Yeah, I've cleaned up my Journal a little bit. I'll make further changes to this nice and free Journal layout as soon as I'm a bit more into HTML/CSS. I've decided to delete the telescope making sections from my journal, since there isn't happening much. Well, on the other hand I resumed grinding the 8 inch mirror and I'm making some big leaps towards the end. I'll post news about the 8 inch and the 12 inch project here in the "Journal Section" . So here is some kind of coutdown for the 8 inch mirror:

get all the stuff to grind a mirror
build a suitable grinding tool
bevel the edges of the mirror
rough cut
fine cut
carbo 180
0.5 h
1.0 h
1.5 h
2.0 h
2.5 h
3.0 h
3.5 h
4.0 h
carbo 320
carbo 600 (?)
Al₂O₃ 15 µm
Al₂O₃ 9 µm
Al₂O₃ 5 µm (?)
polishing, measuring and correction
metallization
first light

Not many shiny pictures, I know...I don't have much equipment at the moment. But I promise that it'll get interesting during the polishing/measuring/correction phase.
The (?)-entries are because I don't know if this stuff is still in my parent's cellar, or if I simply doesn't heave it. I have to have a look next time I visit them.
My personal grinding session lenght is 0.5 h (just to have an idea how long I've already worked with one grain size...usually I work >= 1 h in one go), therefore the above list from 0.5 h to 4.0 h. Note: I just picked 4.0 h to be the maximum - most propably I can switch to a finer grain earlier but especially with the carbo 180 I'm not sure because I somehow got a fissure into the mirror which may be grinded out after some additional sessions.
The difference between carbo and aluminiumoxide (Al₂O₃) is that the carbo grains are round and punch out small pieces of glass from the mirror, this way they hit relatively deep holes into it. The Al₂O₃ is plate-shaped and it planes the glas, therefore it makes a much smoother surface. Some other interesting things happen, during the polishing where ceriumoxide is used, so stay tuned.

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12 inch project material listing:

8x 25 mm x 25 mm x 2000 mm aluminium pipes.................................about 164 $
screws with nuts (100x), M5x40 mm...........................................................11 $
shims (250x)............................................................................................7 $

' Papillon Sur Blanc' in macrophotography





'Rainbow Deluxe' in weather





'I Can Not Hide Forever' in astrophotography

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