TaareWiki | St / Agra Star Counts

A good way of starting astronomy club activities, learning one's way around the constellations while doing some useful hands on activities, would be the star counts project. The activity needs no equipment, to begin with, although sky quality meters to standardise everyone's observations would be a useful addition for the astronomy club.

Well, such sky quality meters could come later.

But, first, a look at the light pollution map of India:

Obtained from the Light Pollution Institute, Italy http://www.lightpollution.it/dmsp/index.html

We obtained permission to use this map for educational purposes and for determining the sky quality from ground, for comparison with these images obtained through satellite views and modeled for the night sky visibility from ground. We set out to use the high resolution version of this map to locate areas around Agra, for measurement of light pollution.

And, comparing it with a map of India, gave an indication of the relative locations of Agra, Mathura, Dholpur and Bharatpur, amidst the blobs of light pollution.

The different colours in the map are modeled estimates of different levels of light pollution. See here for a discussion of the colour scales.

A closer look at the light pollution map around Agra:

And a look at a Google Hybrid map of the same region:

Indicates that moving outward from Agra, in a south westerly direction along the road leading from Malpura to Kagarol and onwards would lead one towards the dark grey low light pollution zones.

This had been the plan - to move along this road, and sample at least one or two locations in each of the light pollution colour zones and collect star count data.

However, the drivers of the vehicles with the students and teachers of St. Peter's college cautioned about the safety issues in these areas and we finally moved along NH 11 towards Fatehpur Sikri about half way, to a place called Joshi Resort. This route would never take one to the dark zones but, we might have had traveled from the city center towards the green and maybe the blue zones. As it happens, the day of our observations - 11th February, turned out rather cloudy from late evening and the early evening was spent in viewing Mars and some deep sky objects through telescopes and thus star counts could not be really collected. However, there is good scope of these star count observations being taken by the students over the coming months.

The route to Joshi Resorts:

Marked with a yellow cross in this wider view:

And, overlaid with a patch of appropriate dimensions from the light pollution map:

Identifies Joshi Resort as a place falling within the green zone in the light pollution map. Our job is to check, through star counts, how this compares now with other locations which might be in the blue or the grey zones. In addition, crossing the village Kirauli, after the Joshi resort and going on upto Kari nadi ka pul well before Fatehpur Sikri, might take us into the darker blue zone. Star counts should be conducted from near the Kari nadi ka pul. We also need to keep in mind that the maps are from satellite data of late 1980s, perhaps. things would have changed so dramatically by now! This also needs to be checked.

Here is some help for the students of St. Peter's college, Agra, for the star count work:

One first needs to familiarise oneself with the sky and a few well known constellations.

The link for obtaining different star maps for the star count data is from the IMO website

http://www.imo.net/visual/major/observation/lm

Horizon Sky Maps Here are some horizon sky maps which give an indication of what can be seen from Agra, over the coming months, looking at specific horizon directions. These maps will be helpful for identifying the constellations and the boundary stars for the star count project.

Star Count Details This page contains some useful information that helps understand the background for these star counts and also details about presenting the star count data and interpreting it.

Star Count Data This page, will, hopefully, get filled by star count data collected by students from many different locations in Agra.