Orion XT12i with Swayze-refigured primary & Protostar secondary
Televue NP101 refractor
William Optics Megrez 90 refractor
Universal Astronomics Deluxe Mounts
If you ever come across this situation again, I recommend that you Acetone to remove the spot. It won't hurt the mirror or coatings..CAUTION: Use it only in open areas, with plenty of ventilation and wear gloves. Keep it away from plastics. Rinse with Demineralised or distilled water.
XT10 classic with premium optics Tri-knob CR2 focuser
Catseye + Glatter collimation tools
StarBlast 4.5" & 6"
Round Table Platform
Happy owner of-- A Mag 1, 12.5 inch Porta Ball A Dual Axis Equatorial Platform A PST Double Stack
Why did you remove your old spot? Was it to reposition it or was it to change the spot shape?
Quote:I missed something. How did you get the scratches?
<2 hour drive to gray/black zone “Contrast is not everything. Outside of aperture, contrast is the only thing” -Carl Zambuto
Quote: ious to hear a bit more about how long you let the old spot soak and what you used before trying to remove it. I find that I am respotting mirrors two or three times a year and would like to know if there are any lessons to be learned. I usually use acetone which sounds like it worked best in your situation.
AD10, NoName8, DS-16 with Spooner primary.
ES, Sterling, Parks, Baader, TV, GSO EP's and a lone Nagler.
Nikon, Celestron binos
Quote:A template is created to assure accuracy of the mark, which will last through several cleanings. When it fades, it's a simple matter to re-mark it again. This will entirely mitigate the hazards inherent in applying a sticker to the delicate mirror surface, much less trying to remove one.
Accurate collimation of a reflector is an inherently easy task; it's when one strives for perfection that the soufflè falls.
Quote:With all due respect, I consider that method overkill, even with a very fast instrument; I'm of the opinion that "perfect" is not the enemy of "excellent" when collimation is being discussed, regardless what the marketplace may claim. Feel free to ignore my suggestions, as I in no way wish to denigrate your use of a sticker and ancillary equipment over an inkspot... if you feel the former is more accurate, and it enhances your observing, so be it.
Quote:Accurate collimation of a reflector is an inherently easy task; it's when one strives for perfection that the soufflè falls.
Striving to hit the center of the 'good collimation' envelope is a practical, not obsessive, thing. The reason is simple: mechanical and structural flexures occur when the scope is in use. If collimation is in the center of the 'envelope', those flexures won't be sufficient to pull the scope outside of the envelope of good collimation.
Quote:". . the phenomena is entirely one of the inherent mechanical flex in the compression ring mechanism, and not one of loose registration in the focuser or imprecision of the collimation tool. ." I think the problem is inherent in the cylindrical slip-fit system with inward radial clamping that we use. Because there's space in between that allows movement between the cylinders, the inner member can easily slide sideways a little at the line of contact where the surfaces are asymptotically flat. The maximum skew can be dramatically reduced by decreasing the space between cylinders to about 0.001" with tighter manufacturing tolerances.So called "compression rings" make the problem worse. Because of the groove machined in the drawtube, there is no drawtube surface directly opposite (180 degrees from) the end of the clamp screw – there is only empty space. This increases the tendency for the accessory to tip when the clamp screw is tightened. The reason for this is that a machined hole is almost always slightly larger in diameter just at the opening.The only good thing compression rings do is to protect the accessory barrel from marks, but this can also be done with a well-designed plastic tip on the clamp screw.