Argo Navis equipped 48" Dobsonian nears completion
A buddy in Texas, Jimi L., recently forwarded me some images of his new
48" f/4 Dobsonian that is nearing completion. I have attached these images here.
The gentleman in front of the telescope is James Mulherin, President and
Lead Optician at Optical Mechanics. Inc (OMI) in Iowa. The pictures were
taken in the OMI workshop where the telescope was constructed.
The primary mirror itself was supplied by Yuri Petrunin at the Telescope Engineering
Company in Russia.
Once complete, the scope will be moved to Jimi's new custom home observatory at
a dark sky site at Limpia Crossing in Texas, only a few miles away from where
the Texas Star Party is held and close to the McDonald Observatory.
The telescope took a remarkably short amount of time to construct. Jimi talked
excitedly about it less than a year ago when we were at the Texas Star Party
and then at RTMC near Los Angeles afterwards. James Mullherin
agreed that OMI would take on the task of building it and with first light now
having been achieved and delivery expected in April, it is a remarkable
achievement.
OMG that is one mother of a telescope !
Thats the kind of scope you build an observatory around and people have to book research time on it.
Naturally enough it is going to Texas
From what I have seen of the Servocat and Argo Navis on 24" scopes it will be a match made in heaven.
Excuse me, Gary, but just say I had two of these telescopes, right, with a view to turn them into binoculars, right, and two servocat thingo systems to drive them, let's say... well, could I get by with only one Argo Navis, or would I need two of those as well?
Looking forward in anticipation to your considered response,
I'm sure that fella ain't gunna have any problems skwinting through the ep's. Why, he'll just have the latest cherry-picker customized with a fully-automated, recliner-like armchair up top (ergonomic seat harness of course) in colour-coordinated, full-thickness leather..........
That is, of course, when he's not slumming it with the (also custom-built) ultra-high definition super-wide screen monitor; viewed sitting in his ground-based, full-thickness, colour-coordinated leather..........
Excuse me, Gary, but just say I had two of these telescopes, right, with a view to turn them into binoculars, right, and two servocat thingo systems to drive them, let's say... well, could I get by with only one Argo Navis, or would I need two of those as well?
Looking forward in anticipation to your considered response,
Brian.
Hi Brian,
Thanks for your question. Let me put it this way. We certainly wouldn't
fool you into buying any more than what you need.
On a more serious note, with regards the ServoCAT drive system, which Argo
Navis performs the drive rate calculations for, the 48" scope is equipped with
relatively modest 23mm servo motors which are then geared 10.6K:1 to provide
slew speeds of over 5 degrees/sec.
The primary mirror alone of the 48" weighs around 317kg.
Gary Myers of StellarCAT, the manufacturer of the ServoCAT, reports to me
with a slightly higher gear ratio, one might be able to move about a ton
(approx 907kg) and still slew at a respectable 4.2 degrees/second.
Therefore, on a hypothetical larger scope such as a giant binocular scope
weighing in around a ton, one could probably get away with a single
ServoCAT drive system.
Archimedes was quoted as saying that "give me a large enough lever
and I can move the world". This is the mechanical advantage that gearing
provides. If you ever get a chance to see the radio telescope at Parkes up
close, it is revealing as to how small the motors are that manage to move such
as massive thing. Again, the gear box provides the magic.
You must be very proud and excited, Gary. A scope like that is gonna get a lot of attention.
Will you get to have a look through it?
Hi Mike,
It certainly is a dream telescope, isn't it?
Indeed, we are proud and excited and I am sure many IceInSpace readers
are likewise proud to see Australian designed and manufactured astronomical
product being deployed in this way.
Having said that, we are also well accustomed by now to seeing Argo Navis
being deployed as the telescope computer of choice on premium telescopes
or on more modest telescopes where the owner simply wanted the best.
For example, it is not uncommon to see Argo Navis used on tiny refractors
or on 8" Newtonians.
The largest aperture scope I am aware of that has an Argo Navis deployment
is the 72" David Dunlap Observatory in Toronto.
As you are aware, a small circle of Australian observing friends have made close
ties with brother and sister observers in North America. In particular, we now
have many good friends in places such as Texas. Many of them have taken
the opportunity to come and observe with us in Australia and likewise we have
responded to their invitations to observe with them in Texas and elsewhere in North
America. In that regard, Jimi has graciously extended myself and colleagues a
standing invitation to come and bring our observing lists and use the 48" next time
we get to Texas. That's an invitation one can't refuse!
So what would you use for an eyepiece if you want an even moderately wide field of view? If it a 120cm f/4 that is 480cm focal length. Even a 50mm plossl will give a true fov of <0.5 degree. Are there monster eyepieces out there to suit monster scopes?
This pure for academic interest. Certainly of no practical use for me - I'm afraid of heights .
48" for visual is a bit nuts when you consider that the lowest magnification where the average human eye can make use of the full aperture is around 200x! But hey, if I had the chance to look through it, I'd step over my mother to do so!
that is one mother of a telescope !
... such is life in today's industry
.
.
Imagine sewing the shroud for that !!! and collimating it !!!
