18" (459 mm, Effective aperture: 455 mm), F 4.5, f: 80.2" (2037 mm).
The secondary mirror is 3.1" (79 mm) with 17 mm thick. The optics have
recoated in June 2015 by Galaxy Optics
Colorado, USA. The reflectivity of the primary and the secondary are
96% and 97%, respectively.
wood bar suspending from the top ring is used to move the telescope
downward: I grab it and pull down when I sweep the sky vertically. The
light shroud was renewed in 2010: the present shroud was made by
USA. The light shield is attached over the eyepiece.
Major modification in 2016 and after
* The Pahse 4 Focuser (AstroSystems)
was replaced with the Feather Touch Focuser
* Installing the filter slider: The Astrocrumb FilterSlide Mark II
* The connection method between truss poles and the top ring (secondary
cage) was changed from the wooden wedge & pole seat to the
Left: Finders and focuser
Two finders, the Telrad and the 50 mm erect finders,
are installed. At the beginning in 2001 I employed the Telrad but it
was bulky and I chaged to piggyback ride Regal Quick-Finder on the 50
mm finder. I go t back to the Telrad as it is easier to use.
The eyepiece, I usually use for comet
hunting, is Ethos
21 mm with 97x and 1.0˚ actual field of view (FOV). A light shield is placed
over a white
plastic part on the eyepiece. Another eyepiece that I use is Planocular
30 mm, manufactured
in Germany with 88˚ apparent FOV, which is combined with Parracor with 78x
and 1.1 ˚
apparent FOV. Once I used Planocular 30 mm alone with 68x and 1.3 ˚
I replaced the focuser, the Phase 4 Focuser (AstroSystems),
with the Feather Touch Focuser
in 2016 because the Phase 4 was broken.
Right: The dew caps and light shield
dew shield made by insulator for water supply pipe (white colored) is
placed on the Telrad Finder and the eyepiece of the 50
mm finder. Only when I peer into finders I remove the dew shields. A long dew shield hood is
placed for the objective of 50 mm finder.
Upper left: Nexsus DSC
is placed on the lower part of the focuser. A part of the filter slider is seen on the upper right.
Lower left: Filter slider
Three filters, (IDAS LPS-P2, Lumicon Comet, Lumicon OIII, are equipped in the US made filter slider, The Astrocrumb FilterSlide Mark II
The dew remover (heater) is built-in in the slider. I often apply
LPS-P2 filter under the condition of the moonlight or enhanced light
pollution due to hazy sky.
Right: iPad mini2 (screen shot)
The digital map, SkySarari 5 Pro
indicated on the iPad mini2. The iPad mini2 receives the signal from
the Nexus DSC via WiFi and indicates the map linked with the FOV of the
comet-seeker. To identify DSOs is very easy because the map shown on
the screen is always linked with the FOV.
Upper left: Cases
A home-made case for iPad mini2 (left) and a carry case for Nexus DSC.
Lower left: Inside the cases
Aluminum form mat is inside of the case for iPad min2 to keep it warm. It makes the lifetime of the battery longer.
The power line extends from the rocker box
the battery is placed to the secondary cage via the heater controller.
are three heaters; the secondary mirror, the
eyepiece and the filter slider. Kendrick Dew Remover is used in the secondary
Disassembled case for iPad mini2.
Front view of the telescope
Rear view of a mirror cell. There is a cooling fan at the center. Two
vertical wood blocks are to protect three light collimation
knobs, when the mirror box is placed on the ground.
Top view of 18 point flotation cell.
Insulator used for truss poles
Insulator used after
July 2017. There is no split like the insulator below. This sponge is
for 22 to 23 mm inner dimameter but applied to 25 mm alminium pole.
Upon inserting the insulator into the pole, the lubricant was sprayed
both on the pole and the inner part of the sponge. Gripping feeling is
better than the previous one and slender. Easy to use.
Insulator used until June 2017. A split type insulator that is fixed using a tape.
iPad mini 2 with the case is placed on the attachment with
flexible arm (not detached every session). A clipboard and a pencil is also connected to the stepladder using the sling.
Right: The case of the iPad mini
2 is opened. Only when I look at the map I open the case to keep the inside warm for longevity of the battery.
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Left: Loaded 46cm comet-seeker
1: primary mirror with PVC cap (sealed in the plastic bag with a zipper with silica gel), 2: step for loading, 3: eight truss-tube poles, 4: eyepiece box, 5: bino-viewer box, 6: rocker box,
7: mirror box, 8: top ring (secondary cage), 9: stepladder
Right: insulator is used in summer.
Before installing the primary mirror.
Inside the mirror box. There is sling that hold the edge of the primari mirror. Two out of three mirror clips are on the photo.
The primary mirror is installed with the home-made white PVC cap.
the PVC cap leaving the primary mirror in the mirror box. After that
the sling is slipped around the primary mirror and the mirror clip is
rotated to avoid the mirror falling.
The white PCV cap removed from the primary mirror and empty plastic bag with the zipper.
Inserted eight truss poles into the pole clumps.
The top ring (secondary cage) placed on the poles. The wooden pole
seats that were used with the wooden wedge until June 2017 function as
a guide of poles to keep them in correct position.
Overlapping crushed truss poles and fix them using a nut.
All poles were tightened with bolts and nuts.
the lower end of poles in the pole clumps using the nobs. The other
thing to set up is installing the light shroud, finders and etc.
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