Some globular clusters in the direction of the bulge are
so much reddened and/or are located in very crowded fields,
that only scanty or preliminary values for metallicity,
reddening and distance are available in the literature.
The present study provides results from an observational effort
with the NTT telescope to obtain optical colour-magnitude
diagrams (CMD) of Terzan 10, ESO 
38 and UKS 1.
Terzan 10 (GCL 
, ESO 
16) was discovered by
Terzan (1971). The coordinates are
,
(
, 
).
Very few information is available for this cluster.
By means of the bright giants method Webbink (1985) estimated
an horizontal branch level of 
which,
combined to a reddening of E(B-V) = 1.71 from the modified cosecant law,
led to a distance from
the Sun of 
.
The cluster is not concentrated, with c = 1.12, as estimated from the
core and limiting radii presented by Webbink.
Liu et al. (1994) presented infrared photometry deriving
a reddening of E(B-V) = 2.6, a metallicity close
to that of 47 Tuc, and a true distance modulus of (m-M)0 =
14.5.
ESO 38 (GCL 
, Djorgovski 2) is located at
,
(
, 
).
ESO 38 was first reported in the sixth list of the
ESO/Uppsala survey of the ESO B Atlas of the southern sky (Holmberg et al.
1978). It was described as an open cluster
with a diameter of 1.4'. It is also the cluster 
in Djorgovski (1987), for
which he presented R and I CCD images,
suggesting that it might be a globular cluster.
An estimate of reddening E(B-V) = 0.87 was given by Djorgovski
(1993). In terms of structure, it is rather loose, with a moderate
concentration parameter c = 1.50, and it does not present a
post-core-collapse morphology (Trager et al. 1993).
UKS 1 or UKS 1751-241 (GCL 1751-2408) is projected near the Galactic
center and is located in the ESO/SERC field 521.
The coordinates are
,
(
, 
).
It was discovered on infrared plates taken with the 1.2 m UK Schmidt
telescope, where it appeared as a small, round and hazy patch (see Malkan
et al. 1980). In the latter paper they obtained infrared images
with an InSb detector and derived a core radius of 13'' and estimated a
visual extinction of
AV = 9.7 or 11.4, depending on whether
the cluster was metal-rich or metal-poor, respectively.
Malkan (1982) derived E(B-V) = 3.1 from
integrated infrared photometry, and
Zinn (1985) based on the same data estimated a metallicity 
. Webbink (1985) estimated an horizontal
branch level of 
, and assuming a reddening
of E(B-V) = 3.07 from Malkan's infrared data, he derived a distance of
10.4 Kpc from the Sun.
Webbink also lists a metallicity of [M/H] = -1.22.
Minniti et al. (1995) presented an infrared CMD in K' vs.
(J-K'). The horizontal branch is not clearly detected. They point out
that the locus of the red giant branch (RGB)
is consistent with E(J-K) = 1.72
(E(B-V) = 3.26), assuming Webbink's (1985) metallicity value.
Liu et al. (1994) also observed UKS 1, and gives
E(B-V) = 2.8, 
and a true distance modulus
(m-M)0 = 14.7.
In terms of structure, it is compact, with a concentration
parameter c = 2.10, and it may have a post-core-collapse morphology
(Trager et al. 1995).
No optical colour-magnitude diagram (CMD) is available for any of the three clusters.
In Sect. 2 the observations are reported. In Sects. 3, 4 and 5
the CMDs are presented
and cluster parameters are derived for Terzan 10, ESO 38 and
UKS 1 respectively.
Concluding remarks are given in Sect. 6.