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Old 02-04-2019, 11:47 PM
Renato1 (Renato)
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Renato1 is offline
 
Join Date: Mar 2014
Location: Frankston South
Posts: 1,263
Hi Scott,
It depends what you want to do with your telescope.

I have a 102x500 Achromat which I use for wide field viewing at low power, which is easy to take outside and setup in a couple of minutes. It's great for that. But at high power on planets, it needs a yellow or yellow-green or chromatic aberration filter to get rid of the blue light that mucks up the view. And it's pretty useless for viewing galaxies except at the darkest of sites.

I don't like the AZ3 mount which comes with it much. The 6X30 finder, is pretty good for finding stars and planets so long as you remember the trick of keeping both eyes open.

For less money, that site has the 6" dob which gives you twice the light gathering power, and much better views of planets - once you've mastered collimation (or how to adjust the three back screws to get a bulls-eye pattern in an out of focus star image). And you may have to leave it outside for half an hour or more before the temperature in the tube settles down to get the very sharp views on planets.
http://www.astroanarchy.com.au/teles..._FullTube.html

But, to hunt down galaxies and faint nebula and planetary nebula, the 8" dob that store has is dearer, but ridiculously better than the 4" achromat.
http://www.astroanarchy.com.au/teles..._FullTube.html
Though it comes with an 8X50 finder, to my mind also needs 1X red-dot finder to make life easier finding objects. It does have a 2" focuser, which the 6" model doesn't.

Over the years, I've spent a very large amount of time looking through a short tube refractor (for the wide field views) and through an 8" telescope for the deep sky views. Yes, you can make do with one or the other, but ideally you'd want both types of telescope.
Regards,
Renato
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