Photometry

Observations for the photometric portion of the WIYN Open Cluster Study have been obtained with the WIYN 0.9m and 3.5m telescopes on Kitt Peak. Observations of the open clusters NGC 188 and M35 with the 3.5m telescope have already been published. Here we summarize the status of the latest observations with the 0.9m.

Three different CCD imagers have been used in this study. Originally, we utilized the T2KA CCD which is a 2048 x 2048 pixel detector with an image scale of 0.68 arcsec/pixel and a FOV of 23 x 23 arcmin. We have now switched to the S2KB CCD, which is also a 2048 x 2048 pixel detector but features an image scale of 0.60 arcsec/pixel and a FOV of 20 x 20 arcmin. Our wide-field observations are mainly taken with the NOAO MOSAIC imager - an array of 8 2048 x 4096 CCDs yielding an image scale of 0.40 arcsec/pixel and a FOV of 59 x 59 arcmin at the 0.9m. Glenn Tiede has produced a cookbook that we use to process our MOSAIC observations. This is done in such a way as to allow the subsequent photometric reduction to be as similar to reducing single images as possible.

We have also begun to extend the WIYN Open Cluster Study photometry effort into the near-infrared passbands by matching our optical photometry with JHKs magnitudes from the Two-Micron All Sky Survey (2MASS). Some of the preliminary results are given in Grocholski & Sarajedini (2003; WOCS XVI).

The tables below list our open cluster targets. For each object, we give the right ascension and declination in epoch 2000 coordinates, the intrinsic distance modulus, the metal abundance, and the age. The last three columns indicate whether the cluster has been observed (Obs?), whether the observations have been reduced (i.e. photometered, Red?), and whether a color-magnitude diagram (CMD?) has been produced. Click on the CMD link for each cluster to view the color-magnitude diagram.

Northern Targets

Cluster (NGC)
Other Name
RA (2000)
Dec
(m-M)o
[Fe/H]
Age (Gyr)
Obs?
Red?
CMD?
NGC 188
00 47 28
+85 16 11
10.9
-0.1
7.2
Y
Y
Y
NGC 1039
M34
02 42 07
+42 44 46
8.7
-0.3
0.2
Y
Y
Y
NGC 1817
05 12 26
+16 41 03
11.2
-0.3
1.3
Y
Y
Y
NGC 1912
M38
05 28 42
+35 51 18
10.9
-0.1
0.3
Y
Y
N
NGC 1960
M36
05 36 18
+34 08 27
11.3
...
0.03
Y
Y
N
NGC 2099
M37
05 52 18
+32 33 11
11.7
+0.1
0.3
Y
Y
N
NGC 2158
06 07 26
+24 05 46
13.0
-0.3
2.2
Y
Y
Y
NGC 2168
M35
06 08 58
+24 21 27
10.4
-0.2
0.1
Y
Y
Y
NGC 2420
07 38 24
+21 34 27
11.8
-0.4*
2.8
Y
Y
Y
NGC 2682
M67
08 51 20
+11 48 43
9.4
0.0
4.5
Y
N
---
NGC 6791
19 20 53
+37 46 19
13.1
+0.2
8
Y
Y
N
NGC 6819
19 41 18
+40 11 12
11.8
+0.1
3.1
Y
N
---
NGC 7092
M39
21 31 48
+48 26 17
7.6
-0.1
0.3
Y
N
---
NGC 7789
23 57 24
+56 42 30
11.3
-0.2
1.7
N
---
---

* Revised in our latest press release.

 

Southern Targets

Cluster (NGC)
Other Name
RA (2000)
Dec
(m-M)o
[Fe/H]
Age (Gyr)
Obs?
Red?
CMD?
NGC 2204
06 15 33
-18 39 54
12.4
-0.3
0.8
Y
---
---
NGC 2243
06 29 34
-31 17 00
13.4
-0.4
4.5
Y
---
---
NGC 2360
07 17 43
-15 38 30
11.7
-0.2
0.6
Y
---
---
Tom 2
07 03 05
-20 49 00
15.9
-0.4
1.0
Y
---
---
Mel 66
07 26 23
-47 40 00
13.6
-0.4
2.8
Y
---
---
NGC 2451
07 44 27
-37 40 00
7.6
-0.5
0.04
N
---
---
Berk 39
07 46 42
-04 36 00
13.8
-0.2
7.9
Y
---
---
NGC 2477
07 52 10
-38 31 48
11.3
+0.01
0.7
Y
---
---
NGC 2516
07 58 04
-60 45 12
8.4
+0.06
0.1
N
---
---
NGC 2506
08 00 01
-10 46 12
13.0
-0.4
1.1
Y
---
---
NGC 2660
08 42 38
-47 12 00
13.2
-0.2
1.1
Y
---
---
NGC 3532
11 05 39
-58 45 12
8.6
-0.02
0.3
Y
Y
Y
NGC 3680
11 25 38
-43 14 36
10.1
-0.1
1.2
Y
---
---
NGC 3960
11 50 33
-55 42 24
12.7
-0.2
0.7
Y
---
---
Cr 261
12 37 57
-68 22 00
12.5
-0.1
8.9
Y
---
---
NGC 5822
15 04 21
-54 23 48
10.3
-0.02
0.7
Y
---
---
IC 4651
17 24 49
-49 56 00
10.1
+0.1
1.1
Y
---
---