This is a direct quote from the Royal Canadian Astronomical Society website that I thought we Pup Hunters would find useful. The 'Superior Power," which I emphasized in red is obviously a reference to BigJoe
Seeing the star
There are several things you can do to increase your chances of success:
- be familiar with the orientation of Sirius B relative to Sirius A in your optical system - this will tell you where to look
- practice on a double star with a similar separation, but less dramatic contrast in brightness between the members - this will give you a sense of the angular separation to expect. Try practising on Rigel (β Orionis) or Almach (γ Andromedae)
- the customary minimum aperture is 200mm, but some have used 100mm - can you detect it with a smaller aperture?
- use a magnification of 200x-300x, and try to place the primary star (Sirius A) on the edge of or just out of the field of view
- make a semicircular filter out of plastic (use a violet, or blue, or green. or red, or brown, or grey [neutral density] colour), and place it either: a) in a regular filter cell; or b) at the field stop or other accessible internal position within the eyepiece (easiest in a modular eyepiece). This half-field filter will diminish the brightness of Sirius A, while leaving the brightness of Sirius B unaffected. As an alternative, you could make a half-field occulting mask and install and use it like the filter (as is demonstrated in this video). If you are unsure about modifying your equipment, do not attempt taking apart an eyepiece for b) - try a) instead
- make a hexagonal diagphram. The central opening should have the shape of a hexagon, and be as large as the aperture will allow. According to Duplessis and Souplet, the angles of the hexagonal diagphram "canalize" the brightness of the primary into "feathers", enhancing the contrast in the zones between those features. Simply position the mask so that an inter-feather zone is where the companion star should be to enhance your chances of observing it. The great E.E. Barnard (a RASC member - also see here) published a description and drawings of this most useful of DIY mods
- owners of go-to telescopes (or traditional equatorial or alt-az telescopes with drives) may wish to use the drift method to find the position of Sirius B. It's simple - turn off your drive! Since the companion is fairly close to due east of the bright primary it will "follow" behind it quite closely. So as Sirius A drifts away from the centre of your FOV, Sirius B will approach it. By a rough estimate, Sirius B trails Sirius A by 2/3s of a second (of time)
- allow sufficient cool-down time for your OTA, and ensure it is well-collimated
- try to pick a calm night of good seeing (fortunately, our winter-wonderland of the frozen north does offer these). It is worth trying in less than optimal conditions, but in such a case remember to choose an observing location shielded from the wind. It is worth attempting the observation from light-polluted areas, provided the full moon isn't near the Sirius system
- dress properly for the weather
- be patient, and rest your eyes! And, to paraphrase William Herschel, "it should be remembered, that when an object is once discovered by a superior power, an inferior one will suffice to see it afterwards" (RSPT 90, 1800, 29). You won't need an 18.5" Clark to detect Sirius B, and once you see it, you'll be able to find it again with comparative ease!