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Anchoku · 01-20-2007, 12:27 AM

Cthulhu et al,

Pixels are generally square, or very nearly so. The panel is 640 x 480. Divide one by the other and you have 1.33 or 0.75, meaning the panel has a 3:4 aspect ratio which is a common format.

Regarding trigonometry, remember there's such a thing as a 3:4:5 triangle. That makes things remarkably simple: the panel is 3" x 4". Dot pitch, or lines per unit length, is # pixels / # length.

640/4" = 480/3" = 160 dpi

You'll need to hold it 12" or less from your face to see all the detail depending on the quality of your eye sight. That's pretty good, or pretty bad depending on whether you use bifocals.

NatCh,

When you replace your big vacuum tube, you're going to have to do some more advanced trig. Measure from the front of the tube to the backrest of your favorite chair. Measure the height of your tube's viewing area and divide that in half. Draw a right triangle on a sheet of paper with one vertex a lot narrower than the other. Label the short side with the tely's measurement and the long side with your chair's distance. Divide short by long and use a calculator to calculate the arc tangent, tan [-1], or tan inv. That's the magic angle to make sure the new flat panel looks the same size as the old tube. Write it down in the narrow corner. Figure out how much closer to the wall you can put the new tely and run the calculations backwards to get the new tely's new height (of the viewing area).

Two things that often disappoint people because they didn't know to consider them are image size when watching NTSC, PAL and SD formats and, pushing that new tely up against the wall to reclaim some of the old tube's space; thus making it look smaller.

01-20-2007, 12:27 AM	#23
Anchoku Connoisseur Posts: 54 Karma: 164 Join Date: Jan 2007	Cthulhu et al, Pixels are generally square, or very nearly so. The panel is 640 x 480. Divide one by the other and you have 1.33 or 0.75, meaning the panel has a 3:4 aspect ratio which is a common format. Regarding trigonometry, remember there's such a thing as a 3:4:5 triangle. That makes things remarkably simple: the panel is 3" x 4". Dot pitch, or lines per unit length, is # pixels / # length. 640/4" = 480/3" = 160 dpi You'll need to hold it 12" or less from your face to see all the detail depending on the quality of your eye sight. That's pretty good, or pretty bad depending on whether you use bifocals. NatCh, When you replace your big vacuum tube, you're going to have to do some more advanced trig. Measure from the front of the tube to the backrest of your favorite chair. Measure the height of your tube's viewing area and divide that in half. Draw a right triangle on a sheet of paper with one vertex a lot narrower than the other. Label the short side with the tely's measurement and the long side with your chair's distance. Divide short by long and use a calculator to calculate the arc tangent, tan [-1], or tan inv. That's the magic angle to make sure the new flat panel looks the same size as the old tube. Write it down in the narrow corner. Figure out how much closer to the wall you can put the new tely and run the calculations backwards to get the new tely's new height (of the viewing area). Two things that often disappoint people because they didn't know to consider them are image size when watching NTSC, PAL and SD formats and, pushing that new tely up against the wall to reclaim some of the old tube's space; thus making it look smaller. Last edited by Anchoku; 01-20-2007 at 12:35 AM.