External Focuser Edge 8HD

Topic starter

7 days ago

Hello

I am finally looking to ditch the zwo eaf on my celestron edge 8HD and go for a separate focuser. This will allow me to lock the mirror down and hopefully have an easier time with hocus focus and mirror flop etc. I currently use the asi 2600mc pro camera and the celestron OAG. I am in between the moonlight CHL focuser and the Esatto 2in LP robotic focuser. Does anyone have any pros or cons? I think I can make both fit with my current setup. I have cross posted to reddit and astrobin to grab the biggest audience.

Thank you!

Keith Mombourquette

7 days ago

I use an Esatto on my Edge 8 and it works perfectly. I've used it for a year off and on, and it has been trouble free.

Well Written

Dan

Topic starter

7 days ago

Keith Mombourquette:
I use an Esatto on my Edge 8 and it works perfectly. I've used it for a year off and on, and it has been trouble free.

Do you ever use it for visual or planetary? One advantage of the moonlight is that you can loosen the clutch and do a manual focus with it. What's your image train? Thanks

Keith Mombourquette

7 days ago · Edited: 7 days ago

No, I use it strictly at f10 for imaging. I have been using it with an ASI2600mm but recently installed a 585MC as I use it for small targets only, so I usually end up cropping. I have an EFW and an OAG and a manual Rotator in the train with the 585. There was no room for the Rotator with the 2600.

Edited to add: the 585 was installed a few days ago and I have not used it yet.

AstroRBA

6 days ago

If you don't want to sleep just deal with the flop … the 8 inch isn't so bad - just check every hour or so - I'm also running a 14 - new tools can save a lot of grief to be honest

JohnAdastra

6 days ago

I have the Moonlite CHL on my C925 EDGE and it works super. I get perfect v-curves and I get to keep the mirror locked down. Moonlite makes some high quality focusers right here in the USA, with plenty of custom adapters for virtually any backfocus needs, and their ASCOM driver has never failed me even once. Their units can last a lifetime if not seriously abused. I vouch for them 100%.

John

Well Written Helpful Concise Engaging Supportive

Kartik Atre

6 days ago

I am using Baader Steeltrack focusser with a ZWO EAF. It does require drilling bigger holes into the EAF bracket. I have been using it for a couple of years now. Finally have collected enough money to be able to afford the Esatto LP and have also splurged on Arco rotator at the same time

Kartik Atre

6 days ago

Keith Mombourquette:
No, I use it strictly at f10 for imaging. I have been using it with an ASI2600mm but recently installed a 585MC as I use it for small targets only, so I usually end up cropping. I have an EFW and an OAG and a manual Rotator in the train with the 585. There was no room for the Rotator with the 2600.

Edited to add: the 585 was installed a few days ago and I have not used it yet.

Hi Keith,

Can you post how you go with 585 sensor paired with the C8? I am super keen on trying this. But worried I will be oversampled. My mount is good but not a premium one, and generally seeing at my location is terrible.

Cheers,
Kartik

Engaging

Bill Powers

6 days ago

I’m a big fan of secondary focusers on SCTs. Trying to achieve good and consistent focus with the internal focuser has caused me nothing but trouble. Once I went over to a secondary focuser and was able to lock down the primary mirror, everything worked as it should.

I am currently using a big Feather Touch focuser, FTF3515 with a EAF on it , and it works fine.

CS
Bill

Well Written Concise

Dan

Topic starter

6 days ago

Thank you everyone for your help!!!

Rob Lyons

4 days ago

I have two 8” Edge HDs and have never had mirror flop or any other focus issues. Usually you would only want a third party focuser for serious planetary work, but if that is your goal you are better off spending the money on a bigger scope.

Concise

Dan

Topic starter

3 days ago

Rob Lyons:
I have two 8” Edge HDs and have never had mirror flop or any other focus issues. Usually you would only want a third party focuser for serious planetary work, but if that is your goal you are better off spending the money on a bigger

Rob Lyons:
I have two 8” Edge HDs and have never had mirror flop or any other focus issues. Usually you would only want a third party focuser for serious planetary work, but if that is your goal you are better off spending the money on a bigger scope.

its not even about planetary it’s about better v curve in hocus focus. Its never great.

Tony Gondola

Frequent contributor

3 days ago

Kartik Atre · Aug 11, 2025, 08:48 AM
Keith Mombourquette:
No, I use it strictly at f10 for imaging. I have been using it with an ASI2600mm but recently installed a 585MC as I use it for small targets only, so I usually end up cropping. I have an EFW and an OAG and a manual Rotator in the train with the 585. There was no room for the Rotator with the 2600.

Edited to add: the 585 was installed a few days ago and I have not used it yet.

Hi Keith,

Can you post how you go with 585 sensor paired with the C8? I am super keen on trying this. But worried I will be oversampled. My mount is good but not a premium one, and generally seeing at my location is terrible.

Cheers,
Kartik

I think over sampling is better then under sampling if you’re interested in resolution. Give it a try…

Area51x

3 days ago

I have the Moonlite CHL on my C925 EDGE and it works super. I get perfect v-curves and I get to keep the mirror locked down. Moonlite makes some high quality focusers right here in the USA, with plenty of custom adapters for virtually any backfocus needs, and their ASCOM driver has never failed me even once. Their units can last a lifetime if not seriously abused. I vouch for them 100%.

John

Which moonlight are you using?

JohnAdastra

2 days ago

Which moonlight are you using?

The CHL is the model number. You can check out their webpage at:

https://focuser.com/

Mine has been working without issue for over 7 years now. No problems with the ASCOM driver either - it always connects. Their webpage is a bit busy, but you can probably call for the best recommendation. They have no shortage of adapters and extensions to get your backfoucus just right. Satisfied customer here.

John

Helpful

Which focuser?