Obsession Telescopes, anyone know about these?

[FredinBroome]

Hi everyone,


I see several comments and a review of the 20" Sky-watcher dobsonian telescope on this forum but nothing on obsession telescopes yet. I know of an outfit in Bunbury WA that use a 22" one in the business and they go up to 25" apparently. They appear to be transportable which is why the company bought one.


I'm not out to buy one anytime in the near future ( maybe for the future hehe...dreaming) but was just wondering if any members had come into contact with one


Web: http://www.obsessiontelescopes.com/

[The Mekon]

Obsession telescopes have been around for quite some time. 25 years ago the founder Dave Kriege was at the first SPSP and brought with him a 20" F5. These were the first commercialised low profile rocker box style dobs available and used either Galaxy optics or optics of your choice. There would be quite a few in Australia as they were the large scope of choice before Peter Reid's SDMs started to become widely known.
Keep an eye out on the classifieds and be ready to buy if one comes up. They are a sound design and sell a bit cheaper than SDMs. A 20" F4 would be my choice.

[Wavytone]

Various clones too, including SDM. But IMHO they’re a big and heavy, old fashioned design.

Sure, they work.

But there are many alternatives where more thought has been applied both structurally and in the choice of modern parts and materials.

[jamespierce]

I wrote a really long reply to this thread. Then lost it - so here's the short version.


Obsessions are good scopes with a few features now which are dated and can be improved on (pole blocks, pole UTA clamps and mirror support sling). Peter at SDM has continued to evolve and improve the design, including refreshing Obsessions - he's also local here in Australia.


Big telescopes have heavy mirrors. That makes them heavy no matter what design. Yes, there are some very impressive carbon fibre designs comming out of europe but they have their own set of compromises.


I've had the luxury of looking through a pretty good number of very large telescopes. You want a big scope to be over built, not underbuilt. Consistent mirror support, holding collimation and pointing accuracy all get more challenging at scale.

[Kunama]

My advice is to keep an eye out for a used SDM telescope...
If you contact Peter Read at SDM I am sure here will let you know if anyone is thinking of selling one.....

(or build one, it is very rewarding...)

[gts055]

I have a 20" F5 Obsession dobsonian telescope. Beginning in 1989, Dave Kriege of Obsession telescopes was one of the first to commercially produce high quality large aperture dobsonian telescopes with precision mirrors. Craftsman made woodwork with the whole telescope being a work of art. Brass plaques are fitted to every one made are inscribed with the original owners name and serial number. Virtually all Obsession telescopes in Australia will have have been imported from the USA as there were no similar offerings available in Australia unless you made your own. Dave Kriege and Richard Berry published a book titled "The Dobsonian Telescope, A Practical Manual For Building Larger Aperture Telescopes" which became the reference for amateur makers. SDM came much later and at a glance appear very similar to the Obsession, however Peter Read has made many refinements to the assembly. Mine has a mirror sling from Peter and it is an improvement over the original mirror support. SDM telescopes are made with pride to the the highest standard and being in Australia, convenient to deal with. Mark

[gary]

Hi Fred,

First a disclaimer. Obsession Telescopes are a customer of ours.

In fact, many telescope manufacturers are customers of ours
but since you were asking about the Obsession I will confine
my comments to them.

When you mention the 22" and "transportable" you will be referring to
the Obsession 22" UC (Ultra Compact).

Dave Kriege of Obsession literally wrote the book (https://www.willbell.com/tm/dobtel.htm) on building large
Dobsonian telescopes and the design outlined in that book gave
rise to many amateur telescope makers (ATMs) and small businesses
either making scopes identical to the blueprints in the book
(commonly termed 'Obsession clones') or inspiring them to customize,
refine and embellish the "classic" design further into bespoke designs.

All the Obsession telescopes use a truss pole design that allows the
scope to be broken down into three primary components - namely
the base with the groundboard, rocker and mirror boxes, the top end,
which holds the secondary mirror and focuser and the truss poles
themselves.

The original Obsession design - what is now referred to as 'the Classic' -
the base components are fabricated in marine ply. This, along with
a top end that has a diameter slightly larger than the primary mirror
and is roughly the size of a musical drum, makes the scope, even when
broken down, relatively heavy and bulky to transport.

For example, when I transport an Obsession 18" Classic I have stored in
my garage, it takes up the entire back of a Subaru Forester with the
back seats folded down with not very much room to squeeze in much else.

Around 2006, when fuel prices began rising in the United States, Americans
began to downsize their cars.

Responding to this, Obsession brought out a new design called the
Ultra Compact or UC for short.

Dave Kriege showcased the 18" UC at the Texas Star Party in 2007
and in front of an astonished audience, removed the components of the
scope from a compact carrier box and assembled it on stage in the
space of a few minutes.

Dave had designed a scope that would fit in the 'trunk' of a small car.

A group I volunteer with, which already owned a large number of
Obsession Classics, purchased one of the first 18" Obsession UC's
and Dave Kriege, a regular visitor to Australia, brought it with him
on the flight to Sydney.

I was custodian for the scope for a while and by comparison, the entire
18" UC fitted in the back of the Forester station wagon area with the
back seats folded up and room to spare.

Whereas when I move the 18" Classic I use a ramp and wheelbarrow
handles to get the base in and out of the vehicle, the 18" UC can
safely be lifted by a couple of average people or by an individual fit
and strong one.

Later, Obsession introduced the 22" UC.

Whereas with the 18" Classic I transport a step ladder with it in order
for an observer to view through the eyepiece at modest zenith distances,
with the 18" UC I can observe at the zenith by standing on a milk crate.

If you have young children, it is much easier for them to access the
eyepiece on the 18" UC compared to the 18" Classic.

The Classic design is heavier, the truss poles thicker and as a result the
Classic is a sturdier scope to use in a breeze. If you have a larger
vehicle and transportation is not an issue, stick with a "Classic" design.

If you have a family and the vehicle won't accommodate both them and
the scope and you don't want to resort to transport the scope in a trailer,
consider a "UC" design.

As they say, the best scope is the one that gets used most often.

You are lucky to live in Broome because of the skies. The one disadvantage
is that it puts some distance between you and the nearest sizeable
club or star party in order to look at and operate other people's
scopes, which is what most of us would normally recommend before
buying a new scope.

The premium Dobs, like the Obsessions, come with mirrors made by
mirror makers in the United States or Australia and as a result, across the
board of all mirrors made, the mirror performance, due to better
quality control, tends to be guaranteed to be better than the commodity
mirrors manufactured in the Far East. If for some reason you are not
happy with the mirror's performance, with the premium Dobs one has
the opportunity to strike up a dialogue with the actual mirror maker.

The movement of the premium Dobs also tends to be much nicer
compared to the commodity Dobs out of the Far East. When one reads
the Kriege book on Dobsonian telescope design, it is filled with the physics,
engineering and mechanics of why the scope is built the way it is.
Moments of inertia, friction and stiction, truss pole rigidity as a function
of truss pole diameter and so on.

The Dobsonian designs out of the Far East are often dictated by other
requirements, such as can they be sold in a flat pack and how many
will fit into a standard shipping container.

When you first push a nice premium big Dob around, I find the experience
akin to having the opportunity to drive some premium high performance
European sports car. Dave Kriege uses the expression "buttery smooth"
when referring to the feel of the motion of his own scopes around
their respective axes. It's a good description and it comes as a revelation
the first time you get to push one around. Like behind the wheel of the
European sports car, it is very refined, which is really nice.

Best Regards

Gary Kopff
Managing Director
Wildcard Innovations Pty. Ltd.
20 Kilmory Place
Mount Kuring-Gai NSW 2080
Australia
Phone +61-2-9457-9049
Fax +61-2-9457-9593
sales@wildcard-innovations.com.au
http://www.wildcard-innovations.com.au

Image 1 - Obsession 18" UC in the back of my Subaru - room for passengers
Image 2 - Obsession 18" Classic in the back of my Subaru - a bit of a squeeze

[FredinBroome]

Hello Gary,


Thank you for a very concise history on Obsession telescopes. Very interesting read.


Cheers,
Fred

[alocky]

I’ve got a 25”f5 obsession, I have a friend with an 18” f4.5, and regularly observe with another friend with a 28” Webster, who also owns a slew of very exotic and experimental modern dobs with large apertures. We all live in WA, so if you’re ever down in Perth send me a pm. I also use a 30” obsession up at the Perth Observatory and have been known to roll mine out alongside the 25” up at Gin Gin.
It always amuses me to read posts about having a large dob from people who don’t own one, so here’s my take.
These ‘older’ dobs have been operating continuously for over 20 years with no problems, take less time to set up than my previous portable scope - a newt on a German equatorial, and when fully motorised with a stellar at and Argo Navis will put a 17th magnitude galaxy right in the middle of the eyepiece. Do bear in mind that a ladder might be required to reach the eyepiece. Doesn’t worry me.
It holds collimation over the whole sky, can be easily setup by one person, and if you damage it, is made of easily sourced materials to replace or repair, and is still backed up by excellent support from David Kriege. I’ve seen a couple of SDMs and they are works of art at a premium, but do not do the job of holding two mirrors and an eyepiece in the correct place any better than the original Obsession.
Your decision should first be about quality of optics - all of the premium mirror makers should be able to give you an interferogram, and what premium you’re willing to pay for ‘bling’.
Cheers, and despite the claims from some people who are unwilling to accept physics, a good quality large aperture scope will deliver better views of everything under any conditions. Must be why there aren’t too many overpriced drinking straws in the Atacama Desert or on Mauna Kea... :P
Cheers
Andrew.

[FredinBroome]

Hello Andrew,


Wow I didn't realise that there were so many of these specialty dobsonians around. I'd love to check out your scope one day when I finally make it to Perth. With two kids under 5 and the main carer, I don't get out much. I bought a smaller 200/1200 dobsonian just to get started and I'm really enjoying looking into the heavens though the full moon is making it hard to see the fainter objects though I one the kids and missus over with close ups of the moon.



I thought that if I was to get a large dobsonian telescope like you own I would need to house it in a special building as carrying it in and outdoors like I do with my Saxon. BTW, did you buy your obsession overseas or locally from a dealer?


Cheers,
Fred

[alocky]

Hi Fred,
I bought it direct from Dave Kriege, who arranged shipping and customs to Perth.
I store mine in a trailer, it means I can head out to an observing session at less than 5 minutes notice.
You can store them in a garage and just roll them out with the handles, although I don’t think you’d want to roll it very far.
Cheers
Andrew.

[glend]

Well what exactly are you wanting to pay for? If your looking for a good large aperture dobsonian there are many choices to 20" available commercially, built using more modern strut designs, easily transportable, and importantly - have realistic resale value. I would stick with a scope that is no more than 20", simply for ease of transport and resale market size - and eventually you will sell it. The problem i see with SDMs and Obsessions, and their ilk, is that the market is extremely small if you decide to sell. Whereas a large Skywatcher, or GSO, or other Dob, can usually be pretty easy to sell.
Sure the owners of these ultra expensive scopes will dabbled in about attention to detail, finish quality, and all sorts or things used to justify jacking up the price, but none of that has much to do with what sort of performance it turns in when your looking through it. Mirrors are easily upgraded if you want to spend more than the very good offerings through the mass market retailers. That's my 2 cents. I am sure my opinion will be ripped to shreds, as usual, but it's your money, don't be fooled by marketing spin.

[Kunama]

I agree, there is a wealth of Chinese offerings that can give a lifetime of enjoyment for a very reasonable budget and if indeed you are not concerned about the last 10% to 15% of performance and some of the niceties that are featured on the top tier scopes then you can save a lot of money.

If however you don't want to gamble on the quality of the optics or the orthogonality of the structure and the scopes ability to hold collimation well, then you may be better off with a custom scope, whether new or secondhand.

I never stress about resale of a large scope, some people think of these things as financial investments where any losses must be minimised. For me, once the money is spent on a hobby I consider it gone and just enjoy what the scope can show me. Anything I get for it later is just a bonus...

Having looked through scopes ranging from 2" aperture to 32" aperture I have come to realise that 18" is the perfect size for me.....

[sn1987a]

Starting out I recommend an 18" or 20" secondhand premium Dob to aim for. They are a safe investment in your viewing pleasure and excellent value for money.

Also they make a great grab and go for when you eventually get a real Dob/s. :D



https://www.youtube.com/watch?v=1vJAsC3AfxQ