October 1, 2010


I found comet 103P Hartley to be too difficult for the city-bound observers. Yesterday night (30 September) I first tried to see the comet through my 25x100 binos and then tried through 10x50 binos and 8-inch Reflecting telescope. I made this observation from my home’s balcony. I was expecting to see something bright, hazy patch of light shining at magnitude 7 or 8. But nothing appeared according to my expectation. Some astronomy websites show the comet’s magnitude to be 5.9 but there was nothing in the exact location given in the finding charts. My updated version of Starry Night software shows the comet shining at mag 5.86. After few attempts through my telescope operating at 34x, I saw something very faint, some 1 deg 39’ SE of Alpha-Cassiopeia. It was nearly 1 degree North of Zeta Cassiopeia. It was exactly in the same location where the comet Hartley has to be.

My city’s observing site allows me to see 11th magnitude comets. I couldn’t understand why so bright comet was so difficult for me. I then had conversations with international comet observers. They told that the comet is nearly 7.5th magnitude and is very diffuse so the light is spread out over a wide area.
That is why it is more difficult than its magnitude would suggest. I saw in the http://www.icq.eps.harvard.edu/CometMags.html#0103P website that according to last observation made in 20th September by J. Cerny, Senohraby from Czech Republic states that the comet was shining at mag 7.9 and had a big diameter of 16’. It is observable through dark sites. It can be detected through 50mm binoculars with averted vision from dark sites.
-Rahul Zota

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