Re: M45 and Machholz on 8 January -- the Sky Cleared!!

From: Michael McCulloch (michaelm_at_nospam.invalid.net)
Date: 01/09/05 

Date: Sun, 09 Jan 2005 10:16:03 -0500

On Sun, 09 Jan 2005 12:06:55 +0000, Pete Lawrence
<pete.lawrence_nospam_@pbl33.co.uk> wrote:

>On Sun, 09 Jan 2005 02:59:51 -0500, Michael McCulloch
><michaelm@nospam.invalid.net> wrote:
>>
>>However, I ran one photo tonight at 3200 ASA for 400 seconds with my
>>10D and cannot see any ion tail. I think the ion tail has really faded
>>in brightness and the dust tail seems less defined.
>
>Wow - no tail at ISO3200 for 400s! I'm quite surprised by that. What
>optical arrangements were there on the front of the camera Michael?

I am surprised as well. I'm still playing with my photos from last
night taken Jan 9th around 4 UT (some 5 hours after your photo), but
so far none of them show any ion tail in the vicinity of the comet
head even in inverted grayscale.

Here is the one shot at 3200 ASA for 400s. I only took it to attempt
to discover the orientation of the ion tail in the frame so I could
maximize coverage in the fov:

http://gamesforone.com/stars/notail.jpg

There may be barely a hint of something at the 1 o'clock position but
the brightness and contrast of that image has been pushed to an
extreme.

My setup is a 105mm apo at f/6.2. The camera was at prime focus. 

---
Michael McCulloch