NGC 5897 is a globular cluster located in the constellation Libra, making it located in the Southern celestial hemisphere. The cluster currently has no official estimates that I could find for its age but is assumed to be very old, predating when the galaxy was in the shape of a disk and had formed spiral arms. This means the cluster is older than 3.6 billion years old, however the age I found through estimation later on was 15.8 billion years old. William Herschel discovered thousands of nebulae, some of which were later found to be star clusters. On 10th March, 1785 Herschel discovered NGC 5897 and noted the beauty of the cluster. It is situated in the Milky Way galaxy as seen here (red dot):
In a study specifically on NGC 5897, Koch (2014) determines the chemical composition of the cluster. This study found more accurate readings than previous studies on the cluster and found it to be more metal-poor than previously thought. Its lower metallicity compared to other globular clusters could explain its unusually long periods of RR Lyrae found in the cluster. Otherwise, it is said that NGC 5897 is a fairly normal globular cluster with very few surprises.
To better understand NGC 5897, I took 15 images using the PROMPT-6 telescope. Three filters were used, being B, V, and R with exposure durations of 280s, 240s, and 220s, respectively. An image would be taken in each filter, roughly one after the other, then a delay of one hour would be set before taking the next set of three images to ensure greater data collection. This process would occur 5 times to reach the 15 images. These images were then used to analyze the relationships between colour, brightness, and the age and chemical composition of the cluster.
Using Afterglow, these images were layered and stacked by filter to then create a batch photometry file to use in analysis using Clustermancer. Using field star removal and then pulling cluster data from various archives, isochrome matching was used to estimate results about the cluster, as follows:
The E(B-V) value, or reddening, was applied to the grouped image of each of the stacked images for the three filters and was used to deredden the final result:
This data estimated was then compared to the data found in the NGC 5897 MWSC Catalogue:
Distance: 12.502 kpc
Log(age): 10.1
Metallicity: -1.745
E(B-V): 0.094
These numerical results do not vary significantly from the data gathered myself. Using a BP-RP vs RP graph using isochrome matching led to the following graphs:
    
My graph (top) is fairly similar to the graph made using the official values (bottom). The data shown is different from the data provided in class and is hard to distinguish notable features of this cluster, however, it appears as though there are a few blue stragglers to the left of the bottom of the main sequence. Although there appear to be no red giants, Koch(2014) mentions there are seven.
This project I had apprehensions about, but I ended up finding myself enjoying it a lot more than I thought I would. This was a unique project that felt far more engaging than plugging in formulas for ordinary assignments and I’m glad I took this course.