Thread: First Telescope
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Old 01-01-2020, 07:01 AM
astro744
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astro744 is offline
 
Join Date: Apr 2007
Posts: 1,244
I have a Skywatcher 250mm, f4.7 solid tube that I bought the kids. It couldn't be simpler or easier to use and carry to the yard. Last thing I wanted was to assemble trusses each time and then require a shroud for a relatively small 'scope. If I were travelling out to remote dark sites then maybe but even then the 'scope fits across the back seat of most cars nicely and the cradle on the front seat. (Of course passengers become an issue!)

The solid tube lifts off the cradle leaving just two pieces to carry out to the back yard. When pointing straight up the eyepiece is at 1230mm from the ground. I am 165cm and have to bend over so you won't have a problem at all.

The front of the primary mirror sits about 300mm from the floor. The focal length is 250 x 4.7 = 1180mm. The eyepiece height = 300+1180-half tube diameter-focuser distance. I find the eyepiece height a little low for lower object angles but the kids like it. I also have a 10.1" f6.4 which I designed to have an eyepiece height at zenith equal to my eye level standing up. This worked great until I got an EQ platform which raised the height a bit. (I don't use the EQ much but its great for extended viewing of the same object at higher power). The Skywatcher 250/f4.7 is at perfect height with the EQ platform. (The new Skywatcher is listed as f5 but the focal length doesn't equate!)

The Bintel/GSO I believe is f5 so focal length is about 75mm longer so still fine for height. I'm not sure how high off the ground the primary of the GSO sits but I doubt it's higher that's the Skywatcher.

I bought mine used and if I were buying new I'd probably buy BINTEL because I don't like the focuser on the Skywatcher I have (I thinks it's earlier model). For some strange reason it has a stop inside the 2' barrel preventing the insertion of a Paracorr fully (unable to active focus with one) and also preventing a 2" laser collimator Barlow plug from being seen from inside the tube. (I used the Astrosystems model). This may have been addressed on the newer models and it's not really an issue for general use as the focuser is solid. The kids don't use the Paracorr and as a beginner you won't need one to enjoy the views. As for collimation I have reverted to visual sight tube and star test and once done it holds collimation nicely.

If you are near BINTEL go into store and have a look at their models. If 250mm is not too big for you and you can afford it then don't even consider smaller apertures. As for eyepieces that is a whole new topic and you will likely add to your set in years to come but you can still enjoy the night sky with the eyepieces that come with it.

Whatever you choose, enjoy!
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