Sirius 11.5' Observatory
By Daniel L. McConaughy, PhD
It's been two and a half years since I received and built my
Sirius 11.5' Observatory; so enough time has elapsed for me to comment beyond
initial impressions. I got an
observatory because I don't have a lot of free time and I don't like setting up
a telescope any more. The
observatory allows me to begin observing with less than five minutes of
setup. I chose a round observatory
with a dome in order to reduce the 'footprint' in my small backyard. A roll off roof observatory has a much
larger footprint due to its squareness and its tracks. My location is suburban (Santa Clarita
Valley, north of Los Angeles) with a national forest seven miles to the north;
so it is not really dark, but I can still see quite a lot - the Milky Way is
visible on a really 'good' night.
First of all, I have never been more pleased with
anything I've ever bought. The Sirius Observatory exceeded my
expectations from the beginning. I
bought it directly from the good people at Sirius Observatories in
Australia. They communicated well
and never over-sold their product. The observatory arrived packed very well in a huge wooden
crate. Nothing was damaged and
every part was present. All the
pieces were manageable by one person.
They are helpful by phone and email and provide good follow up service.
Construction went very easily - watch their video - it
explains everything without any exaggeration or misrepresentation. While awaiting
the arrival of the observatory, I had a concrete slab built.
It was 12' in diameter, 4Ó thick and had a central portion isolated from
the rest of the floor by a 12Ó by 3' sonotube. The sonotube was filled with
concrete to the bottom with rebar and with 4 bolts protruding for bolting a
pier to the floor. This has worked quite well. The slab was also cut like a
pie to a
depth of an inch so that as it settles it will not crack randomly but along
the cuts (there is probably a technical name for this but I don't know it.)
If I were to do it again, I'd have made
the slab 12.5' to give a bit more room for the observatory walls - the slab
wasn't perfectly round.
Nevertheless, 12' worked fine and there has been no problem with the
bolts in the concrete along the periphery that hold the wall (more on this
later).
I also ran electricity out to the observatory and had the
plastic conduit pipe come up through the cement floor by the center and by the
door so that I could have two power outlets. This I recommend.
The outlet in the center powers the telescope and accessories. The one
by the door powers the lights and a fan.
I used little tiny red Christmas tree lights strung along the top of the
wall. I also have a rheostat
switch to dim them. They give
plenty of light.
After the observatory arrived, I had a couple friends help
me assemble it. The dome is a bit
hard to assemble with one person, at least until you bolt two pieces together
and then they stand up. The walls
can be done without help. Everything
is pre-drilled and numbered because the whole observatory was pre-assembled
before shipment (standard feature of all the Sirius models); so all the bolt
holes fitted together with no problems.
If you follow the video instructions, you will have no problem. Once the walls are up and the dome assembled,
you will need several friends to lift the dome on the walls. It only weighs a couple hundred pounds;
so the weight isn't the issue but balance is; so make sure you have half a
dozen friends to help. Apply all
the lubricant to the upper walls that they supply before you put the dome on
the walls. Look at the video and
do what they do on it. Once the
dome is on the walls, you rotate the dome several times and the walls self-adjust
like magic. Then you can tighten
the wall panels to one another really securely.
Bolting the walls to the floor was easy. I borrowed a hammer drill and got
the fasteners they recommend from a local construction supply store. I drilled
holes through the bottom of
the wall panels (follow the video) into the concrete and inserted the fasteners
and bolted the thing in place. One
thing I dealt with was that my slab wasn't perfectly smooth; so I shimmed at
every hole so that when I tightened the bolt, it did not stress the wall.
I used some heavy black plastic from left over edging material from some of
the planters we have. It's about 1/16Ó thick and weather
proof. Be sure to position it so
that it does not stick outside the wall so that the caulk bead on the outside
is smooth. After all this, I
sealed the outside of the wall at the slab with the recommended 3M sealant,
which is really good stuff. It
took quite a bit as my slab was not perfectly smooth; so there were some gaps
that had to be filled. I also
installed carpet before installing the pier.
The observatory dome rotation and shutter work quite well;
so I would assume that the motorized features would work well. I do not have
the dome motorized. It moves quite easily, which amazes me. I had one problem
after I
lubricated it with Vaseline petroleum jelly after about a year. That stuff
gets stiff and acts like glue after a while. So when you
relubricate, use something other than that. I got some Lubriplate grease that
works well in cold weather (it's also good for your mount). I apply additional
grease with a small 1Ó paint brush from the outside by lifting up the rubber dust shield and
inserting a small 1ž4Ó thick oak board as a lever to lift up the dome
enough to get the brush inside (remember the dome isn't all that heavy). This
works pretty well and I haven't had to disassemble anything from the inside
to get to the track for
lubricating.
There are some trim pieces to cover the inside wall joints
that I have never installed. This
was just as well because periodically I need to tighten the wall bolts. They are a nice touch and show the
extent to which the good people at Sirius have thought about the design of the
observatory. The fact that the
observatory works so well speaks volumes as to their design and manufacturing
capabilities.
Periodically I do have to tighten the bolts holding the
walls and dome together. The folks
at Sirius told me that if I'd tightened them enough at the beginning, this
wouldn't be necessary. Since I've
retightened the bolts at least twice, I'm not so sure that they will stay tight
indefinitely. One should be sure
that the bolts on the dome around the shutter stay tight - there is some
movement and stress where the hinged part of the shutter comes down.
Every so often I hose off the observatory. And less often, I clean it with a mild
detergent using a mop with an extension pole. I'm careful not to scratch the gel coat. Once a year, I take some
lime-dissolving cleaner to the walls because of the overspray from our
sprinklers which use very hard water.
This cleans off the minerals on the wall quite well.
As far as ordering one from Australia, don't worry about
dealing with the good folks down under.
Be sure to identify all the costs so you are not surprised. Sirius covered
shipping to the US, but that does not get the box off the ship!!
It cost several hundred dollars just to get it off the ship and onto the
wharf and another several hundred to put it in the warehouse and through
customs.
Then there is the shipping by truck. The only surprise to me was the cost
of getting it off
the ship to the wharf.
The 11.5' size is quite adequate for several people. The
walls are 5' high and the dome goes on top of them; so there are no problems
with people hitting their heads once they are inside. One does need to watch his or her head and feet when
entering and exiting. We have
groups of third graders (whom my wife teaches) and their families over for
viewing sessions and it works well.
It very nicely holds my C14 on a Byers German Equatorial mount with
Gemini Goto.
My review is necessarily short because their video really
tells it all and in an accurate manner.
I heartily recommend Sirius Observatories.
