TELESCOPE BUILDING &
PARTS & INFORMATION
TELESCOPES & ASTRONOMY
CLICK HERE FOR REFRACTOR LENSES
UPDATED 16th April 2013
If you wish to make a telescope yourself we have all parts and
accessories to do the job.
TELESCOPE MAKING BOOKS
(INDEX) A REFLECTING TELESCOPE'S PARTS LIST- Main Mirror
- Secondary/Diagonal Mirror
- Main Mirror Cell (Holder)
- Secondary Mirror Cell (Holder and Spider)
- Focusing Unit
- Dobsonian Mount
- Equatorial Mount
A REFLECTING TELESCOPE'S TOOLS LIST (SUGGESTED)Simple Hand Tools
EQUIPMENT FOR MAKING A TELESCOPE MIRROR (SUGGESTED)- Grinding Materials
- Sagitta gauge (to measure the center depth)
- 8 containers to hold the grinding compounds
- 1 small container to hold the polishing compound
- Spray Bottle for water
- Small clean brush to apply polish
- Towel or similar to wrap the mirror in for protection
- Clean area (highly important for mirror making)
- Barrel or similar (44 Gallon Drum) to grind and polish the mirror on
- Mirror testing Stand
- Access to a sink (not for washing compounds and getting blocked!)
- Bucket to wash mirror's compounds into
- Ronchi (Ron-Key) Tester (to test mirror shape)
- Lots of patience and/or plenty of time
PRICES & PARTS GUIDE LIST
The Build Your Own Telescope (BYOT) kits have changed to enable builders to buy only the components they need. The Complete Instruction Notes can be purchased separately which includes a complete course on all the science, maths and instruction for making the Main Mirror. There are many web sites which have instructions on how to build the rest of the telescope. Here is one of the better ones:
Any parts which you don't want to make can be purchased through us.
Here is a list of an 10", 8" and 6" Dobsonian Telescope parts and prices. Please note the prices are a guide only, although fairly accurate. Other sizes available too.
$110AUD$ of the following components is reuseable as this is the price for the Ronchi Tester, Sagitta gauge and Complete Instruction Notes - if you wish to make more than one telescope. Larger telescopes can be made using the same Ronchi Tester and Complete Instruction Notes with only the Sagitta gauge needing replacement (bigger one $10).
10" Dobsonian Telescope:
-Glass Mirror Blank $99AUD$
-Glass Mirror Tool $90AUD$
-Grinding and Polishing Materials $90AUD$
-Aluminisng of the completed mirror $210AUD$
-Ronchi Tester $60AUD$
-Sagitta gauge $10AUD$
-Primary Mirror Cell $80AUD$
-Secondary Mirror Cell $90AUD$
-Secondary Mirror $80AUD$ to $95AUD$ depending on size once main mirror is complete
-Focuser either $65AUD$ basic, $90AUD$ large, $180AUD$ low profile, $285AUD$ 2" low profile - I'll go through these later if you wish.
-Dobsonian Mount made from standard Weswood from a hardware store. I can send some plans if you like. $20AUD4
-Teflon Bearings $45AUD$
-Finderscope $80AUD$ (Telrad) or Red Dot Finderscope $62
-Complete Instruction Notes including educational parts $40AUD$
8" Dobsonian Telescope:
-Glass Mirror Blank $68AUD$
-Glass Mirror Tool $60AUD$
-Grinding and Polishing Materials $56AUD$
-Aluminisng of the completed mirror $180AUD$
-Ronchi Tester $60AUD$
-Sagitta gauge $10AUD$
-Primary Mirror Cell $65AUD$
-Secondary Mirror Cell $75AUD$
-Secondary Mirror $65AUD$ to $80AUD$ depending on size once main mirror is complete
-Focuser either $65AUD$ basic, $90AUD$ large, $180AUD$ low profile, $285AUD$ 2" low profile - I'll go through these later if you wish.
-Dobsonian Mount made from standard Weswood from a hardware store. I can send some plans if you like. $15AUD$ for the wood.
-Teflon Bearings $35AUD$
-Finderscope $80 (Telrad) or Red Dot Finderscope $62AUD$
-Complete Instruction Notes including educational parts $40AUD$
6" Dobsonian Telescope:
-Glass Mirror Blank $45AUD$
-Glass Mirror Tool $40AUD$
-Grinding and Polishing Materials $42AUD$
-Aluminisng of the completed mirror $130AUD$
-Ronchi Tester $60AUD$
-Sagitta gauge $10AUD$
-Primary Mirror Cell $60AUD$
-Secondary Mirror Cell $70AUD$
-Secondary Mirror $50 to $65AUD$ depending on size once main mirror is complete
-Focuser either $65 basic, $90AUD$ large, $180AUD$ low profile, $285AUD$ 2" low profile - I'll go through these later if you wish.
-Dobsonian Mount made from standard Weswood from a hardware store. I can send some plans if you like. $10AUD$ will pay for the wood.
-Teflon Bearings $30AUD$
-Finderscope $80AUD$ (Telrad) or Red Dot Finderscope $62AUD$
-Complete Instruction Notes including educational parts $40AUD$
The following are variables for the telescope:
-EYEPIECE DEAL - ANY 6 for $180AUD$ (See Above)
-Or single Plossl Eyepieces are $50AUD$ - $60AUD$ each. Generally a telescope has a minimum of 3 eyepieces, low medium and high power.
-High quality eyepieces cost around $130AUD$ to $190AUD$. I can mix and match with the eyepiece deal depending on your budget.
-Solar Film - Black Polymer or Baader, for observing the Sun safely (Eclipses, Sun spots etc.) $45AUD$ per Sq. Ft. (smaller sizes available).
-Moon Filter $30AUD$
Mirrors which are completed with the aluminised or silver coating are available from 1" (25mm)
to 40" (1016mm) diameter and varying focal ratios. There are many different qualities to
suit your budget.
The following Mirrors have an overcoating of Al+SiO2.
Strehl Ratio of better than 0.88
Wave rating of 1/8.
114mm (4.5") Glass f/8 Parabolic Mirror $90AUD
153mm (6") Soda Lime f/5 Parabolic Mirror $215AUD
153mm (6") Soda Lime f/7.8 Parabolic Mirror $215AUD
200mm (8") Soda Lime f/4 Parabolic Mirror $340AUD
200mm (8") BK7 f/4 Parabolic Mirror $360AUD
200mm (8") Pyrex f/4 Parabolic Mirror $375AUD
200mm (8") Soda Lime f/6 Parabolic Mirror $340AUD
200mm (8") BK7 f/6 Parabolic Mirror $360AUD
200mm (8") Pyrex f/6 Parabolic Mirror $375AUD
250mm (10") BK7 f/5 Parabolic Mirror $470AUD
250mm (10") Pyrex f/5 Parabolic Mirror $510AUD
300mm (12") BK7 f/5 Parabolic Mirror $650AUD
300mm (12") Pyrex f/5 Parabolic Mirror $700AUD
The following mirrors have been hand finished and corrected for optimal performance by highly experienced mirror makers. The Aluminium and additional Coatings are also the highest quality.
300mm (12") Glass F/5 Parabolic Mirror $1480AUD
300mm (12") Glass F/6 Parabolic Mirror $1400AUD
350mm (13.7") Glass F/5 Parabolic Mirror $1800AUD
350mm (13.7") Glass F/6 Parabolic Mirror $1700AUD
400mm (15.8") Glass F/5 Parabolic Mirror $1980AUD
450mm (17.7") Glass F/5 Parabolic Mirror $2270AUD
Larger sizes are available.
Telescopes & Astronomy Mirrors Galaxy Optics Mirrors Nova Optics Mirrors Standard Mirrors Plate Glass: Plate Glass is the least expensive material to build a mirror from. The thicker the glass, the less is will bend out of shape if the mirror is to be large. Thinner glass is perfectly well to work with as long as the glass is supported properly in the finished telescope. Thinner glass is less expensive and reduces the overall weight of the telescope. To reduce the cost further, the Tool Glass doesn't have to be as thick as the Mirror Glass. Sizes available: 1" (100mm) to 25" (635mm) diameter. PLATE GLASS 148mm diameter x 8.4mm thick $25AUD 150mm (6") diameter x 25mm (1") thick $50AUD 150mm (6") diameter x 19mm (3/4") thick $45AUD 200mm (8") diameter x 25mm (1") thick $75AUD 200mm (8") diameter x 19mm (3/4") thick $68AUD 254mm (10") diameter x 25mm (1") thick $118AUD 254mm (10") diameter x 19mm (3/4") thick $105AUD 305mm (12") diameter x 25mm (1") thick $162AUD 305mm (12") diameter x 19mm (3/4") thick $145AUD 330mm (13") diameter x 25mm (1") thick $170AUD 330mm (13") diameter x 19mm (3/4") thick $155AUD 457mm (18") diameter x 25mm (1") thick $365AUD 457mm (18") diameter x 19mm (3/4") thick $335AUD 457mm (18") diameter x 16mm (5/8") thick $315AUD 500mm (19.6") diameter x 25mm (1") thick $425AUD 600mm (23.6") diameter x 25mm (1") thick $480AUD SUPRAX GLASS (LOWER EXPANSION THAN PYREX - REALLY GOOD SHINE) 100mm diameter x 23-26mm thick $58AUD 148mm diameter x 24mm thick $65AUD 175mm diameter x 28-31mm thick $125AUD 198mm diameter x 30mm thick $145AUD 250mm diameter x 30mm thick $220AUD Other Materials, Diameters and Thicknesses available, please enquire. Pyrex: Please Note - Dow Corning no longer produce Pyrex. The next best thing to Pyrex in price and Expansion Rate is Borosilicate - see below.
Pyrex has a lower expansion rate than glass. When there is a change of temperature, either by the conditions where the telescope is being used or by the heat generated by the hands while grinding or polishing, pyrex will be less effected. Since Pyrex is harder than glass the grinding and polishing time is longer. Pyrex blank thickness is a ratio of 6:1 which is the theoretical thickness best suited for mirror making. Sizes available: 1" (25mm) to 40" (1016mm) Pre-generated Pyrex: These blanks have the focal ratio curve already made so minimal grinding needs to be done. It also aids in obtaining the correct curve which can be difficult for the beginner mirror maker. The tool supplied is a matching curve. Sizes available: 1" (25mm) to 40" (1016mm) Borosilicate: Next best thing to Pyrex for price and Expansion Rate. See Wiki Entry; Borosilicate Glass Contact us with your specifications for a quote. Fused Silica: Larger diameter mirrors tend to bend under their own weight. Fused silica between thin blanks supports the mirror and also keeps the weight to a minimum. These blanks have the lowest expansion rate and are also the most expensive. Flat surfaces or pregenerted blanks are available. Light Weight: Thin Pyres blanks are available which are less than the recommended theoretical 6:1 ratio thickness. Pyrex Schmidt-Cassegrain: It doesn't take much more to make a Schmidt-Cassegrain mirror. Blanks are supplied with a started hole in the middle eliminating having to drill. The primary mirror is a full parabola and the secondary is a hyperbola. Custom Blanks: Different shapes and sizes are available. Let us know your specifications.
GRINDING AND POLISHING MATERIALSAluminium oxide grinding powder per kilo $40AUD Tin oxide grinding powder per kilo $30AUD Pumice grinding powder per kilo $30AUD 80 Grade grinding powder per 8" mirror $4AUD 120 " " $4AUD 220 " " $6AUD 320 " " $8AUD 500 " " $10AUD 1000 " " $12AUD 1600 " " $12AUD Cerium Oxide " $12AUD Lap resin kit " $25AUD
SECONDARY/DIAGONAL MIRRORSSecondary Mirrors available in all sizes from 15mm to 215mm. All measurements are taken across the narrow diameter (minor axis) of the mirror. CHOOSING THE CORRECT SECONDARY/DIAGONAL SIZE The size of the diagonal is measured by its width across the mirror (minor axis). To work out what size Secondary Mirror is needed for the telescope, things need to be worked out in order. Knowing the diameter of your Main Mirror. Firstly, find the focal length of the completed mirror. Secondly, work out the height of your focusing unit. The focuser needs to be wound out about 25mm (1") (roughly where you expect the focus or eyepiece to be) then take the height measurement. Thirdly, the outside diameter of the telescope tube (where the focuser will go) needs to be measured and halved. Having these measurements, the Secondary Mirror size can now be worked out. Add the height of the focuser to the halved outside diameter of the telescope tube. This gives the distance from the Secondary Mirror to the eyepiece. The formula now used is: Main Mirror diameter divided by Focal length times the distance from the diagonal to the eyepiece. eg. Main Mirror Diameter 200mm (8") Focal Length = 1000mm Height of Focuser = 70mm Outside Diameter of Tube = 230mm divided by 2 (half) = 115mm Total distance from Secondary to Eyepiece = 70mm + 115mm = 185mm Using Formula: eg. 200mm divided by 1000mm times 185mm = 37mm diameter Secondary Mirror. Take note that the diameter of the diagonal across the Minor Axis is about 1mm less due to the glass being beveled Most common Secondary Mirror bought in Bulk 34mm Standard Secondary Mirror, Coated $35AUD Highest Quality Pyrex 1/10 Wave Secondary Mirrors with Enhanced Coatings Commonly kept sizes: 25.4mm (1") dia $55AUD 28mm (1.1") (dia $60AUD 31mm (1.25") dia $65AUD 32mm (1.29") dia $68AUD 33mm (1.33") dia $70AUD 35mm (1.37") dia $75AUD 40mm (1.57") dia $80AUD 42mm (1.65") dia $85AUD 46.5mm (1.83") dia $95AUD 50mm (1.97")") dia $105AUD 50.8mm (2") dia $109AUD 62mm (2.44") dia $160AUD 63mm (2.48") dia $165AUD 65mm (2.56) dia $180AUD 70mm (2.76) dia $220AUD Standard Quality BK7 1/6 Wave Secondary Mirrors with Coating Commonly kept sizes: 23mm (0.91") dia $15AUD 28mm (1.11") dia $35AUD 31mm (1.22") dia $40AUD 41mm (1.62") dia $45AUD 50mm (1.97") dia $50AUD 63mm (2.33") dia $60AUD 70mm (2.29") dia $70AUD
SECONDARY HOLDERS3 Vane Secondary Holder and Spider 6" $70AUD 4 Vane Secondary Holder and Spider 6" $75AUD 3 Vane Secondary Holder and Spider 8" $75AUD 4 Vane Secondary Holder and Spider 8" $80AUD 3 Vane Secondary Holder and Spider 10" $80AUD 3 Vane Secondary Holder and Spider 10" $85AUD 3 Vane Secondary Holder and Spider 12.5" $110AUD 4 Vane Secondary Holder and Spider 12.5" $120AUD 2 Vane straight Secondary Holder straight type over 12.5" start at $90AUD
FINDERSCOPESS/H 60mm Refractor lens, F/11.6, Screw type $30AUD S/H 6x30mm Finderscope mount, 6 screw, 2 screw attach $25AUD S/H 6x30mm Finderscope mount, 3 screw, 2 screw attach $10AUD S/H 5x24mm Finderscope mount, 6 screw, 4 screw dual attach $10AUD S/H Tube tripod legs, Heavy steel, Extendable, 4'6" (115cm) $15AUD
OPF630 Optex 6x30mm Finderscope $95AUD OPF850 Optex 8x50mm Finderscope $130AUD Siebert 10x50mm Finderscope with 90 degree diagonal $285AUD Siebert 6x50mm Red lighted illuminated reticle, 90 degree diagonal, With high eye relief eyepiece $430AUD Siebert 10x50mm Red lighted fibre optic reticle, 90 degree diagonal, With high eye relief eyepiece $490AUD Meade 5x24mm Finderscope and mount $35AUD Pin hole finderscope $5AUD 5x24mm Finderscope mount, 3 screw scope, 2 screw attach $10AUD Tasco 5x24mm Finderscope mount, 3 screw adjust, 2 screw attach $15AUD STFS850 8x50 Black Finder $112AUD STFB850 50mm Dovetail Bracket $74AUD STFS630 6x30 Black Finder $85AUD STFB630 30mm Dovetail Bracket $65AUD STLS LightSight Red Dot $68AUD STLSB Extra Base for LightSight $9AUD Telrad 1x, illuminated reticle bulls eye, Excellent device $82AUD Telrad Dew Shield $28AUD Mounting Base only $18AUD Telrad Pulser $39AUD Telrad Dew Shield+ $42AUD (w/mirror for 90° viewing) Telrad 2” Riser Base $32AUD Telrad 4” Riser Base $32AUD Reticle $8AUD Lens $16AUD Combining Glass (clear or tinted) $12AUD Potentiometer $12AUD Thumb Screw (steel w/plastic knob) $2AUD Thumb Screw (brass) $3AUD
FOCUSING UNITSThere are many types of Focusers available in 32mm (1.25") or 50mm (2") diameters. Heavy duty "Crayford" style Focusers are recommended if the weight of a camera is to be attached to the telescope. The lower the profile of the Focuser, the smaller the secondary mirror. Firstly, smaller mirrors are cheaper and secondly, they create less obstruction to the main mirror giving higher definition (clarity). Reflector Slide 1.25" $40AUS Reflector Rand and Pinion (small) 1.25" $70AUD$ or $43US$ Reflector Rack and Pinion (large) 1.25" $90AUD$ or $54US$ Reflector Rack and Pinion 1.25"/2" $110AUD AstroSystems Phase 1 Low Profile Crayford Type 1.25" Teflon Bearings $150AUD AstroSystems Phase 4 Low Profile Crayford Type 1.25"/2" Steel Bearings $250AUD STNF125 * 2" Newtonian Focuser $112AUD STNF2125 * 2" to 1.25" Newtonian Focuser $134AUD STRF125 * 1.25" Refractor Focuser $118AUD
VARIOUS PARTS8" Single arm, Aluminium, Secondary mirror holder, 2 screw adjust $10AUD 6"x7/8" (153x22mm) Blank and tool $75AUD Secondary mirror, 1.33" (33mm), 1/10 wave, Enhanced coating $75AUD Secondary mirror, 1.83" (46mm), 1/10 wave, Enhanced coating $90AUD 6" Mirror box, Posting etc. $10AUD 6" Mirror cell, Aluminium $40AUD Teflon Bearing Kits suit 8" Dobsonians $45AUD
Teflon Pivot Kits suit Dobsonians $36AUD
ASK US ABOUT OUR CARBON FIBRE TUBES
TUBESAll sizes available. Please specify optics to be used for compatability. Carbon Fibre Tubing is now available for telescope builders. Let us know your requirements including length, diameter and wall thickness and we'll quote. Don't forget your location if a shipping quote is needed.
ALUMINISING AND SILVERINGThe aluminium coating placed onto the surface of the glass returns about 90% reflectivity. The overall reflectivity combined with the secondary mirror drops down to about 80%. Different enhanced coatings brought out by manufacturers can bring this figure back up to around 90%. It is possible to get more reflectivity from a mirror by using silver for the coating. The reflectivity can go up to 95% overall but there are disadvantages. Silvering, although cheaper, is messy to do yourself and will only last up to a year or two. In comparison aluminising will last up to ten years. If you wish to silver your mirror, do it just before you have a big session of observing to get the most out of it before it fades. The following aluminsisng prices include enhanced overcoating for maximum reflectivity. Mirrors, once recoated, need to be sent back to their owners in a mirror box. This prevents the coating from being scratched or rubbed off. We can supply a mirror box if you don't have one, or we can tell you how to make one easily. We also have a refiguring service. Many Chinese telescopes have a spherical shaped mirror instead of a parabolic shaped mirror. The difference in shape isn't much, but the result of the image is, especially using high magnification. Some mirrors are just not accurate enough to produce good images. We can refigure the mirror to the correct shape before adding the new coating. Please inquire. ALUMINISING - please contact us for current pricing. Enhanced, Multi-Coating 4.5" (114mm) 6" (153mm) 8" (200mm) 10" (254mm) 12.5" (318mm) 16" (406mm) 18" (457mm) SILVERING 4.5" (114mm) $60AUD$ or $42US$ 6" (153mm) $75AUD$ or $51US$ 8" (200mm) $90AUD$ or $50US$ 10" (254mm) $110AUD$ or $76US$ 12.5" (318mm) $140AUD$ 16" (406mm) $180AUD$ 18" (457mm) $230AUD$ Please inquire for larger size mirrors.
MOUNTSDECENT MOUNTS FOR ACCURATE TRACKING Having a decent mount for accurate tracking is becoming more popular as they become more affordable. Accurate mounts are used for a number of things including computer guided telescopes, accurate encoder locating (see below) and astrophotography. Of course, you only get what you pay for, although with right know how, many mounts can be improved to greatly increase their accuracy. Once these mounts are improved the Vixen SkySensor 2000 PC can be attached. VIXEN GP-DX One of the best mounts available is the Vixen GP-DX. The mount comes as the 'mount head only' with a tripod or pier needed to complete it. Included with the mount head is slow motion controls, polar alignment scope, bubble level and built in illuminator. The GP-DX can have a dual axis drive added. The mount can handle upto 10kg easily. Vixen SkySensor can be attached to the GP-DX (see below). SKYWATCHER EQ5 There are a few copies of the Vixen GP-DX mounts available. The EQ5 comes complete with tripod. It can have single or double axis motor drive attached. Standard features of the EQ5 include a built-in holder for polar scope, a latitude adjuster with micrometer scale, an azimuth polar-alignment adjuster, slow-motion tracking controls, and a bubble level. The EQ5 can be greatly improved and the best way to do this is to follow the guidelines set out by AstroBoy at his site: http://www.astronomyboy.com/ Once the EQ5 has been improved, the Vixen SkySensor 2000 PC (see below) will work accurately and can be attached without difficulty (bolts straight on). SKYWATCHER HDEQ5MNT This is the heavy-duty version of the EQ5 mount and is a smaller version of the sturdy EQ6 mount. It is able to handle around 12kg. (up to 10" reflector) The HDEQ5MNT includes dual axis drive, built-in polarscope for both North and Southern Hemisphere use, large R.A. and DEC. locking clamps and retractable counterweight shaft and counterweight. The tripod has 1.5"- diameter steel legs. Once again, when the HDEQ5MNT has been improved, the Vixen SkySensor 2000 PC (see below) will work accurately and can be attached without difficulty (bolts straight on). SKYWATCHER EQ6 This is the largest and heaviest mount. This mount can handle a 12.5" Reflector or similar (up to 18kg). Features include built-in polarscope for both North and Southern Hemisphere use, large R.A. and DEC. locking clamps, dual axis drive, and retractable counterweight shaft and counterweight. The field tripod has adjustable height, incorporating 2"-diameter steel tripod legs. Same again, once the EQ6 has been improved, the Vixen SkySensor 2000 PC (see below) will work accurately and can be attached without difficulty (bolts straight on). Further information about the SkySensor and the EQ6 can be seen on this site: http://www.iteastronomy.com//products/accessories/overview.php?p=EQ-6+MOUNT CELESTRON CG5 The Celestron CG5 is basically the same as the EQ5. The CG5 has the Polar Alignment tool as an optional extra. AstroBoy gives the CG5 a full going over on his site: http://www.astronomyboy.com/ Same again, once the CG5 has been improved, the Vixen SkySensor 2000 PC (see below) will work accurately and can be attached without difficulty (bolts straight on). Call or email for further information. CELESTRON CG5 COMPUTERISED MOUNT This is the same mount as the CG5 with computerised GOTO and object database. Celestron has all the specifications on the following page: http://www.celestron.com/prod_pgs/tel/c8sgt.htm CELESTRON CGE COMPUTERISED MOUNT This is Celestron's top of the line mount. I haven't seen one personally yet, although, going by the reviews it is a very good mount indeed. The largest telescope Celestron place on it is the 14" Schmidt-Cassegrain which weighs 20kg (45 pounds). This doesn't include any extra accessories which could be an extra 2kg. The best way to see the specifications is to go straight to Celestron's web page: http://www.celestron.com/prod_pgs/tel/cge_index.htm Any additional information can be obtained from us. VIXEN SKYSENSOR 2000 PC Probably the best update to the GP-DX is encoders (see below) or the Vixen SkySensor 2000 PC. SkySensor enables the telescope to be attached to a PC to use astronomical software (see below also). SkySensor has many features including: - high speed search of objects - 13,942 objects in data base plus 30 additional - remote auto centering - periodic error correction - compatable with any optical tube - automatic tracking of satellites - atmospheric correction Vixen's web site: http://www.vixen-global.com/ Telescopes and Astronomy's Vixen Pages: http://www.telescopes-astronomy.com.au/vixen103.htm 8" Dobsonian mount unassebled, unpainted, with bearings $230AUS 10" Dobsonian mount unassebled, unpainted, with bearings $280AUS
EYEPIECES, BARLOWS ETC.6601 1" (25.4mm)dia. 4mm Huygen $43AUS 6620 " 5mm Huygen $43AUS 6605 " 9mm Huygen $43AUS 6607 " 12.5mm Huygen $43AUS 6608 " 20mm Huygen $43AUS 3514 " 10mm Kellner - Japan $158AUS 3515 " 20mm Kellner - Japan $158AUS 3516 " 25mm Kellner - Japan $158AUS 6610 " 25mm Kellner - Taiwan $68AUS 6602 " 4mm Orthoscopic - Japan $198AUS 3511 " 9mm Orthoscopic - Japan $179AUS 3512 " 12.5mm Orthoscopic - Japan $179AUS 3518 " 25mm Orthoscopic - Japan $224AUS 3671 " Vixen K25mm, " " $132AUS 6631 1.25" (31.7mm)dia. 6.3mm Kellner $85AUS Special 9mm Kellner 1.25" $50AUS Special 25mm Kellner 1.25" $50AUS 6632 " 12.5mm Kellner $85AUS 6633 " 25mm Kellner $85AUS 6636 " 7.5mm Super Plossl $125AUS 6637 " 17mm Super Plossl $125AUS 6633 " 25mm Super Plossl $125AUS OPP4 " 4mm Plossl $69AUS OPP6 " 6mm Plossl $69AUS OPP9 " 9mm Plossl $69AUS OPP15 " 15mm Plossl $79AUS OPP25 " 25mm Plossl $79AUS OPP40 " 40mm Plossl $89AUS 3668 " 18mm Orthoscopic $158AUS 3683 " 25mm Orthoscopic $158AUS VIXEN LV SUPER VIEW 3714 " 2.5mm Lanthanum $264AUS 3715 " 4mm Lanthanum $257AUS 3716 " 5mm Lanthanum $237AUS 3717 " 6mm Lanthanum $224AUS 3864 " 7mm Lanthanum $237AUS 3718 " 9mm Lanthanum $237AUS 3719 " 10mm Lanthanum $224AUS 3865 " 12mm Lanthanum $237AUS 3756 " 15mm Lanthanum $237AUS 3757 " 20mm Lanthanum $264AUS 3758 " 25mm Lanthanum $336AUS 3777 " 8-24mm Lanthanum $336AUS 3759 " 30mm Lanthanum $356AUS 3745 " 50mm Lanthanum $283AUS 3707 " K70mm Lanthanum $290AUS VIXEN LVW SERIES 3856 " 3.5mm Lanthanum - Long eye relief $442AUS 3857 " 5mm Lanthanum - Long eye relief $442AUS 3895 " 8mm Lanthanum - Long eye relief $411AUS 3896 " 13mm Lanthanum - Long eye relief $430AUS 3897 " 17mm Lanthanum - Long eye relief $442AUS 3898 " 22mm Lanthanum - Long eye relief $442AUS 3727 " 42mm Lanthanum - Long eye relief $586AUS 3759 2" (50.8mm) dia. 30mm Lanthanum - Long eye relief $415AUS 3745 " 50mm Lanthanum - Long eye relief $330AUS 3707 " 70mm Kellner - Long eye relief (30.6mm) $330AUS VIXEN PLOSSLS 3625 " 7.3mm Plossl $135 3626 " 9.5mm Plossl $135 3627 " 13mm Plossl $143 3620 " 26mm Plossl $150
PENTAX XL EYEPIECESExtra low dispersion (ED) glass, super multi-coatings, 65 degree apparent field of view, 20mm eye relief. Pentax 5.2mm $CALL Pentax 7.0mm $CALL Pentax 10.5mm $CALL Pentax 14mm $CALL Pentax 21.0mm $CALL Pentax 28.0mm $CALL Pentax 40.0mm $CALL
TELE VUE EYEPIECES- Please inquire 6619 1" (25.4mm) barrel, 1.5x Erecting image tube/lens $30AUS 6621 6-18x Zoom erecting image tube/lens $62AUS 3530 Vixen 25mm dia. 2x Barlow $85AUS 3531 Vixen 25mm dia. 3x Barlow $103AUS 3677 Vixen 32mm dia. 2x Barlow $113AUS 3678 Vixen 32mm dia. 3x Barlow $138AUS 3674 Vixen 32mm dia. 2x Barlow DX $245AUS 3709 Vixen 50.8mm dia. 2x Barlow $390AUS Siebert 1.25" (32mm)7mm, 4 element, coated, 65d FOV., 6mm E.R $130AUS Siebert 1.25" (32mm)12.5mm, 3 element, coated, 65d FOV, 7mm E.R $125AUS Siebert 1.25" (32mm) 18mm, 4 element, coated, 65d FOV, 7mm E.R $125AUS Siebert 1.25" (32mm) 21mm, 3 element, coated, 80d FOV, 7mm E.R $125AUS Siebert 1.25" (32mm) 29mm, 6 element, coated, 52d FOV, 25mm E.R $199AUS Siebert 1.25" (32mm) 32mm, 6 element, coated, 52d FOV, 27mm E.R $199AUS Siebert 1.25" (32mm) 35mm, 6 element, coated, 50d FOV, 27mm E.R $199AUS Siebert 1.25" (32mm) 45mm, 6 element, coated, 42d FOV, 29mm E.R $220AUS Siebert Binoc. viewer, high quality, 2x 21mm SWA Eyepieces free!! $999AUS Siebert 1.5x Barlow for Binoc. viewer, 1.25" (25mm) $442AUS Siebert 1.5x Barlow for Binoc. viewer, 2" (50.8mm) $499AUS Siebert 2" (50.8mm)19mm Wide angle, Coated, 75d FOV, 8mm E.R $335AUS Siebert " 32mm Wide angle, Coated, 67d FOV, 24mm E.R $335AUS Siebert " 35mm Wide angle, Coated, 62d FOV, 26mm E.R $335AUS Siebert " 38mm Wide angle, Coated, 60d FOV, 26mm E.R $335AUS Siebert " 45mm Wide angle, Coated, 57d FOV, 27mm E.R $335AUS Siebert " 51mm Wide angle, Coated, 52d FOV, 27mm E.R $335AUS 6635 25mm to 32mm Diagonal prism eyepiece adaptor $23AUS 6630 25mm to 32mm Eyepiece adaptor $6AUS 6631 32mm to 25mm Eyepiece Adaptor sleeve $2AUS Eyepieces 1" dia., Inexpensive replacements, Huygens, 4,8,12.5mm $10AUS Barlow eyepiece 2x, 1" dia., Inexpensive replacement $10AUS STWA14 * 14mm WA Eyepiece/Adapter (Nikon) $EMAIL STWA18 * 18mm WA Eyepiece/Adapter (Nikon) $EMAIL STZ721 * 1.25" Zoom Eyepiece 7-21mm $EMAIL STMV40 * MaxView 40mm Eyepiece/Adapter $EMAIL STPL04 4mm ST Series Plossl $EMAIL STPL06 6mm ST Series Plossl $EMAIL STPL09 9mm ST Series Plossl $EMAIL STPL15 15mm ST Series Plossl $EMAIL STPL25 25mm ST Series Plossl $EMAIL STPL30 30mm ST Series Plossl $EMAIL STPL40 40mm ST Series Plossl $EMAIL ST2EP26 26mm ST Series 2" Eyepiece $EMAIL ST2EP32 32mm ST Series 2" Eyepiece $EMAIL ST2EP40 40mm ST Series 2" Eyepiece $EMAIL
ASTROSYSTEMS PARTS FOR LARGER TELESCOPESEyepiece Adapter 50mm to 32mm, threaded for 48mm filters $CALL Low eyepiece adaptor 50mm to 32mm, extra 13mm lower $CALL Heavy Duty Spiders $CALL Secondary Holders $CALL Lower Truss Fasteners $CALL Upper Truss Clamps $CALL Pivot Kit $CALL Teflon Bearing Kits $CALL
WHAT'S THE BIG IDEA?The larger a telescope is, the higher the light gathering power, resolution and magnification capabilites. Prices Go Up and Down. Please Call or Email to confirm Price and Availability.
TELESCOPE MIRROR MAKING
WHAT'S INVOLVED WITH MAKING A TELESCOPE MIRROR?The reflecting type telescope mirror can be made at home easily and inexpensively. Making your own mirror also allows the builder to choose their own focal ratio. The finished mirror will, hopefully, be better than the average mirror bought commercially, or with TIME, PRACTISE and PATIENCE, a hell of a lot better than obtained commercially. TIME - The longest and harder part about making a mirror is the polishing and repeated testing of the mirror until a sphere shape is reached. An 8" diameter will take up to 50 hours of polishing which must be completed in no less than 1/2 an hour sessions. PRACTISE - To aquire the final shape (parabola) of the mirror a few minutes of accurate polishing work needs to be done right at the end. PATIENCE - If you're not happy with the final shaping, the mirror is polished a bit more until its returns to the sphere shape and another attempt is made to reach the parabola. Its perfectly ok to fluke it too as long as you started with a sphere.
BUT WHAT AM I ACTUALLY DOING?Rubbing 2 disks of glass together. If you have a look at the "Web Making Ring" link at the bottom of the page you will see a pair of hands working at it. If the top piece of Glass (mirror) overhangs the bottom glass (Tool) by half (center over edge), as the top piece moves around the edge of the bottom piece the top one will wear in the middle and the bottom one will wear on the edge. Eventually one will become concaved and the other will be convexed. Depending on what type of stroke is used between the 2 pieces of glass, determines where the glass is removed for us to obtain a sphere. There are only 3 general strokes used. BUILDING TIP: Many keen telescope builders make a 6" or 8" first off. This is excellent practise for making a larger mirror.Don't try to make your secondary mirror, its not worth the time effort and expense. STARTING THE PROCESS OF GRINDING MIRROR: First things first! As the mirror is ground and then polished we use finer compounds. This means once the first grade of compound is finished with, the whole area and mirror needs to be cleaned, throughly, so none of the first grade contaminates next finer grade and causes a scratch larger and deeper. The cleanup it done after each grade. When it comes to the final process of polishing, its important that nothing contamintes the process. The smallest particle of dirt, grinding compound or even dust can cause a scratch or put a sleek on the mirror surface. If its a nasty, deep, large scratch or sleek, going back to fine grinding (1600) will need to done to remove the scratch. The mirror will have to be polished again. Don't take the chance with cleanliness, as it will result in heart ache and time.
GRINDING AND POLISHING MATERIALSAluminium oxide grinding powder per kilo $40AUS Tin oxide grinding powder per kilo $30AUS Pumice grinding powder per kilo $30AUS 80 Grade grinding powder per 8" mirror $2AUS 120 " " $2AUS 220 " " $3AUS 320 " " $4AUS 500 " " $6AUS 1000 " " $8AUS 1600 " " $8AUS Cerium Oxide " $8AUS Lap resin kit " $15AUS
RESIN LAP PREPARATIONFor polishing the tool is replaced by the Resin Lap. Tropical Lap This lap was initially introduced by Dr. C. Tenukest at the Optical Department of the University of New South Wales. We have uesed it for many years and find it superior to most pure pitch laps. Use good ventilation when preparing resin. Using an old saucepan or similar, on low heat, gently heat and stir all of the resin until fully melted. Add all of the woodflour (not necessarily needed, makes up the bulk) and mix in thoroughly. Mix in Castor Oil, 30ml (8" diameter lap) to start with, and progressively test the hardness of the mix before pouring the lap. A bottle top or bottom of drink can is ideal for pouring a test sample. The thumb nail test over about 30 seconds should produce an indentation with slight raising of the surrounding area. If the lap is too hard, add more Castor Oil and gently melt and stir the mix for a few more minutes. Make sure it is mixed properly. Make sure the mix is liquid enough so it doesn't solidify while being poured onto the Tool. A thickness of around 5 or 8mm is fine. Two thicknesses of paper will be enough, as a wall around the Tool, to stop it running over the side. Once the lap is cooled, the paper can be torn off. Looking After Your Lap The lap needs a series of channels running horizontal and vertical impressed or cut into it. These channels hold the polishing paste while polishing and also help cut into the mirror for faster polishing. The channels need to be offset from the center of the tool as this will cause a repetative polishing action in the very center of the mirror. Polishing has to be evenly random all over. The lap resin needs to be warm before any manipulation can be done. This can be done by sitting the tool and resin in hot water for several minutes. The channels can be made by different methods. Firstly, cutting "V" shaped channels with a knife. Secondly, using a flat peice of metal around 3mm thick to press the channel lines one at a time. Thirdly, using a grid, made of plastic, rubber or Nylon, press the lines into the lap resin by placing the mirror face down, sandwiching the grid. Weight can be added. It's important to coat the grid, lap resin and mirror with polishing paste so they don't stick together.
Channels cut into the lap resin
TELESCOPE MIRROR POLISHINGTURNED DOWN EDGE One of the bigget errors encountered by the telescope mirror maker is the Turned Down Edge Usually this is caused by the stroke being too long. Short strokes with 1/4 to 1/8 overhang (that's 2" to 1" overhang on an 8" diameter mirror), will fix this and also many other defects in the mirror's shape. Since the Turned Down Edge defect is such a small area, (just round the outer edge) compared to the rest of the mirror, it is hard and time consuming to correct since the rest of the mirror now needs to be lowered to the Turned Down Edges level. A Turned Down Edge cannot be seen with the eye since it is very minutely different in shape. Correction is slow and requires short strokes and a hard Resin Lap which is trimmed around the edge to be less diameter than the mirror. Other problems causing the Turned Down Edge are the Lap Resin being to soft or thick. This causes the edge of the mirror to plough into it. HOLE IN THE MIDDLE A Central Hole in the middle of the mirror can be corrected by using shorter, narrower strokes. A second way is to place Wax Paper, cut out in the shape of a star and the same diameter as the hole. Cold Press the wax paper star until it leaves an indent in the middle of the Lap Resin. The mirror will not rub on this part of the Lap Resin for a while getting rid of the hole. EDGE NOT POLISHING OUT The mirror's polish process starts in the middle and makes its way to the outside edge. This becomes slower and slower and the very edge seems to take forever compared to the rapid rate of polishing the middle. This of course is because of the area becoming polished getting larger and larger. Somtimes the edge just doesn't want to polish out at all. If this occurs, try turning the mirror upside down with the lap on top and polishing that way for a while. POLISHING WITH THE LAP ON TOP If an error just won't dissappear, turning the process upside down with the lap on top will usually give results especially if you've reached a stale mate with the mirror on top. BUILDING: The size of the diagonal is measured by its width across the mirror (minor axis). To work out what size Secondary Mirror is needed for the telescope, things need to be worked out in order. Knowing the diameter of your Main Mirror. Firstly, find the focal length of the completed mirror. Secondly, work out the height of your focusing unit. The focuser needs to be wound out about 25mm (1") (roughly where you expect the focus or eyepiece to be) then take the height measurement. Thirdly, the outside diameter of the telescope tube (where the focuser will go) needs to be measured and halved. Having these measurements, the Secondary Mirror size can now be worked out. Add the height of the focuser to the halved outside diameter of the telescope tube. This gives the distance from the Secondary Mirror to the eyepiece. The formula now used is: Main Mirror diameter divided by Focal length times the distance from the diagonal to the eyepiece. eg. Main Mirror Diameter 200mm (8") Focal Length = 1000mm Height of Focuser = 70mm Outside Diameter of Tube = 230mm divided by 2 (half) = 115mm Total distance from Secondary to Eyepiece = 70mm + 115mm = 185mm Using Formula: eg. 200mm divided by 1000mm times 185mm = 37mm diameter Secondary Mirror. BUILDING: The lower the profile of the Focuser, the smaller the secondary mirror. Firstly, smaller mirrors are cheaper and secondly, they create less obstruction to the main mirror giving higher definition (clarity). BUILDING TIP: "How do I work out the distances of the optics inside the tube?" Install the Main Mirror Last. Firstly, work out the Focal Length of the completed mirror. Secondly, install the Secondary Mirror and Focuser to the tube. Thirdly, work out the distance from the Secondary Mirror to the Eyepiece (see Secondary Mirrors below). Fourthly, take the distance of the Secondary Mirror to the Eyepiece away from the Focal Length of the Main Mirror. This figure is the distance the Main Mirror should be from the Secondary Mirror. Finally, install the main mirror the correct distance from the Secondary Mirror and cut the excess of the tube off. BUILDING TIP: Keep the Secondary Mirror covered, once its installed, until the telescope is ready to be used. BUILDING TIP: - with the tube standing vertical, Secondary Mirror end up, make a block the correct length so that the Main Mirror, connected the Main Mirror Cell, sits in the correct position where it is to be attached. As long as the tube end is square (and the block) the mirror will be attached squarely. - you may want to remove the Main Mirror before cutting the end off so no saw dust etc. goes onto the mirror. BUILDING TIPS: - To align a finderscope, find an image in the telescope first with fairly high magnification then adjust the Finderscope to match. Finderscopes are much easier to align in the day time. - Smaller Finderscopes with a single arm stay in position better when some tape is placed over the arm and Finderscope together.
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