My ASA 12"N Focuser modification

[floastro]

Hi guys,

After my TeleVue NP101is ( http://www.poigetdigitalpics.com/photo-equipment3.html ), i decided to change the focuser of my ASA 12" newtonian reflector. The native focuser was the ASA OK3-Z for heavy imaging train. But i had several big problems with it, mechanical problems, impossible to do automatic focusing, backlash..... etc. It was impossible to me to use the huge KAF-16803 chip of my Moravian G4-16000. And with the mechanical problems, i had a shifting of my imaging train inside the OK3-Z focuser and the CCD chip was not aligned with the optics even if my collimation was great with the CATSEYE kit.

After several nights of tests and when i found the real problem, i decided to change the focuser by a high-end focuser : a low profile focuser.

 

2 choices : one FLI ATLAS as on my TeleVue but very expensive or the new low profile focuser on the market released by OPTEC, the TCF LEO. The LEO specifications are the same that the FLI except for the price, the LEO is 50% cheaper.

After a few mails with Jeff from OPTEC, i ordered their last version, the Split-Clamp, of the LEO designed for heavy Wynne 3" corrector for newtonian.

I calculated the effective length for the adapter installed between the ASA OTA and the LEO focuser. The adapter has been made by Precise Parts in Florida.

 

The last weekend, with the Full Moon, i installed and tested the OPTEC TCF LEO on the ASA 12"N f/3.62 .

 

All is OK now with a high precision Auto focusing. I can use my 16803 chip now on my newtonian.

 

A few images of the mounting :

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

This is a test of 300sec of subexposure taken with the G4-16000 CCD camera / ASA 12"N f/3.62 with its ASA 3" Wynne corrector / OPTEC TCF LEO.

Full 4K x 4K image, no cropped : http://www.poigetdigitalpics.com/Fichiers_Divers/t_NGC7000_RED_[2019_09_14]-001.jpg

 

 

 

 

 

 

 

 

Florent 🙂

Edited September 22, 2019 by floastro

[Guest]

Hello, and thank you for sharing the information,

I have the same problem but with my ASA 8N ( from year 2006 ).. and searching also for a solution or a replacement of the focuser.

Cheers

 

Martin

 

[floastro]

12 hours ago, artem said:

Hello, and thank you for sharing the information,

I have the same problem but with my ASA 8N ( from year 2006 ).. and searching also for a solution or a replacement of the focuser.

Cheers

 

Martin

 

Hi Martin,

My ASA 12" is from year 2007. The native focuser was a JMI NGF xTn 3" replaced with an ASA OK3-Z. My OK3-Z was catastrophic. The OPTEC LEO is an incredible focuser for imaging.

Florent

[Guest]

Hi Florent,

Thank you for your answer., my focuser is already partly broken, I must be very patient when I focus + a BAHTINOV, I am now searching for an alternate focuser to exchange the old one..

 Cheers

Martin

[MWDaveT]

I have the ASA 10N and need to replace the focuser - couple of questions - how did you calculate the size of the precise part adapter on the telescope side and what are you using to connect the camera and hold the wayne corrector in place - Thanks David