Big Dob reviews

[Pathan07]

Anyone know of any equipment review sites on big dobs??

[Kevnool]

Gday

Have a look through this link.

http://www.iceinspace.com.au/reviews.html

Cheers Kev.

[wavelandscott]

Any particular brand or just in general?

[Rodstar]

Hi Pathan 07,

Like Scott has suggested, if you were to seek feedback about a particular brand or model, there is a very good chance you will get some feedback from members of this forum who own/have owned that particular dob.

A number of us on the forum own an SDM telescope. SDM stands for Size Does Matter, and so, as the name suggests, this manufacturer works on large scale dobs. I believe he has a 40" in the pipeline, although on the SDM website the largest you will find to date is about 32" ( www.sdmtelescopes.com.au ).

In all of the years that I have been involved in this Noble Pursuit of ours, I have never come a across another maker of big dobs who comes anywhere near to being as good as SDM. And, as a local producer, Peter Read is able to provide post-sales support like no one else.

Obsession Telescopes in the US are the biggest makers of big dobs in the world, and the quality is very good. However, they are on the other side of the world, so postage and handling is likely to be over the $1000 mark (when I made enquiries 6 years ago, it was going to be about $1,400, not sure what it would be now), and you have to pay GST as it is over $1,000 in total cost. I know of one Obsession which has had to be rebuilt by SDM because it did not withstand Australian conditions.

There are many mass-produced dobs available on the marketplace - eg Meade lightbridges, Skywatcher, Orion intelliscopes etc, all of which have proud and happy owners on this forum. These are generally reliable, and a lot cheaper, but you get what you pay for.....

Good luck with your decision-making!

[spacezebra]

Well said Rod.

http://www.sdmtelescopes.com.au/SDM013.html

Cheers Petra d.

[alocky]

I bought direct from Obsession as the freight cost to Western Australia and the strong Aussie dollar made it the better option at the time. My friend purchased his direct from the US a year earlier, and neither of these instruments have needed any maintenance beyond their annual bath. I would have no problem recommending them again. I was extremely impressed by the level of service and engagement from the manufacturer and shipper - in complete contrast to my ongoing, unresolved experience with Losmandy and their dealer in Adelaide.
It's my understanding that the SDM instruments are at least the equal of the Obsessions, but I have yet to put them side by side. In addition, if you're lucky enough to get optics from Deep Sky Optics, then you'll have nothing to worry about on that front.
Onto the actual observing experience with a large scope - beware, once you look through one, there is a good chance you will be addicted. Or for the same money, you could buy a 6" APO...
regards,
Andrew.

[barx1963]

As others have stated, really depends on what you mean by big. I am currently the owner of a GSO 12" dob and reckon that in value for money terms they cannot be beat, under $1k and give you thousands oif objects to view. However in the commercial scope world (GSO, Meade, Skywatcher etc) of mass produced scopes the biggest are 16" so the term big dobs often refers to 18+" inches made by specialists such as SDM or Obsession.
As I am considering a big dob myself I have made contact with Peter from SDM and Dave Kreig from Obsession. Both I have found to be helpful and responsive to my queries. People I have come across who have their products are universal in singing their praises as far as the quality of their products.

Malcolm

[dave brock]

Try this.

http://www.scopereviews.com/ (http://www.scopereviews.com/)

Dave

[ausastronomer]

Hi Andrew,

I have both scopes. The standard of fit and finish and quality of components used on the SDM is a clear notch above the Obsession. It's not even close. That having been said the Obsession is an excellent scope and the basis of the design for the SDM scopes. The Obsession is a workhorse and works very well, the SDM is a Rolls Royce.

Some of the improvements and design modifications Peter has incorporated into his SDM scopes are:-

1) Delrin Split Blocks, which are not subject to temperature change or splitting.

2) Choice of mirror maker, including Carl Zambuto, Mike Lockwood and Mark Suchting.

3) Stainless steel fittings and hardware used exclusively throughout the scope.

4) The altitude and azimuth bearings are done with a special epoxy paint on aluminium which IMO is an improvement over the ebony star laminate.

5) The light baffle on the upper cage assembly is made from thin plywood (1.5mm or 2mm depending on aperture); as opposed to kydex. The plywood does not bend or buckle when the scope is left in the sun. Nor does it come adrift of the UCA rings.

6) The truss poles are powered, as is the top end of the scope, for running dew heaters etc. Thousand Oaks or Kendrick dew heater controllers are fitted as standard.

7) The servocat controller is mounted internal to the rocker box and all servocat and argo navis cabling is wired in channels routed into the inside of the rocker box.

8) Boundary layer fans are fitted as standard on all scopes.

9) Feathertouch dual speed focusers are fitted as standard. Moonlite dual speed focusers are available as a price reduction option.

I haven't done the exercise on price recently but I can tell you if you kit out an Obsession with all the toys which come standard on an SDM, it will be pretty close, for a lower quality of fittings and finish. I have used scopes in the USA from several of the premium manufacturers (Starmaster, Teeter, Webster, Astrosystems and Obsession) and none are better than the SDM's. Teeter probably coses the closest. Rob Teeters' scopes, like Peter's, are very nice but IMO the bearings are not nearly as nice.

Cheers,
John B

[alocky]

Thanks for that. I've never seen an SDM in the flesh, and although I can't put my finger on any design deficiencies of the Obsessions I've seen, the SDM does sound very nice. Given that obsession don't go any bigger than 25", I might have to look at SDM for the next one! Could take a while to outgrow mine, though.
Cheers,
Andrew.

[Zubenel]

I had the pleasure of looking though rodstar's 20"SDM , Brian's 20"SDM and Peter's 30"SD#1 at Astrofest last Saturday night. Awesome views :eyepop: ( 47 TUC) that , arguably could not be beaten with all the bells and whistles . Rod's even has remote collimation !!! Amazing scopes and Peter Read is a top bloke to top it off. Certainly on my list.............:question:

[Gem]

On the 'smaller' end of the scale... I am very happy with my GSO 16". It is great value for money. :)