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Everything posted by johninderby
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SCT, Mak or frac?
johninderby replied to OK Apricot's topic in Getting Started Equipment Help and Advice
Reminds me of the old joke about guitar players. They spend half their time playing out of tune and the other half tuning. 😁 That’s the greatest weakness of the SCT design at least in the medium and bigger apertures. Keeping one in perfect collimation all the time is the problem. -
Aperture calculation
johninderby replied to bomberbaz's topic in Discussions - Scopes / Whole setups
You just have to accept that every scope is a compromise and no one scope does ot all so it’s more about finding the best comprimise rather than the perfect scope. Also explains why most have more than one scope. 😁 -
That would indicate a problem with the focuser not being squarely mounted.. The wooden part the focuser is mounted to may be slightly out.So perhaps a bit of shimming is called for.
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Aperture calculation
johninderby replied to bomberbaz's topic in Discussions - Scopes / Whole setups
An article by Damien Peach that might be of interest. An examination of the effects of optical aberrations, obstruction and seeing on real Planetary images. http://www.damianpeach.com/simulation.htm Used an area calculator and came up with the same answer of 15,029 -
SCT, Mak or frac?
johninderby replied to OK Apricot's topic in Getting Started Equipment Help and Advice
I did ask Steve about a 10” solid tube CC. With the carbon tube wouldn’t be much heavier than the 8”. He said it would be possible if there was enough demand. 🤔 -
1.25 Diagonal - economical suggestions please
johninderby replied to Justin P's topic in Discussions - Eyepieces
The Svbony 1.25” diagonal is pretty good despote it’s bargain price. https://www.amazon.co.uk/Diagonal-Adapter-Refracting-Telescope-Eyepiece/dp/B07GPMX7BN The StellaMira diagonal is a bit better. https://www.firstlightoptics.com/diagonals/stellamira-1-25-90-di-electric-diagonal.html And better still. https://www.firstlightoptics.com/diagonals/william-optics-125-dura-bright-dielectric-diagonal.html Or if you would prefer a prism. https://www.rothervalleyoptics.co.uk/baader-prism-diagonal-t-2-90-with-focusing-eyepiece-holder-and-125-nosepiece.html -
SCT, Mak or frac?
johninderby replied to OK Apricot's topic in Getting Started Equipment Help and Advice
And that’s the reason I went from the C8 to the CC8” . So sharp on axis. -
SCT, Mak or frac?
johninderby replied to OK Apricot's topic in Getting Started Equipment Help and Advice
As much as I love my CC8” can’t help wonder what the CC10” would be like. 🤔 -
SCT, Mak or frac?
johninderby replied to OK Apricot's topic in Getting Started Equipment Help and Advice
Yes collimation is still perfect. 👍🏻 Would be intesting to compare the Mewlon 180 with the Tecnosky 125. 🤔 -
#12 piano wire is 0.7mm and comes in a 1m length. Strong stiff and doesn’t kink like copper. Violin E string is 0.54mm You don’t want to go too fine otherwise the crosshairs can be hard to see.
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SCT, Mak or frac?
johninderby replied to OK Apricot's topic in Getting Started Equipment Help and Advice
The Skymax127 AZ-GTi is very popular and just over £500.00. The AZ-GTi mount is pretty good and can be used in EQ mode with the addition of a wedge. https://www.firstlightoptics.com/telescopes-in-stock/sky-watcher-skymax-127-az-gti.html -
SCT, Mak or frac?
johninderby replied to OK Apricot's topic in Getting Started Equipment Help and Advice
Yup and fits nicely into my scope lineup. Hope the OP finds a scope that will suit them but there are so many nice scopes out there now can be a confusing choice. -
SCT, Mak or frac?
johninderby replied to OK Apricot's topic in Getting Started Equipment Help and Advice
I’ve found the CC6” holds collimation as well as a mak. Never had to touch the collimation since I got it. You should not disregard the increased resolution of a bigger aperture plus the ability to take higher magnification. My CC6” on a report tripod can be carried outside single handed. Fitted a carry handle to the OTA. Thought about a 4” frac but bought a 5” APO instead. Lot heavier than the CC6” though and requires a solid mount. Not exactly grab’n’go. but a wonderful scope.🙂. -
Piano wire is very good and comes in lots of thicknesses so just pick a fine one. You can get it on Amazon or eBay and normaly comes in 1m lengths. Or a local music shop of course.
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Question about size of objective lens
johninderby replied to dazzystar's topic in Discussions - Scopes / Whole setups
I’ve had an ST102 and while it was fine for low power wide field use trying to use higher magnification wasn’t nice due to CA and other aberations. One of the other scopes is far better suited for AP due to their excellent quality optics that will allow higher magnification and lack of CA. BTW it shoild be The history of telescopes since Thomas Harriot in 1609 to James Webb. Thomas Harriot was the first person to use a telescope for astronomical observation not Galileo.