Quote:
Originally Posted by AG Hybrid
So... as an experiment I followed the advice that has been given so far in this thread and really gave a proper go.
I can now say I did it. It took me to the very limit of my skill and experience but I DID IT! I spotted the Pup for the first time in my $400 Explore Scientific AR102.
It took some experimentation especially deciding which view was best between using a Baader Semo-Apo filter or no filter. The CA was overwhelming on Sirius so I used the filter at the expense of a little bit of light lost.
I put my 2x barlow in front of my diagonal as to produce more magnification as it would if it were behind the diagonal and then putting the eyepiece straight into the barlow.
I then used a Baader Hyperion Zoom to gauge the best magnification and exit pupil the atmosphere would support. Atmospheric seeing was decent tonight as I observed Jupiter prior, as it rose. I was able to see four bands on Jupiter which was pretty good for the AR102 especially considering how low it was in the sky.
The advise to use Rigel in Orion as a benchmark and test object is a very wise idea. It gave me an idea what I was in for and I noted that CA was overwhelming too. Had to use the filter and glad that I did because it was the first time I saw Rigel B in the AR102 as well. While still lots of CA the little white dot was there with direct vision. Nice.
So, to Sirius. This was hard. Very hard. As I mentioned earlier the CA caused by Sirius was overwhelming at the magnification I was using. Would have been well over 200x. I would approximate that over 40% of the field was blue haze. The filter was necessary. It did a good job, the CA was less then 10% of the field now. Still rather intense around the Sirius itself, just contained. Using the zoom I gauged the best magnification to find that sweet spot between image brightness and contrast. This took some time. I also was using an alt azimuth mount which means Sirius was always on the move and moving fast. It was only a for a few seconds in the center of the field where the best field correction is and my windows of best observing were constantly being reset. But, I've never owned a tracking mount so it was second nature to me. Muscle memory even.
While watching Sirius floating from top left to bottom right going through the field it appeared as it floated through the center of the field. For about 4 seconds the little white dot appeared on the outer most diffraction ring. It looked to be about 2 o'clock. I'm certain it was a positive result as I had spent the last 30 min noting false-positives caused by eye floaters. I don't have many but they are really obvious when they do appear at that tiny exit pupil. I knew exactly how the floaters looked and how the moved and acted. That little white dot I saw stuck right by Sirius as it zoomed through the field of view. The eye floater moved around and rarely in a straight line.
Pretty pleased with that as a whole. Although next time I'm just going to roll out the 12" 
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Adrian, that is a huge achievement if you found it in such a small scope with CA issues as well. However,I am confused about your use of the clock for directions. The Pup should trail Sirius A in an undriven scope. If I am using the clock in the same manner as yourself, my observation was that it was at about at 7 o'clock position. Given that you saw it in your 12" reflector at the 11 o'clock position, I thought our observations were in agreement when you swap the up and down positions between at refractor and a reflector. (Left and right being unchanged of course).
However, you say that you saw it at 2o'clock in the refractor.
I am not saying that you did not see it, but was there anything else going on to confuse the directions; like did you have the star diagonal twisted to the side or something?