For observing: 6 inch refractor or 8 inch reflector?

[Gem (Grant)]

Ok, I know this is subjective! For general observing (both deep space and planets), given a choice between a 6 inch refractor and an 8 inch reflector of the same brand and quality (e.g. Skywatcher) - which would people choose?

[AG Hybrid (Adrian)]

Hi Grant.

Theres a saying these here parts.

"Aperture is King" - particularly for observing. Unless your getting a 6inch triplet refractor, I'd choose a 8 inch newt/dob every time for observing. A little contrast maybe lost when comparing a 8 inch newt to a refractor but the extra light gathering power makes all the difference. About 77% more light I believe. That will make all the difference when looking at deep sky objects. If you just wanted to look at planets a 4 inch will do you nicely. Also if you get an 8 inch newt on a dobsonian mount it will be a hell of a lot cheaper then getting a 6 inch refractor plus an equatorial mount to put it on. Even if you only plan to get an Alt/Azi for the refractor it will still cost more. Resolution and light gathering power is also important for planetary viewing. By getting the newt the money you save can afford you some nice eyepieces.

However, in my opinion. Get a 10 inch Dob instead

[Gem (Grant)]

Thanks! I already have a 10 inch dob! The problem is it hasn't fit into the car for over a decade and is now stuck in QLD! I need to get something that will easily move in and out of the house and fit into the boot of the camry... and maybe do some imaging down the track too. So it won't be a dob, it will be on a HEQ5 Pro or something similar.
I am used to the "bigger is better" from years ago, but was unsure if things have changed over the years with changes in quality of optics, changes in prices, etc... I need something that I can use and use regularly. Just tearing my hair out trying to decide!!!
Seems you have confirmed my gut instinct...

[Waxing_Gibbous (Peter)]

If I had $10,000 odd dollars, I'd choose the refractor.
OK. Granted there are a few 6" Achromats that will cost you 1/5 of that but their views will still be inferior to an 8" Newt/Dob of decent quality.
Figuring a lens or three is considerably more difficult (and expensive) than figuring a mirror. Cheap, large aperture refractors almost invariably suffer one or both of chromatic abberation (fringing around bright objects), or spherical abberation (distorted objects), plus one or two other nasties. The shorter the focal length, the more pronounced are the errors. I recently had a chance to view through one of the better rated ones, a 152mm f6.5 sold under various brand names and it was truly abysmal!

An 8" quality reflector is an excellent choice. Mirrored scopes are inherently colour-free, and while they still need to be corrected for S.A. it is much simpler to get a 'diffraction limited' mirror.
Asian mirrors have become very good and even excellent over the last 10 years and I think you would get much more satisfaction out of an 8" GSO or Skwatcher than you would a crappy refactor.

[ballaratdragons (Ken)]

I use both a 6" Achro and an 8" Dob.

Visual - Go the 8" Dob

Imaging - Go the 6" Achro

[AG Hybrid (Adrian)]

Originally Posted by Gem

Thanks! I already have a 10 inch dob! The problem is it hasn't fit into the car for over a decade and is now stuck in QLD! I need to get something that will easily move in and out of the house and fit into the boot of the camry... and maybe do some imaging down the track too. So it won't be a dob, it will be on a HEQ5 Pro or something similar.
I am used to the "bigger is better" from years ago, but was unsure if things have changed over the years with changes in quality of optics, changes in prices, etc... I need something that I can use and use regularly. Just tearing my hair out trying to decide!!!
Seems you have confirmed my gut instinct...

Skywatcher collapsable newts are the answer to squeezing it into your Camry. Dunno if you can buy them as just a newt without the eq mount / dob mount.
But, a 8 inch f6 newt would probably be too much for imaging with a HEQ5 Pro. 8 inch f4 astrograph newt might work though.
maybe an 8inch f4 is the answer. Perhaps get a coma corrector too though.

[Gem (Grant)]

Out of curiousity: Does a 12 inch collapsible fit into a camry boot?

[AG Hybrid (Adrian)]

Originally Posted by Gem

Out of curiousity: Does a 12 inch collapsible fit into a camry boot?

Good question. It collapses down to 950mm maybe give that a measure. Will fit across your back seats though.

[dannat (Daniel)]

I like refractors & would choose it, cool down will be a little less & stars should be tighter, no collimation issues either(provided you get a good unit) They are heavy though. I like to observe quickly on alt/az, refractor is great for that

[Suzy]

Hi Grant,

I hope these links help as I've always found them to be very educational.

http://www.iceinspace.com.au/63-260-0-0-1-0.html

http://www.iceinspace.com.au/63-261-0-0-1-0.html

[Gem (Grant)]

Thanks everyone for the help and advice!
Appreciate it!