Introduction
The Spectra-L200 is a Littrow
Spectrograph designed by Ken Harrison. Ken was gracious enough to put
together a few kits for those of use with an interest in getting into
Spectroscopy but now having the money to buy the limited number of ready made
units or the expertise to design our own (not to mention source the few
specialist parts for them...)
Above is a picture of Ken's bench testing setup.
(image courtesy Ken Harrison)
Above is a picture of the HHO L200 and ST-8 CCD Camera
So, once the Ken's first batch was done and dusted (and
lessons learnt), I put my hand up for his second (and probably last) batch.
Deposit down and several months later (after supply issues for the adjustable
slits) and I was ready to go. The box only took 4 days to arrive from
Belgium and squeezing in just under the Customs/GST threshold meant there were
no unexpected delays.
On a quiet Saturday morning, the doorbell rang. By the
time I got there the delivery guy was gone and a smallish innocuous brown box
was sitting on my doorstep.
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Pre Construction - 12 February 2011
Here you can see the
contents of the box laid out on the kitchen floor. Ken did a great
job at packaging up this kit. Everything was easily
distinguishable.
This is the Neon Reference Lamp kit which I ordered with
the L200. With the second batch of L200's, Ken made some design
changes that allowed the reference lamp to be mounted inside the housing
on a flip lever. |
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Preparation - 13 February 2011
First order of business was
to undercoat all the bare metal parts. Ken recommended an etch
primer so a visit to the local hardware store (Magnet Mart) to pick up
KillRust Etch Primer, Matt Black and Royal Blue. Ken would have
liked all his customers to adopt his chosen colour scheme (Maroon) but I
love the Blue Colour of my Meade Scopes so picked the closest colour to
that I could find. |
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Preparation - Internal Colour - Matt Black - 14 February 2011
Once the primer was
dry it was time to do some masking and pain the internal matt black.
The Black required 16hrs between coats so this was a 4 day job to get 2
coats on all surfaces. |
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Preparation - External Colour - Blue - 18 February 2011
So went the Internal
surfaces were finished, the chassis components were re-masked and the
Gloss Blue colour applied. Unlike the Undercoat and Matt Black,
the Gloss Blue stayed in suspension a long time coating everything.
It required a lot of cleanup! |
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Let the construction begin - 20 February 2011
Construction was
straightforward and went as planned. As expected there was a
little bit of cleanup required to remove excess paint from holes and
threads and some holes need a very small amount of easing out but in
general this was a trivial task. Images from top down are:
- Micrometer mounting - Outside
- Micrometer mounting - Inside
- Camera Mounting plate - Outside
- 600 l/mm mounting (with protective cover)
- That awkward Grating tension spring
- Collimation Lens
- Completed Spectrometer without side plates
- Completed Spectrometer (less Telescope mounting
plate).
There was a problem with the T Thread in the Telescope
mounting plate, it was cut to a minimum size and did not allow T
adapters with a large thread size. A new Male/Female adapter is
being made to suit and will be distributed to kit owners.
Another small setback involved stripping the thread on
the Micrometer locking screw (see second image). To repair this, I
had to completely dismantle the spectrograph :(
After a couple of weeks I found some 6mm x 1.0 thread bolts and a
matching tap so re-tapped the Micrometer Mount block. I also filed
a flat/groove in the micrometer itself to better facilitate locking.
To my surprise it took less than 30 minutes to completely rebuild the
Spectrograph (see last image in this series) |
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