Bresser Messier AR-80/640 Nano re­frac­tor

Por­ta­ble and easy to use, the Nano of­fers ev­ery­thing a new stargazer needs

Sky at Night Magazine - - CONTENTS - WORDS: STEVE RICHARDS

The Bresser Messier AR-80/640 Nano is a com­plete beginner’s tele­scope. It’s a 3-inch achro­matic re­frac­tor that’s bun­dled with ev­ery­thing a new­comer needs to get started: a man­ual al­taz mount, a red dot fin­der, a star di­ag­o­nal and a 26mm Plössl eyepiece. Its 3-inch aper­ture is more than ad­e­quate to al­low ob­ser­va­tions of a wide range of ce­les­tial ob­jects, its al­taz mount is in­tu­itive to use and the whole thing is a dod­dle to set up.

Achro­matic dou­blet lenses, like the ones in this scope, are made from two types of glass that work to­gether to min­imise chro­matic aber­ra­tions – an un­wanted ef­fect that pro­duces coloured ha­los around bright ob­jects. More ex­pen­sive op­tics have a num­ber of spe­cial coat­ings ap­plied to re­duce re­flec­tions and in­crease light through­put, but this lens assem­bly has only one coat­ing of mag­ne­sium flu­o­ride (MgF2) – the min­i­mum re­quired.

The in­side of the seam­less alu­minium op­ti­cal tube is nicely black­ened, though and has a sin­gle baf­fle to help re­duce un­wanted in­ter­nal re­flec­tions. A sub­stan­tial, non-re­tract­ing, alu­minium dew shield (also with a nicely black­ened in­te­rior) cuts down on un­wanted light en­ter­ing the tele­scope, as well as do­ing an ex­cel­lent job of keep­ing dew at bay.

Ex­ter­nally, the op­ti­cal tube is fin­ished in high-gloss white with Bresser’s trade­mark red pinstripe around the base of the dew shield. The op­ti­cal tube is clamped in a plas­tic clamshell mount­ing ring, which at­taches to an alu­minium Vixen-style dove­tail bar. The dove­tail bar has been drilled and tapped to take both 1/4-20 and 3/8-16 tri­pod mount­ing bolts, so it can be used with other mounts, while the scope’s alu­minium con­struc­tion keeps the weight down, mak­ing it highly por­ta­ble.

A com­plete pack­age

The left side of the plas­tic fo­cuser hous­ing has an in­verted T-slot for mount­ing the supplied red dot fin­der. The fin­der has ad­justable bright­ness and makes lo­cat­ing bright ce­les­tial ob­jects very easy.

The com­plete sys­tem comes al­most fully as­sem­bled and, to fur­ther as­sist in any beginner’s first for­ays into ob­serv­ing, it’s supplied with Stel­lar­ium plan­e­tar­ium soft­ware on a CD and a wa­ter­proof plani­sphere to help lo­cate suit­able

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