C/2002T7 Comet Linear Image Mosaic (270404)

Post by **rcj** » Tue Apr 27, 2004 2:47 pm

Hi all,
Here is another attempt at Comet Linear, this time round, a 3-piece mosaic was tried on the "dusty-snow-ball"
Exposures had been increased to 180seconds since there was almost no presence of thin cloud cover towards the eastern horizon. Observation of the comet started at 5:26AM and it has "travelled" to 22 Piscum. The comet is very easily visible through the 7X50 binoculars and in the 7X50 finder of the 4-inch refractor as well. You must try to look at this comet if you haven't!
In the following image you can see the streamers from the tail, especially in the inverted image version. As this is about the fifth or sixth time viewing the comet, the comet was "tracked down" almost as soon as it cleared the tree canopies (about 13 degrees high). Stars could be seen in the finder all the way into the horizon tree canopy making it easy to see the comet as early as 5:30AM. Do note this is not a good image as there is some trailing of the stars below the comet nucleus! Nevertheless, I am pretty excited to see the comet streamers coming from the tail!

http://www.star-matrix.com/C2002T72604042150UT.JPG

Image Details:
3-frame mosaic comprising of 3X180 seconds, 3X120seconds exposure.
Processing done on the mac platform almost imeediately after comet capture.
Mount: Los G11
Instrument: Tak 4-inch refractor (820mm f.l.)
Guidescope: Pentax 75SDHF, manual guiding.

Clear Skies,
rcj

Post by **Airconvent** » Wed Apr 28, 2004 12:13 am

mmm yummy..
Pretty amazing we can have a 3 minute exposure in Singapore near daybreak and still a black background on the image...
BTW, visually can we see the tail here? Or is it a astrophotography item?
Also, how big is the core? i.e. where does the comet end and its "corona" begin?

rich

Post by **rcj** » Wed Apr 28, 2004 1:34 pm

Hi Richard,
The tail stub can be seen barely through the 4-inch refractor but is expected to brighten up as days goes by. Nevertheless, whatever the case, it is certainly a hot imaging item. The core is estimated to be non-stellar-like and diffuse, about 10 arc-minutes across, probably around the same diameter as NGC4755.