Going out my mind! Advice needed!! 200p vs Dob

[spaceboy]

Hi Everone I'm Nick and a newbie to the forum.

I need help PLEASE!! :confused:

I have a second hand Helios 200mm Reflector which although old works great, but the mount (EQ5 no motor drives) just makes such a chore of the experience.

I am on a tight budget £400 (wife & kids making sure of that) and I am debating between either improving my EQ5 with some kind of steel tripod or investment in a second hand heq5 or EQ6. My stressing swirling head comes from the cost of even a second hand HEQ5 or EQ6 can be £300 - £500 which I could get a secondhand or even new 10" dob for the same kind of money. Having never used a dob is the whole nudging thing a pain? and how do the wooden bases hold up to a dew covered field? Most concerned about .."how do you get them level???" do you have to take a shovel to flatten the ground?

I hope someone can understand my delema and offer advice. Good mounts rarely come up second hand at a price I can afford and will not have any kind of guarentee but tracking even with slow mo controls is easier if it should get lost from view. A 10" dob can be purchased new for £400 and I would have a 2" appature gain and an easier set up but can exspect a night of nudged views and the possibility I loose the subject all together. would there be any significant gain from the 10" over the 8" (mag 5.5 - 5.75 Sky)

Thanks for any help in advance.

Spaceboy

[richbyers]

from a dob user i can say that you would get used to it- its not so much hard work- more the beauty of it is its simplicity

rich

[insomnia]

If using a dob then you could just plop the whole thing on top of a separate piece of board so the actual dob base does not get damp in any way.

[dweller25]

Even at high mags for the planets a dob is a good scope - as long as you use a wide angle eyepiece.

I have my Skywatcher 200mm F/6 scope on a CG-5 with motors and a 2" legged tripod - it is very stable even at x343.

You can pick a used CG-5 up for around £130 and motors for around £150.

HTH

[beamer3.6m]

If you want to ever take photos with your scope then a Dob will be limited and the HEQ5 would be better.

There is a decent one on sale on Ebay at the moment. It is the white pro version.

[Bizibilder]

Are you any good at DIY? If even average you could make a serviceable Dob mount from a sheet of 12mm ply plus a few bits and bobs and trial it. Then, if you get on with it buy the "real thing". Or you could motorise the EQ5 for around £100 (+£25 for a battery) and use that. You could pick up a good (new!) tripod second hand as folk who mount their scopes on piers will have a tripod spare.

I hope I've added to the confusion! lol!!

[Ogri]

I used my 200p dob for the first time in earnest last night, and managed 300 x magnification on Jupiter with a Barlow'd 8mm Hyperion, with no problem.

The alloy handles JohninDerby fitted to the tube when he owned it, came to the hands nicely, and were a help as they were nice to use (top picture here in the for sale thread shows the handles on the OTA http://stargazerslounge.com/completed/113081-skywatcher-200p-8-dobsonian.html ).

I just put the base on a picnic blanket on the lawn. The blanket has a waterproof base, and a carpet like top (I usually use it as an effective base insulation layer in the tent when camping). £6 from Tesco's, or £4 on a Sale which was how I got mine.

[Keiran]

I have both... SW250px (dob), a SW200p (newt) on a HEQ5 ( was on an EQ5) and a WO meg 72 (frac)....

Where to start.... Hmmmm.

Well, I have only recently bought the dob, and to be hounest i am loving it...

I am getting in to imaging, and got annoyed at looking at the laptop while it was taking photos.... being unable to look at the stars myself.

If you know the sky or are able to star hop then the dob is great... I am using a 20mm EP, and It showed amazing detail on the M27 last night.... and you didnt need to nudge the scope too often, less than i thought. TBH I was getting bored of the GOTO, i wasnt learning the sky.... now i am

For ease of use though GOTO is brilliant... if you have limited time, and you want to look at 'x' then it is there... no fuss... go indoors, have a cuppa come back.... it hasnt moved.

I havnt compare the 8" and the 10" yet, but in those kind of dark skies i dont think there is that much difference.

I dont think you shuld buy a goto upgrade kit for the Eq5.... I dont know how old your mount is but you could sell it and buy a HEQ5 goto for around £500....

I think it all comes down to what you are really wanting.

HTH keiran

[Moonshane]

if you can handle the size, you could get a 12" dob for about £400 if you wait a while. get to 50 posts on here and they come up every now and again in the for sale section; after 50 you can 'see' it. if you can buy the larger scope first then compare the two and if appropriate sell the smaller one to fund maybe some eyepieces etc. if you can, get a look through a larger scope before you buy. my dob bases are much more stable and with less 'wobble' than my Vixen GP mount (equivalent to CG5) ever was and with a much lighter scope on the GP.

the difference in what you'll see between a 12" dob and your 8" is substantial.

I'd have no reservations about the manual nature of a dob unless you are likely to get into imaging. if you are then you'll possibly have to up your budget anyway to get good result unless you stick to solar system objects (others will comment on this though as I know nothing about imaging). I have looked at the moon with my 12" dob at 500x+ with a 50 degree field eyepiece and followed it easily - you don't even think about it after a bit. you don't have to be dead level unless you buy one of the more expensive tracking dobs (again above your budget).

good luck whichever way you go.

[perrin6]

Having never owned an equatorial mount I can only advise on dobsonians. It's always tempting to go for a bigger aperture and perhaps you could raise extra funds by selling your old scope and even go for a 12 inch dob although a 10inch is still a noticeable improvement over an 8 inch ??

Are lifting weight & transportability issues eg in a car to a dark sky site ?

Nudging is only really a problem at high magnifications above 200 X. I use a reasonable quality eyepiece with a 50 degree field of view at 300 X which requires nudging every 30-40 seconds which I do not find a problem as the bearings are made of teflon and 'buttery-smooth', probably (I imagine) easier than a non-motor-driven equatorial mount. I can understand how this would be annoying to those who are used to motor-driven mounts but I prefer a large-aperture Dobsonian to a moderate aperture equatorial of equal cost as there is so much more visible with the former. To complicate matters I think larger aperture views are not as perfect as smaller due to being more subject to atmospheric turbulence so there is a 'prettiness' issue to consider.

It would also help to consider what types of objects you will spend most of your time observing as you would generally use high powers for close double stars, the planets & the moon.

Having a good quality wide-angled eyepiece helps although these are expensive.

It would be very useful to go to a star party to get advice and try out different types of telescope.

Good luck,

Alan

[Moonshane]

Alan makes a good point about larger apertures and seeing but generally the view is good to excellent on most targets (doubles and planets being the exception). That said, I recently bought a 6" f11 scope in addition to my 12" and the 6" gives far sharper, more contrasty views views of planets based on my early experiences with the smaller aperture. You will note that a lot of people on here have two or more scopes which serve slightly different purposes.

the other advantage of dobs is they take up much less space than a mount tripod and OTA and much quicker to set up and break down.

here's my 6" and 12" together.

[spaceboy]

Hi

Thank you all for the advice. Looks like the dob wins. Any advice on the SW 250px dob and what's the pyrex mirror all about?

[black5f]

I've recently started up again and have a 150 refector on an old mount (EQ5 size) no motors. The head seems stiff enough but its the legs? I've wedged mine with some bits of wood across the tray to stop and damp the twisting vibration which helped a lot. They wedge in quite tight but easily pull out. Not used a dob but it's very apealling, from an engineering point of view... far more study, if made from wood nicely damped, where as a tripod twice the size is only ever going to be a little stiffer radially. My solution is going to be a bit of 4ft long 5 inch square MBS I've got my eye on and build a pillar I think. The plan is to use a cast iron lathe face plate for the base (10inch from axminster is £30), just need to figure the legs out, again, very limited budget but that would easily prop up 1/2 tonne and be easier to setup than a tripod.

Hope that helps. Tom

[spaceboy]

I have seen a lot mentioned about wooden tripods but with fabrications skills I was going to go down the path of steel. Granted a nightmare ensues setting up but suerly the weight alone should make for rigid support. The aluminum tripod I have with the EQ5 has already been filled with a bag of concrete in an attempt to dampen the frustraiting wobble. I know the 200 reflector is up on the limits of the EQ5 head but suerly they couldn't sell them so readily on this mount and tripod if there was not some improvement to be made. The tripod is heavier and feels more sturdy but I just think it's in the nature of aluminum and plastic to flex.

[black5f]

I have seen a lot mentioned about wooden tripods but with fabrications skills I was going to go down the path of steel. Granted a nightmare ensues setting up but suerly the weight alone should make for rigid support. The aluminum tripod I have with the EQ5 has already been filled with a bag of concrete in an attempt to dampen the frustraiting wobble. I know the 200 reflector is up on the limits of the EQ5 head but suerly they couldn't sell them so readily on this mount and tripod if there was not some improvement to be made. The tripod is heavier and feels more sturdy but I just think it's in the nature of aluminum and plastic to flex.

I think it does flex, quite often their hollow and a thin skin where something like MBS is filled with diagonals. I also don't like the counter balance, basically a big mass on a bit of (very) springy rod. I have noticed that even walking next to the tripod sets up a vibration, (and if the dog brushes past once more it'll get shot! (only jesting)), gently touch the counter balance and it goes away. Too much undamped mass. There must be a simple fix that'll damp these flimsy things. If I knock mine vertically its OK, radially it just keep going! Blown EVA is a good shock absorber, the rings are usually lined with it but thin. Not doing the rings up too tight is also a help. It takes a good 10 seconds before the scope suddenly drops into focus, but it's wobble. Thats more than enough time for Jupiter to move through the field x2. I could shell out on a new mount, but I'd get shot s well ;-) Isn't it all fun? Tom

[Moonshane]

you both sound like you are concluding in your minds that a dob is the best way to have a solid base IF you don't intend to image.

look at the Orion Optics site. If you can fabricate metal then their base is superb and made of aluminium.

look to the right of the page on this link Dobsonian OD300 L

[black5f]

you both sound like you are concluding in your minds that a dob is the best way to have a solid base IF you don't intend to image.

look at the Orion Optics site. If you can fabricate metal then their base is superb and made of aluminium.

look to the right of the page on this link Dobsonian OD300 L

Looks like a good design. Suddenly I feel the urge to head into the garage looking for material! Next project, dob mount.

[Moonshane]

good luck! you won't regret going over to the 'dob side'

[spaceboy]

Well after the advice I decided to go with a SW 250PX there was one on ebay and he agreed to end the auction early so I popped to get it last night. Although it could be considered a little pricey for a second hand dob it is in mint almost unused condition and he chucked in a revelation collimator for my troubles. The guy had only had it a couple of months and decided it was to much hassle carting it outside. I see there are some mods to be made but as I've splashed out I'm skint so the only mod I plan for now is the plastic milk bottle washer for the bolt :confused: Advice to what actually is required to be done would be much appretiated. I had a go at the guys house just to check it over but the clouds came over as I was on my way home so never got to try it out on any dso's

Thank you all for your advice

[ATTACH]42582[/ATTACH]

[aussi skywatcher]

Hi, looks like you got a bargain there, I have the 8" and the only mod I have found needed is to fit the biggest "lazy Susan" bearing you can get into the base. This makes it much smoother to rotate (bit too much at times!!!) - I fitted 3 felt pads (velcro) to add a little friction - works a treat. Hope you enjoy your scope as much as I do

Cheers Paul

[Patrick1948]

Nice scope Spaceboy...I don't think you will regret coming over to the 'Dob side'...I have a 250px and I'm just getting used to it..long way to go but I love it...Enjoy your Dob, and Clear skies to you.

[Ogri]

Congrats on the 'scope! The 200p is nice isn't it?

[spaceboy]

My bad guys it's the 250PX not the 200P Told you I've been going out my mind Where do you get the bearings from? As the scope is practically new ( no wear on any contact surfaces ) I thought it would have to be used a few times to wear it in before it loosened up. I was gona a drop some silicone spray on the pads just to help get going.

[Moonshane]

top choice of scope, you will never regret this.

I wouldn't add any spray to the bearings, just let them wear in - if it's not had much use then it will probably get smoother but see how it goes.

good luck with it and welcome to the dob club!

[Rusty Strings]

Great scope there spaceboy, you'll get some great views with it. I must, however, question the usefulness of the astro-accessories behind it!