P r i m a L u c e L a b i S r l
E SAT TO u s e r m a n u a l
Since ESATTO
2" is installed after the corrector or after the focal reducer, it can also be used to perfectly set
the backfocus
distance using the 15mm draw tube travel
(thus obtaining the best performance from the telescope). In order to do this,
just follow these
steps:
1) Adjust the backfocus distance from the corrector or reducer to the camera sensor: in the example of the EdgeHD
9.25" telescope with focal reducer in the photo above, since we still have 73mm of backfocus and since the sensor of
a DSLR
camera is
55mm away from the front T2 thread (by connecting a T2 ring to the camera body), we will still
have
18mm distance, so we used a 10mm T2 extension (screwed in front of the camera) and we will use 8mm of fo-
cus travel to bring the camera sensor perfectly at 146mm distance from the reducer. Note: using the saved positions
of the Virtual HandPad you can also save the ESATTO
position that brings the sensor to the perfect backfocus distan-
ce and recall it on the following nights!
2) Point the telescope to
the stars and focus with the internal focuser: this way we will find the
focus point without
changing the rear backfocus and therefore we will obtain the ideal optical configuration that allows the telescope to
work with the best performance.
3) Close the locking knobs of the EdgeHD primary mirror: this
will avoid problems associated with mirror flop.
Celestron EdgeHD telescope is now ready to be used with the ESATTO
focuser that you will use to adjust the focus vary-
ing the position of the camera only by fractions of a millimeter. These very small
movements in fact do not affect the tele-
scope's performance since
the EdgeHD optics (with or without reducer) are designed to allow a certain tolerance (+ -
0.5mm) in the backfocus distance.
p a g e 2 8
