50 replies to this topic

[sky_lounge]

So far had several observing sessions with my new 8" Dob.

 

Since conditions are good for DSO's right now, primarily been hunting for them.  I really enjoy the way they look through the scope.  Globular clusters in particular have almost a magical/occult aura to them.

 

I travel about 1.5 hours to a Bortle 4ish sky (21.34 mag/arcsec2) for this.

 

Just reflecting that, given the time investment involved, it probably would have been better to get the 10" Dob to see the DSO's just a little bit more clearly. (Although understanding 2" more aperture would not be game-changing).  I will say DSO's aren't necessary the only thing I'm interested in, but they interesting targets while the moon is not out.

 

Since I'm only interested in visual astro right now, I suppose my upgrade path would be a 12" Dob in a couple years or or after doing as much as I can with the 8"; will just have to see if that could even fit that in my CX-5. 

 

I also assume selling the 8 for a 10 is probably not worth the hassle.

 

I guess a benefit right now too is learning the maintenance and care aspects on the 8".  Already made one mistake taking it out on a night that had very high moisture (rel humidity: 86% , temp: 48 F, dewpt: 44 F), and got just about all the optics coated in dew, so I won't be doing that again.

 

That said I'm very much enjoying the visual astronomy part; just went out last night and got a bunch of more messier objects checked off on my list.

Edited by sky_lounge, 26 May 2025 - 03:40 PM.

[GolgafrinchanB]

I have a 10" and drive similarly far to a similar quality site in a similar car.

 

My wrist hurts from picking it up wrong once 6 months ago, so that's not ideal. It fits in the car the same as the 8 (sideways on the back seat bench) and the movement is less smooth but not a big deal.

 

As far as I can tell it's about a wash. You've traded a subtle bit of brightness (I've compared my views to 8" views a few times now and the difference is minor) for better ergonomics and less chance of injuring yourself. Enjoy the scope!

Edited by GolgafrinchanB, 26 May 2025 - 03:39 PM.

[Tony Cifani]

21.34 MPSAS isn't bad (I'm speaking as a city dweller), but if you could add an extra half hour to 45 minutes to your drive and get to even darker skies like 21.5-21.75, your 8" Dob will really shine. It depends on how close you are to the city, what size city you live in and the distance needed to get away from the light pollution. I'd say keep the 8" Dob for now until you're ready to go much bigger. I live in the city with approximately 18.50 MPSAS skies, and a two hour drive out of the city to 21.5+ skies makes a big difference.

 

Good luck!

[arg0s]

So far had several observing sessions with my new 8" Dob.

 

Since conditions are good for DSO's right now, primarily been hunting for them.  I really enjoy the way they look through the scope.  Globular clusters in particular have almost a magical/occult aura to them.

 

I travel about 1.5 hours to a Bortle 4ish sky (21.34 mag/arcsec2) for this.

 

Just reflecting that, given the time investment involved, it probably would have been better to get the 10" Dob to see the DSO's just a little bit more clearly. (Although understanding 2" more aperture would not be game-changing).  I will say DSO's aren't necessary the only thing I'm interested in, but they interesting targets while the moon is not out.

 

Since I'm only interested in visual astro right now, I suppose my upgrade path would be a 12" Dob in a couple years or or after doing as much as I can with the 8"; will just have to see if that could even fit that in my CX-5. 

 

I also assume selling the 8 for a 10 is probably not worth the hassle.

 

I guess a benefit right now too is learning the maintenance and care aspects on the 8".  Already made one mistake taking it out on a night that had very high moisture (rel humidity: 86% , temp: 48 F, dewpt: 44 F), and got just about all the optics coated in dew, so I won't be doing that again.

 

That said I'm very much enjoying the visual astronomy part; just went out last night and got a bunch of more messier objects checked off on my list.

 

The feeling you have right now is so common it is jokingly called "aperture fever". It's often difficult for people to consider the counterfactual case of them never getting into astronomy if their only option was larger and more expensive.

 

I would not get a 10 inch, a fairly nominal upgrade that's more hassle than the relative value you'll get out of it.  If possible, try and sit on your current gear for a while. Experience plays a big role in getting value of visual observation, and maybe you'll also find that your gear's weak point isn't aperture, maybe it's actually eye pieces, your finder setup, your collimation, observing site, etc.

 

If and when you know deep down you just want a big Dob, there's still value in stepping back and looking at your options. Look into trussable Dobs, you can definitely fit more than 12" into a CX-5. Ask yourself at what point will you be confident you won't use your new telescope and come back and say "Man, x inch telescope was great, but I kinda want x+2 inch telescope now."
 

Edited by arg0s, 26 May 2025 - 04:24 PM.

[RalphMeisterTigerMan]

You may think about getting a Skywatcher 250mm Flextube dob. I had one for a while but circumstaces forced me to sell it. While I did not have the GoTo option, I did have the primary fan , the shroud and laser collimator. Along with the 21-Ethos and Pacorr this thing was amazing. I did have a decent high-power eyepiece (can't remember which exactly) but Jupiter was incredible. As were DSO's. I purchased a dolley for mine to make taking out for observing easier. Believe or not, the 2 extra inches does make a difference. Just make sure that your back and the rest of your body can handle. After three hernia surguries I think I know what I'm taking about.

 

Clear skies and keep looking up!

RalphMeisterTigerMan

[havasman]

I think a 10" Dob is where lifetime scopes start. But as you see there is a great wealth of amazing targets for an 8". A smart pathway forward might be to start saving up some cash for a used 12.5 to 14.5" premium Dob you can find some day in the CN classifieds or on AstroMart. And yes, moving from 8 to 10" aperture is much less significant than you'd hope for. I moved from an XT10i to a 16" Starmaster with a great mirror and THAT was very, very significant.

[Barlowbill]

8" to a 10"?  No

8" to a 12"?  Yes

[NiteGuy]

While a 10 is certainly better than an 8, it's not going to be a big enough upgrade. Obviously, besides the visual, there are other aspects to be considered like budget, set-up/tear-down, transportability, storage, etc.

 

I was told many years ago that, if you want a "meaningful" upgrade, you should try to choose an aperture that will give you at least one full magnitude of gain over your current scope. In your case, that means going from 8-inches to 12.5-inches.

[ClsscLib]

I started (re-started, really — long story) a few months ago with a 10” solid-tube Dob and wonder whether I should have gotten an 8” instead.  The 10” is a lot of poorly distributed weight to manage!

[sevenofnine]

Ed Ting's video may help. Just enjoy what you have, IMO 

 

https://www.youtube....h?v=I_pmtt3NhTo.

[Jon Isaacs]

Ed Ting's video may help. Just enjoy what you have, IMO 

 

https://www.youtube....h?v=I_pmtt3NhTo.

 

Ed Ting likes 8 inch Dobs. When you look at the video, look at Ed compared to the scopes.. He's appears to be on the smaller side...

 

I'm 77 years old, still think of my 10 inch Dob as an "easy" scope. I suspect I'm some what larger physically than Ed...

 

There's a noticeable difference between and 8 inch and 10 inch Dob but in the first couple of years, the biggest differences come learning and becoming a skilled observer. 

 

Either one is very capable and very potent.. 

 

Jon

Edited by Jon Isaacs, 27 May 2025 - 04:53 PM.

[vintageair]

I'm on the other side of the coin as I bought the 10" Apertura and sometimes think I maybe should have just gotten the 8 inch. It doesn't sound like much but the 10 is just that much bigger that I really had to put straps on it, I can't comfortably support the end of the tube with just my hand under it. Also you need to consider the base, it's 22 inches in diameter and if I want to put it in the trunk of my Civic there is only one specific procedural series of moves that will get it in there and back out again. It's also heavier.

 

In the end I just conceded I got what I got, no going back so I'm resolved to being happy with my choice. You should do the same.

[Dragon Man]

. . . .   Already made one mistake taking it out on a night that had very high moisture (rel humidity: 86% , temp: 48 F, dewpt: 44 F), and got just about all the optics coated in dew, so I won't be doing that again.

 

That said I'm very much enjoying the visual astronomy part; just went out last night and got a bunch of more messier objects checked off on my list.

Rest assured that dew won't ruin your telescope.

Almost every astronomer has had dew, many of us regularly.

 

Manufacturers are aware that we take this gear outside at night where dew is. That is why they make Dew Heaters 

The danger comes when you put your scope away after a session and seal it up with the lid or heavy covers on it.

The dew itself won't hurt your mirrors, but leaving them sealed up will.

By sealing the scope when dewed up can cause mold to grow. Allow it to dry, then cover it.

 

When you pack up for the night, leave the scope covers off and allow the dew to evaporate over night, then cover it against dust once it's dry. Usually the next morning.

 

If you can't, or don't want to leave your scope uncovered overnight, attack the optics with a hair dryer on warm setting, not hot. Once dry, cover it.

 

We've all been there. 

[astro.nanuuuuuu]

Hi sky_lounge,

 

I have been in a similar situation. I started out with a 130mm tabletop dob, then moved up to an 8" dob. This upgrade was a game changer. Then, a club member was selling his old Orion SkyQuest 10" dob, which I bought. The difference between the 8" and the 10" was not that big. I ended up selling the 10" and kept the 8" (smaller and easier to move).

 

Now, late last year, I found a used 12" dob. This was a game changer from the 8" (I still have the 8" and the 130mm).

 

I thought open clusters came to life with the 8". Well, the 12" did that for me all over again. The downside is its size. Much larger than the 8". I installed casters to the base, so it's easier to move (I did that to the 8" too, actually), but still, the OTA and the base are big. (The 8" looks small beside it.)

 

I haven't done much observing with the 12", but the DSOs I've been able to observe with it do pop up.

 

Here is a family photo: 130mm, 8", and 12" scopes.

 

 

Hope this helps!

 

Clear skies to you.

 

So far had several observing sessions with my new 8" Dob.

 

Since conditions are good for DSO's right now, primarily been hunting for them.  I really enjoy the way they look through the scope.  Globular clusters in particular have almost a magical/occult aura to them.

 

I travel about 1.5 hours to a Bortle 4ish sky (21.34 mag/arcsec2) for this.

 

Just reflecting that, given the time investment involved, it probably would have been better to get the 10" Dob to see the DSO's just a little bit more clearly. (Although understanding 2" more aperture would not be game-changing).  I will say DSO's aren't necessary the only thing I'm interested in, but they interesting targets while the moon is not out.

 

Since I'm only interested in visual astro right now, I suppose my upgrade path would be a 12" Dob in a couple years or or after doing as much as I can with the 8"; will just have to see if that could even fit that in my CX-5. 

 

I also assume selling the 8 for a 10 is probably not worth the hassle.

 

I guess a benefit right now too is learning the maintenance and care aspects on the 8".  Already made one mistake taking it out on a night that had very high moisture (rel humidity: 86% , temp: 48 F, dewpt: 44 F), and got just about all the optics coated in dew, so I won't be doing that again.

 

That said I'm very much enjoying the visual astronomy part; just went out last night and got a bunch of more messier objects checked off on my list.

[HenkSB]

I am 6'3 and had a 10" Coulter Odyssey that I could easily manage and throw in the back of my car across the entire rear seat.  When Zhumell offered a Z12 for $630 to put Apertura out of business I could not refuse.  It is a great telescope but putting it in the car (Chevy Cruze Eco) was not great at all.  It took up 3 seats.  Since then, I turned it into a collapsible so I can finally put (most of it) on one seat.  In retrospect I should have got the collapsible Skywatcher Flextube (though I love the Z12 bearings).  If you go bigger, give a big thought to the transportability aspects.  About aperture fever, I once looked through a 28" telescope and was blown away, so now any size less than that is never good enough.

[Don W]

Portable = dobs up to 10”

 

Transportable = dobs over 10”

[Jon Isaacs]

Portable = dobs up to 10”

 

Transportable = dobs over 10”

 

 

My 12.5 inch is F/4.06 so it's reasonably portable. The footprint is 19" x 20" and nested, it's 28" tall so it takes up much less space than my 10 inch GSO Dob, it's one passenger space.

 

 

Transportable:

 

 

Transportable:

 

 

Jon

Edited by Jon Isaacs, 27 May 2025 - 10:37 AM.

[vtornado]

8 vs 10 vs 12.

 

It's all about you.  How big and strong are you?  How big is your car?   How easy is it to get it out of storage and into a car?  How much thermal issues are you prepared to deal with?

 

The 8 being f/6 will be slightly easier to colimate and slightly easier on low cost eyepieces.

 

For stellar objects such as doubles, open clusters, globs I thought the extra pop of the 10 was worth the additional hassle.  For faint fuzzies not so much.  Note that this evaluation is from 18 Mpas not 21.

 

Since you have the 8 you can bide your time.  Perhaps a nice used 10 or 12 will pop up and it can be a near frictionless trade.  

Edited by vtornado, 27 May 2025 - 10:43 AM.

[Little Zhang]

The potential of the 8-inch DOB is huge, and a person on zhihu (a Chinese social media platform similar to Twitter) has observed more than 1,000 DSOs with the 8-inch DOB (he is at 21 degrees north latitude). And you should have enough money for your eyepieces, which will cost you a third of the price of your telescope. If you're going to drive a lot of distances to observe, it's going to be a tough task to carry it, especially if you're observing for hours until the middle of the night, and you sometimes really want to just leave it there......8 英寸 Dobsonian 反射望远镜的潜力巨大，知乎（类似于推特的中国社交媒体平台）上有人用它观测了超过 1000 个深空天体（他位于北纬 21 度）。而且你得有足够的钱买目镜，这会花掉你望远镜价格的三分之一。如果你要驱车前往很远的地方观测，携带它会是个艰巨的任务，尤其是当你观测到半夜，有时你真想就把它留在那里！

 

Clear sky! 晴朗的天空!

Edited by Little Zhang, 27 May 2025 - 11:10 AM.

[sky_lounge]

Lots of great added context here; I appreciate everyone's viewpoint.  Seeing the sum total of everyone's input really helps me understand where I'm at in the landscape, thanks!

[AstroVPK]

So far had several observing sessions with my new 8" Dob.

Since conditions are good for DSO's right now, primarily been hunting for them. I really enjoy the way they look through the scope. Globular clusters in particular have almost a magical/occult aura to them.

I travel about 1.5 hours to a Bortle 4ish sky (21.34 mag/arcsec2) for this.

Just reflecting that, given the time investment involved, it probably would have been better to get the 10" Dob to see the DSO's just a little bit more clearly. (Although understanding 2" more aperture would not be game-changing). I will say DSO's aren't necessary the only thing I'm interested in, but they interesting targets while the moon is not out.

Since I'm only interested in visual astro right now, I suppose my upgrade path would be a 12" Dob in a couple years or or after doing as much as I can with the 8"; will just have to see if that could even fit that in my CX-5.

I also assume selling the 8 for a 10 is probably not worth the hassle.

I guess a benefit right now too is learning the maintenance and care aspects on the 8". Already made one mistake taking it out on a night that had very high moisture (rel humidity: 86% , temp: 48 F, dewpt: 44 F), and got just about all the optics coated in dew, so I won't be doing that again.

That said I'm very much enjoying the visual astronomy part; just went out last night and got a bunch of more messier objects checked off on my list.

I think you should be a little more ambitious and consider moving to a 16" or maybe even a 20" in a couple of years. The wow factor going from 8" to 20" is pretty give, but having looked through my fair share of 12" scopes, I wouldn't call the difference significant enough to be worth the upgrade unless you're sure you'll never go even larger.

[Inkie]

I have been reading older threads in the 'archival' section, six or more pages back and deeper.  I'm seeing that everyone looks for magic, and those two additional inches of aperture are all that are needed.  They're woefully inadequate.  Really badly woefully.  In order to see what you think a 'good' telescope should show you, we're talking 20" and larger.  That's what reading 200 replies over 20 threads have made clear to me. I think we all get excited, and fool ourselves, into thinking that a 12" or even a 14/16" Dob is going to be the cat's backside.  Leaving aside mobility challenges and quality variances, and assuming we all have the same visual acuity, it takes a really large Dob mirror to yield truly impressive views.  I don't mean to diminish my own 12" Dob, the largest I'll ever own and probably look through...I love it.  But, it's just not enough. 

 

Then, getting a bit into the philosophy of the hobby, the old-timers with thousands of hours using various eyepieces and scopes in varying conditions will tell you that the educated eye and brain see a lot more with a given aperture than will a relative newcomer to the hobby. So, before you go wishing upon a star, a bigger star, I think the wisdom of the ages and age-old fellers is...dance with the gal you brung. Learn not to step on her toes, learn to make her smile, and you'll be rewarded.  Then, when you really do 'need' that extra oomph, you'll know what to do with it and what to expect.

[havasman]

I started (re-started, really — long story) a few months ago with a 10” solid-tube Dob and wonder whether I should have gotten an 8” instead.  The 10” is a lot of poorly distributed weight to manage!

I never really thought so. Well except maybe when tearing down after a long night's observing. But all such thoughts were permanently banished when I got the 16".

 

Importantly, Dobs assemble very easily by design. Generally they should be moved in pieces and assembled on site. Then even a 12" solid tube's weight is manageable for most adult men.

[havasman]

Ed Ting likes 8 inch Dobs. When you look at the video, look at Ed compared to the scopes.. He's appears to be on the smaller side...

 

I'm 77 years old, still think of my 10 inch Dob as an "easy" scope. I suspect I'm some what larger physically than ED...

 

In order to see what you think a 'good' telescope should show you, we're talking 20" and larger... I think we all get excited, and fool ourselves, into thinking that a 12" or even a 14/16" Dob is going to be the cat's backside.  

I am no fan of Ed Ting nor do I favor any guru-esque recognized expert who knows what's good for everyone. Ed's bias does not match mine AT ALL yet he has become the go-to authority for 'most any newb with an internet connection. I do not fault him for his success but I do wish he was more open about his limiting biases and back WAY off on the absolutist nature of his opinions.

 

The largest scope I'll ever own is a 16" and I have observed well with 20 and 32" premium Dobs. All have wonderful primaries and secondaries by Zambuto, Lightholder and Lockwood. As apertures increase the capability of the scopes invariably does too. But I and many guest observers have been well pleased with the observations made with my 16" including tracing the variability of Gyulbudghian's Nebula over time, high power (600x) observations of the loops and swirls mostly on the NE & N edges of NGC604 sometimes with O-III filter, and views of showpiece galaxies like M51 that caused a science museum director to gasp and declare she did not know visual observing could show such detail.  Most of the HCG catalog is available, though obviously not all members of each group. Lyon Galaxy Groups are favorite treats. Years ago a very experienced friend, head of a local university physics department, and I spent several sessions one summer repeatedly observing M57's central star as a clear and stable sight at as little as 350x. I have enjoyed the small Gx pair IC412/413, observed their faint common halo and, once, the faint arm extending north. Those are objects many would think require a very good telescope. My thoughts are that premium 16" apertures in good locations are where large begins.

 

Relatively recently I have downsized to an equally premium 12.5" Dob and it is NOT a large aperture telescope. But it is a very good scope, just less capable due to aperture.

[vintageair]

I look at my telescope as an instrument, you have to learn how to play it and it's not easy.