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|For Sale -Dealer Ad |
|Status: Active Ad Category: Telescope-Reflector Ad # 41747|
| 24-INCH F/4 TELESCOPE FOR SALE LATEST DESIGN|
I am offering for Astrobuysell members one 24 inch telescope with special price. Compare the price with 30,000 CAD for inferior classic design Dobsonian to get it from elsewhere. It is F/4 so it will be ideal for deep sky observing somewhere from a dark place because of its bright images it gives at this focal ratio and also because of its wide field of view. Nagler 31 mm eyepiece will give 64 minutes of field without coma corrector. Stunning views with multiple galaxies in same field, pairs of globular clusters in same field.....
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Mirror Diameter - 610 mm (24 inch)
Mirror Thickness - 28 mm (1.5 inch)
Focal Length - 2400 mm
Focal Ratio - only F/4
Material - Supremax33 low expansion glass, fine annealed, made in Schott AG factory in Germany
Coating - Aluminum coating 91% reflectivity
Mirror Weight - 18 Kg
Circle in the center for easy and minute collimation
Primary mirror - 610 mm diameter (24 inch) - see above mentioned mirror specifications. The 1.5" thin mirror cools fast in about 1 hour and after follows the air temperature drop during the night. Compare this with thicker mirrors which are not capable to follow the temperature drop during the night. Primary mirror which is 2 inches thick will need forever to cool down, and even if we suppose is cooled down, it is not capable to follow the fast temperature drop of the air after the sunset.
Focal Ratio - F/4
Focal Length - 2400 mm
Secondary mirror - 4.0 inch minor diagonal secondary mirror Astrosystems, expensive with 1/10 wavefront error (1/20 wave surface error), enhanced aluminum coatings 96-97% reflectivity, interferometer test report included.
Heavy duty spider and secondary mirror holder with requred off-set also from Astrosystems
Top of the line Feathertouch dual focuser 10:1, low-profile, the newest model FTF2015BCR, only 1.5 inch travel. Feathertouch focusers from Starlight Instruments are the best focusers in the world.
Secondary mirror dew heater from Kendrick with RCA jack ready to connect to 12 V DC power
Cooling fan ready to connect to 12 V DC power
1.25 inch diameter aluminum trusses, strong and lightweight, they are connected in pairs at their top ends for faster and easier installation.
Aluminum handles, lightweight with 8" pneumatic wheels
Wooden box for storing and protecting the mirror when not in use.
Light shroud made from quality non-transparent material stretchable.
Baltic birch cabinet grade hardwood used - stained and varnished several times.
Four big handles installed on the mirror box for easy two-person lifting of the mirror box.
The telescope is optically and mechanically excellent. It holds the collimation without any problems all night - once you collimate the scope - it is collimated till the end of observing. Very easy to collimate. It takes maximum 5 minutes total time.
Mirror cell is with 18 points supporting without problem the mirror. No fancy things placed bellow the mirror to act like a mirror cell reinforced with some scientific theories to make you think that the mirror is supported properly. Mirror cell is all steel in order to be strong and not deformed under the weight of the mirror.
Mirror is held by steel cable with adjustable length (again no fancy mirror supports coupled with some scientific theories) - very easy to place the cable around the mirror and also very easy to center the mirror inside the mirror box simply with adjusting the length of the cable sling - you just tighten the cable sling and as soon as the mirror touch the top mirror pin that means it is centered in the mirror box. Everything is adjusted by me - no need for you to adjust anything. Adjusting the cable length is very easy with turnbuckle. Also cable sling can be adjusted in height for proper support of the mirror.
All above mentioned adjustment and all work in the mirror box: positioning and centering the mirror, attaching and adjusting the sling around the mirror, tightening the mirror pins and clips and whatever else can be done by hand and very easy without effort and frustration, no tools required. Everything is with knobs. All above mentioned adjustments are even easier now with this latest design because the mirror box is completely open from top making everything inside the box accesible and easy to work. Once you collimate the scope there is no need to check and do it again, it is collimated till the end of the observing.
Fine 24 TPI (threads per inch) collimation rods and big 3.25 diameter collimation knobs make the colimation very easy.
The telescope is designed to perfection - it is with classic design, but lightweight and portable at the same time - making it easy to load, transport, unload, move around and set up. Also the bearings are detachable which allows the whole scope when disassembled to fit probably even in a bigger car to transport it to dark location for observing. Excellent design allowed the mirror box to be only 6 inches tall and rocker box to be only 5 inches tall. Pictures do not tell everything - you need to see the design to believe it.
Moving the scope in altitude and azimuth is very smooth and precise and requires very little force. Big bearings make the movement even smoother and easier and allow very precise positioning on the target.
The telescope has perfect balance. You can load the telescope on its top side with heavy Paracorr2 and heavy Nagler31 and 4-channel dew controller with three dew heaters and 9x50 finderscope and it will still hold its balance with no counterweights needed to be attached at the bottom. Or you can go in other extreme situation - use on top side only small light eyepiece and 9x50 finderscope and on bottom side hang a heavy battery 12 V 12 AH at the back side of the mirror box and still the telescope will hold its balance with no counterweights needed to be attached at the top. And the telescope will hold its balance even if you tilt it completely at the maximum tilt, which is 82 degrees. Moving the scope is smooth and easy and you can move them up-down and left-right with one finger.
Compare the sizes, the heights of the mirror box, rocker box and the base and their weight with the classic Dobsonian designs of the other manufacturers.
Compare all above mentioned with other manufacturers. Quality optical and mechanical components (quality primary mirror, quality secondary mirror, Feathertouch focuser, strong and 27 point mirror cell, 24 TPI fine threaded collimation rods and big collimation knobs for easy collimation) and so many free extras (secondary dew heater already installed with wires pulled outside with RCA jack ready to be connected to the controller, heavy duty spider and heavy duty holder, off-set of the holder already done, thin primary mirror, lightweight primary mirror, cooling fan with jack ready to be connected, dew controller holder installed on the secondary cage you attach the dew controller with Velcro, interferometer test for secondary mirror, primary mirror center spot for easy collimation, super low profile focuser, detachable bearings, lightweight mirror box and lightweight rocker box.
Every telescope after finishing is tested two or three evenings real observing to ensure that it performs perfectly optically and mechanically and to check that every single component functions properly, and to adjust the optical alignment of the components. No need to disassemble the secondary holder in order to install secondary heater and to attach or glue its wires, no need to drill holes for the much needed dew controller holder, no need to install new bigger and better collimation knobs and new and better collimation bolts, no need to install fan, no need to cut by yourself and adjust the trusses when you receive the scope, no need again to assemble and align the secondary holder and so on. The scope is ready for observing.
Mirror Box + Mirror Cell + Bearings = 30 Kg
Rocker Box + Base = 18 Kg
Trusses = 7 Kg
Secondary Cage = 7 kg
Mirror = 17 Kg
Eyepiece height at zenith = inches = mm
For observing objects up to 45 degrees altitude 1 step of stepladder needed, from 45 to 70 degrees altitude where you will do most of observing two steps of the stepladder needed.
30-31 mm - use without coma corrector for widefield observing of the objects, for scanning the sky and the milky way and for easy finding the objects ( 64 minutes field of view and 77 magnification)
13-14 mm - use with or without coma corrector for close up observing of the galaxies, nebulas and clusters (around 30 minutes field of view and 200x magnification)
Regular Price - 12,000 CAD
Availability - this fall
Thanks for viewing, Zoran
Posted on: 2017-09-06 09:16:59
Last Updated on: 2017-09-06 09:16:59
Contact: Sky Observing   (user details & view my other ads)
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Location: Toronto, ON (view map of area)
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