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Very happy with it! Wish the sky were clear, but as we all know, when we buy astro equipment, it's cloudy! Argh!
The telescope was collected from David Lukehurst at noon and then we travelled back to Cambridge.
John Nichol primary mirror: 37mm thickness, Suprax. Hilux coated. Optics 1/8 PV wavefront 1/27 wave RMS. Strehl .95. Secondary mirror: 62mm MA.
Here a few photos:
Hope someone with more experience than I, which basically means anyone that has successfully collimated a Newtonian, can answer a couple of compound questions I have based on my first and only attempt at secondary collimation of my SkyWatcher Flextube 250.
1) All three of my secondary collimation screws were extremely snug before I did anything and I was only able to comfortably turn them counter-clockwise. Is this normal? Do I need to loosen all three screws first before I can properly start collimation? Should I be turning any screw beyond "snug"?
2) Before collimating, I placed a yellow sheet inside my OTA opposite my focuser tube and I placed a red sheet between my secondary and primary. The view this gave through my focuser tube was of a red circle surrounded by a partial yellow ring (the secondary mirror stalk blocking a portion of this yellow annulus). While independently turning each of the secondary collimation screws counter-clockwise I looked down the focuser tube (both with and without a sight tube installed) expecting to see some change in the shape of the red area (more or less circular) and/or the yellow area (less or more even thickness). I turned the screws no more that 2 complete revolutions. I did not perceive any appreciable difference in what I saw and I turned each screw back (clockwise) to their original tightness before working with another of the screws. Does it make sense that I didn't perceive any change? Should I have turned the screws more revolutions? Should I have loosened more than one at a time?
Very confused and looking for your help. Thanks
I just installed this Lacerta 1:10 Micro Transmission focuser on my 8” Skywatcher Dobsonian. It is a direct replacement for the stock focuser and works extremely well. I was surprised at how easy it was to install! Ordered it from 365Astronomy and got fast shipping.
I have just got a second hand Astromaster 130EQ. I want to say that i have collimated scopes before without the use of a laser but in this case i have 2 questions as this is so far out i cant see what i am looking at half the time. So hopefully you can help, thank you.
Info about the first problem:
The secondary mirror fixing screw that hold the mirror and the collimation allen key bolts were so loose the secondary mirror had rolled facing the bottom of the OTE. In every other case the holding screw never needed touching and all i had to do were make small adjustments with an allen key, no screwdriver was needed. So this case is a whole different scale then any other collimation i have ever needed to do. You probably all know that i need to get the center of the eyepiece in line with the center of the mirror before can move on with this step.
What is the best way to do this, shall i just eye it for now? (i have seen people measuring to the center of the eyepiece and then do the same with mirror but then i still dont know if the mirror is facing me directly.)
Info about the second problem
Every other time i have collimated a scope the mirror and scope were very low quality and just used for practice basically. The old scopes were used to see if i wanted to go further into this hobby which i definitely do. Any how the old scopes had a flat mirror and i could find the center by placing the mirror on paper and tracing a circle template. The thing is this mirror is concaved so any template iswill have to be pushed into the vurve (i think).
So how can i center the mirror without placing it face down on a piece of paper which cant be a good thing?
Thank you. I hope i have not gone on to much, thank you for your patience in reading a long winded post.
I need a a really accurate,easy to use collimating tool. I have a used laser collimator but it does not fit snugly in the focuser so I feel it’s not very accurate. The idea of collimating causes me some anxiety anyway, so accurate and easy is the key! Can any of you offer any suggestions to help me out?