GSO 10" Deluxe vs GSO 12" Ltd

[lost_in_space]

My telescope procrastination is almost over. It's down to either of the above 2 scopes. There is $100 difference between the 10" Deluxe and the 12" Limited GSO dobs.

Given the deluxe has a fan, a crayford focuser and better glass for the main mirror, in the considered wisdom of this group would the better features of the 10" be worth sacrificing for the extra aperture of the 12" with the $100 difference going into better EP selection?

My inclination is to go with the 10" after all I have read in the forums here. Thoughts anyone?

[iceman]

You don't mention 12" deluxe! :)

It's a tough choice.. aperture rules, so I'd go the 12", and then spend $99 extra ontop to get the GS crayford put on. You don't need to worry about the fan just yet, although it's handy to have.

As long as the 12" is portable enough for you, moving in and out of the house, to and from dark skies etc, you'll love the aperture!

[asimov]

Hmmm...I don't know all the specs on the 2 in question. Seeing aperture is supposedly king, I think for an extra $100 for 2 more inches would temp me.

Doesn't the 12" come standard with a crayford these days?

[slice of heaven]

Go the 12". Aperture upgrading is the most expensive item, focusers..fans.. add them as you can.

[Astroman]

Go with apature you can always build on it.

[Robert_T]

I reckon you''l be happy with either... if I were starting out myself I'd take the 10in because I'm lazy and I'd want to make sure size didn't put me off carting it around and using it.


good luck

[mickoking]

G,day


A telescope will work fine with out a crayford focuser or a cooling fan so I would go for the 300mm Dob. ;)

[ballaratdragons]

It is well worth paying the extra for the 12" but get it with the Crayford!!!! Pay the extra for it.

Don't worry about the fan. One can be fitted any time, they are only 12v computer fans.

As for the quality of glass, because we don't get down to minus 15 degrees any of the optical glasses will do. Plate Glass, BK7, or Pyrex. With Australias weather you will never see any difference between them. But if you are worried about using Plate Glass, the 12" deluxe has BK7 Glass, and the fan already fitted. And a Crayford Focuser!

Look down the bottom of the page on this link and you will see:
Guan Sheng GS-980-BK7-CRF
$999.00 AUD

BK7 = BK7 Optical Glass (good stuff) CRF = Crayford Focuser (lovely)


http://www.andrewscom.com.au/site-content-section-10-dobsonian.htm

p.s. I'm not saying this just because I own a 12" Deluxe. It's because they are a good buy! And coz I own one!

I will mark 12" in your poll, but recommend you get the Deluxe!

[lost_in_space]

The 12" Deluxe will push me over my budget with the other kit I am buying. It's tempting though. Freight is the same for 10" and 12" to Tassie. I am not frightened of getting the basic model and modding it to my requirements though, in fact I am planning some serious mods anyway.

Bugga, you guys are supposed to be helping me, and now you are making me change my mind all over again:confuse3:

Seriously though, I appreciate the comments so keep 'em coming, and WILL make a decision in the next couple of days.

[wavelandscott]

Without knowing you physical size, vehicle and how far from dark skies I will error on the side caution...get the 10 inch deluxe and put the extra $100 toward a quality widefield eyepiece...

Yes, "size" does rule but I reckon you will enjoy looking through a better eyepiece or two as much as the extra light...the 10 inch maybe a little easier to handle and the "deluxe" stuff (crayford and fan) are things you are ultiimately going to modify up to sometime anyway...

My 2 cents...

[janoskiss]

If transportation is not an issue (when you want to take it to darker skies), then get the 12". There is a big difference in this regard between the 10 & 12". As far as the extras go, Crayford, fan, ... you can always get these later as more funds become available.

[ballaratdragons]

Yeah, after a bit of thought it would be cheaper to get the standard 12" at $799 and buy a Crayford Focuser at $99 and fit it yourself! All up it is $100 cheaper than the Deluxe and you still get an excellent 12".

The difference between a 10" and 12" isn't just 2" either. There is a mathematical way to work out the extra surface area (light gathering power) but I don't know it. But it is quite a big difference!

[acropolite]

Go the 12 inch, the other niceties such as fans and crayford, you can add later for not much extra cost (just over 100 recession riddled buckazoids). On the other hand the 10 inch can't easily (or cheaply) be made into a 12.....and the 12 inch has 44% more light gathering area than the 10 inch....:thumbsup:

[gaa_ian]

I have the 10" Dob, but so long as you can transport it, go the 12"
Remember the #1 Rule: Aperture rules !
When you are trying to tease detail out of the humonculus nebula, or see the Spiral arms of NGC 1365 etc etc ... you will be glad of the extra aperture !

[danielsun]

yes i agree with steve . go aperture 12" focusers and stuff can be put on later BUT if you go 10" then go SAXON cause SAXONS RULE!!!!!!!!!!............

[ballaratdragons]

Does anyone know the formula for working out the extra % surface area between a 10" & 12" mirror?

[lost_in_space]

The fan is not really an issue, as I am a computer tech. Temperature may be an issue though, it can get down to -5 here on a clear winter night, and has gone as low as -9.

[janoskiss]

Daniel, I know you like the altitude motion tensioner adjustment, but is there anything else about Saxon Dobs that RULEs over GSO Dobs?

[acropolite]

pi r squared gives the area Ken but if it's a percentage comparison you can forget pi. Work it out like this. 10 inch (250mm) is 125x125=15625. 12 inch (300mm) is 150x150=22500 Difference is (22500-15625)/15625 which is 44%.

[danielsun]

Sorry to go off the topic but i had a giggle imagining all you GS owners must have read that and simultaneously went :scared: in unicen!!!:lol: :lol:

[danielsun]

Yes Steve it has handles that go through the sideboards and into the alt bearings making it able to pick up the complete unit and carry around easily! and nice thick round bolted alt pads not stapled teflon.

[lost_in_space]

I was wondering why you voted "Neither" :lol:

[janoskiss]

area goes like the square of the diameter (aperture).
Aperture for area,
12" to 10" is like
12*12=144 to 10*10=100,
so the 12" has 44% more area. But the eye's sensitivity is "logarithmic" so this seemingly big change on paper amounts to a relatively subtle difference when you look through the scope.

[danielsun]

just having a bit of fun cause i know there are a lot of GS owners out there and i was waiting for someone to coment.

But back on track again it seems majority agree if transport is no problem go the 12" !! The GS's are a good scope and the saying goes aperture rules!!!!.

[janoskiss]

Daniel, I think I know what you mean about the altitude bearings. They must be like the ones on the Celestrons I saw at York in Melbourne. Great big polyurethane things (at least that's what they looked like to me), very smooth. They felt much nicer than the altitude bearings on my Dob. But they also add bulk (width) to the mount.

[danielsun]

yes your probably right Steve, the extra material around the bearings on the side plates for the handle set up and the 20 mm polyurethane rollers probably does add a tiny little weight but not much!. but if i was to upgrade again it would probably be a 12 GS with the crayford which is a much better focuser than the standard r&p on the saxons, but as you know the story how would i hide it from the wife, GS's are silver!!!:lol:

[davidpretorius]

12" if not a transport problem as I want you to come to Bridenorth every now and then.

Deluxe or Ltd???

Cooling: The way our temps drop here in tassie during summer, a fan is a must. i have just bought a $30 ball bearing fan the same that is on Simon's 12" bintel. Ian has made up a backing for them to fit around the collimation screws etc, so I believe it would be better to add the fan after purchase.

Crayford: simply a must. Playing with Ian rack and pinion on his 8" and then my crayford on my 10", well there is no question. On the down side, two guys on this site have bought the $99 crayford and have had hassles fitting and getting focus from memory. Now they were for non gs scopes I believe.

So, 12", crayford and a cooling fan must be there eventually. Then a dob driver II and a ..... and a....

[ving]

i picked 10" for transport reasons... and lugging around a 12er could be a viewing killer. "its clear, but could i really be bothered lugging this thing outside, the seeing might be bad then I've wasted the energy..." etc.

aperture does rule tho :)

[davidpretorius]

vingo.......dob buggy is good!!!.....no transport probs unless stairs!!

[ausastronomer]

Well, I have owned 6", 8" and 10" tubed dobs. I have no inclination at present to change my scope.

The 10" to me is the best compromise between cost, portabilty and what you will see. That doesn't mean its the best option for everyone. When I do my lunar/planetary observing from home I like to be seated as you can extract infinitely more detail seated than you can standing. The focuser on the 12" is too high for me to use seated. The 10" also fits perfectly in my wifes car and its also a lot easier to carry in and out of the garage.

Just some things to think about before you jump in head first and then realise
O fu-k !!!!! its a big sucker.

Granted the 12" will show a little more than the 10" but having used both scopes on many occasions I prefer the 10" as being the ideal size for my own observing needs.

The crayford and the cooling fan are also necessary options IMO, if not initially at some time in the future.

CS-John B

[Robert_T]

looks like the 10 is gaining, but the 12's still got a hefty lead there... decisions decisions :confuse3:

[lost_in_space]

Thanks for the feedback peoples. In line with the popular choice in the poll I have decided to go with the 12" Ltd with the 4 bundled plossls at 4, 6, 20 and 25mm, (I already have a 15mm) along with a Rigel QF, Cheshire Collimator, GS 26 & 32mm 65deg 2" EP's, and a GS achro 2x Barlow. I also wanted the 40mm GS EP, but Andrews had no stock. I ordered yesterday, and they are shipping today so I won't see it for the weekend.:sad:

I figure this is a good enough mixture to get me launched, and will add the Crayford focuser and better EP's once I have looked through others and have a clearer idea of where I am heading with this. The first job I will be doing (after collimating it) is to add either a 80 or 100 mm computer case fan to the base of the mirror cell. I have both, but will need to see which is the better fit.

Suck or blow? I think blow would be better, especially if I can somehow direct the air flow over the mirror to break up the boundry layer effect.

Once again thanks for the great advice, and I'm sorry about the next 6 weeks of cloud cover and bad weather!

[davidpretorius]

welcome to the dob team.... we now show you the secret handshake that the SCT boys don't know about and we vacate posting informative stuff on this forum. The new forum address is !#!@#**(((!()))!..!#!#!! (security coded of course.)

The tie and jacket have been sent from headquarters. Words for the dob team song are being emailed and the gentlemen's pleasure evenings with miss universe contestants serving refreshments and cigars start next thursday

---------------------------

Re th fan. Blow if you are from the bottom or if like i have done, i have cut a hole in the side to suck the boundary layer out.

Stay tuned, i have ordered my peltier coolers to builder a cooling system for the base of the newt.

[ving]

wiggle, wiggle, shake, slap, wiggle.....

[acropolite]

Geez, more bad weather in Tas now....Good decision though..:D

[ballaratdragons]

Tha fan will need to blow onto the back of the mirror.

Luckily, the 12" has a larger gap between mirror & cell than other GS models, so the air will easily blow around the mirror and across the surface. How do I know this? Whenever I get a fogged mirror I turn the fan on and watch it demist. Also I noticed at Camp that other GS mirror cells are closer to the back of the mirror than the 12".