Newboy Questions - Help re Dobs

[NGC2264]

Hey everyone. I just joined the website, and it looks pretty cool.

I have had my interest sparked with astronomy, and have for the last 6 months taken all the experts advice and been star gazing with my binocs and guess what - I still like it. So now I am thinking about purchasing a telescope. I have a limited budget of around $1500 and portability for me is required as I will always have to travel away from my home to a local park or golf course to do some star gazing.

At the moment I am thinking about an 8" or 10" Dob, and one of the young guys at the local astro club had a Skywatcher collapsible Dob.

I was wondering whether anyone has one of these and how they find it. Do they have problems holding their collimation throughout the night as you move around the sky? Or should I settle on a solid tube Dob?

What kind of eyepieces (sizes and brands) should I look to partner up with a Dob for about $100-$200 per eye piece?

The other recommendation I received was getting an 80mm refractor on an EQ6 mount. If there are any brand recommendations I will be interested to hear them.

I am not sure I will be leaping into astrophography any time soon, and if I do down the track then I suspect I will be getting a second telescope to do so. Personally I leaning towards to Dob just for the bang for buck on the light gathering capacity.

What do people think?

[bmitchell82]

if your going visual get the biggest dob you can get a hold of that means looking at portability vs light grab. dobs can be converted to a german equatorial mount with full goto. as for eps, get one good one and a barlow. i have a soft spot for a meade eye pieces.

from personal exp a 20mm meade series 5000 ep in my 10" is my workhorse ep. i run the high power mags out in dark skies on specific objects.

[renormalised]

Welcome to IIS Gordon:)

Either the 8 or the 10" is a good choice. personally I'd go for the 10" just for the extra light gathering capacity, even though it is somewhat heavier. Although if portability is critical to you, then an 8" would be the choice. Either way, you're going to get some fantastic views:)

Eyepieces....$100-$200....Meade series 5000 or TV (Televue) Ploosls (1.25") wouldn't too bad a choice. TV Naglers or Ethos EP's would be ideal but way out of that price range:)

You could pickup a set of Meade 5000's (2") from Bintel for $529...4 per set in a carry case. Not a bad deal. You could probably do the same with the TV's by getting a case as well, and 3-4 EP's.

[Solanum]

I haven't used a collapsible dob, so can't comment, but I'm pretty happy with my 10" solid tube. It's portable enough to shuffle it round the back yard by hand and move it around the house with a hand cart. Sometimes I wish I had a 12", but I get to see most of what I want with the 10" and would be unable to shift the 12" by hand without shifting the tube and base separately. Get the biggest scope you can move about to whatever extent you want to move it about.... you'll only wish you had if you don't!



Well, many many of us have been in this same boat. I think your range is reasonable (though I might restrict it to $150-200). From the (limited number of) EPs I have bought anything under $100 new wasn't worth the difference from the ones that came with the original scope. My Pentax is great, but cost $220, my Vixen EPs are optically really good too, but have a smaller field of view, they are around $175 and much better than the standard GSO ones you get.

Keep an eye on the second hand EP forum here, but you have to be quick....

[Miaplacidus]

I've also been interested in these collapsible Skywatcher dobs, but I have reservations about the stability of the three extension poles. And I would dearly love to hear anyone's efforts to adjust the length to accommodate binoviewers.

Brian

[Tallstock]

Hi Gordon,
I have had my 8" SW Collapsible Dob for about a month.
It is big, bulky and ackward to transport. Be warned. If you are going to use public parks etc for viewing then be prepared for some physical effort.
The "collapsed" tube fits across the back seat of my Falcon sedan.The base then takes up most of the boot. Not much room for anything else.

My 8" SW dob had an annoying problem with a sticky (stiction) azimuth mount and although there are various fixes (I have installed a roller bearing/lazy susan) you can avoid the problem by going to the 12" which, although much more expensive, comes with a needle bearing as standard.

Collimation has not been a problem, despite my bumping the tube a few times during transport. I am not tinkering with collimation until some expert tells me I must do it.

The 25mm and 10mm eyepieces that SW supply with the 8" work well for me.

The SW 8" collapsible dob is excellent value.
Peter

[JethroB76]

Not a big fan of the Meade 5000s in fast-ish scopes personally, if going the plossl route get TV IMO.

The Baader Hyperions or Orion Stratus are very good quality widefields for the money (IMO the best bang for buck EP).
The Pentax XF range is excellent albeit perhaps a bit more expensive and with fewer focal lengths.

Having said all that it can be a good idea to observe with the standard supplied EPs for a little while before lashing out and buying EPs that don't suit your preferences.

Unless you have particular portability requirements you could save yourself some money for accessories/EPs by getting a solid tube if you're only getting a 10" or 8" especially

[Vartigy]

Hi Gordon,

My SW 8" Col Dob is just over half a week old.
Having a blast with it!
I had to travel over 600kms to return it to my residence from whence I bought it, and haven't had to collimate yet. (REALLY bumpy roads too!).

Pretty much same observations of its performance as Peter has mentioned above.
Slightly sticky az (base plate rotation). There's a few recommendations from others for fixes in a thread i made under Equipment Discussion - SW Dobs (http://www.iceinspace.com.au/forum/showthread.php?t=40796).

Other than that, visuals have been amazing.
Make sure you sight in your finderscope to the telescope itself during daylight.
The x on the finderscope is amazing itself!

The patented tension handle is somewhat tricky at first. It's about practicing and mucking around with it until you find the happy medium.

If you're around the 6' height, I recommend getting a box or platform, something around half a foot in height to place your telescope on.
I just screwed together few bits of MDF to make the platform.
Reduces back strain.

First out of the box, the extendable truss is quite "stictiony" to drop back to the scope. Almost pushed the top part right through the bottom first time. Theres a few fixes I'm going to try to make it smoother. Will post when i find a decent one.

Oh, and regarding the tools they give you in the box to construct the scope... Get your own ones!
The ones they supply are junk. Not to mention the "spanners" don't even fit the nut and bolt on the azi base plate. Grab a pair of small shifters to do the trick.

Eyepieces come included in the SW box set. You get a 10mm and a 25mm one. Plossls too!
Not bad to start out with.

Scope approaches ambient temp quickly too as it's a mid open system.

All in all. Having a blast with it.
Anyone on here will tell you Dobs are great noobie kits.

Aaron.

[Quark]

Hi Gordon and welcome to IIS.

I have an observatory mounted 16" Newt on a GEM, a 12" Lightbridge and a 120mm Scanner refractor on a eq6 mount.

I run an astronomy group out of my local community college and within my group is a 16" Bintel strut dob, 10" Lightbridge, 12" Bintel Tube dob, two 8" Bintel Tube dobs and a Meade ETX.

Undoubtedly the tube dobs are the easiest to live with, admittedly they take up more room to transport but they have less collimation problems, that said ounce you have some experience with collimation this would be less of a problem.

Dobs tend to be much less affected by any breeze than scopes on aluminum tripods. My 120mm refractor becomes unusable with a bit of wind, its aluminum tripod is just not stable enough, even after considerable modification. I have no doubt that better tripods are available .

If you have a vehicle that can take it I would recommend a 10" dob, tube or Lightbridge design. There is a fair difference in the images that a 10 will show you over an 8. Not that there is anything wrong with an 8.

Dobs are just so intuitive to use, you will spend more time looking at objects with a Dob, as a beginner, than you would with an equatorial mount. As you mention, you will get more bang for your buck's, with an eq mount at least half of the price is for the mount. A very good mount could run into many thousands of dollars.

I am sure you will receive much advice on this topic, read the stickies at the top of this forum on selecting a scope.

Regards
Trevor

[NGC2264]

Thank you all for the info. Simply brilliant. Has given me a lot to think about. I think the next step is to go look at some scopes in the shop and get a feel for the styles of Dobs that are about. It's hard to rein in the excitement. Interesting point made about the eyepieces and waiting to see what you get with it. I could go to the viewing nights and "try out" other eye pieces.....good point. Again my sincere thanks.

Just for your interest I emailed a chap in the US who did a review on the Skywatcher Collapsible Dobs and he had some interesting points to make:

"I am very pleased with my scope. I live in a light-polluted area of suburban Detroit, and with nearly one foot of snow on the ground, it has been next to impossible to travel to remote sites. As such, my viewing has been limited to outside my home. I use O-III filters (oxygen) on my eyepieces and they do a good job with the light pollution. While we're on the subject of eyepieces, I own the following: Astro-Tech Widefield (70 degree FOV) in 32, 26, 20, 15, and 10mm. TMB planetary in 6 and 3.2mm. All were purchased with the scope from Astronomics. www.astronomics.com (http://www.astronomics.com/) .

As I mentioned in my review, when you pull UTA up to the viewing position, it locks into place with a distinctive "snap." You then tighten the three wing screws on the bottom tube assembly, and it is as solid as a rock. There is no loss of collimation while viewing.

I think that some of the collimation issues with larger dobs are limited to the solid-tube design. I would guess that that is because the solid tube can approach five feet in length, and as such, has a lot of metal to expand/contract with temperature fluctuations during a night of viewing.

The optics are better than my Meade 8" LightBridge. I had a chance to look through an Orion 10" dob, and again the Sky-Watcher was superior.

Again, as I stated in my review, the construction of the Sky-Watcher is impressive. The cast-aluminum focuser to me, is a big plus. Plastic as found on competitive units, is much more sensitive to temperature fluctuations.

The down side of the scope is the same as with other large dobs. The size. I have had two different truss-dobs, and I really like the fact that with the Sky-Watcher, for transport, I slide the UTA into the lower tube, remove the handles, and lift the tube off of the base. To assemble, I simply place the tube on the bearings in the base, replace the handles, and on to collimation. Much easier and quicker than either the Meade or Orion models.

Another reason for choosing the Sky-Watcher over a solid tube design is the bulkiness and weight of the solid tubes. To my mind, every time you transport a dob, you're going to have to collimate anyway, so why struggle with the bulk and weight?

I also worked with Astrozap, ( www.astrozap.com (http://www.astrozap.com/) ) to develop a light shroud for the Sky-Watcher. If you go to their site, you will see my scope with the shroud. The shroud makes a big difference in keeping stray light out of the scope.

All in all, the Sky-Watcher is quite "fair dinkum!"