6 Inch F8 Refractor or 8 Inch F6 Dobsonian

[refractordude]

I currently own a 6 inch aperture F8 Celestron achromatic refractor. I have been thinking about buying a 8 inch F6 Dobsonian for better light gathering. Has anyone compared the two on deep space objects? Read that there is not much difference in brightness of objects between a 8 inch and 10 inch Dob. I really do not want to deal with the weight etc of a 12 inch Dob.


Is the 8 inch Dob worth it? Thanks to you all

[Rainmaker (Matt)]

Not a lot of difference in real terms as far as light gathering but there will be a noticeable difference as the reflector will not suffer the chromatic aberration of the achromatic refractor. To make a worthwhile difference I think you need to get a 10” F5

[Startrek (Martin)]

I’ve used a 8” f6 SW Dob , 10” f5 GSO Dob and currently use a 12” f5 SW Goto Dob since 2018.
Unless you have restrictions with storage space , observing space or intend to drive to a dark site to observe then personally I’d go for a bigger Dob like my SW 12” Goto Dob.
I’m 63 years old , 5’ 11” and 70 kgs dripping wet with a history of lower back problems and moving my 12” out of the garage to my observing position 10m away is a piece of cake with a Bunnings parcel trolley. The 12” Sky-Watcher Goto Dobs are truss designed and only take up a footprint of about 800mm x 800mm x 1.1m high.
I do use high end Televue eye pieces at my Bortle 3 location and the views are spectacular, both Planetary and DSO
You can beat a Dob and my 12” is only a tiddler compared to what folk use out there.
The 12” is a great scope and Goto works really well , not so good on the 8’s and 10’s as they don’t have adjustable clutches on Alt and Az drives.

You didn’t mention your budget so I assumed a 12” Goto Dob would be ok ( they retail for about $3,500 )


My 2 cents …..

Cheers
Martin

[Leo.G (Leo)]

Originally Posted by Startrek

I’m 63 years old , 5’ 11” and 70 kgs dripping wet with a history of lower back problems

We sound somewhat alike, too much except I think I weigh in at around 66kg and desperately trying to lose a mid pudding, I look like a piece of string with a knot tied in the middle, lol.


To the question, while I think the larger unit as Martin has mentioned sounds great, I have a 6" achromat refractor and rarely take it out now. Nothing wrong with it, I love the scope but I also have an RC8 carbon fibre I've taken quite a liking to. I also have an 8" GSO Newtonian but the weight means the RC often wins out. I like the lack of CA playing with the two 8" scopes. In saying that I've never considered the CA an issue visually with the 152 Skywatcher (original blue model I've owned for many years (but don't remember how many, just many)) but it does show up in images. Plus add the trees I mention a little later (this is an edit, I'm not from the future, YET), living beyond the Blue Mountains means by the time something appears over the horizon and beyond the tree line I'm near laying on my back. With the GSO Newt I use a small step ladder.
Not that I won't take my 6" achromat out again. I need to travel to a friends farm with a few scopes and play but my back yard isn't the best with huge trees all around the neighbours yards and only a small window of opportunity to play before I'm seeing nothing but trees.

In my case I don't have a dob and my mount is a modified EQ5 PRO (tapered roller on RA axis and a few other little changes) and I'm somewhat obsessed with slapping a camera on every time I pull a scope out so the fibre tube wins hands down weight wise. One day though I do hope to own a 12" or 14" dob. In my case I'll be leaving that to the grace of the lotto gods, I haven't worked in over 30 years through no fault of my own.


I've had more brain scans than most people and they still can't find anything!
Hmmm

[refractordude]

Thanks for the help/replys. Kinda still undecided. May just stick with my 6 inch frac and drive out further for darker skies. What I like about the 8 inch dob is the ease of setup. It may not go deeper than my 6 inch frac, but that ease of setup is very enticing towards buying. Was out last night observing Orion with my APM/Celesroon 30mm UFF. Nothing like those tight refractor stars. When observing the moon I get 300 mag using a 4 inch aperture mask. This 6 inch frac is a great scope, but. Thanks all