Although the seeing wasn’t too cooperative earlier this morning (11th Nov 2008), nor were the clouds, I managed to grab some images of Sirius that also revealed the position of the Pup, Sirius B.
Due to the poor 5/10 seeing, the image was generally quite unstable, so to remove any potential seeing or system artefacts, I rotated the CCD camera CCW ( approx 0, 90, 180 & 270 degrees) between successive shots, in an attempt to place the Pup in-between the diffraction spikes.
Images taken with a Mewlon 180 F12, TeleVue x4 PowerMate and DMK31AF04 CCD camera. The apparent difference in size of the stellar disc of Sirius A between frames is mainly due to my experimenting with exposures of 1/5 sec and 1/15 second and Gain of 600 and 850. Gamma was set at 18.
Cheers
Dennis
Sirius, aka Alpha CMa, Magnitude: -1.46.
AB: -1.44+8.5 mag
PA 95° Sep 8.38" (2008.9)
Sirius is 9 times more brilliant than a standard first magnitude star.
B is first white dwarf ever discovered; predicted by Bessel (1844) on basis of orbital motion of Sirius, it was first seen by Alvan Clark in 1862, and its peculiar high temperature, small size and great density established by W. Adams in 1925.
Thanks Dave; the gear I use is perhaps more of a legend than the operator – all I need do is set it up and point it in the right direction!
Here are a couple that I have really “pumped”, to reveal the Pup a little better. They are full size to illustrate what appears on the screen at the time of capture.
We used to have a saying that one mans noise is another mans signal! You are that man!
Bert
Thanks Bert!
There are some amazing tools out there, such as Registax that can literally pluck the Pup from out of nowhere, with a high confidence level that it is indeed the Pup, not some artefact.
In the initial start position there are a couple of concentrations or clumps of light that arguably, could be mistaken for the Pup but when I rotated the CCD, it soon became apparent that the software had indeed found the true Pup.
Cheers
Dennis
Quote:
Originally Posted by leon
An exceptional image, very well taken indeed, well done Dennis
Leon
Thanks Leon!
Quote:
Originally Posted by Matty P
Wow amazing work Dennis. Well done
Thanks Matt!
Quote:
Originally Posted by multiweb
Wow. That's pretty tight. What's the angular distance between the two at the maximum?
Dennis, just wondering, can you actually visualise the pup yourself looking down the scope?
i.e. are the images representative or much more sensitive than what the eye would perceive?
Dennis, just wondering, can you actually visualise the pup yourself looking down the scope?
i.e. are the images representative or much more sensitive than what the eye would perceive?
Hi Rob
Sadly, although I have been sorely tempted, I tend not to mix visual observing and imaging during a session.
To remove the camera can be quite onerous in terms of having to physically remove it, insert an eyepiece, re-focus for the eyes, re-fit the camera and then re-focus the camera.
The camera cables (power & signal) are usually routed along the mount/OTA and tied up with little slack, so it’s not easy to just unplug the camera to insert an eyepiece. Once you have the target acquired, nicely framed, with perhaps good seeing and precise focus achieved, it would probably take an act of God to cause you to unplug that camera!
that's a fantastic effort..never fully realised till now how faint the pup is...just knowing magnitudes doesnt tell the tale fully does it
I agree with Narayan, knowing the magnitudes alone doesn't give you the full story.
Your brilliant imaging has really shown just how much of a difference there is between the two.
