrections

of Bohlin (2016) and the zero-points defined in Sirianni et al. (2005).

On average, the central pixel of a star as seen by the ACS/WFC through the F606W

filter contains ∼22.4% of the total stellar light. The number of electrons accumulated in

the central pixel of each star can easily be found by inverting the instrumental-magnitude

equation and rescaling by the central-pixel factor. The 5σ detection limit is found when

the flux in the central pixel of a star Pcen = sky + 5 × rmssky, where sky is the local sky

background value, in electrons.

A histogram of the stellar magnitude limit is shown in Fig. 6. The bin size is 0.1 mag,

and is twice as large as the typical photometric calibration errors. The mean photometric

limit is found to be mF606W = 26.5, with a rms of 0.3 mag. When precision astrometry is

not required, then aperture photometry on the combined drc sci images can push the

stellar magnitude limit ∼0.4 mag fainter.

6. Conclusions

Starting from Cycle 24, we have initiated the HST ’s “program of last resort”, a

lowest-priority ACS/WFC snapshot campaign with the goal of taking useful data in HST ’s

orbits that absolutely no other program is able to use. The chosen targets are relatively

bright, previously HST -unobserved NGC/IC galaxies in the F606W or similar filters. An

average of 2.3 such galaxies are observed every week as part of the campaign.

Of the 491 targets of SNAP-14840, 27 of them have been imaged by HST ’s ACS/WFC

or WFC3/UVIS through B-like (F435W, F438W, or F475W) and I-like (F775W, F814W,

or F850LP) filters. Five of these 27 targets have now also been observed in F606W as part

of the SNAP-14840 program. For them, we can construct trichromatic images (see Fig. 7).

We strongly encourage the astronomical community to use the current archival data

of SNAP-14840 for science purposes. From the most obvious studies such as galaxy

11During its 96-minute orbital period around the Earth, HST is cyclically heated by the Earth and Sun.

As a result, the focal length changes slightly during each orbit. This effect, known as telescope breathing,

affects the shape of the PSF in a non-linear way across the FoV.

– 14 –

NGC 2082 NGC 6786 NGC 1222

NGC 4283 NGC 1483

Fig. 7.— Trichromatic stacked images (blue: ∼ B; green: F606W; red: ∼ I) of the 5

galaxies observed so far with prior HST observations in B-like and I-like filters. NGC 2082,

NGC 6786 and NGC 1222 are on the top. NGC 4283 and NGC 1483 are on the bottom.

morphology, formation history, galaxy interactions, globular-cluster systems, AGNs, etc., to

all-sky studies of the stellar population of the Milky Way’s Disk and Halo, there is a vast

variety of scientific applications that can greatly benefit from these high-resolution HST

images. For instance, we are finding an appreciable fraction of early-type galaxies in our

sample showing dusty filaments and/or rings around their core, suggesting recent merging

events. Last but not least, the dataset offers an intrinsic opportunity to make serendipitous

discoveries (e.g., new supernovae), or to provide first-epoch imaging (at HST resolution)

of future supernovae explosions and/or gamma-ray bursts. Apropos of this are the recent

rumors of a neutron star binary merger in NGC 4993 discovered by LIGO12. NGC 4993 was

observed as part of this SNAP program, 4 months prior to the LIGO event (see Fig. 8).

Starting from Cycle 25, an even-lower priority superSNAP program (SNAP-15364, PI:

Bellini) will re-observe in F814W the same targets of SNAP-14840 that do not have prior

HST observations in either F775W, F814W, or F850LP. Again, these data are intended for

12http://www.nature.com/news/rumours-swell-over-new-kind-of-gravitational-wave-sighting-1.22482.

http://www.nature.com/news/rumours-swell-over-new-kind-of-gravitational-wave-sighting-1.22482

– 15 –

NGC 4993

V mag: 12.4

Trgt ID: 278

R.A.: 13:09:48.6

Dec.: -23:23:02.0

Obs.: 2017-04-28

Fig. 8.— Summary slide for visit 6W. The observed target is the galaxy NGC 4993. This

image was taken 4 months before the supposed neutron star binary merger detected in this

galaxy by LIGO, as rumored on the Nature website in August 2017.

legacy science only; STScI encourages the astronomy community to make the best use of

them.

In August 2017, the HST Mission Offce solicited the astronomical community for

additional target lists (with potentially different filter choice) to be added to these

superSNAP programs later in Cycle 25.

Acknowledgments. This publication is based on archival observations with the

NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute,

– 16 –

which is operated by AURA, Inc., under NASA contract NAS 5-26555. This publication

also makes use of data products from the Two Micron All Sky Survey, which is a joint

project of the University of Massachusetts and the Infrared Processing and Analysis

Center/California Institute of Technology, funded by the National Aeronautics and Space

Administration and the National Science Foundation. The authors gratefully acknowledge

W. Steinicke for making available the latest edition of his Revised New General Catalog

and Index Catalog.

References

Anderson, J., & King, I. R. 2006, Instrument Science Report ACS 2006-01 (Baltimore:

STScI)

Bohlin, R. C. 2016, AJ, 152, 60

Gilliland, R. L. 2004, Instrument Science Report ACS 2004-01 (Baltimore: STScI)

Hathi, N. P., Jansen, R. A., Windhorst, R. A., et al. 2008, AJ, 135, 156

Porterfield, B., Coe, D., Gonzaga, S., Anderson, J., Grogin, N. A., 2016, Instrument Science

Report ACS 2016-06 (Baltimore: STScI)

Sirianni, M., Jee, M. J., Benıtez, N., et al. 2005, PASP, 117, 1049

Skrutskie, M. F., Cutri, R. M., Stiening, R., et al. 2006, AJ, 131, 1163

7. Appendix

Table 1 lists all the targets of the SNAP-14840 program. Those already observedat the time of writing (August 26, 2017) are also indicated. Galaxy positions arefrom the revised NGC/IC catalog maintained by W. Steinicke. A “†” symbol neara galaxy name means the galaxy was previously observed by HST in B-like andI-like filters. For an updated list of observed and scheduled targets, please visithttp://www.stsci.edu/cgi-bin/get-visit-status?id=14840&markupFormat=html&observatory=HST.

Table 1:: SNAP-14840 target list

ID Target R.A. Decl. V Date obs.

(h :m:s) (◦ :′:′′) (mag)

1 NGC 7823 0: 4:46.8 -62: 3:40 12.6 2017 May 8

1 NGC 7823 0: 4:46.8 -62: 3:40 12.6 2017 May 8

2 NGC 43 0:13: 1.9 30:54:56 12.6

Continued on the next page

http://www.stsci.edu/cgi-bin/get-visit-status?id=14840&markupFormat=html&observatory=HST

– 17 –

Continued from previous page


(h :m:s) (◦ :′:′′) (mag)

3 NGC 80 0:21:11.9 22:21:28 12.1

4 NGC 83 0:21:23.6 22:26: 3 12.5

5 NGC 95 0:22:14.6 10:29:31 12.5

6 NGC 97 0:22:30.0 29:44:44 12.3

7 NGC 29 0:10:47.0 33:21: 7 12.7

8 NGC 98 0:22:49.3 -45:16: 6 12.7

9 NGC 7820 0: 4:31.9 5:11:59 12.9

10 NGC 78 0:20:26.8 0:49:35 12.8

11 NGC 234 0:43:32.3 14:20:33 12.6

12 NGC 218 0:46:32.0 36:19:32 12.6

13 NGC 252 0:48: 2.7 27:37:24 12.4

14 NGC 274 + NGC 275 0:51: 3.1 -7: 3:40 11.8

15 NGC 312 0:56:16.7 -52:46:59 12.4

16 NGC 323 0:56:42.7 -52:58:33 12.6

17 NGC 194 0:39:18.3 3: 2:15 12.2

18 NGC 227 0:42:37.6 -1:31:41 12.2

19 NGC 193 0:39:18.5 3:19:52 12.3

20 NGC 245 0:46: 6.5 -1:43:24 12.3

21 IC 1616 1: 4:56.1 -27:25:44 12.6

22 NGC 380 1: 7:18.6 32:28:58 12.5

23 IC 1625 1: 7:43.6 -46:54:30 12.0

24 IC 1628 1: 8:48.5 -28:34:56 12.5

25 NGC 430 1:12:60.9 -0:15: 9 12.5

26 NGC 448 1:15:16.5 -1:37:31 12.1

27 NGC 491 1:21:20.2 -34: 3:49 12.5

28 NGC 517 1:24:44.8 33:25:44 12.5

29 NGC 528 1:25:34.6 33:40:14 12.5

30 NGC 564 1:27:48.2 -1:52:43 12.5

31 NGC 656 1:42:27.3 26: 8:36 12.4

32 NGC 661† 1:44:15.6 28:42:24 12.2

33 IC 1729 1:47:55.2 -26:53:31 12.6

34 NGC 687 1:50:33.2 36:22:15 12.3

35 NGC 723 1:53:46.6 -23:45:26 12.5

36 NGC 745 1:54: 8.8 -56:41:37 12.5

37 IC 171 1:55:10.3 35:16:55 12.2

38 NGC 630 1:35:37.6 -39:21:28 11.9

39 NGC 750 + NGC 751 1:57:33.8 33:12:22 11.9

40 NGC 641 1:38:39.0 -42:31:39 12.1

41 IC 179 2: 0:12.5 38: 1:17 12.6

42 NGC 788 2: 1: 6.4 -6:48:56 12.1

43 NGC 783 2: 1: 7.6 31:52:55 12.2

44 NGC 835 2: 9:25.6 -10: 8: 7 12.1


– 18 –



(h :m:s) (◦ :′:′′) (mag)

45 NGC 873 2:16:32.3 -11:20:55 12.6

46 NGC 883 2:19: 5.2 -6:47:26 12.6

47 IC 1796 2:22:47.3 -41:22:15 12.0

48 NGC 910 2:25:27.8 41:49:27 12.2

49 NGC 938 2:28:34.5 20:17: 2 12.4

50 NGC 940 2:29:27.4 31:38:29 12.4 2016 October 5

51 NGC 967 2:32:13.8 -17:12:59 12.5

52 NGC 976 2:33:60.9 20:58:38 12.4

53 NGC 978 2:34:47.0 32:50:42 12.2

54 NGC 982 2:35:25.8 40:52:10 12.5

55 NGC 987 2:36:50.5 33:19:38 12.4

56 NGC 1045 2:40:29.1 -11:16:40 12.4

57 NGC 1094 2:47:28.8 -0:17: 7 12.5

58 IC 257 2:49:45.2 46:58:32 12.6 2016 November 12

59 NGC 1106 2:50:40.5 41:40:20 12.3

60 IC 1864 2:53:39.4 -34:11:53 11.6 2017 March 9

61 NGC 1153 2:58:10.2 3:21:43 12.4

62 NGC 1162 2:58:56.9 -12:23:54 12.5

63 IC 1875 3: 3:57.6 -39:26:27 12.5

64 NGC 1198 3: 6:13.3 41:50:56 12.5

65 NGC 1222† 3: 8:57.9 -2:57:20 12.5 2016 December 11

66 NGC 1248 3:12:48.4 -5:13:29 12.5

67 NGC 1278† 3:19:54.1 41:33:49 12.4

68 NGC 1315 3:23: 6.5 -21:22:29 12.6

69 NGC 1341 3:27:58.3 -37: 8:58 11.8

70 NGC 1339† 3:28: 6.5 -32:17: 8 11.6

71 NGC 1210 3: 6:45.3 -25:42:59 12.7

72 IC 310 3:16:43.0 41:19:29 12.7

73 NGC 1329 3:26: 2.5 -17:35:30 12.7

74 NGC 1370† 3:35:14.4 -20:22:24 12.6

75 NGC 1419† 3:40:42.0 -37:30:40 12.6

76 NGC 1460† 3:46:14.6 -36:41:48 12.6

77 NGC 1490 3:53:34.1 -66: 1: 5 12.4 2017 January 7

78 NGC 1403 3:39:11.8 -22:23:20 12.7

79 NGC 1483† 3:52:48.7 -47:28:42 12.7 2017 August 15

80 NGC 1362 3:33:53.0 -20:16:56 12.8 2017 June 12

81 NGC 1394 3:39: 7.7 -18:17:32 12.8

82 NGC 1416 3:41: 3.8 -22:43: 9 12.9

83 NGC 1428† 3:42:23.9 -35: 9:14 12.9

84 NGC 1473 3:47:26.2 -68:13:14 12.9

85 IC 2035† 4: 9: 2.8 -45:31: 2 11.8

86 NGC 1531 4:11:59.1 -32:51: 3 11.9


– 19 –



(h :m:s) (◦ :′:′′) (mag)

87 NGC 1567 4:21: 9.7 -48:15:17 11.5

88 NGC 1570 4:22: 9.9 -43:37:48 12.3

89 NGC 1577 4:26:20.5 -10: 5:56 12.6 2017 January 31

90 NGC 1595 4:28:22.6 -47:48:55 12.7

91 IC 2082 4:29: 8.8 -53:49:40 12.7 2016 November 11

92 IC 2059 4:20:26.2 -31:43:28 12.9

93 NGC 1591 4:29:31.7 -26:42:46 12.9

94 NGC 1635 4:40: 8.9 -0:32:50 12.4

95 NGC 1653 4:45:48.5 -2:23:34 12.0

96 NGC 1659 4:46:30.0 -4:47:19 12.5

97 NGC 1666 4:48:33.8 -6:34:10 12.6

98 NGC 1667 4:48:37.0 -6:19:13 12.1

99 NGC 1706 4:52:31.1 -62:59:10 12.6 2016 November 13

100 IC 392 4:46:26.8 3:30:20 12.7

101 NGC 1710 4:57:17.8 -15:17:20 12.7

102 NGC 1713 4:58:55.7 -0:29:19 12.7

103 NGC 1588 4:30:44.7 0:39:55 12.9

104 NGC 1781 5: 7:55.1 -18:11:24 12.6

105 NGC 1812 5: 8:53.8 -29:15: 6 12.6

106 NGC 1819† 5:11:46.0 5:12: 3 12.5

107 NGC 1924 5:28: 2.9 -5:18:37 12.5

108 IC 2122 5:19: 1.4 -37: 5:21 12.7

109 NGC 1759 5: 0:49.0 -38:40:25 12.8 2017 February 24

110 NGC 1738 5: 1:46.5 -18: 9:27 12.9

111 NGC 1740 5: 1:55.7 -3:17:45 12.9

112 NGC 1803 5: 5:26.5 -49:34: 3 12.9 2017 April 22

113 NGC 2012 5:22:35.1 -79:51: 7 12.9

114 NGC 1993 5:35:25.4 -17:48:54 12.4

115 NGC 2082† 5:41:51.9 -64:18: 5 12.1 2017 February 26

116 NGC 2073 5:45:54.8 -21:59:57 12.5 2017 July 16

117 NGC 1989 5:34:23.4 -30:48: 2 12.9 2017 September 2

118 IC 2132 5:32:29.6 -13:55:36 13.3 2017 July 27

119 IC 2137 5:34:22.5 -23:32: 0 13.0 2017 February 27

120 NGC 1992 5:34:32.8 -30:53:49 13.5

121 NGC 2008 5:35: 4.8 -50:57:58 13.2 2017 June 17

122 NGC 2144 5:40:56.3 -82: 7: 8 13.0

123 IC 2151 5:52:37.8 -17:47:15 13.3

124 NGC 2150 5:55:46.4 -69:33:39 13.0 2017 February 24

125 NGC 2187 6: 3:52.4 -69:34:40 12.2 2017 June 17

126 NGC 2128 6: 4:34.0 57:37:39 12.6 2017 April 2

127 NGC 2179 6: 8: 2.1 -21:44:46 12.3 2017 August 14

128 NGC 2205 6:10:33.8 -62:32:19 12.7 2016 November 13


– 20 –



(h :m:s) (◦ :′:′′) (mag)

129 NGC 2211 6:18:30.2 -18:32:16 12.7 2016 November 16

130 NGC 2235 6:22:22.2 -64:56: 5 12.7 2017 February 27

131 NGC 2178 6: 2:48.5 -63:45:50 12.9 2017 August 11

132 NGC 2230 6:21:28.9 -64:59:34 12.8 2016 December 1

133 NGC 2216 6:21:31.7 -22: 5:14 12.8 2016 December 14

134 NGC 2208 6:22:35.6 51:54:36 12.8

135 NGC 2274 6:47:17.4 33:34: 3 12.1

136 NGC 2303 6:56:17.4 45:29:36 12.6

137 IC 442 6:36:12.9 82:58: 8 12.9 2016 October 12

138 NGC 2255 6:33:59.6 -34:48:42 13.5 2017 July 28

139 IC 445 6:37:21.0 67:51:36 13.2 2017 February 1

140 NGC 2275 6:47:18.9 33:35:57 13.2

141 NGC 2289 6:50:54.5 33:28:44 13.1

142 NGC 2290 6:50:57.9 33:26:15 13.2

143 NGC 2291 6:50:59.6 33:31:30 13.2

144 IC 454 6:51: 6.2 12:55:21 13.4 2016 December 31

145 NGC 2328 7: 2:36.1 -42: 4: 5 12.1 2017 April 21

146 NGC 2320 7: 5:42.9 50:34:51 11.9

147 NGC 2329 7: 9: 8.9 48:36:57 12.5

148 NGC 2342 7: 9:18.1 20:38:13 12.6 2017 January 5

149 NGC 2314 7:10:32.8 75:19:40 12.2

150 NGC 2344 7:12:29.6 47:10: 2 12.0

151 NGC 2350 7:13:12.1 12:15:59 12.3 2016 December 28

152 IC 2179 7:15:32.3 64:55:34 12.4

153 IC 2200 7:28: 7.6 -62:21:47 12.7 2017 January 3

154 NGC 2332 7: 9:34.8 50:10:55 12.8

155 NGC 2381 7:19:57.4 -63: 4: 1 12.8 2017 July 8

156 NGC 2415 7:36:56.5 35:14:31 12.4 2017 April 29

157 NGC 2476 7:56:45.2 39:55:40 12.6

158 NGC 2469 7:58: 3.2 56:40:48 12.7

159 NGC 2492 7:59:30.7 27: 1:35 12.7

160 NGC 2407 7:31:57.6 18:20: 1 13.4 2016 October 21

161 IC 455 7:34:58.7 85:32:16 13.3

162 NGC 2426 7:43:18.4 52:19: 5 13.1

163 NGC 2485 7:56:49.7 7:28:39 12.2 2017 January 6

164 IC 2196 7:34:10.7 31:24:22 12.7

165 NGC 2496 7:58:37.4 8: 1:41 12.9

166 NGC 2488 8: 1:46.6 56:33:10 12.4

167 NGC 2517 8: 2:47.0 -12:19: 2 11.8 2017 January 30

168 NGC 2528 8: 7:25.0 39:11:41 12.6

169 NGC 2538 8:11:23.0 3:37:59 12.6

170 IC 500 8:12:40.5 -16: 3: 4 12.5 2017 March 23


– 21 –



(h :m:s) (◦ :′:′′) (mag)

171 NGC 2564 8:18:30.0 -21:48:58 12.4 2017 March 26

172 IC 2311 8:18:46.9 -25:22:12 11.5 2017 May 1

173 NGC 2601 8:25:30.4 -68: 7: 4 12.5 2017 January 1

174 NGC 2508 8: 1:57.1 8:33: 7 12.7

175 NGC 2524 8: 8:10.6 39: 9:28 12.7

176 NGC 2550 8:28:39.1 73:44:53 12.7

177 NGC 2616 8:35:34.0 -1:51: 3 12.5

178 NGC 2649 8:44: 8.1 34:43: 3 12.3

179 NGC 2629 8:47:15.2 72:59: 8 12.2 2017 August 22

180 NGC 2646 8:50:22.8 73:27:46 12.1

181 NGC 2679 8:51:33.9 30:51:54 12.6 2017 February 3

182 IC 520 8:53:42.1 73:29:27 11.7 2017 August 20

183 NGC 2698 8:55:36.4 -3:11: 3 12.6

184 NGC 2699 8:55:49.8 -3: 7:38 12.6

185 NGC 2716 8:57:36.8 3: 5:25 11.8

186 NGC 2662 8:45:32.0 -15: 7:16 12.8

187 NGC 2661 8:45:60.5 12:37:11 12.8 2017 February 25

188 NGC 2726 9: 4:57.8 59:56: 0 12.5 2017 May 14

189 NGC 2778† 9:12:24.5 35: 1:40 12.4

190 NGC 2789 9:14:60.7 29:43:49 12.2

191 NGC 2842 9:15:36.4 -63: 4:10 12.5

192 NGC 2888 9:26:20.6 -28: 2:10 12.6

193 NGC 2882 9:26:36.9 7:57:15 12.6 2017 April 20

194 NGC 2891 9:26:57.6 -24:46:58 12.6 2017 May 10

195 NGC 2764 9: 8:17.4 21:26:35 12.9

196 NGC 2795 9:16: 4.7 17:37:42 12.8

197 NGC 2804 9:16:50.9 20:11:54 12.8

198 IC 2450 9:17: 6.5 25:25:40 12.8 2017 January 24

199 NGC 2945 9:37:41.0 -22: 2: 4 12.1 2017 May 10

200 NGC 2954 9:40:24.0 14:55:21 12.4

201 NGC 2991 9:46:50.9 22: 0:48 12.6 2017 February 6

202 NGC 2924 9:35:11.9 -16:23:53 12.0

203 NGC 2947 9:36: 6.8 -12:26:12 12.1

204 NGC 2902 9:30:53.1 -14:44: 8 12.2 2017 May 2

205 NGC 2904 9:30:17.9 -30:23: 6 12.3 2017 July 29

206 NGC 2979 9:43: 9.6 -10:22:59 12.3

207 NGC 3070 9:58: 7.9 10:21:37 12.3 2017 June 9

208 NGC 2960† 9:40:36.5 3:34:38 12.4

209 NGC 3094 10: 1:26.9 15:46:12 12.3

210 IC 2534 10: 1:30.8 -34: 6:45 12.5

211 NGC 3122 10: 4: 2.9 -6:28:29 12.2

212 NGC 3136 10:10:13.2 -67: 0:18 11.7


– 22 –



(h :m:s) (◦ :′:′′) (mag)

213 IC 2552 10:10:46.1 -34:50:40 12.5 2017 June 12

214 NGC 3177 10:16:34.1 21: 7:23 12.4

215 NGC 3260 10:29: 6.1 -35:35:45 12.6

216 NGC 3178 10:16: 9.4 -15:47:28 12.7 2017 March 6

217 NGC 3209 10:20:38.5 25:30:17 12.7

218 NGC 3243 10:26:21.3 -2:37:20 12.7

219 IC 2584 10:29:51.4 -34:54:42 12.7

220 NGC 3266 10:33:18.6 64:44:59 12.4

221 IC 2594 10:36: 4.2 -24:19:22 12.4

222 NGC 3352 10:44:15.8 22:22:17 12.6

223 IC 642 10:48: 8.9 18:11:19 12.6

224 NGC 3380 10:48:12.1 28:36: 7 12.5

225 NGC 3445 10:54:36.8 56:59:24 12.6

226 NGC 3458 10:56: 1.4 57: 7: 2 12.3

227 IC 2597 10:37:47.3 -27: 4:51 11.8

228 NGC 3278 10:31:36.5 -39:57:21 12.2 2016 October 24

229 NGC 3302 10:35:47.4 -32:21:30 12.3

230 NGC 3508 11: 2:60.7 -16:17:19 12.4

231 NGC 3506† 11: 3:13.8 11: 4:37 12.5

232 NGC 3512 11: 4: 3.7 28: 2:15 12.3

233 NGC 3595 11:15:25.4 47:26:49 12.1

234 NGC 3606 11:16:16.6 -33:49:39 12.3

235 NGC 3605 11:16:47.6 18: 1: 3 12.3

236 NGC 3636 11:20:25.0 -10:16:55 12.4 2016 December 24

237 NGC 3648 11:22:31.3 39:52:37 12.6

238 NGC 3655 11:22:55.7 16:35:23 11.7

239 NGC 3656 11:23:39.6 53:50:32 12.3 2016 November 30

240 NGC 3657 11:23:55.4 52:55:16 12.4

241 NGC 3691 11:28: 9.4 16:55:12 12.4

242 NGC 3842 11:44: 2.0 19:57: 0 11.8

243 NGC 3838 11:44:13.4 57:56:55 12.3 2017 May 10

244 NGC 4028 11:58:36.8 16:10:38 12.3

245 NGC 3768 11:37:14.4 17:50:22 12.4

246 NGC 3782 11:39:20.5 46:30:47 12.4

247 NGC 3853 11:44:28.3 16:33:30 12.4

248 NGC 3912 11:50: 4.5 26:28:49 12.4

249 NGC 3985 11:56:42.5 48:20: 8 12.5

250 NGC 3757 11:37: 3.9 58:24:58 12.6

251 NGC 3796 11:40:31.0 60:17:56 12.6 2017 January 20

252 NGC 4032 12: 0:33.9 20: 4:29 12.3

253 NGC 4047 12: 2:51.6 48:38:12 12.2

254 NGC 4065 12: 4: 6.3 20:14: 9 12.6


– 23 –



(h :m:s) (◦ :′:′′) (mag)

255 NGC 4218 12:15:46.0 48: 7:54 12.5

256 NGC 4271 12:19:33.7 56:44:14 12.6 2017 August 17

257 NGC 4283† 12:20:21.6 29:18:39 12.1 2017 April 23

258 NGC 4405 12:26: 7.1 16:10:52 12.0 2017 March 6

259 NGC 4106† 12: 6:46.5 -29:46: 6 11.4

260 NGC 4112 12: 7: 9.2 -40:12:28 12.0 2017 July 23

261 NGC 4415 12:26:40.5 8:26:10 12.1

262 NGC 4515† 12:33: 5.9 16:15:56 12.3

263 NGC 4671 12:45:48.5 -7: 4:11 12.6 2017 May 23

264 NGC 4681 12:47:29.7 -43:20: 5 12.5

265 NGC 4692 12:47:55.2 27:13:20 12.5 2017 April 13

266 IC 3813 12:50: 2.3 -25:55:12 12.6 2017 March 23

267 NGC 4739 12:51:37.1 -8:24:35 12.5

268 NGC 4786 12:54:32.3 -6:51:33 11.7

269 IC 3927 12:58:10.4 -22:52:34 12.6

270 NGC 4868 12:59: 9.0 37:18:34 12.2

271 NGC 4696† 12:47:22.7 -41:14:14 11.6

272 NGC 4915 13: 1:28.1 -4:32:46 12.1 2017 August 6

273 NGC 4928 13: 3: 0.5 -8: 5: 5 12.5

274 NGC 4940 13: 5: 0.2 -47:14:13 12.3 2017 July 21

275 NGC 4956 13: 5: 1.0 35:10:40 12.4

276 NGC 4946 13: 5:29.2 -43:35:30 12.4

277 IC 4197 13: 8: 4.3 -23:47:49 12.4

278 NGC 4993 13: 9:48.6 -23:23: 2 12.4 2017 April 28

279 NGC 5082 13:20:40.8 -43:42: 1 12.6

280 NGC 5173 13:28:25.2 46:35:32 12.2

281 NGC 5150 13:27:36.4 -29:33:45 11.8

282 IC 4280 13:32:53.4 -24:12:25 12.6

283 NGC 5217 13:34: 6.9 17:51:26 12.6

284 IC 4293 13:36: 2.2 -25:52:56 12.5 2017 April 19

285 NGC 5232 13:36: 8.2 -8:29:52 12.4

286 NGC 5244 13:38:42.8 -45:51:17 12.6

287 IC 4312 13:40:31.8 -51: 4:17 12.3 2017 July 28

288 NGC 5303 13:47:45.2 38:18:16 12.4

289 NGC 5306 13:49:11.2 -7:13:24 12.2

290 NGC 5354† 13:53:27.7 40:18:11 11.4

291 IC 4350 13:57:14.9 -25:14:45 12.6

292 NGC 5480 14: 6:22.5 50:43:30 12.1 2017 January 17

293 NGC 5489 14:12: 1.7 -46: 5:20 12.2

294 NGC 5507 14:13:20.8 -3: 8:54 12.5

295 NGC 5548† 14:17:59.4 25: 8:12 12.6

296 NGC 5600 14:23:49.3 14:38:19 12.1


– 24 –



(h :m:s) (◦ :′:′′) (mag)

297 NGC 5397 14: 1:10.5 -33:56:44 11.6

298 NGC 5532 14:16:53.9 10:48:27 11.9

299 NGC 5546 14:18: 9.1 7:33:50 12.3

300 NGC 5605 14:25: 8.5 -13: 9:49 12.3

301 IC 4421 14:28:31.2 -37:35: 1 12.3

302 NGC 5644 14:30:26.5 11:55:41 12.5

303 IC 4441 14:31:39.8 -43:25: 6 11.4

304 NGC 5670 14:35:36.1 -45:58: 0 12.0

305 IC 4464 14:37:49.9 -36:52:43 11.8

306 NGC 5734 14:45: 9.1 -20:52:13 12.6

307 NGC 5761 14:49: 8.2 -20:22:32 12.4

308 IC 1077 14:57:22.6 -19:12:53 12.6

309 NGC 5684 14:35:50.0 36:32:37 12.7

310 NGC 5726 14:42:56.8 -18:26:39 12.7

311 IC 1024† 14:31:27.0 3: 0:28 12.9

312 NGC 5666 14:33: 9.3 10:30:39 12.9

313 NGC 5858 15: 8:49.1 -11:12:29 12.4

314 NGC 5872 15:10:56.6 -11:28:46 12.6

315 NGC 5915 15:21:33.0 -13: 5:30 12.3

316 NGC 5930 15:26: 8.0 41:40:33 12.2

317 NGC 5839 15: 5:27.4 1:38: 4 12.7

318 NGC 5890 15:17:51.1 -17:35:19 12.7

319 NGC 5799 15: 5:36.5 -72:25:58 12.9 2017 July 12

320 NGC 5863 15:10:48.3 -18:25:52 12.9 2017 May 20

321 IC 1116 15:21:55.2 8:25:26 12.9

322 NGC 5936 15:30: 1.8 12:59:20 12.5

323 N5953 + NGC 5954 15:34:34.6 15:11:52 12.3

324 NGC 5956 15:34:58.5 11:45: 1 12.3

325 IC 4562 15:35:57.1 43:29:35 12.6

326 NGC 5990 15:46:16.4 2:24:56 12.4

327 IC 4571 15:48:52.6 -67:19:25 12.6

328 IC 1153 15:57: 3.1 48:10: 7 12.6

329 NGC 5958 15:34:49.1 28:39:19 12.7

330 NGC 6020 15:57: 8.1 22:24:18 12.7

331 NGC 6068 15:55:26.5 78:59:48 12.8

332 NGC 6125 16:19:11.2 57:59: 5 12.0

333 NGC 6155 16:26: 8.3 48:22: 3 12.3

334 NGC 6146 16:25:10.2 40:53:33 12.5

335 NGC 6079 16: 4:29.7 69:39:58 12.7

336 IC 1211 16:16:52.9 53: 0:22 12.7 2016 November 13

337 NGC 6109 16:17:40.5 35: 0:15 12.7

338 NGC 6030 16: 1:51.3 17:57:27 12.8


– 25 –



(h :m:s) (◦ :′:′′) (mag)

339 NGC 6085 16:12:35.1 29:21:56 13.0

340 NGC 6051 16: 4:57.6 23:55:56 13.1

341 IC 1210 16:14:30.0 62:32:10 13.1 2017 August 16

342 NGC 6232 16:43:20.9 70:37:57 12.5

343 NGC 6190 16:32: 6.4 58:26:21 12.6

344 NGC 6211 16:41:28.6 57:47: 2 12.6

345 NGC 6186 16:34:25.4 21:32:29 12.9

346 NGC 6247 16:48:19.4 62:58:38 12.9

347 NGC 6283 16:59:26.5 49:55:19 12.9

348 NGC 6195 16:36:33.6 39: 1:42 13.0

349 NGC 6267 16:58: 9.7 22:59: 7 13.1

350 IC 1228 16:42: 6.4 65:35: 8 13.3

351 NGC 6233 16:50:16.6 23:34:49 13.3

352 NGC 6338† 17:15:23.6 57:24:41 12.3

353 NGC 6359 17:17:53.0 61:46:51 12.6

354 NGC 6324 17: 5:25.3 75:24:28 12.9 2017 May 24

355 NGC 6307 17: 7:40.4 60:45: 2 12.9

356 NGC 6370 17:23:25.1 56:58:30 12.9

357 NGC 6364 17:24:27.3 29:23:28 12.9

358 NGC 6314 17:12:39.7 23:16:14 13.0

359 NGC 6381 17:27:17.9 60: 0:50 13.0

360 IC 1241 17: 1:28.1 63:41:28 13.1

361 IC 4641 17:24:11.7 -80: 8:50 13.1

362 IC 4654 17:37: 8.9 -74:22:52 12.4

363 NGC 6392 17:43:31.6 -69:47: 4 11.6

364 NGC 6509 17:59:25.3 6:17:14 12.5

365 NGC 6483 17:59:30.5 -63:40: 7 11.9

366 NGC 6408 17:38:47.3 18:52:42 12.7

367 IC 4661 17:51: 2.4 -74: 1:58 12.7

368 NGC 6379 17:30:35.0 16:17:19 12.9

369 NGC 6447 17:46:17.1 35:34:20 12.8

370 NGC 6508 17:49:46.3 72: 1:18 12.8

371 NGC 6485 17:51:53.8 31:27:43 12.9

372 NGC 6521 17:55:48.3 62:36:42 12.9

373 NGC 6502 18: 4:14.0 -65:24:35 12.5 2017 August 17

374 NGC 6574 18:11:51.2 14:58:54 12.0

375 NGC 6577 18:12: 1.1 21:27:50 12.6

376 NGC 6600 18:15:43.9 24:54:47 12.6

377 NGC 6438 18:22:16.9 -85:24: 6 11.7

378 NGC 6614 18:25: 7.3 -63:14:54 12.5

379 IC 4704 18:27:54.7 -71:36:33 12.1

380 NGC 6646 18:29:39.7 39:51:54 12.6


– 26 –



(h :m:s) (◦ :′:′′) (mag)

381 IC 4705 18:28:10.4 -71:41:35 12.7

382 NGC 6587 18:13:51.8 18:49:33 12.9

383 NGC 6557 18:21:25.7 -76:34:58 12.9 2016 October 20

384 IC 4731 18:38:43.7 -62:56:36 11.4

385 IC 4729 18:39:56.3 -67:25:34 12.6

386 NGC 6688 18:40:40.9 36:17:22 12.6

387 IC 4741 18:41:44.6 -63:56:51 12.6

388 NGC 6701 18:43:13.6 60:39:11 12.1 2017 January 5

389 NGC 6699 18:52: 2.9 -57:19:14 12.0

390 NGC 6708 18:55:36.6 -53:43:24 12.0

391 IC 4796 18:56:28.9 -54:12:48 12.3

392 IC 4798 18:58:21.0 -62: 7: 4 12.2 2017 August 29

393 NGC 6697 18:45:15.9 25:30:46 12.7

394 NGC 6721 19: 0:51.9 -57:45:34 12.0

395 NGC 6746 19:10:22.3 -61:58: 6 12.6

396 NGC 6768 19:16:33.7 -40:12:31 12.2

397 IC 4842 19:19:24.5 -60:38:39 12.4

398 IC 4845 19:20:22.1 -60:23:20 11.6

399 NGC 6776 19:25:19.1 -63:51:36 12.1

400 NGC 6734 19: 7:14.4 -65:27:39 12.7

401 IC 4836 19:16:18.1 -60:12: 0 12.7 2017 May 18

402 NGC 6786† 19:10:54.8 73:24:39 12.9 2017 February 25

403 NGC 6799 19:32:17.7 -55:54:28 12.4

404 NGC 6810 19:43:34.3 -58:39:22 11.4

405 NGC 6808 19:43:54.4 -70:37:56 11.8

406 NGC 6812 19:45:24.9 -55:20:49 12.5

407 IC 4906 19:56:48.7 -60:28: 7 12.0 2017 September 2

408 NGC 6841 19:57:49.1 -31:48:39 12.7

409 NGC 6805 19:36:46.8 -37:33:14 12.8

410 NGC 6816 19:44: 2.4 -28:24: 3 12.9 2017 July 2

411 NGC 6869 20: 0:42.3 66:13:41 12.0 2016 December 19

412 NGC 6890 20:18:18.0 -44:48:23 12.3

413 NGC 6903 20:23:45.9 -19:19:33 11.9

414 NGC 6915 20:27:46.0 -3: 4:36 12.2 2017 July 16

415 IC 4943 20: 6:28.2 -48:22:33 12.7

416 NGC 6862 20: 8:54.5 -56:23:30 12.7 2017 July 19

417 NGC 6878 20:13:53.2 -44:31:36 12.7

418 NGC 6877 20:18:36.9 -70:51:10 12.2

419 NGC 6906 20:23:34.0 6:26:40 12.3 2016 October 16

420 NGC 6860 20: 8:47.1 -61: 5:59 12.6

421 NGC 6987 20:58:10.4 -48:37:48 12.4

422 NGC 6970 20:52: 9.4 -48:46:41 12.6 2017 March 19


– 27 –



(h :m:s) (◦ :′:′′) (mag)

423 NGC 6919 20:31:38.0 -44:13: 0 13.0

424 NGC 6993 20:53:54.0 -25:28:20 13.1 2017 July 21

425 NGC 6977 20:52:30.6 -5:44:45 13.2

426 IC 5064 20:52:38.1 -57:13:57 13.2 2017 July 11

427 NGC 6990 20:59:57.0 -55:33:43 13.2

428 NGC 6968 20:48:32.4 -8:21:35 13.3

429 NGC 6978 20:52:35.4 -5:42:40 13.3

430 NGC 6945 20:39: 0.5 -4:58:20 13.4 2017 July 27

431 NGC 7002 21: 3:45.0 -49: 1:45 12.4

432 IC 5084 21: 9:14.4 -63:17:23 12.0 2016 October 8

433 NGC 7057 21:24:58.5 -42:27:37 12.6

434 NGC 7001 21: 1: 8.7 -0:11:41 12.9

435 NGC 7004 21: 4: 2.0 -49: 6:51 12.8

436 IC 5086 21: 8:32.0 -29:46: 8 12.9 2017 August 2

437 NGC 7056 21:22: 8.5 18:39:56 12.9

438 IC 5105 21:26: 0.2 -40:50: 6 12.9

439 IC 5106 21:28:38.9 -70:50: 5 12.9

440 IC 1392 21:35:33.6 35:23:55 12.0 2017 May 20

441 NGC 7118 21:46:10.8 -48:21:12 12.6

442 IC 5131 21:47:25.3 -34:53: 4 12.3 2017 August 6

443 NGC 7137 21:48:13.0 22: 9:35 12.4

444 NGC 7081 21:31:24.3 2:29:28 12.7 2017 August 5

445 NGC 7075 21:31:33.9 -38:37: 5 12.7

446 NGC 7117 21:45:47.0 -48:25:16 12.8

447 NGC 7119 21:46:16.7 -46:30:56 12.8

448 NGC 7173† 22: 2: 3.1 -31:58:23 12.0

449 NGC 7180 22: 2:18.5 -20:32:52 12.6

450 NGC 7187 22: 2:44.4 -32:48:12 12.5

451 IC 5157 22: 3:27.0 -34:56:29 12.0

452 NGC 7223 22:10: 9.2 41: 1: 2 12.2 2016 October 18

453 NGC 7247 22:17:41.1 -23:43:50 12.6

454 NGC 7267 22:24:22.5 -33:41:36 12.2

455 NGC 7286 22:27:50.5 29: 5:48 12.5

456 NGC 7203 22: 6:44.8 -31: 9:48 12.7

457 IC 1445 22:25:30.2 -17:14:37 12.7

458 NGC 7311 22:34: 7.7 5:34:12 12.5

459 NGC 7315 22:35:32.6 34:48:14 12.5

460 NGC 7330 22:36:56.1 38:32:53 12.2

461 NGC 7362 22:43:49.2 8:42:21 12.6

462 NGC 7408 22:55:57.7 -63:41:43 12.6

463 NGC 7378 22:47:48.5 -11:49: 0 12.7

464 NGC 7303 22:31:33.0 30:57:24 12.8


– 28 –



(h :m:s) (◦ :′:′′) (mag)

465 NGC 7321 22:36:28.9 21:37:19 12.9

466 IC 5252 22:48: 9.8 -68:54:10 12.9 2017 August 23

467 IC 5258 22:51:32.5 23: 4:52 12.8

468 NGC 7404 22:54:19.6 -39:18:53 12.8

469 NGC 7443 23: 0: 9.7 -12:48:28 11.6

470 NGC 7458 23: 1:28.5 1:45:12 12.5

471 NGC 7469† 23: 3:16.5 8:52:26 12.3

472 IC 5285 23: 6:59.9 22:56:13 12.6

473 NGC 7514 23:12:26.5 34:52:52 12.6

474 NGC 7539 23:14:29.4 23:41: 5 12.5

475 NGC 7550 23:15:16.0 18:57:39 12.2 2017 September 3

476 NGC 7611 23:19:36.5 8: 3:49 12.5

477 NGC 7625 23:20:30.2 17:13:36 12.1

478 NGC 7634 23:21:42.7 8:53:15 12.6

479 NGC 7676 23:29: 2.7 -59:43: 0 11.5 2017 March 15

480 NGC 7720† 23:38:29.3 27: 1:52 12.3

481 NGC 7768 23:50:58.4 27: 8:52 12.3

482 NGC 7794 23:58:34.1 10:43:42 12.6

483 NGC 7798 23:59:26.6 20:45: 0 12.4

484 NGC 7712 23:35:52.5 23:37: 6 12.7

485 NGC 7778 23:53:20.5 7:52:14 12.7 2016 December 15

486 NGC 7779 23:53:27.6 7:52:34 12.7

487 NGC 7717 23:37:44.6 -15: 7: 7 12.8

488 NGC 7724 23:39: 7.0 -12:13:27 12.9

489 NGC 7731 23:41:29.0 3:44:26 12.8

490 NGC 7749 23:45:48.5 -29:31: 4 12.8

491 IC 5362 23:51:37.8 -28:21:55 12.8

Documents

The Hubble Space Telescope - Home | STScI€“ 2 – 1. Introduction About 3000 orbits of Hubble Space Telescope (HST) time are allocated each year by the Space Telescope Science