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CN Report: The Obsession 30

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Obsession 30
Obsessive Compulsive Observing:
The Obsession 30

Tom Trusock

Note the SUV and Trailer in the background.

So you've read The Dobsonian Telescope by Kriege and Berry half a dozen times, stared longingly at those big ole scopes that dominate the major star parties and - more to the point, have put enough cash away to purchase a used car (and a very very nice used car at that).  Where do you turn?

Good question, cause Dave ain't makin em anymore.    There are indeed other dob makers out there, but there's no denying Obsession has a following.  And with good reason.  Kriege and company have a rather unique business model in the dobsonian industry - they stock (although admittedly not these puppies).  They've shipped over 1700 telescopes through the years, and have recently become one of the first companies to bring to market an UltraCompact telescope (in both 18" and 15" sizes - check the CN Report section for quick looks at both) so us folks with our little cars will actually have some hope of bringing some real aperture to a dark site.

This 30" reunites with Papa - Dave Kriege.

The Classic Obsession line up starts at 12.5 inches and works it's way up to (what I would have termed a monster before this, but lets just call it a "rather large") 25" f5 (also available in an f4 "non-nosebleed" model).  Obsession did, at one time, offer a very limited run of  36" telescopes (IIRC 4), but Dave tells me - "Never again!".  The 30" is currently out of production, so unless you want to beg, borrow or steal one from a current owner, you're pretty much out of luck.  So this ain't gonna be a real hardcore review, but just the same, I thought y'all would enjoy taking a look.

Lets get the drooling out of the way, and look at the specs.  Got handkerchief?

Obsession 30"
  • F 4.5 (focal length of ~135 inches)
  • OMI Mirror
  • Coatings: 96% Enhanced (Primary), 98% Super Enhanced Secondary
  • 4.5" Secondary (United Lens)
  • Mirror Cell: 27 point flotation w/ Sling
  • UTA Weight: 20 lbs
  • UTA Diameter: 92 cm
  • Mirror Box appx: 100cm x 100cm x 100cm
  • Mirror Box weight: 210 lbs
  • Eyepiece height at Zenith:  335cm (11 feet)
  • Limiting Stellar Magnitude (Visual): 17.5
  • Rayleigh Limit:  .2 arc seconds
  • Fan included: Yes (but you'd either best plan on adding some or just giving up the idea of cool down entirely)
  • Base Price: $16,995

Recommended Accessories/Upgrades
  • Shroud
  • Ladder
  • FeatherTouch Upgrade
  • Telrad
  • Anti-Dew System
  • Argo Navis
  • Servocat
  • Scope Cover
  • Truck and Trailer
  • Hoist
  • 4" Apo (mounted as finder, alternate suggestion: 80mm Apo)
  • 12" Obsession (mounted as finder - ok, that's a joke - kinda)
  • Box Fan / Additional cooling fans
  • Several good friends or indentured servants.

This 30" f4.5 behemoth has more than twice the light gathering power of the 20", and goes about a mag deeper.  If that's not enough to get your saliva flowing then I don't know what is.  In the interest of redundancy, I'd point out stats for the beast include an eyepiece height at zenith of 11 feet (forget about having your feet on the floor for this one), and a mirror box weight of 210 lbs.  That's JUST the mirror box, not the scope.

A rare moment - one of us actually broke down and helped.

This beast is BIG.  Gargantuan begins to do it justice.  Oh, ok, so 11 feet up isn't really that high, but holy moley, you just have to see the thing.  For all but the extremely motivated .01 percent of us, there's no chance that this is a single person telescope.  Consider Transport:  90 inch truss poles,  a three foot diameter UTA, and a lower box as big as a desk - this thing needs dedicated transport.  Prius owners need not apply.  Nope, this one needs a good old fashioned fuel gulping vehicle.  Something like a Dodge sprinter van or a truck/SUV with a dedicated trailer.  Seriously, this is something you'd buy a truck and trailer for as accessories.  And then how are you getting it in there?  Plan on 3 close friends, or you'd best get creative with a winch or lift.  Maybe both.  

Staring in awe and wonder - the most common phrase was
"Geeze, that's big."  (Notice no one's helping either....)

And then, once you get it to that magical mag 7 nirvana, just what are you going to observe on?  Forget those namby pamby step stools, you need a ladder.  And not just any ladder you need a real ma... er, astronomers ladder.   Where you gonna get one of those?   Don't know?  Don't sweat it- Tallman Ladders has you covered.

The UTA ring allows for the observer to "easily" attach the UTA.

My buddy owns one of these, and let me tell you, it's by far the most stable ladder I've ever been up on.  I *highly* recommend it.  The steps are spaced 8" apart for ease of viewing, it's very comfortable to stand on.  Wondering what size to get?  Go for the 10 foot, but beware - these are special, built to order.  Surprised?  Don't be.  When you get to stuff at this level, everything is special.   Don't go with that ladder from Home Depot.  You'll be climbing it a lot over the next few years.  And in the dark to boot.

Check out the size of the secondary.
It's larger than the objective of the scope I took that weekend!

While I'd never really think of this as a one person setup, the gent who owns the scope is a master of ingenuity and truthfully, I think he really dislikes the idea of having to depend on someone else so he's worked out a method for setup with little to no external assistance.  Me, being the lazy gent I am... er... I mean... uh, wanting to see his ingenuity first hand, I pretty much just stepped back and let him unload and set up on his own.  He's developed quite the system.  If memory serves, it involves a winch, several different sized blocks, some reinforcement for his ramp,  4 gawkers and 6 of the 7 dwarves (although I could be mistaken about the dwarves).

A happy, happy, happy man.

Setup isn't inconsequential, but it's not nearly as tough as you'd think either.  When you have a good system, (and maybe an occasional) helper, you can be ready to observe in considerably less than an hour.  (And when you bring a scope of this class to the party, there's no lack of helpers.)

Assembly is about what you'd imagine for a typical dob - every thing's just a bit larger so it takes a bit longer.  Think scale.  One real nice touch is the addition of the UTA ring.   You mount the ring to the truss poles, then mount the UTA to the ring.  It makes assembling one of these solo - well I was going to say easier - but I suppose possible is a better word.   This particular unit came with the Argo Navis and Servocat pre-installed, and I'd highly recommend them.  I mean, if you're spending as much as a small car, what's another grand in additional expense.  I'd also recommend a multitude of finders.  A Telrad kinda sorta works (if you've got it bang spot on), but honestly,  you'll really be wanting something a bit more.  An 80mm finder up on the UTA would of great assistance - a TV76 probably would be a nice touch.  Not only does that work as a finder, but it will supply some wonderful widefield views as well.  Who cares that you've got to add another 25lbs to the rocker box for counterbalance?  It's not like it's lightweight as it is.

One of the indentured servants poses by the mirror cell for scale.  Note the one supplied fan.  (See those 4 bolts in the middle?  No, the ones in the middle.... yeah - you'll need more fans.)

I've been privileged to use this scope twice so far, and since the owner is a good friend of mine I look forward to lots of trips up and down that ladder over the next few years. 

Observing with one of these is like being in a different world.  Really.  I observe with a plethora of other telescopes, but the largest ones I typically use are 18 and 20" - this is a different league.   First light was at a small star party (BEOTS) down in Ohio.  Not truly prime conditions, the weather was moving in and while the site was dark - it wasn't what I'd really consider a dark site.  But hey - a 30" is a 30", right?  Well, after some discussion, the first target we turned the 30" to was the Ring. 

So, how was it?

The central star is sort of blase at this point - I mean it's been done in many of the scopes I've used over the years, and it's a pretty common sight in my 18".   But this was a new view.  Due to the family friendly nature of the site, I can't repeat what slipped out of my mouth when I first found the Ring, but I will say that friends who know me know I rarely express myself in coarse euphemisms - and I think I cracked up everybody in earshot.  I was awe struck.  All the times I've looked at the Ring, under pristine sites and large scopes - I'd never seen anything other but green in the nebula.  this was different.  The green was more of a vibrant blue green, and there was this pinkish hue.   And two stars inside.  And I swear there was more structure than I'd ever come across.  That little galaxy close by?  IC1296?  Well, it looked like a Messier object.  I about fell off the ladder.

A month later at a really dark site up in Michigan's Upper Peninsula (SQM 21.57), the 30" had an opportunity to really strut it's stuff.  A small group of us viewed a plethora of typical summer time targets.  Although I've seen them for decades, this monster gave me an all new window on the night.  Seriously, it became obvious as to why the Swan is also referred to as "The Omega Nebula", and while like the rest of you, I've looked at M13 a million times, I've never seen spacing between the stars at the core.  I've seen the Pillars (in M16) before with the aid of a Collins I3, but man oh man.  You should have seen them in the 30".  And yes, we had both the Collins and the new BIPH to toss in there to ensure we had just too much of a good thing.  For me tho, the best target of the evening  was the view of  Seyfert's Sextet.  I've never seen all six members, let alone with direct vision.

For a visual observer, having one of these at a truly dark site is an extremely rewarding experience, to say the least.

Anybody who buys one of these is going to have to seriously think about their eyepiece selection.  The true field of the 31 Nagler was a mere 44 arc minutes, and provided 111x.  A 41 Pano gets you down to 84x, but only manages to increase the real field by 5 arc minutes.  Face it - you just aren't going to be doing any low power viewing.

But you really don't buy this to sweep the Milky Way.

As per a star test - well, to be honest - I can't tell you.  Because of the sheer size of the beast, I may never get a chance to star test it.  The atmosphere just won't support it.  I can tell you that everything looked good.  Really really good.  And that's all that really matters.

This beast brings it's own rewards, and truthfully, isn't quite as complicated as it seems.   In fact, it brings unlooked for advantages.  After using this giant for a few nights, my own 18" f4.5 Obsession is a toy.  Truly, it's positively puny in comparison.  And so is the light gathering ability. 

Hm, I wonder - do I really need  that new car?

Do NOT look at or near the Moon. Immediate and irreversible eye damage may occur. Minors should have adult supervision at all times.  Obsession Telescopes is not responsible
for blindness or fires which may result from improper use.


  • Joe Bruessow, John J. Risti, CharLakeAstro and 2 others like this


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