Hadley Instructions v1.pdf

114 "HADLEY" REFLECTING TELESCOPE Assembly and use guide Jonathan "Maff" Kissner Rob Davidoff SECTION LIST 1. Parts to Buy Appendices 2. Parts to Print A. Eyepieces in Detail 3. Preparing to Build B. Telescope Mounts 4. Lower Tube Assembly...

114 "HADLEY" REFLECTING TELESCOPE Assembly and use guide Jonathan "Maff" Kissner Rob Davidoff SECTION LIST 1. Parts to Buy Appendices 2. Parts to Print A. Eyepieces in Detail 3. Preparing to Build B. Telescope Mounts 4. Lower Tube Assembly C. Mirror Testing and Performance 5. Middle Tube Assembly 6. Secondary Mirror Cell 7. Upper Tube Assembly 8. Optical Tube Assembly 9. Initial Setup and Calibration PART 1: PARTS TO BUY  1.1: MIRRORS AND EYEPIECES Optics – you need a mirror pair, and eyepieces: Hadley only accepts 1.25" eyepieces (for reasoning, see wiki for details) Mirrors — the primary/secondary set is commonly found on Amazon, eBay, and AliExpress. Low power  Look for a "d114/f900mm" set that includes a 25mm elliptical flat + spherical primary  Typical price approximately $30 USD. Eyepieces — come standard in 1.25" and 2", listed by focal length (mm). Shorter focal lengths provide higher magnification, but a smaller view of the sky. It pays to have at least one "high" and "low" power. See Appendix A. High power Low Power: 25mm plossl (better & sharper view) OR 23mm aspheric (~$5 to 10 USD cheaper, slight blur) High Power: "66°/68° UWA" or "TMB Planetary" in 6mm or 9mm. (AVOID short focal lengths of plossl and aspheric, as at short lengths these distort light badly) 1.2: PARTS LIST: BOLTS AND SCREWS  Screws:  #10-24, ½" long machine screw All hardware is in #10 (any head) - 50x (imperial). There are metric remixes; these instructions still apply  #10-24, 3/4" long machine screw (any otherwise. head) - 8x Quantities are matched to typical box  #10-24, 2" long machine screw (any quantities for some commonly-used head) - 4x sizes to ensure margin for loss and excess for modifications or mounts.  #10-24, 1" long (OR LONGER) Screws should all be fully threaded. machine screw (ideally, thumb head) - 3x  #10-24 nuts - 50x  Optional/recommended: #10-24, ½" long thumb screws  #10-24 nuts (nylon locknuts) - 3x (ideally, NYLON)  Spring, diameter able to fit over 10- –2x minimum, up to 4x 24 screw, 0.75" to 1" or 20-25mm -4x 1.3: RODS OR TUBES  "Hadley 114" is built using three main  Outer diameter needs relatively tight rods, which should be ½" in diameter tolerance to slide printed parts on and ideally 36" long  If buying rod or tube from a hardware  Excess rod length is acceptable, with store or other in-person location, it is a practical minimum of ~33" (850mm) recommended to bring a test fit part (see 2.3.1) to check fit of rods with  The intended material is aluminum printed parts solid rod, but aluminum tube (2mm wall, ½" outer diameter), steel rod or  NOTE: ½" EMT conduit pipe tube, carbon fiber tube, and even is actually 0.706" outer diameter, wooden dowels have been used in and thus cannot be used with this builds by community members project's standard models. Adjusted and remixed CAD (not currently available) would be required.  1.4: ADHESIVE FOR MIRROR ATTACHMENT  Attaching the mirrors to the telescope Any silicone-based adhesive should requires an adhesive which cures work well for this, as silicone adhesive "soft" - superglue or epoxy, for cures "soft" and bonds excellently to instance, will pull the mirror out of both glass and plastic. shape (on a microscopic scale). This worsens the image. Examples of silicone adhesives:  The mirror is also susceptible  Loctite clear silicone to thermal expansion, further  RTV silicone glue necessitating the glue cure "soft."  Silicone caulk  Silicone aquarium sealant PART 2: PARTS TO PRINT 2.1: PART PRINTING GENERAL  This section lists the parts which need to  Do not scale the prints excessively. With be printed to assemble a Hadley 114 proper print settings, scaling shouldn't be telescope required, and scaling more than 1-2% can cause issues with fit of purchased parts  Parts marked "BLACKOUT" should be like eyepieces and nuts printed black if available, other parts may be printed in any color desired (see Part 3  Recommended print settings: for further discussion of blackening)  30% cubic infill  The design allows printing without  4 perimeters (0.4mm nozzle) OR supports for most materials on common 3 perimeters (0.6mm nozzle) machines  Whatever layer height makes you happy & works with your nozzle  Telescope prints excellently in PLA, and has been printed successfully in PETG and ABS, though those materials have their own challenges (temperature control and dimensional accuracy) Note: The way to stronger prints is "more perimeters" rather than higher infill. 2.2: TEST PRINT & ANALYSIS  Test print shown can be used as a quick  If fit is poor, check for over-extrusion in check of rods acquired from a store or print settings, or "elephant's foot" in vendor before printing all parts initial layers of print which can be adjusted in settings or fixed by  Rod should fit smoothly into large hole sanding/filing the lip of the hole with some slack, gap of 0.5 to 1mm  Also check a #10-24 nut and screw fit pocket and through-hole respectively  With screw tightened into nut, test print should lock in place on rod https://commons.wikimedia.org/wiki/File:3D _printing_calibration_elephant_foot.svg 2.3.1: PRINTED PART LIST  Sights (lower and upper): Orientation  Bearings: These are mirrors of each other; matters, pay mind so sight needles print the combined file, or individually. Just are not floating on your printbed. don't print the same one twice! These carry the weight of the whole telescope, so print with extra perimeters for strength! In my prints, I use 5 walls with a  Mirror Cell: Note that a pre-made 0.6mm nozzle. STL includes both sights and the cell. 2.3.2: PRINTED PART LIST  Lower Tube Assembly (LTA) Housing  Upper Tube Assembly (UTA) Housing  The three on this page are the parts you want interior-blackened  Middle Tube Assembly (MTA) Ring  2.3.3: PRINTED PART LIST (BLACK)  Focuser Base  Secondary mirror holder: print this part with thick walls as well. It is subject to a lot of stresses  Focuser Screw/drawtube: The focuser base and tube are challenging prints, make sure your printer is up for accuracy on the threads to ensure they screw together. Consider a finer layer height BLACKOUT: These parts should all be printed in black filament! Glossy is acceptable, matte is slightly preferable  2.3.4: PRINTED PART LIST  Baffle: if you have an i3 ("bed-slinger")  Knobs (print three of these), OR you may printer, be sure to orient this Parallel to purchase #10-24 wing nuts, thumb nuts or the y-axis motion. Your bed adhesion through-knobs instead needs to be good for this piece  These prints have a "sacrificial" layer for  This part can be colored, but the clean bridging above a hexagonal cavity inside face needs to be black  During assembly, you will "punch through" this layer with a screw  2.3.5: PRINTED SPIDER  Spider (PICK ONE) There are several to choose from. The spider selected changes how stars will appear (see below). This effect is minor for planets and the moon, and spiders can be interchanged on Hadley 114  This guide will use the single-curved shown at right  Unless you choose a slot-in remix, you need to add a "pause print" in your slicer application, at the top of the hexagonal cavities  After pause, insert nut and ensure it is flush with the layer. Resume print and monitor for adhesion for next several layers 2.4: OPTIONAL ADDITIONAL PARTS  Mirror covers — Covers useful to  Single or Double Dovetail — These are protect mirrors from dust and damage standardized mounting brackets to add in storage, available in Hadley Remixes accessories like finder-scopes and red dot on Printables. Solid is for primary, sights available in Hadley Remixes on holed is for over spider end of scope Printables 2.5: PRINT COMPLETE  Congratulations! You have now printed all the parts required for a Hadley 114 telescope.  A little more preparation is required for light control, then you are ready to begin assembly. PART 3: PREPARING TO BUILD 3.1: PREPARING TO BUILD  Before beginning assembly, a few  Second is a process called steps are recommended to streamline "blackening," involving coloring the assembly process and to provide certain parts partially black if not optimal results already printed in black.  First, use one of the purchased rods,  The reasoning is explained on and validate all printed holes of size to the next slide, but in short, blackening take the rods (three each in LTA improves telescope function in housing, UTA housing, and MTA ring) conditions with ambient light will fit the rods smoothly. Adjust any that do not  This can be left for later, but is easiest to do before beginning assembly, as it avoids excessive disassembly later 3.2: OPEN TRUSS TELESCOPES AND LIGHT Hadley is an open-truss telescope, lacking a full tube to save on prints & simplify assembly. This works as most light (green at left) passes through the tube without reaching the eyepiece. Any extra light entering the eyepiece (red, blue lines) worsens contrast in your view. Direct paths (blue) are blocked by design of UTA & baffle. Stray light reflecting off the interior like the red path in the top diagram can be an issue if observing with lots of ambient light (streetlights, a neighbor's porch light, etc). Blackened interiors help – see next slide. Pink path is not prevented, though minimal, but can be minimized by using a darker observing site and maximizing contrast between ambient light and the target. An additional baffle design may be added in modifications.  3.3: WHICH PARTS TO BLACKEN These parts are best printed in black (matte These parts may be printed in any color, but is preferred, though glossy is acceptable) or should be blackened as shown on the next fully blackened on all surfaces: slide for best results:  Focuser drawtube (interior)  Upper Tube Assembly (UTA) Housing  Secondary holder  Lower Tube Assembly (LTA) Housing  Spider of choice  Middle Tube Assembly (MTA) Ring  Light baffle  Light baffle (if desired to match color of upper tube assembly exterior)  Primary mirror holder If the parts from the first list are printed black, Hadley will function if only some or even none of the second list are blackened, but the telescope will be more sensitive to stray light particularly in daytime observing. If required, blackening can be done as a later modification for all critical parts. THIS IS A MODULAR TELESCOPE, YOU CAN ALWAYS FIX OR SWAP THINGS LATER  3.4: BLACKENING THE PARTS  The parts shown below should have the interior For baffle, choice of printing in black, fully surfaces blackened with a brush and ink or paint, or blackening all surfaces, or printing in color and masked & sprayed with black spray paint blackening inside  Printing in black (whether matte or glossy) is an Baffle is the second most critical part to acceptable substitute if you don't want a colored exterior blacken, even before MTA or LTA  Single most important part to blacken is the UTA Middle Tube Assembly Lower Tube Upper Tube Assembly Assembly 3.5: PREPARATIONS COMPLETE  Congratulations! With the parts listed on the previous slides, you should now have everything required to assemble the tube for a Hadley 114 telescope!  The next section will begin walking through the assembly sequence  Hadley 114 is a modular telescope, so can be assembled several possible sequences. This is not the only possible order, but it is designed to leave the mirrors (the most delicate parts) to last for safety. PART 4: LOWER TUBE ASSEMBLY  4.1: LOWER TUBE ASSEMBLY SEQUENCE  Parts required for this are listed below  When complete, this produces the "Lower Tube Assembly" which will support the primary mirror and attach it to the three main rods Primary (3x) Collimation Mirror Cell Knobs LTA Housing (3x) #10-24 Nuts (3x) Springs (3x) #10-24 Locknuts (3x) #10-24 Screws, 2-Inch  4.2: PREPARING PRIMARY MIRROR CELL Blackening of the primary cell is not critical, the Insert three nylon lock-nuts to the cell. mirror covers most of this piece. (Note gasket orientation—rounded side with gasket down) Blackening the outer ring is sufficient If you don't have locknuts, see appendix.  4.3: PREPARING THE PRIMARY KNOBS Find the three knobs, insert one standard nut into the Find lower tube assembly hexagonal pocket, then screw one of the long (2"+) machine screws through each knob Seat knobs Don't tighten the screws fully, leave space as shown. They should fit freely 3x  4.4: ASSEMBLE PRIMARY COLLIMATION CELL Slide a spring over the three loose Push the cell down over the springs, and tighten screws (spring should fit freely) the screws into the nyloc nuts using a matching screwdriver or allen key Carefully position mirror cell over the three screws Just a few turns should seat each screw into the nut  4.5: FINISH PRIMARY COLLIMATION CELL Once all three screws are seated, tighten Test the knobs turn freely, and clear the holes in the each bolt further LTA for the rods Ensure ends of bolt remain below the level of Note adjusting the knobs compresses the screws, the end of the nut—it is acceptable if the bolt adjusting mirror position in/out and angle is several threads below the end of the nut Precise setting of the knobs is not critical at this time, and will be handled in collimation Lower Tube Assembly is now complete, and can be set aside until final assembly begins PART 5: MIDDLE TUBE ASSEMBLY  5.1: MIDDLE TUBE ASSEMBLY START  Middle Tube Assembly, also known as the  If a tripod mount is being used as an interim "mid-ring" or the "altitude bearing," solution, consult appendix for discussion of provides a mounting spot for the two how to supplement or replace the MTA with bearing wheels which allow it to turn on a a tripod mount mount  Completed Middle Tube Assembly:  Uses components listed below (8x) #10-24 Screw ¾" Long Left & Right (8x) #10-24 Nut Crescent Bearing Middle Tube Assembly Ring  5.2: MIDDLE TUBE ASSEMBLY Test fit crescent bearings to the sides of the Middle Tube Assembly ring Note the curved surfaces, make sure the fit is perfect and the bearings are in the right orientation. Bearings should be flush Note absent "chamfer" & align as shown Flat side of ring from printing 5.3: MIDDLE TUBE ASSEMBLY Insert nuts into each of the outer four Insert medium-length (¾"+) screw to matching nut pockets on the two bearing holes through bearing (note orientation) mounting pads (8 total) Tighten all four on each bearing first loosely to Center of pattern is for attaching engage nuts & hold bearing in place, then tighten accessories if desired (see appendix) fully until bearings are attached firmly 5.4: MIDDLE TUBE ASSEMBLY COMPLETE  Middle Tube Assembly is now complete and can be set aside until final assembly PART 6: SECONDARY MIRROR CELL 6.1: SECONDARY MIRROR CELL  The secondary mirror cell consists of:  Secondary Mirror Cell Parts List: (1x) 2" Long 1. Secondary mirror holder—supports #10-24 Screw the secondary mirror at an angle (3x) #10-24 Screw, At 2. Spider—holds the Least Length 1 ¼" collimation assembly and mirror in (Ideally Thumbscrew) the middle of the telescope (1x) Spring 3. Collimation assembly—bolts used Secondary for controlling the position of the Selected Spider Mirror Holder secondary holder (1x) #10-24 Nut  6.2: SECONDARY COLLIMATION CELL Take 2" screw and one standard #10-24 nut. Drop spring over the screw. Thread nut over screw until nut is jammed against Find the spider and place center hole of spider head of screw. over end of screw, ensuring spring remains between spider and secondary holder Insert screw and nut through secondary holder. 6.3: SECONDARY COLLIMATION CELL Twist a nut over the exposed screw Pushing on screw or secondary holder should allow slack to tighten nut and adjust position of Ensure it sits into the hexagonal cavity secondary. in the spider. Cavity is larger than nut, and nut should be free to wiggle Adjust nut enough to tension spring, fine without spinning adjustment of position will be carried out later.  6.4: SECONDARY COLLIMATION CELL Add three secondary collimation bolts. Screw partway through the spider Long thumbscrews or socket head screws Leave a gap between screws and the are ideal, but any long enough screw works. secondary mirror holder for now Note Gap 6.5: SECONDARY MIRROR CELL COMPLETE  Assembly of secondary mirror cell is now complete, and it can be set aside until final assembly  Gluing of mirrors and collimation process will be discussed after major assembly is complete PART 7: UPPER TUBE ASSEMBLY 7.1: UPPER TUBE ASSEMBLY  Upper tube assembly attaches the  This will show the basic printed helical spider to the rods, and contains the focuser. Some additional focuser options focuser, which is where eyepieces are discussed in appendix which require will be mounted and allows slightly different assembly adjustment of the focus of telescope (6x) #10-24 Nuts Focuser Base Focuser Tube (4x) #10-24 Screws, ½" (2x) #10-24 Thumbscrews Upper Tube Assembly Housing 7.2: UPPER TUBE ASSEMBLY Locate Upper Tube Assembly Locate focuser base Insert 4 nuts into the four pockets shown Assemble to Upper Tube Assembly and attach with four screws (medium length, ¾") through nuts 7.3: FOCUSER ASSEMBLY Insert a nut into pocket on focuser base, Insert a nut into one of three pockets on then insert ½" screw (ideally nylon focuser wheel, then insert ½" screw thumb screw) into nut from outside (ideally nylon thumb screw) into nut base as shown from outside base as shown Additional spots are for extra nuts & screws if desired and are discussed later. They can be inserted later with same procedure if desired. For now, leave off. 7.4: COMPLETING UTA ASSEMBLY  Screw focuser handwheel into focuser base. Precise positioning does not matter at this point in assembly.  Upper Tube Assembly is now complete, completing all major sub- assemblies. You are now ready to assemble the main Optical Tube Assembly from the sub-assemblies and remaining parts! PART 8: OPTICAL TUBE ASSEMBLY 8.1: PARTS NEEDED All finished sub-assemblies & all remaining prints (18x )#10-24 Nuts (18x) #10-24 screws, ½" Mirror Pair Set (3x) Aluminum or Steel Rod/Tube  8.2: ATTACHING LTA TO RODS  Gather the UTA, MTA, and LTA and  Insert three rods into holes on LTA, allowing Three (3) ½" Rods or Tubes. (If using enough excess to be longer than collimation metric, 12mm rods.) bolts. Measure excess to have same amount of excess on each rod. Middle Tube Assembly Upper Tube Assembly Lower Tube Assembly 8.3: LTA NUTS & BOLTS  Insert six nuts into pockets on rods as shown (two pockets per rod) Inert six short (½") screw into each nut/pocket  Tighten this set screw against rod until tube will not slide up and down. Use care not to over- tighten. Excessive pressure can crack printed parts.  Cracked parts may still be usable, especially if only one pocket per ring is cracked, but are to be avoided if possible. 8.4: MIDDLE TUBE ASSEMBLY & LOWER SIGHT  Slide MTA onto rods, positioning  Locate lower sight and slide onto one roughly at middle. (Precise position rod as shown. will be set later in balancing.)  Attach to rod with one nut and one  Attach to rods with three nuts and short (½") screw. Precise positioning three short (½") screws in pockets as will be set later. show, similar to with LTA.  8.5: BAFFLE & UTA  Slide baffle onto indicated rod, note position  If alternate orientation of UTA and focuser is opposite focuser hole in UTA. Attach with one nut desired, move baffle and UTA to alternate in pocket and one short (½") screw as shown. arrangements as shown later in presentation.  Slide UTA onto rods, aligned as shown relative  Slide upper printed sight onto same rod as to baffle. Attach with three nuts and three screws lower printed sight, and attach with one nut as shown. Positioning will not need to be precise and one short (½") screw. and will be set in focusing later. Leave gap between UTA & baffle for now.  8.6: MIRROR GLUING—PRIMARY MIRROR  Place three dots of glue (~¼") on pads as  If possible, have a second person hold shown. the telescope, reach up through the primary cell, and use your other hand to lower the  Carefully lower mirror onto cell. mirror onto the first hand.  Be very careful to never touch the reflecting surface of the mirror. Clean rubber/latex gloves may be useful. 8.7: MIRROR GLUING—SECONDARY MIRROR  Apply silicone adhesive to surface of secondary holder. Use a small blob (roughly 5mm in diameter) and spread across surface.  Holding secondary mirror by edge, press into adhesive on holder for a few seconds.  Avoid touching mirror surface as much as possible. Clean latex/rubber gloves may be useful.  Leave aside for several hours to cure – prop it so the mirror is facing upwards. 8.8: MOUNTING SPIDER TO UTA  After mirror adhesive has been  Pocket positions will only allow allowed time to cure (1-2 hours) insert one orientation. spider and secondary mirror assembly into Upper Tube Assembly  Attach with 3 nuts in pockets and three short (½") screws. 8.9: OPTICAL TUBE ASSEMBLY COMPLETE Congratulations! With assembly complete, you now have a telescope! Before it becomes a "useful" telescope, we need to align the mirrors and reach focus. This will be covered next. PART 9: INITIAL SETUP AND CALIBRATION 9.1: COLLIMATION PROCESS  In a reflecting telescope, "collimation" Secondary light cone (green) does not is the term for aligning the mirrors to properly point at primary properly point light into the eyepiece Primary light cone (red) is not pointed parallel to axis of tube  Hadley is forgiving of small errors in Light reflected to eyepiece off-center collimation, so it can be adjusted by eye if needed  If additional precision is desired, some useful tools for collimation (including Collimated telescope: one which can be printed) are Secondary now properly pointed at primary explained on the next slides Primary light cone parallel to axis of tube 9.2.1: COLLIMATION TOOL—COLLIMATION CAP  A collimation cap is an eyepiece with a small pinhole to look through and a reflective inner surface  Eyepiece restricts the view when collimating, ensuring repeatable alignment of your eye and the mirrors of the telescope, while inner surface helps with finding center of secondary when looking through eyepiece  With added features, becomes a Cheshire Eyepiece, seen on next slide 9.2.2: COLLIMATION TOOL—CHESHIRE EYEPIECE  As with a collimation cap, Cheshire collimation eyepiece (right) has a small hole which ensures repeatable positioning of your eye relative to the telescope to judge alignment  Angled portion can be lit from the side with a flashlight, creating a bright area around the center spot much like with a collimation cap  This is visible when looking into eyepiece for collimation, and helps locate secondary and primary  Useful to have and easy to print, & file available on Printables (https://www.printables.com/model/256728-cheshire- collimation-eyepiece-for-reflector-telesc) 9.2.3: COLLIMATION TOOL—LASER COLLIMATOR  A laser collimator replaces looking down the eyepiece with a laser projecting a spot through the focuser, bouncing off the secondary, and onto the primary.  Looking at the spot allows adjusting the bolts for collimation to center the spot on the primary mirror while looking at effects without also having to be looking through the eyepiece  Laser collimation is more useful with telescopes requiring more sensitive collimation, and is overkill for Hadley. 9.3: SECONDARY MIRROR ALIGNMENT  Adjustment of the secondary mirror is carried out with the collimation bolts on the secondary mirror/spider assembly.  Adjust the secondary mirror height by turning secondary holder to adjust the length of the center collimation bolt, compressing or releasing the spring  Adjust the angle of the mirror by using any two of the three outer collimation bolts to press on the mirror and "tip" It slightly on the center bolt  Note how a small difference between the outer bolt distances makes for a large change in angle (+/-6 degrees in images at right) 9.4: SECONDARY MIRROR HEIGHT & ROTATION  Start by ensuring the secondary  Next, align the secondary mirror to mirror is aligned properly vertically. aim into the eyepiece. Look for the circle of the primary mirror—it should  Adjust nut on center bolt up or down be centered in the view. until secondary mirror is centered in view through focuser  If the view of the primary is off-center, adjust the rotation. Small angles have big effects! 9.5: SETTING SECONDARY ANGLE  Screw two outer collimation bolts on  Looking through eyepiece, adjust collimation the spider until they touch the mirror bolts until view of primary is centered in holder. Further adjustment of these secondary as shown below will now adjust the angle of the mirror as shown on slide 9.4.  Once centered, adjust third bolt to touch and stabilize  Angle of secondary adjusts what part of secondary holder primary is visible as seen below. 9.6: ALIGNING THE PRIMARY  Final step of collimation is to adjust  Adjust one knob at a time on the the primary cell so the primary is primary mirror cell until image looking out along the axis of the of the spider is centered in the telescope as shown below image visible on the secondary as shown below  Perfection is not required  9.7: SETUP FOR INITIAL FOCUS  Insert an eyepiece, secure it in the focuser.  Position focuser near the upper end of its travel range (screwed nearly entirely out) & loosen the screws securing the UTA so it slides freely  Adjust UTA to LTA distance to baseline of roughly 26.75"/68 cm ~26.75"/68cm WARNING: This telescope is now a complete light concentrating system. Do NOT point it at the sun! The risk of fire, vision damage, or blindness is severe!  9.8: INITIAL FOCUS PROCESS  Rest the telescope in your lap or on a table, pointing it at as distant an object as you can comfortably find, ideally at least half a mile  Look into the eyepiece. Slide the upper cage until an image comes to focus. Fine tune the sharpness, and then tighten the screws by hand  Adjust baffle to snugly fit against base of UTA in final position WARNING: This telescope is now a complete light concentrating system. Do NOT point it at the sun! The risk of fire, vision damage, or blindness is severe! 9.9: BALANCING THE TELESCOPE  In aiming up/down ("altitude)", the  Loosen screws on the middle ring so it can telescope functions like a see-saw, slide freely. Insert eyepiece. with its fulcrum at the bearings  Rest telescope on flat surface  To balance the Hadley, the middle ring (or tripod mount) should  Adjust center ring until it balances, resting on be at the balance point only the bearings.  Tighten screws. Your scope is now balanced! 9.10: ADJUSTING SIGHTS  Insert lowest-power eyepiece into the  Adjust lower sight up and down on focuser and point Hadley at rod until lower sight and upper sight an identifiable target (such as a tree, circles are roughly the same size building, or the moon)  Rotate lower sight around rod until  Loosen the screws on the lower sight the two rings capture the same image as seen through eyepiece. Tighten. Locate eyepiece target with identifiable context Adjust lower sight to match Rotate on rod to capture (Note eyepiece view will upper sight circle size target seen in eyepiece be inverted) 9.11: CONGRATULATIONS (AGAIN)  You now have a functional telescope, ready to attach to the mount of your choice (printed or wood)  Mounting options are discussed in Appendix B A. EYEPIECES IN DETAIL A.1: WHY FOCUS ON EYEPIECES?  Eyepieces are necessary to Author's note: It is my opinion that an magnify/project the image telescopes eyepiece is about a 40% contribution to form into something usable by our the view. It takes a decent telescope to eyes. get a good view of anything, but where do you go from  Poor quality eyepieces can worsen the there? Closer/further/wider/sharper, image, and premium eyepieces can the rest is up to the eyepieces. be quite expensive  Hadley is forgiving on inexpensive eyepieces, and this is an area of diminishing returns. Note that premium eyepieces can cost more than the whole telescope. A.2: EYEPIECE DIAMETER  1.25" is a common standard, and good 2-inch eyepieces require a large secondary eyepieces are "future proof" even if to illuminate the off-axis parts of the field. you get a nicer telescope (Effect of undersized secondary below)  2" eyepieces exist; Hadley cannot Larger secondaries (slightly) worsen use these. This is for several practical contrast, however. reasons, including the illumination profile.  Quality is unrelated to barrel size; most 2-inch eyepieces have 1.25- inch cousins that are just as good.  2-inch eyepieces are a consequence of internal optics size; very wide fields require a larger unobstructed path. A.3: FIELD OF VIEW  "Field of view" can mean two different things – "true field" or "apparent field."  True field (TFoV) is a measure in arc- size of the sky. A 25mm plossl has a 1.4 degree true field in Hadley.  Apparent field (AFoV) is how wide  Magnification relates the apparent field of view of a view the eyepiece presents for your the eyepiece to the true field you will see through eye. A 25mm plossl has roughly a 50- it in your telescope: a 25mm plossl has a 36x degree apparent field. magnification in Hadley 114, and thus the 50 degree apparent view gives 1.4 degree TFoV  Apparent field is nice to have a lot of. It is one of the most expensive qualities of any eyepiece. A.4: BUDGET LOW-POWER EYEPIECES 25mm Plossl 23mm Aspheric  Comes in Hadley kit, roughly $20 USD  This eyepiece is the best you will find for $12 USD. It works but softens the  Sharp, good all-round eyepiece image.  FoV tends to be ~50 degrees (often  Recommended minimum-cost option mis-stated)  Recommended mid-cost option 32mm Plossl  Slightly pricier than the 25mm, costs $25-30 USD  More "zoomed out" for easy finding  A.5: BUDGET HIGH-POWER EYEPIECES "Redline"/"Goldline" series 6mm vs 9mm Focal Length  These two have the same internal  9mm makes 100x power and 0.68 optics, but are listed differently degrees true field of view  They come in 6, 9, 15 and 20mm;  6mm makes 150x power and 0.44 the 6 and 9 are much better than degrees true field of view the 15 and 20  6mm gives more power for larger  Redline: "68-Degree Ultra Wide views of planets or lunar features but Angle)" smaller field of view makes finding targets more challenging and motion  Goldline: "66-Degree Ultra of objects across the sky cross the Wide Angle HD" view faster - requiring more frequent adjustment. A.6: "FANCY" GLASS FOR SPECIAL EYES 82 degree 16mm UWA 82 degree 7mm UWA  Notably more expensive, $99 USD,  Similar cost, ~$99 USD similar in cost to entire rest of 'scope  Similar power to 6mm or 9mmm  Exceptionally wide apparent field of eyepieces, but much larger field of view makes for remarkable viewing view with a very sharp image  More of lunar surface visible at  Similar true field of view as 25mm once, or easier time finding planets Plossl, apparent field of view much and longer without repositioning due larger (see graphic on page 73) to motion of sky objects These are the "Rolls-Royce" of Hadley eyepieces, and very future-proof for use with larger telescopes. Given expense, consider deferring as an upgrade to initial kit, but very worth the money if you stick with the hobby A.7: HIGH POWER/ EYEPIECES TO AVOID Avoid Short Focal Length Aspheric or Avoid Eyepiece "Kits" Plossl Eyepieces  Aspherics have bad focus and  These include the worst versions of bad distortion at short focal any series, including those mentioned lengths due incorporating a lens at left made of acrylic.  They tend to include a bunch of  "Scaling designs" such unnecessary accessories like cleaning as the plossl, kellner and others cloths, color filters, or cheap barlows may still produce sharp images -  But short (