8" or 10" Dobsonian? (My first telescope)

[nwink]

8" or 10" Dobsonian? I'm trying to decide between these two for my first telescope: which should I get?

Some people say stepping up the aperture size by 2" doesn't make a significant difference for viewing, but lots of people say the increase in light (56% increase) is very noticeable...and that more aperture is always better.  My limiting factor in size will be what I can fit in my car, so that's why I'm not going higher than 10".  I really want to view DSO's and Messiers, so I think I should get the bigger aperture to take advantage of letting more light in. But I've also never compared an 8" and 10" side-by-side on various celestial objects, nor have I used both for periods in my life to have experience knowing what the difference would look like.

Would a 10" be very heavy to move? I wonder if I would use the 8" more often for size reasons...but not necessarily. I'm ok with lifting the weight of a 10" per telescope specifications, but I can tell they look pretty bulky. Are 10" dobs easy enough to handle and setup for one person?

My thoughts are that while I am just a newbie figuring things out, I want to spend money on a telescope that I'll like just as much when I get more advanced with more experience. So I feel like other factors aside, maybe it's better to go with a 10" that will be my primary telescope all my life. (I don't plan to ever be spending much more money for another telescope, but mostly just for accessories on the primary telescope I'd have. So I need a good choice for the telescope I'll use for years to come.)

Any advice and personal experience you could share would be very helpful. Thank you, all, for the input!

[Liquid360]

I'll take the wildly unpopular view that manageability trumps aperture. As far as the "lifetime" scope purchase... Good luck with that [emoji6]

[bingevader]

Purely personal experience!

The 8" is great.

Set up in a couple of mins.

Manageable in one piece, but very easy to manoeuvre and assemble in 2.

FIts in the car in one piece too with the back seat down.

Whilst I will be after a larger 'scope in my dotage, this more than fits the bill for the next decade or so!  

[Daniel-K]

a 10" will be far better. ive had a 8 & 10, the 10 could resolve most globs to the core where as 8 was struggling. also getting the 10 keeps you from thinking well imagine what i could see with a 10"! 10" is also super portable the tube isnt that big so can fit in most cars.

[Charic]

If I were to upgrade to something bigger, I would like a  Skyliner  (12") 300P with  solid tube construction.  The more Aperture for visual work, the better, but not too steep with the focal ratio, as compared to the 10", so I can continue with my present collection of eyepieces?

[Paul73]

10" is / was my first scope. If you can easily fit it in the car and not give yourself a hernia putting it together - go for the 10".

This is especially true if you are heading for dark sky.

However...... If you need to carry the thing down a few flights of stairs to get to the car..... This might be oK once or twice but you will soon get bored of it and start making excuses not to go out.

I have a flex tube Dob which collapses in 3 seconds (looses 50cm off the length of the tube). This is great if you want to get it into your car boot (sorry "trunk") or hide it behind a sofa when not using!

Don't forget to buy a good pair of Binoculars as well. 10x50's are perfect in my book!

Good luck.

Paul

[dweller25]

I had a Skywatcher 8" and 10" .........

The 10" gave much better deep sky and planetary views than the 8"

The 10" base did my back in.

Now I have a super light 8"

[buzzlightyear]

Im led to believe that with this kind of aperture diffrence you will only really notice the results of yhe larger aperture in dark skies and low light pollution. I may be wrong tho!

[Kropster]

Go for the 10".

It is easy to handle in two pieces and quite compact enough to fit a small car.

56% more light.... just think of it!!

[Daniel-K]

Im led to believe that with this kind of aperture diffrence you will only really notice the results of yhe larger aperture in dark skies and low light pollution. I may be wrong tho!

 yes you are!

[Liquid360]

To each eye their own. I can't discern any difference unless we're talking 4in+ unless I strain. Other eyes are more sensitive. Just depends.

[Cjg]

I've had a 10 inch Dob, stunning views, and not that heavy. But, at least two trips to and from the car to load it, ota across the back seat and mount in the boot. Was a Skoda Fabia. I don't think an 8 inch would have taken up much less space. If you get the 8" you'll always be wondering what if... I'd go for the 10, but may be worth visiting your local Astro soc to see?

Good luck.

Chris

[tarotrocola]

Do you plan to go out a lot and short times or only every new moon? The 8 is lighter, cools down quicker, holds collimation better, and is slightly less demanding in eyepieces. If you will observe once a month go for the bigger (even a 12-14-16 truss) , if you want to enjoy unplanned observations, the 8 is better.

[Daniel-K]

Do you plan to go out a lot and short times or only every new moon? The 8 is lighter, cools down quicker, holds collimation better, and is slightly less demanding in eyepieces. If you will observe once a month go for the bigger (even a 12-14-16 truss) , if you want to enjoy unplanned observations, the 8 is better.

the 8 is a great scope no doubt about it but the 10 offers just that bit more, my old 10 gave me the best view ive had of jupiter yet! seeing the festoons swirling around the belts. 10" is still manageable in one go over short distance ie moving around the garden to avoid a tree or something, but is space is limited you cant go far wrong with a 8" as above the collimation on the 8" is pretty solid only needs a tweak every so often. the 10" will need doing every time.

[John]

Given that your primary interest is in deep sky objects I think the 10" will better deliver your ambitions as every bit of aperture really does deliver on such targets. The F/4.7 focal ratio of the 10" will mean that you need to think a little carefully when you come to eyepiece selection, especially if you have a taste for wide field views. The tube length is the same with the 8" F/6 and the 10" F/4.7 but the weight and overall breadth of the 10 is that much more as you might expect.

If your primary interest had been solar system targets I might have swayed more towards the 8" F/6.

I've owned both scopes and personally preferred the 8" because of above are my preferred targets and I just felt the planetary and lunar views were crisper with the 8" F/6.

I can recall thinking that the 8" and the 10" were quite large scopes when they first arrived but since having my current 12" F/5.3 I thought the 8" F/6 looked rather dainty when I saw one recently.

[Moonshane]

Either will be great. About the same size but 10" a bit heavier.

Both will give good views esp from darker skies. Plan for a right ange correct image finder, red dot finder (your neck will thank you for both), a red torch - could be home made, collimation tool and a star map. If this means the 10" is over budget get the 8". Buy used and get it all.

[buzzlightyear]

Dont just say im wrong, but give the reasons why? My answer is based on some reading in astronomy magazines who say what I have quoted on this thread. It is only based on uk observing tho and importantly the viewing conditions to notice a significant difference between the two apertures.

[jetstream]

Buzz, I think that an increase in aperture will give benefit in LP skies and dark skies. There may be a point of diminishing returns with really big dobs ( as far as LP skies are concerned). For globs/DSO I wish I had a 14" -16" from home (LP) or dark sites, but my 10" does very well, espc under very dark skies (DSO). A 12" f5.3 with great optics may be the best all round (DSO/high quality planetary) scope there is IMHO, regardless of the viewing location.

I don't think your wrong really, we are all just learning, myself included.

[alan potts]

I was always lead to believe that the 8 inch scope was the first step on the ladder to a serious telescope, it was when I started. The other week I read on here that 16 inch scopes were the new 12 inches, so if that is true then 10 inches must be the new 8 inch. The 10 will show you more under dark conditions but will be a bit heavier but this is nothing if you are young and fit as oppossed to fit to drop like me.

I am wrestling with the 12 inch and 10 inch question myself at the moment for my EQ mount for planetary and so far the only real answer I have come up with is buy both.

Get the 10 inch!

Alan 

[buzzlightyear]

When I had this decision to make last year I too sought expert advice. After researching the difference you gain in visual to the difference saved in price then I opted for the 8inch and spent the savings on some decent EP to go with it.

Was just my personal choice tho but im sure you will be happy with either scopes capabilities.

Good luck.

[hippie]

Go for the 10" Dob you won't regret it,  I have to carry my 10"  downstairs & up again out to the car every time we get clear sky's (which seem to be rare this year so far  ),  However the 10" is a great scope and easy manageable in & out of the car!, With a few mods to it also you won't regret it  .

Ian. 

[iamjulian]

You will love either scope. If you go for the 8 and start looking at faint stuff, you may wish you had the 10 for a little more reach. But I have just stepped from a 12 down to an 8 and I am still really happy. You will love either scope. Go with your heart.

[iam4208]

I jumped from 8" to 10" only because I was getting a used package with some top quality eyepieces.

My advice would be that good quality eyepieces are just as important as the scope aperture.

If you are working to a certain budget, I'd be tempted to invest some of it in eyepieces or at least recognise that you will discover the limitations of standard eyepieces pretty quickly (especially if you look through someone else's).

Good luck!

[jetstream]

When I had this decision to make last year I too sought expert advice. After researching the difference you gain in visual to the difference saved in price then I opted for the 8inch and spent the savings on some decent EP to go with it.

Was just my personal choice tho but im sure you will be happy with either scopes capabilities.

Good luck.

The 8" f6 dob is a very good choice and recommendation for a telescope. Acceptable coma, easy on eyepieces and has a nice aperture. A while back a member bought an f4.7 10" dob on recommendations and was very unhappy with the performance in regards to coma. Thread after thread , post after post about the issue, but coma is an inherent aberration with a fast dob, mine shows it.

The 10" f4.7 recommendation is a very good one, if people are aware of the coma present, but the 8" f6 is most likely the better all round choice and will have a much larger coma free area to view with ( great for planets/lunar).

Cotterless (Nick) just recommended your scope in another thread and he is one of the most experienced and best observers here.

[Kropster]

All this talk of big scopes suffering from light pollution....

Surely the focal ratio of a telescope dictates how it suffers, not the aperture?

An 8" and 10" of the same focal ratio will suffer the same amount, won't they?