Explore Scientific ED127 127mm f/7.5 Carbon Fiber - Forums

I'm relatively new to Astrobin. I recently bought an Explore Scientific ED127 127mm f/7.5 carbon fiber refractor. I didn't think I would ever own a 5 inch APO because most of them are really quite heavy and those that aren't are outside my budget. But just this week I found that the ES ED127 carbon fiber triplet was on sale at about 25% off so i took the plunge. In addition to its fine optics it weighs only 14lb. This is outside a 12lb limit I had previously imposed for any item in my gear but not by much. I'm 68 and I don't like lifting stuff.

I'll mount it primarily on my ZWO AM5 and sometimes on my Stellarvue M2C for visual.

I'll be putting a ZWO EAF on it and I believe that should ameliorate issues with the focuser that have been discuss. I have the ES 0.7 reducer/flattener and also the HoTech 2" SCA Field Flattener for imaging in prime focus or with Powermates.

I look forward to any comments/suggestion/observations that you may have.

Clear Skies !

ps. Boy, is this scope front heavy !

I got one for Christmas, used a couple times , and I am really impressed with the quality:

here are the images I got with it:

https://www.astrobin.com/37t595/C/

and

https://www.astrobin.com/sk22uy/

and here is the monster

https://www.astrobin.com/s581dd/

Clear Skies,
F.

You chose a very nice refractor. You can load 10lbs of equipment onto the 2.5" focuser! Very good choice, fair price too. For the 5" aperture make sure you have dark skies if you want to do visual.

Congratulations on your new Explore Scientific ED127 refractor! It sounds like a great choice, and the lightweight carbon fiber construction should help make it easier to handle.Using a ZWO EAF to focus the telescope should help with the focuser issues you mentioned. It's always a good idea to have a smooth and reliable focuser when imaging or observing.The ES 0.7 reducer/flattener and the HoTech 2" SCA Field Flattener are both excellent options for reducing the focal length of the telescope and providing a flat field for imaging. Just make sure to follow the manufacturer's instructions for their use and setup to ensure the best results.One thing to keep in mind with a refractor of this size is that it can be front-heavy, as you mentioned. This can be a challenge when it comes to balancing the telescope on the mount. Make sure to take the time to carefully balance the telescope, as an imbalanced setup can cause tracking issues and other problems.Overall, it sounds like you have a great setup for both visual and imaging use. I hope you have clear skies and enjoy your new telescope!

Congratulations on the new scope! I bought this scope last year and it is very good. Lightweight as you say but front end heavy. To get balance I added a long adm Losmandy dovetail https://www.firstlightoptics.com/adm-losmandy-type-d-series/adm-losmandy-style-universal-dovetail-bars.html and counterweight kit https://www.firstlightoptics.com/adm-counterweight-kits/adm-dovetail-counterweight-kit-d-series.html.
I have an EAF attached and have had no problems with the focuser. I also use an ZWO OAG which works great. Better than a guidescope I think.

I also use the Hotech flattener and it works really well on this scope. Haven’t had a chance to use the reducer as I found so many targets to image at the full FL.

One thing to be aware of is not to tighten the front clamp too tight as this can cause pinched optics.

It is my favourite scope next to my Redcat and the one I always take out first.

You can see some example images on my Astrobin page https://www.astrobin.com/users/Paul.Puntin/

You chose a very nice refractor. You can load 10lbs of equipment onto the 2.5" focuser! Very good choice, fair price too. For the 5" aperture make sure you have dark skies if you want to do visual.

Thanks. I'm a Bortle 5 location so visual is challenging for DSO's but solar system objects are easily observed. I don't to stay up past midnight but my sky is gets pretty good then.

Paul Puntin:
Congratulations on the new scope! I bought this scope last year and it is very good. Lightweight as you say but front end heavy. To get balance I added a long adm Losmandy dovetail https://www.firstlightoptics.com/adm-losmandy-type-d-series/adm-losmandy-style-universal-dovetail-bars.html and counterweight kit https://www.firstlightoptics.com/adm-counterweight-kits/adm-dovetail-counterweight-kit-d-series.html.
I have an EAF attached and have had no problems with the focuser. I also use an ZWO OAG which works great. Better than a guidescope I think.

I also use the Hotech flattener and it works really well on this scope. Haven’t had a chance to use the reducer as I found so many targets to image at the full FL.

One thing to be aware of is not to tighten the front clamp too tight as this can cause pinched optics.

It is my favourite scope next to my Redcat and the one I always take out first.

You can see some example images on my Astrobin page https://www.astrobin.com/users/Paul.Puntin/

Thanks very much for your comments. I have a longer handle and dovetail coming from Astronomies. I got one these previous for my Tak 100mm. The longer handle allows me to use two hands. I'll look into the counterweight kit as well.

Your images are really good. Something to aspire to !

George M.:
Congratulations on your new Explore Scientific ED127 refractor! It sounds like a great choice, and the lightweight carbon fiber construction should help make it easier to handle.Using a ZWO EAF to focus the telescope should help with the focuser issues you mentioned. It's always a good idea to have a smooth and reliable focuser when imaging or observing.The ES 0.7 reducer/flattener and the HoTech 2" SCA Field Flattener are both excellent options for reducing the focal length of the telescope and providing a flat field for imaging. Just make sure to follow the manufacturer's instructions for their use and setup to ensure the best results.One thing to keep in mind with a refractor of this size is that it can be front-heavy, as you mentioned. This can be a challenge when it comes to balancing the telescope on the mount. Make sure to take the time to carefully balance the telescope, as an imbalanced setup can cause tracking issues and other problems.Overall, it sounds like you have a great setup for both visual and imaging use. I hope you have clear skies and enjoy your new telescope!

Thanks for your comments. I'll be balancing the scope on a table before mounting, with all the rear end accessories (eyepiece, diagonal, cameras etc) attached. I routinely do this for all my scopes with the AM5 already.

I've used the ZWO EAF for visual as well as imaging with my Tak 100mm and my C8. I've been very happy with the results.

F. Londe:
I got one for Christmas, used a couple times , and I am really impressed with the quality:

here are the images I got with it:

https://www.astrobin.com/37t595/C/

and

https://www.astrobin.com/sk22uy/

and here is the monster

https://www.astrobin.com/s581dd/

Clear Skies,
F.

Thanks for your comments. Great images.

You chose a very nice refractor. You can load 10lbs of equipment onto the 2.5" focuser! Very good choice, fair price too. For the 5" aperture make sure you have dark skies if you want to do visual.

Thanks. I'm a Bortle 5 location so visual is challenging for DSO's but solar system objects are easily observed. I don't to stay up past midnight but my sky is gets pretty good then.

I'm also bortle 5 (Supposedly, but I think it is mostly bortle 5.5 until about 2 or 3 AM). What can you see in your bortle 5 location? I just got my new 8" telescope and don't know what to expect.

I'm a bit of a novice at this.

My image gallery gives a guide to what I can image with my gear. Most were shot between sunset and midnight. The DSO's were all processed just with ASI Studio and I assume better processing and more integration time will reveal more.

I've been unable to do much for 6 weeks due to recovery from foot surgery but I was out with my 7 x 32 and 15 x 75 binoculars a couple of nights and got good views of the Orion nebula, the double cluster and andromeda galaxy.

Congrats on your new ES127! I also have the ES127 but the aluminum version and I use it for all of my DSO photography. After you put the ZWO EAF on it you will not have any problems with the focuser. I paired it up with 36mm filters, a ZWO 7x36mm EFW and the ZWO 2600MM. I keep a .8x flattener/reducer on it to make it a little faster at f/6 for imaging and your .7x will make it a speedy f/5.25! My main focus lately has been planetary and emission nebulas.

You can check out my images here:

https://www.astrobin.com/users/Starman609/

Best of Luck! -Eddie

Thanks very much.

I'm thinking to put Losmandy dovetail on it, primarily to make it easier for my M2C mount but also for more solid mounting in general.

Your images are excellent. I was especially interested in the solar shot. I have a Lunt Ha 50mm which is very nice but you have me thinking with what you get with the ES127 and the daystar.

You can't beat that weight/aperture ratio in a triplet! I'm constantly eyeballing the EC152 and ED127. Great choice

This looks like a fantastic scope! I hope to get one someday, to upgrade my Newtonian.

I recommend you to check out Wissam Ayoub's fantastic pictures, most of them are taken with the ED127. That will give you an idea of what you can achieve with this great telescope -- not to mention Wissam's excellent processing techniques.

https://www.astrobin.com/0l6rbr/
https://www.astrobin.com/ckobje/
https://www.astrobin.com/58cuqx/

Nick Grundy:
You can't beat that weight/aperture ratio in a triplet! I'm constantly eyeballing the EC152 and ED127. Great choice

Thanks very much.

If it wasn’t for the weight issue I might have gone with one of the Astro-Tech offerings.

I have the AT60ED and AT70ED which are both excellent.

This looks like a fantastic scope! I hope to get one someday, to upgrade my Newtonian.

I recommend you to check out Wissam Ayoub's fantastic pictures, most of them are taken with the ED127. That will give you an idea of what you can achieve with this great telescope -- not to mention Wissam's excellent processing techniques.

https://www.astrobin.com/0l6rbr/
https://www.astrobin.com/ckobje/
https://www.astrobin.com/58cuqx/

Thanks very much. This is very helpful.

Paul Puntin · Feb 19, 2023, 02:58 PM
Congratulations on the new scope! I bought this scope last year and it is very good. Lightweight as you say but front end heavy. To get balance I added a long adm Losmandy dovetail https://www.firstlightoptics.com/adm-losmandy-type-d-series/adm-losmandy-style-universal-dovetail-bars.html and counterweight kit https://www.firstlightoptics.com/adm-counterweight-kits/adm-dovetail-counterweight-kit-d-series.html.
I have an EAF attached and have had no problems with the focuser. I also use an ZWO OAG which works great. Better than a guidescope I think.

I also use the Hotech flattener and it works really well on this scope. Haven’t had a chance to use the reducer as I found so many targets to image at the full FL.

One thing to be aware of is not to tighten the front clamp too tight as this can cause pinched optics.

It is my favourite scope next to my Redcat and the one I always take out first.

You can see some example images on my Astrobin page https://www.astrobin.com/users/Paul.Puntin/

What step size do you have your EAF at for this scope? Assuming you have the original focuser, if not which focuser did you end up upgrading too?

I still use the original focuser, as I have never had an issue with it. It performs very well. I use a step size of 60 and for backlash compensation, I have it set to “overshoot” with a setting of 200 out.

I plan on using the hotech flattener since i already have it lol, did you have to use any if the extenders on the focuser to achieve focus? I will be using an oag/filterwheel/camera which has the correct backfocus ~55 for the flattener.

Yes, I had to use both extender tubes to reach focus (though I have a rotator attached now so just need one of them). With both attached, the focuser reached focus at about 20-30mm travel. Try it in daylight on a distant object as that gets you in the ballpark for stars. I was limited in distance so used a house about 300 metres away. Reached focus at 30mm travel and then had to go in by 10mm to reach focus on stars.

The Hotech flattener works great on this scope. Round stars right to the corners, at least on my 294. Don’t know about APS-C.

Congratulations!

I’ve always drooled over ES scopes, especially the black CF models. My first telescope was an Orion ED80T CF, a carbon fiber tube. CF holds its focus best of all tube constructions in temperature changes overnight.

When I had imaged “everything” in my night skies where I am, it was time to up my game. I decided on my AT130EDT.

It is an aluminum tube (The worst for expansion and contraction) but I got into automatic focusers and forgot about focusing issues. I learned I wanted a geared focuser for absolute focusing.

I got an EAF and it didn’t have any repeat accuracy. It wouldn’t return to a setting.

I tried it on both my telescopes and tracked it down to the EAF unit itself, it would stop arbitrarily on its inward travel. I sent it to ZWO and they sent it back as “No problem found”. Yeah, because they did not actually test it. The asked for a short video of what it was doing. Funny, they have no way to accept a video. So I made my video documenting what it was doing and sent them a You Tube link. Eventually they had to replace the ASI EAF.

But by then I’d replaced the focuser with a Pegasus Astro Focus Cube2. With a 12-volt input to a 12-volt motor for absolute stepping. That, with the helical geared focuser absolutely gives me the sharpest focus possible. I found USB power like the EAF uses is far too meager for bigger telescopes with heavier imaging trains. Even though my USB hub can supply 2 amps to its USB ports.

So that’s my .02¢ about focusers. Try to “Future Proof” your happiness. 😉

Automatic focusers in my experiences are far better than hand focusing. And will give you sharp focusing all night every night.

Enjoy your new Scope!

Any suggestions on a losmandy dovetail?

Emran Ismail · Feb 3, 2026, 10:01 PM
Any suggestions on a losmandy dovetail?

Losmandy. If you want the quality. Others make Losmandy style dovetails. But I would wonder what grade the aluminum is. Losmandy is 6000 series (Aircraft grade).

I have 3 myself, A 7” that I used for my 80mm, and two 14” that are on my 130mm (Sandwiched).