background image

What is backfocus?

     

Backfocus is a critical distance from the end of field flattener 

to the camera sensor. The field flattener can provide the best 
image quality if a backfocus set correctly.
     We recommend you to chose our adjustable field flattener 
which is designed for W.O. scope.

10

BACKFOCUS

5

5

5

10

10

10

T-mount

Sensor

Sensor

T-mount

Adjustable part

Adjustable part

For the 

DSLR

 and 

Mirrorless Camera

 user:

- the backfocus, The distance from the end of the flattener 

to the sensor is 

67.9 mm

.

- the distance from the T-mount to the sensor. The distance 

is 

55 mm

.

C

 - the distance which needs to be adjusted according to the 

combination of Scope-Flattener for the best image quality. In 

this case, C is 

12.9mm

C (12.9 mm) = A (67.9 mm) - B (55 mm)

For the 

Astrocamera

 user:

A

 - the backfocus, The distance from the end of the flattener 

to the sensor is 

67.9 mm

.

B

 - the distance from the sensor to the end of the accessories 

(OGA, Filter wheel etc.) and adapters. The distance depends 

on the Astrocamera and the accessories you plan to use.

C

 - the distance which needs to be adjusted according to the 

combination of Scope-Flattener and the Astrocamera system 

for the best image quality. C = A (67.9 mm) - B

Astrocamera

Sensor

Accessories 

(Filter wheel, OGA etc.) 

and adapters

A

B

C

A

B

C

Adjustable part

Mirrorless

Camera

DSLR

FLAT61A

FLAT61A

FLAT61A

Summary of Contents for ZenithStar 61

Page 1: ...ZenithStar 61 User Manual Version 3 Date 2020 08 19...

Page 2: ...1 CONTENTS Warning SPECIFICATION PACKAGE CONTENTS DIAGRAM ACCESSORIES MAP BACKFOCUS USER GUIDE 2 3 4 5 8 9 10 11 12...

Page 3: ...r even a moment may permanently damage your vision Proper Solar filters consist of filters made by reputable manufacturers designed to fit tightly over the front of the dew shield Solar eyepiece filte...

Page 4: ...er 61mm Aperture f 5 9 Camera Format APS C Full Frame Focuser 2 R P focuser Image Circle Full Frame Recommended Flattener FLAT61A Tube Weight 2 2 kg Accessories included 3 Unit cm 24 SPECIFICATION 21...

Page 5: ...1 3 2 5 4 1 Bahtinov Mask 2 OTA 3 CAT saddle handle bar 4 M54 to 2 inch and 2 inch to 1 25 inch adapters 5 210 mm dovetail plate Soft carry case is included in the standard package 4 PACKAGE CONTENTS...

Page 6: ...and dew shield 2 CAT saddle handle bar mounting ring and dovetail plate 3 2 inch dual speed 10 1 R P focuser Tools you may need 1 5 mm Hex Wrench 2 mm Hex Wrench 2 5 mm Hex Wrench 3mm Hex Wrench 5mm...

Page 7: ...6 DIAGRAM A B A W O patented diffraction spikes Bahtinov focusing mask Three times brighter than the traditional type B Retractable dew shield...

Page 8: ...niguide B CNC made stable and reliable Mounting Ring C 210 mm dual side dovetail plate which is suitable for Vixen and Arca Swiss type saddle plate A M4 thumb screws for attaching the guiding scope B...

Page 9: ...2 5 mm Hex Wrench A M54 to 2 eyepiece adapter B 2 to 1 25 eyepiece adapter C M4 thumb screws for fixing the adapter and eyepiece A M4 screws for attaching the focuser retrofit NOTE DO NOT adjust it b...

Page 10: ...Diagonals 1 25 Diagonals or Erecting Prisms T mount Adapter that comes with astrocamera 2 Eyepiece 1 25 Eyepiece DSLR Mirrorless camera Astrocamera 2 to 1 25 adapter Visual Imaging Vistit W O webpage...

Page 11: ...55 mm C the distance which needs to be adjusted according to the combination of Scope Flattener for the best image quality In this case C is 12 9mm C 12 9 mm A 67 9 mm B 55 mm For the Astrocamera user...

Page 12: ...11 User Guide How to connect the filter Step 1 Remove the part A Step 2 Connect the M48 filter at the end of the flattener Step 3 Connect the part A back to the flattener A A A...

Page 13: ...Guide How to connect the flattener Step 1 Remove the adapter by twisting Step 2 Connect the flattener to M54 telescope thread Note Don t retract the focuser drawtube all the way in it could damage th...

Reviews: