Go Dobsonian?

[davehunt]

I am only a few weeks into this absorbing interest,and am quite blown away,despite only having seen jupiter,M42,Pleiades and the moon through the murk of recent weeks. I feel my Celestron 130 EQ was good value for money.But.....the EQ mount,or rather its adjustments,are exacerbating an arthritic condition in my hands.The Dobsonian set-up looks more user friendly,even if I choose(which I do!) to up the inches soon.How heavy are Dobsonians compared to EQ mounted scopes,and have others got comments to make on my line of thinking? Would the benefits of fewer manual adjustments be offset by increased weight-only really need to hump it into the garden.And would my telrad affect it's balance?

[Ben Ritchie]

An 8" Dob is relatively light - especially when split into base and optical tube - and fairly easy to handle. It's also somewhat simpler to put a the OTA onto a Dob base than onto an EQ mount. Above 8" the weight goes up quite rapidly, and they're also increasingly awkward to carry. If you're considering anything 10" or above then would very much recommend trying to find someone local with one first - they're larger than you might think. Used adverts from people "downgrading" because their 'scope is too big to store or handle are nearly as common as people getting aperture fever and upgrading

Once they're setup they are very easy to use, although the SkyWatcher ones need a bit of tweaking to get the Alt and/or Az motion smooth. A Telrad doesn't affect the balance much, and a bit of DIY and/or magnetic counterweights can sort it out easily.

edit: one other thought is that it may be worth picking one you can use seated - that can be a very comfortable observing position. The larger ones generally require you to stand up to observe anywhere near the zenith.

[davehunt]

Thanks for that-8" sounds pretty good to me with a 5" Celestron, so I'll think no bigger than that....for the time being!

[pvaz]

I can 2nd that. An 8" is just under 20kg fully assembled so most people can handle it. Split into 2, it's even easier.

This is how I use mine:

[umadog]

I use a garden chair with my 12". I sit on the set, chair arm, or chair back, depending on the elevation of the object. Works pretty well.

[LMC]

The base is usually the heaviest part of a 6-8" Dob.

If I can recommend an 8" Newt on a decent alt/az mount?

An 8" GSO (Revelation, TS) Newt can be well handled by an Astro-Tech Voyager or Giro type mount.

A tad more money, but none of the fuss of a Dob - easier to transport, cabable of locking both axis points and doesn't get blown by the wind as much.

Plus you can use it with other scopes.

Oh yes! And a whole lot easier to balance.

[pvaz]

LMC, I can't really see how is a dob susceptible to wind. The Azores are as windy as can be. Just last night I had 65km/h gusts and the XT8i handled it fine. Regarding balance, the only challenges I have are when I use the Ethos 21mm or the Nagler 31T5 with barlow. This are heavy hand grenades so I do have to tighten the alt friction which makes it a bit stiff in alt. I could solve that by adding a counter weight system, but that would mean to re-balance the scope when switching from an Ethos to an Ortho (and vice versa). Adjusting the friction is easier/faster.

[dweller25]

I had a Skywatcher 8" F/6 dob and it was an excellent scope. So I upgraded to a 10" which was also excellent but too much for my bad back !!

Dobs are great and tracking at high powers for planetary is easy if you have a wide field eyepiece. A lazy susan bearing was a major improvement too.

[LMC]

pvaz,

Its terminally windy here also. If we get 65Kmh we breathe a sigh of relief!!!

The long tubes and near frictionless bases of Dobs mean they just grab the wind like a sail.

I originally started with a 12" Skywatcher doDob. It would be blown around (and around) by the slightest gust of wind. Short of clamping the base - which sort of defeats the object of a Dob - there was no way to secure it. Also the Alt tensioners were in no way adequate to the task of holding it still.

If I mounted a 28 UWAN or a 31 Nagler, it's nose would head for the ground.

I don't particularly want to hang a bunch of extra weights or attach bungee cords to my scope - too much faff!

Getting an OTA to sit tight on a good Alt/Az mount is a piece of cake - plus you have slow motion control on most. I don't know anyone with steady enough hands to move an f5 without jiggling the view.

Perhaps an 8" IS easier to mange on the classic Dosonian base, but all the problems disappeared when I mounted a new 10" on my Alt/Az.

Granted, its quite a heavy-duty mount and will take up to a 12" Newt without grumbling, but the OP wanted to stick to 8" and both mounts I suggested are adequate and IMHO much easier to use in the field.

[pvaz]

Maybe the dobs you've used don't use the friction adjustable system. The one from Orion US works well. It wont be smooth when you nudge but it works fine.

[johnkirkpatrick]

I had the same scope as you a after a month I wanted to move to a bigger scope. After months of studying the internet I went ahead and got the skyliner 200p And never looked back. my next scope will be a 12" or 14" skyliner. I love the simplistic method of observing the night skies and the views are mind blowing compared to the old astromaster 130 ( hated it lol )

[gedmac]

regarding weight i lug my 200p skyliner out of the shed into place all in one piece but it is easily split into ota and base:p

[davehunt]

Thanks to everyone who chipped in.I too suffer from the wind,but fortunately it doesn't blow my telescope over.I now want a Dobsonian and an EQ5...my fear is that this interest is rapidly becoming a consumer-catch-up nightmare instead of an going fascination with the heavens.

[PARTY MARTY]

I have a 12" Dob, But I have to agree that a 8" is hard to beat, If want performance and you wanna see DSO's, I've highly recomend the 8" to beginners.

You can pick one up from FLO for less than £300, now that's a bargain!!!

[Orion_the_Hunter]

Hi Dave,

I got an 8" Dob this week. I REALLY had to be sure it was right for me because I have quite servere & progressive multiple sclerosis. I can't walk, I can take a few steps if I have something to hold on to, and basically my body is pretty useless.

I love the Dob for it's ease of use, my review is worth a look: http://stargazerslounge.com/equipment-reviews/132996-skywatcher-skyliner-200p-8-dob.html

Also, the base is the heaviest part but there are lots of solutions to moving this round, here's mine: http://stargazerslounge.com/equipment-discussion/132484-plant-pot-stand-dob.html

I wish you luck and hope this helps,

Ed

[davehunt]

Thank you very much for that-your difficulties plainly put mine in the shade,so I deeply appreciate the directness and usefulness of your response. I am leaning towards Mr Dobson!

[swamp thing]

A tad more money, but none of the fuss of a Dob - easier to transport, cabable of locking both axis points and doesn't get blown by the wind as much.

Whilst i do agree that the bigger dobs are more susceptible to wind I cannot see how anything could be easier to transport or balance.

A small dob goes in the car in 1 or 2 bits or You can carry it around the garden to your hearts content it's light as a feather. whats hard to transport about that?

Regards Steve

[PARTY MARTY]

I agree on Swamp thing on this!

A small dob is easier to carry about, However when you if go beyond the 10" boundary the dob becomes a weight issue, more than a set up issue.

My 12" dob weighs around 20kg's and the base is 24Kg, it's almost weighing up to 50Kg, once all the attachment's and accessiories are in placed.

I don't have much a problem with it, cos I go to gym on a regular basis.

However forsake for an better light grasp the 8" is the a good choice, even if it's little bit heavy for some people.

I wouldn't get any smaller apeture dob's, I just can't see much point in getting a Dob smaller than a 8" for that matter???

[ken spencer]

I have a 10 DOB and can assemble and disassemble it fairly easily into two pieces, not sure about a 12! So I guess an 8 is a good size.

Ken

[Skillganon]

I have the same scope and mount, although I had not the chance to fully test it out fully the only problem is tha the fine controls are placed in awkard hard to reach position if you are trying to look through the eypiece at the same time.

I personally think a motorised track thingy would be better considering ones condition.

[Smooth]

I can agree on the weight and assembly issues of a large dob. I always need another person to help me if I take my 16" Lightbridge to different sites. I wouldn't even attempt it myself as any slip could be a costly mistake! I would agree that an 8" dob would be a good choice. I may even get one for the occasions where a rare glimpse of the heavens appears, and the Lightbridge is too much to quickly setup, and I want to use more than my Mak 127 GOTO.

[LukeSkywatcher]

I can 2nd that. An 8" is just under 20kg fully assembled so most people can handle it. Split into 2, it's even easier.

This is how I use mine:

I am in a wheelchair and own a 5" Dob.

I am honestly thinking of upgrading to an 8" as Paulo says.

I honestly think i could handle such a scope

[Trull]

Ah the delights of a sorted 8" dob, made with quality mirrors and a decent eyepice are many to behold. Personally, TorcDobIV has a virtual counterweight, two arm truss, curved sec mirror supports, fan system, and the ability to determine the angle of the Owl Neb's eyes... nice :-P