Comet Siding Spring - October 15th

[jsmoraes (Jorge)]

I was betrayed by CDC because it says that Siding Spring has magnitude 8.40. Therefore I thought that the comet was the star TYC in the photo. Only during the graphic process I perceived the mistake. By luck I didn't loose the comet.

With IRIS, using of 3 photos, I got 3 different measures of the magnitude: 12.55 , 11.88 , 10.46
Some sites say that the magintue for October, 15th was 10.03

They were five photos: 4 with ISO 800 and 60 seg and one with ISO 1600 - 60 seg. The seeing was terrible ! Nor Mars could be seen !

I am not sure about the identification of star TYC. The star HD, I am surre !

[PeterEde (Peter)]

Lucky
Nice graphic

[jsmoraes (Jorge)]

Thank you Peter.
I didn't get a good result of stacking with DSS because of signal lack. So I tryed IRIS, with Add tool, after align by One Star. The image has the photos at 19:01, 19:04, 19:13 and 19:20 hs.

The image is B&W and they were converted from CR2 to FIT in IRIS, too. The initial goal was only measure the magnitude.

Noise cleaning and adjust of level and bright/contrast was in Photoshop.

[cometcatcher (Kevin)]

Cool animation Jorge. If you average your IRIS magnitude estimates, you get a figure that is very similar to the very latest visual reports, which are about magnitude 11.

[jsmoraes (Jorge)]

Thank you, Kevin. IRIS isn't the best to estimate magnitudes, but it works fine in this task. And it is free.

The quality of the photo, and some procedures that I didn't, like dark, flat and bias subtractions are needed to get good precision.

It works better if you use to register the variation of magnitude of a star, were the true value isn't important, since you want the amount of the variation. And this is just that I need, by now.

[Rex]

Great shots Jorge, Love the animation too.