Re: [Utah-astronomy] Double stars
Chuck, Where do you get an apodizing mask and how much do they cost? I think my main problem with this SCT is the fork mount. I think I will get rid of it in July and put it on my equatorial mount. Hopefully it will be more stable. I noticed when I tried to focus the 8" SCT, the mount would vibrate so I would wait for the vibrations to dampen before I tried focusing again. Once I got it focused, the stars looked pretty good except near the horizon. One of the problems of splitting Antares is it low declination in the sky. When I get to Flagstaff Saturday, I'll try again to split this star. This time I will try it with the 15". Glad you are back, Debbie
Hi Deb: You can make an apodizing mask easily. Take a piece of cardboard, and cut a hexagonal opening such that it is just smaller than your aperture. When you look through the focuser with no eyepiece, your primary mirror will then appear to be hexagonal instead of round. In use, this will produce diffraction spikes. Rotate the mask until the suspected position of the dimmer star is in the "valley" between the spikes. What it does is channel energy away from the central spot, into the spikes, thus reducing it's apparent size and possibly revealing a companion star. Good move on upgrading the mount. Mount problems are always accentuated at the high powers usually needed to split close doubles. Antares is usually split easier off-season, when it's on the meridian at about 4 am. Then the skies are usually calm enough to allow the split, with good optics a given. Let us know if Flagstaff gives you enough elevation to make the split this time of year. Chuck --- UTAHDEB@aol.com wrote:
Chuck,
Where do you get an apodizing mask and how much do they cost? I think my main problem with this SCT is the fork mount. I think I will get rid of it in July and put it on my equatorial mount. Hopefully it will be more stable. I noticed when I tried to focus the 8" SCT, the mount would vibrate so I would wait for the vibrations to dampen before I tried focusing again. Once I got it focused, the stars looked pretty good except near the horizon. One of the problems of splitting Antares is it low declination in the sky. When I get to Flagstaff Saturday, I'll try again to split this star. This time I will try it with the 15".
Glad you are back,
Debbie
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