After last weeks 'oh so close' encounter with Sirius B, I was enthusiastic to get out and have another go at finding
the elusive white dwarf. Having clearly seen 'B' on my DSLR images I felt confident I could find it visually. Last nights Astro-Cafe at Davis Bay had a very turbulent atmosphere. Several of us had compared
views of Rigel and its double in 8" and 10" Newtonians. It was barely detectable in the 8". But tonight the
atmosphere seemed a little more steady and being up the hill - 250ft altitude - and away from the ocean I
figured I had a good chance.
20:30 PST
I wanted to try Celestron's Software Assisted Polar Alignment and so I did a quick check by putting Polaris in the
centre of the Polar Scope. I found I could not put the telescope on Polaris no matter what position I moved the
mount to. This told me the telescope was not parallel to the RA Axis - and would be a big problem for accurate tracking \- but not for visual. I brought out some spanners and adjusted the rear of the OTA on the rail. I couldn't fully
correct the problem out on the driveway, but was able to bring Polaris within the FOV of a 42mm E.P.
A half hour had slipped past and I was anxious to slew to Sirius.
(I would need everyone of the Scopes light baffles
to baffle the nearby blazing street lights)
21:10 PST
My first impression was that Sirius looked a little more defined than previously. I was using an Antares 4.3mm W70 EP
with 2" Antares 1.6x Barlow for 298x. I was surprised to see the same 3 reflection ghosts that had plagued me on
an earlier observation. I moved my eye around to see what effect that had on the reflections.
Suddenly I had a revelation. Two of the faint light echoes were ever present. What if they were
really faint stars? I had to use averted vision to convince myself these really were faint stars.
Then a bright white point of light appeared below them dancing in the atmosphere - moving more than
I have ever seen a star move. It was clear and precise and persisted for around 5 seconds before
disappearing for about the same time, then reappearing again. I was stunned! This is Sirius B! No wonder I hadn't seen it before - its appearance (and disappearance) was not what I expected. Rather than a faintly visible hard to focus star, I was seeing a clear (dare I say bright) white point of light; much more defined than the other field stars. I watched Sirius B appear and disappear over several minutes. I was elated, finally Sirius B. In only my 3rd attempt of trying. Quite an achievement I thought. I should phone someone! I decided I should attach my camera and get some photographic confirmation. I spent some time taking images at various exposures. Then I used a 25mm EP with a 1.6x Barlow for 51x. I wanted to confirm my orientation by noting the field stars around Sirius.
(Transcribed from my notes at the scope)
22:05 PST
Around 45 minutes had passed since my first sighting and I wanted to confirm Sirius B's position now that some time had passed. However my 4.3mm EP had fogged up quite badly. I put the 4.3 EP in my pocket to warm up and used my
13mm 2" EP instead. I also had in place a 1.6x Barlow for 99x Sirius B was a clear white dot. Its brightness matched
well its stated magnitude of 8.5. It was a very small point but reasonably bright. It was the only star near Sirius.
I was pleased to confirm the sighting and noted Sirius B did not jump around at this lower magnification.
22:20 PST
I was now having trouble with the 13mm EP fogging up too. I could clear the field lens with my glove but
within a few seconds of my eye being against the EP it would fog up again. When this happened, another
- what appeared to a diffraction spike - appeared making the view less clear and quite murky. I could no
longer detect Sirius B. Then a bright point appeared in the lower right diffraction spike! This was clear and
persistent but made no sense with the earlier 100% certain observation of B at 1 O'Clock position.
Observing Factors:
I noted that Sirius was now directly above a very bright street light. There were several neighbours exterior lights
spilling light onto me from several directions. Behind and above me were the unshielded interior '5 light fixture' of my
neighbours upstairs dining room light! My glasses were removed which would have limited the most obvious
source of reflections. Despite being 100% certain of my earlier sighting (and by 'certain' I mean certain that I
observed a star at a particular position), I was now beginning to doubt what I had seen. I had even
confirmed the earlier sighting at different powers and with different EP's. I continued observing for another
20 minutes during which time I could not detect Sirius B again.
Conclusions:
Considering this observing session as a whole, I felt the sighting of a star close to Sirius at the 1 O'Clock position
with the 13mm Ultima Lx EP at 99x was the best quality observation. The star was steady and its brightness consistent
with B's 8.5 magnitude. The deciding factor will have to be the photos! Was there a star at that position?
Was Sirius B at that position?
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Sirius B is at the 10 O'Clock Position.
this view is inverted compared to my
my view at the eyepiece |
This image of Sirius more closely resembles the
appearance of the stars visually.
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Sympathy for Lovell
I now have sympathy for Lovell (Mars, Canals, Vegetation - but lets not forget also a brilliant Astronomer).
Despite being very careful I have never seen so many 'here one minute, gone the next' points of lights,
reflections, and fleeting glimpses. A couple of nights later while viewing Sirius again, I watched an object
cruise slowly past the field stars, with an almost matching brightness. I had to rub my eyes to be
sure it really was moving. And it was - a satellite at high orbit most likely.
Thank goodness for DSLR's. Its clear my Sirius B was not the real Sirius B!
The star I was observing, I believe was the star at the 7 O'Clock position.
Remember things are much clearer on the images than they were through the eyepiece.
I will have to try again. Next time I will go out armed with Sirius B's real position
relative to the field stars. I think the chances of seeing it without knowing where it is
are very slim. I also think I will need exceptional or unusual conditions to visually
detect Sirius B in an 8" scope - despite stories of people with 3" refractors seeing it!
Another great night under the stars!
Location: West Sechelt
Time: 20:00 hrs - 23:10 hrs PST
Temp: -1 C
Sky: Thin high cloud
Equipment: Astro-Tech AT8IN - 8" Imaging Newtonian
Camera: Nikon D5000 DSLR
Eyepieces:
Celestron Ultima LX - 13mm 2" - 70 AFOV
Antares 4.3mm W70 - 70 AFOV
Antares 1.6x 2" Barlow
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