Here are a series of images of Sirius A & B captured from Brisbane on 8th March 2008 using the Tak Mewlon 180 and Televue x2.5 Powermate and later, a TV x3 Barlow.
The seeing was probably 7/10 at best, with spells of 5 to 6/10. The “Pup” (Sirius B) was often visible at the time of capture but as the evening progressed, the slight reduction is seeing made its appearance more sporadic.
In an attempt to verify that I wasn’t “seeing” a processing or system artefact, I rotated the CCD camera approx 90 deg then 180 deg from the starting position and the “Pup” made his appearance in the appropriate location, therefore making this series a good candidate for having captured both A & B.
In visible light Sirius A (Alpha Canis Majoris) is the brightest star in the night sky. SkyTools provides the following data:
AB: -1.44+8.5 mag, PA 97° Sep 8.11" (2008.2)
Sirius is 9 times more brilliant than a standard first magnitude star.
Cheers
Dennis
Last edited by Dennis; 09-03-2008 at 06:08 PM.
Reason: Removed original 5 pane collage and replaced it with updated 6 pane version.
Thank you Al, Petra and Steve, I hope you enjoyed seeing the split as much as I did in recording it.
I was simply astonished when I first saw the tiny, but distinct dot of the Pup appear on the notebook display. I really didn’t imagine that the DMK would have the dynamic range of brightness to display both components simultaneously, without B being swamped by the much brighter A component.
A testimony to the amazing arsenal of equipment available to the modern amateur!
I 'recovered' the Pup a couple of months ago in my 12.5" at around 238x. It was a persistent point within the flare and then would become very distinct for a half a second or so every 5 to ten seconds. I did it again the following month - got the view confirmed (both times) by Darren (dhumpie). Your images (particularly 2 and 3) is similar to the view we had through the eyepiece when it became distinct. Thanks for posting.
I am suffering “complex system set up” exhaustion at the moment and just couldn’t face the prospect of setting up and configuring the side-by-side system to use the separate guide scope for some long exposure, auto guided DSO work.
So, it was an absolute joy to just haul out the rig, plug in the DMK and be up and running in a few minutes. The thrill and experience almost converted me to the life of an eyeballer!
Right now, the simplicity of visual observing is proving a strong attraction, its effortlessness quite seductive, although I am not jaded enough to subscribe to the black art of star hopping; nor do I want to push a dob!
Thanks everyone for your nice comments; I hope you enjoyed the results as much as I enjoyed the speedy set up compared to auto guided DSO imaging!
I actually found that the collimation was a little off when later viewing Acrux (DMK with x2.5 Powermate) and had to tweak the Bob’s knobs a little. I find the Bob’s knobs really tight and difficult to turn on the M180 compared to those on the C9.25.
I haven’t been game enough to play with them too much yet, as how the centre spot moves within the concentric circles of the out-of-focus diffraction rings is a little counter intuitive compared to the standard logic of the C9.25, unless it’s just my dull, aging brain!
I understand that this may seem preposterous, but Sirius B may have also been recorded after I swapped the Televue x2.5 Powermate with its bigger brother, my Televue x5 Powermate at an efl of 10,800mm which is F60!
Just to refresh our memories, I was using a Takahashi Mewlon 180 F12 (2160mm fl). With the x2.5 Powermate this gives an efl of 5400mm (F30) and with the x5 Powermate, this becomes an amazing 10,800mm (F60).
Originally, I consigned this x5 Powermate 3000 frame avi (movie file) to the “don’t bother processing” bin as whilst it was being recorded, I didn’t see Sirius B on the notebook display as I had done with the x2.5 Powermate. Anyhow, last night I had some spare time so I punched the 3000 frame avi through Registax, stacking 962 of the better frames when lo and behold, Sirius B appeared to arise from the somewhat messy image.
The size of the DMK 21 AF04 CCD chip is 640x480 pixels with 5.6 µm pixels. This gives a FOV of 1.1 x 0.9 arc mins and an image scale of 0.11 arc sec/pixel. Using the Ruler in Adobe Photoshop, I measured the separation to be approx 80 pixels which at an image scale of 0.11 arc/pixel gives a value of 8.8 arcsec for their separation.
The actual magnification of the Televue x2.5 and x5 Powermates varies slightly depending on the distance of the CCD chip (or film plane) from the top surface of the lens, along with no doubt manufacturing tolerances, so the measurements are not absolute as I did not calibrate the imaging system.
Congrats Dennis fine work, what an exciting evening to record that
![[1ponders]'s Avatar](../vbiis/customavatars/avatar45_9.gif){kind=avatar}
