

-----------------------------------

gpaunescu

08 Sep 2022 13:52


Achizitie focuser pentru Newton 8&quot; F4

-----------------------------------

Salut,

As vrea sa cumpar un focalizator pentru un telescope Newton si nu prea stiu ce sa aleg.

Telescopul  (TS Photon 203/800) are acum pe el focalizatorul acesta:
TS-Optics 2" MONORAIL Newtonian Focuser (Crayford)
https://www.teleskop-express.de/shop/product_info.php/info/p3700_TS-Optics-MONORAIL-2--Newtonian-Focuser--Dual-Speed.html
Este cam inalt si as vrea unul mai mic.
Cateva din caracteristiciile lui:
 -Dovetail ring - 78 mm large diameter 
 - Eyepiece side connection: 2" and 1.25" receptacle with compression ring
 - Minimal height with base: 75 mm
 - Draw tube travel: 50 mm
 - Bearing via stainless steel rail - absolutely free from twisting
 - Central locking of the draw tube, guaranteed without tilting
 - loads of up to 4 kg
 - Weight:  730 g

 Asta e facut cam din topor; pare solid, dar tot pare ceva care e pus pe tub ca sa fie cat mai ieftin 

***** Cele pe care le-am studiat sunt urmatoarele: *****
  1**. TS-Optics 2" Low Profile Rack And Pinion Newtonian Focuser - 8 kg Payload
  https://www.teleskop-express.de/shop/product_info.php/info/p974_TS-Optics-2--Low-Profile-Rack-And-Pinion-Newtonian-Focuser---8-kg-Payload.html

  - Load capacity up to 8 kg without loss of stiffness - due to 8 ball bearings
  - Gentle clamping via 2" bronze compression ring or 1.25" collet adapter
  - Short design - only about 50-55 mm from the tube to the upper edge of the 2" connection (depends on the tube diameter)
  -  Rack and pinion with additional reduction for fine adjustment
  - No tilting when locking the focus, as the adjustment shaft is clamped, not the drawtube
  - highest stiffness - the draw tube is held by 8 ball bearings and the adjustment of the draw tube is done by gear drive
  - integrated coarse adjustment with 42 mm extension length
  - Weight:  900 grams

  2**. TS-Optics 2 Inch UNC Gen. 2 Newtonian Focuserwith additional thread - loads up to 5 kg
  https://www.teleskop-express.de/shop/product_info.php/info/p14361_TS-Optics-2-Inch-UNC-Gen--2-Newtonian-Focuserwith-additional-thread---loads-up-to-5-kg.html

  - 8x large dimensioned ball bearings for a clean bearing of the drawtube.
  - Adjustment of the drawtube by rack and pinion drive - even at maximum load the adjustment is sensitive
  - No tilting possible when clamping the focuser - clamping takes place directly on the adjustment shaft, thus the focus position is held 100%.
  - Short height including base - only 58 mm to the 2" receptacle - only 50 mm to the M54x0.75 female thread of the drawtube
  - Highest rigidity - the drawtube is held by 8 ball bearings and the adjustment of the drawtube is done via gear drive
  - 22 mm adjustment range via the gear drive
  - The focuser is not clamped by pressure on the drawtube, which can cause tilting. It is clamped by the adjustment shaft. This keeps the focus position at 100% without the risk of tilting, which is important for astrophotography
  - The coma correctors MPCC from Baader and TSGPU from TS-Optics have an additional M48 thread for screw adaptations. You can use these threads and have the full working distance of 55 mm available.
  - Fixing of the focuser to the base:  Self-centering ring dovetail with 80 mm diameter
  - Weight: 900 grams

  3**. Baader 2" Diamond Steeltrack Newtonian Focuser
  https://www.teleskop-express.de/shop/product_info.php/info/p8215_Baader-2--Diamond-Steeltrack-Newtonian-Focuser.html

  - Micro-geared drive system with zero backlash, zero cogging, and zero flexure
  - Payload 6 kg
  - 40 mm Drawtube travel
  - Zero shift locking knob to precisely stop any movement without affecting optical axis adjustment
  -  Total weight (incl. 2" clamp): 1000 g
  - Basic hole spacing lengthwise to tube:  65 - 94.5 mm variablel


  4**. Omegon 2" Newton Hybrid Crayford focuser
  https://www.omegon.eu/focusers/omegon-2-newton-hybrid-crayford-focuser-dual-speed/p,32972

  - very low-profile design : eliminating many focusing problems - a squat 50mm
  - Tiger Crayford - The improved Crayford focuser
  - 8 large rollers keep the inner tube firmly in position and allow the tube to slide smoothly into the desired position
  - built-in extension tube : allows length to be adjusted between 50mm and 100mm
  - load-bearing capacity up to 8kg
  - Connection (to the telescope)   80mm 

  5**. Omegon Steeltrail 2'' Newtonian dual speed Crayford focuser 
  https://www.omegon.eu/focusers/omegon-steeltrail-2-newtonian-dual-speed-crayford-focuser/p,45073

  - exclusive 2" Crayford focuser with stainless steel ball bearings 
  - high load capacity for any accessory - even with an open clamp  5Kg
  - Attach a suitable adapter to the focuser via an 80mm dovetail ring

  Poate aveti experinte cu unele dintre ele.

  Asa din ce am citit in specs si pe ici pe colo (foarte putine informatii din viata reala) as inclina spre nr. 5 sau 3 sau 2.

  Din cate am vazut cel de la Baader multi zic ca e ok (probabil si de asta e si mai scump).

  Cel de la nr. 5 nu e in stoc si se zice ca vine la 1 noiembrie (cine stie - initial am vrut sa iau telescopul de la Omegon dar nu era in stoc si a venit dupa cateva luni. Singura diferenta intre ele e acest focuser de la nr. 5 cu care Omegon vine din facbrica).

  Va rog sa-mi spuneti si mie ce credeti ca ar fi mai bun.
  Am pus mai multe detalii de la fiecare ca sa fie mai usor sa le evaluati fara sa fiti nevoiti sa mergeti la site.

  Va multumesc si cer senin va doresc.

  Gabi

