Thanks Malcolm. It involved a bit of averted vision whilst sweeping the area. Jupiter is easier, but still needs patience. Pre-focussing is a must.
I'm going to try for Venus (should be no prob!) and Mercury if possible. When Mars comes out again I'll try for that. Given that Jupiter's moons are visible during daylight, I wonder how much of a stretch it might be to catch Uranus??
In daytime observing I ALWAYS make sure that all parts of the telescope are in shade and that it will remain out of the sun for the time it is outside, so that there is no chance of exposure.
Venus is fairly high in the sky early in the morning so it should be easy to capture during the dark. Uranus is difficult but not impossible but not in the daytime or dusk, it is just too weak to see.
I remember many years ago at 16 (in 1987) trying to see Sirius in daylight with my trusty 75mm Tasco 3T-RB Newtonian on alt/az tripod.
I figured that if Venus at mag -4 could be seen with the naked eye in daylight, then the daytime sky must take about 10 magnitudes off the apparent brightness of anything else (ie Venus' -4 becomes the equivalent of mag 6 or so for daytime viewing). With that in mind, and because my 3 inch scope had a limiting magnitude of 11.5, then Sirius at -1.46 would become equivalent to mag 9.46 through the scope during the day. Theoretically! Still not sure if that's a valid way of looking at it.
On to the search for Sirius. I thought if I pointed it at a star, the night before, with the same declination and left the telescope outside (covered over) for the length of time that the Right Acension between the two stars was different, I would see Sirius the next morning. It worked a treat and it was an amazing sight to see another sun in the daytime sky.
If the 10 mag difference between night and day is (very!) roughly true, then a 12" scope should be able to see down to 14.8 then Mag 4.8 should be possible. I have seen Io, Europa and Ganymede which were just visible so maybe there's something to it. In an image I could see 20 Psc (at mag 5.5) just barely. Also in my 50mm finderscope Jupiter is just visible at mag -2.2.
Anyway, this probably belongs in the observing forum! : )
With a 12" I think you will be OK to try but just be careful, the sun is close by and if the 12" drops like mine the mirror could fall into the path of the sun. Not only could it damage the camera or eyes, there are some photos on the forums somewhere showing the damage it can do to the scope. 12" is extremely powerful.
Every time I go out I ensure that the telescope is in the shade and will remain so. Absolutely not worth the risk. Neighbours wonder what I could possibly be doing!
