NEW Sky-Watcher 0.77x Reducers for Esprit 120 & 150

[Scott Homstead]

On 18/11/2020 at 13:56, Sp@ce_d said:

Mine arrived today.. (Thank you @FLO prompt service as always )...  along with more rain.. let alone clouds! That's over a month now with no let up.. no idea when I'll get a chance to test it.. if this year!

Meantime.. here's some pics & initial thoughts. If you are someone that judges value by weight then you certainly won't be disappointed. It has a very solid and well built "attitude" about it. Smooth, clean feeling threads, very happy

Pics show the adapter taken apart to reveal the 2" filter thread.. I've fitted one to show it clearer. Also, less bits are needed with this to attach it to the scope. It fits straight onto the tube rather than needing the extra reducer that the standard flattener uses. One observation I think is an error on @FLO's website. The adapter presents as M48 which is correct in the description but the list of Features and Specs talks about a T2 adapter? As with the standard flattener you'll need an M48 to T2 adapter if going to a T2 thread as I am with my QSI that's going on this. Other than that, I'm at the mercy of the weather until I can get some photons through it to see how it performs.

 

Mine finally arrived.  I went out to put it on and wasn't sure if I was going to feel stupid or worse feel irritated.  Thank you for this post with how it attaches...I just feel stupid and that is o.k.

[StuartT]

A question on this reducer.. it has an M48 thread on the back which plays nicely with a camera of course (which is the main use case), but can a diagonal and an eyepiece be used with it? I can't figure out how you'd do that.

Thanks

[gorann]

On 07/01/2021 at 22:21, Frank_Teunissen said:

I own an “older” Esprit 150ED with the red marks on it. The new dedicated SW reducer 0.77x for the Esprit 150ED won’t fit into drawtube of the focusser. Why doesn’t SkyWatcher warn the users of these Esprit’s?

 

 

Very important info from you Frank, and missing info from SW! I have two Esprit 150 with the aim of using them as a double rig. One is the older version that I just bought used and one is the newer, and as you say the end of the focuser is quite different, and 74 mm diameter will not fit in the old one. Have you had any response from FLO or SW about this issue?

[Frank_Teunissen]

On 10/01/2021 at 13:01, msacco said:

Is it possible to replace that to match?

No, that's not possible. The tubes: outside reducer and inside fucusser won't fit. 

 

[Frank_Teunissen]

11 hours ago, gorann said:

Very important info from you Frank, and missing info from SW! I have two Esprit 150 with the aim of using them as a double rig. One is the older version that I just bought used and one is the newer, and as you say the end of the focuser is quite different, and 74 mm diameter will not fit in the old one. Have you had any response from FLO or SW about this issue?

Hi, Yes I had contact with FLO and they understood the problem. They told me that SW could for me make an adapter.   I declined that offer and returned the reducer. Meanwhile I own a TS 3" PhotoLine 0,79x reducer with a great image circle of 45mm! The only problem is the very short backfocus of 55mm...

Kind regards 

 

[gorann]

54 minutes ago, Frank_Teunissen said:

Hi, Yes I had contact with FLO and they understood the problem. They told me that SW could for me make an adapter.   I declined that offer and returned the reducer. Meanwhile I own a TS 3" PhotoLine 0,79x reducer with a great image circle of 45mm! The only problem is the very short backfocus of 55mm...

Kind regards 

 

Thanks Frank! I also have that TS reducer so I will do as you did with the old Esprit 150 and maybe buy the SW reducer for the newer one.

[bluesilver]

Hi,  Sorry to jump in on this,  But i have this same reducer and is going to be used on a Esprit 150

Just a quick question on that back focus of 55mm that is on the box,

Where it says 55mm back focus with the standard adaptor,   Dose this just mean to need to add 55mm of back focus from the end of the adaptor?

So just basically add the standard 16mm and 21mm spacers that come with a ZWO camera?

 

 

 

[Mdopp]

On 18/11/2020 at 23:47, gorann said:

No reducer can work for a full frame chip (=43 mm diagonal) with the Esprits since they are already full frame (40 - 44 mm imaging circle with Esprit 100 - 150) so a reducer would only cause a dark ring along the edges with a full frame camera and loss of resolution, so utterly useless. For Esprit 150, the image circle with the new reducer would be 44mm x 0.77 = 34 mm, so it would just about fill the frame of an APS-C.

I came across this rather old thread when I was looking for more information on this reducer. Maybe other people find it useful so I would like to share my experience with the 0,77 reducer on an 150ED and a full frame camera (ZWO ASI 6200MM).

Of course, there is noticeable vignetting. But this can be corrected nicely by applying flats. The stars in the outmost corners are somewhat elongated but not too much. There are no dark areas in any of the corners. All in all, I think the reducer works quite OK with a full frame camera.
This may be because the first lens of the reducer is actually placed inside the telescope‘s tube much further to the front than the camera sensor or the normal 1x field flattener. I assume that at this position the field is actually larger and so the reducer can indeed provide a full frame image.

I am attaching an image that was shot with this setup. I only cropped some 10 pixels around the edges to remove the effects of dithering. Otherwise, this is the entire full frame.

Edited February 10, 2022 by Mdopp

[StuartT]

2 hours ago, Mdopp said:

I came across this rather old thread when I was looking for more information on this reducer. Maybe other people find it useful so I would like to share my experience with the 0,77 reducer on an 150ED and a full frame camera (ZWO ASI 6200MM).

Of course, there is noticeable vignetting. But this can be corrected nicely by applying flats. The stars in the outmost corners are somewhat elongated but not too much. There are no dark areas in any of the corners. All in all, I think the reducer works quite OK with a full frame camera.
This may be because the first lens of the reducer is actually placed inside the telescope‘s tube much further to the front than the camera sensor or the normal 1x field flattener. I assume that at this position the field is actually larger and so the reducer can indeed provide a full frame image.

I am attaching an image that was shot with this setup. I only cropped some 10 pixels around the edges to remove the effects of dithering. Otherwise, this is the entire full frame.

Oh wow! That is a superb image! I have the Esprit 150 too. Lovely scope. I'm using the 2600MC Pro with it (as I'm not brave enough to shoot mono yet)