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Help with attaching old Sky-Watcher ED-100 to DSLR

William Optics Flat61 Nikon D750 Equipment Beginner Help Needed
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bluespeck avatar
bluespeck avatar
Hi folks.  I have newbie question that I hope someone can assist with. 

I have borrowed an old Sky-Watcher ED-100 refractor (circa 1980s) and am trying to attach it to a Nikon D750 DSLR.  The 48mm t-mount adapter ring that I normally use with my William Optics Zenithstar 61 (with Flat61 field flattener) does not fit the ED-100.  Can anyone advise what accessories I might need to attach the ED-100 to my Nikon DSLR?

I suspect that the ED-100 isn’t ideal for imaging, but if possible, I’d like to give it a try.  Any guidance would be very much appreciated.  

Thanks.
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andrea tasselli avatar
andrea tasselli avatar
Try a 2" push-fit adaptor with a M42/48 flange. That was the standard those days.
bluespeck avatar
bluespeck avatar
andrea tasselli:
Try a 2" push-fit adaptor with a M42/48 flange. That was the standard those days.

Thanks Andrea.  That is a good start and I'll see what I can find.  Do you know if I will also need a field flattener (or anything else) with this ED-100/D750 combo?
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andrea tasselli avatar
andrea tasselli avatar
It depends. If you're using the D750 in DX mode then probably not. In FX mode I wouldn't be too sure. I'd start without and see how it goes. One thing you'd need if the D750 is modded (i.e., with the front filter removed) is a IR-cut filter. Also, most likely you would need a minus-violet filter of some sort as the colour correction of EDs isn't great. If you see blue bloating in stars you'd most definitely need one. I'd venture to suggest the Baader Semi-APO which also serve as IR/UV cut.
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Stuart Taylor avatar
Stuart Taylor avatar
I have borrowed an old Sky-Watcher ED-100 refractor (circa 1980s)

I (for one) would be interested in seeing a photo of this scope (if you can be bothered). I own a new SW scope and I'd like to see how the old ones looked.
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bluespeck avatar
bluespeck avatar
andrea tasselli:
It depends. If you're using the D750 in DX mode then probably not. In FX mode I wouldn't be too sure. I'd start without and see how it goes. One thing you'd need if the D750 is modded (i.e., with the front filter removed) is a IR-cut filter. Also, most likely you would need a minus-violet filter of some sort as the colour correction of EDs isn't great. If you see blue bloating in stars you'd most definitely need one. I'd venture to suggest the Baader Semi-APO which also serve as IR/UV cut.

 
andrea tasselli:
It depends. If you're using the D750 in DX mode then probably not. In FX mode I wouldn't be too sure. I'd start without and see how it goes. One thing you'd need if the D750 is modded (i.e., with the front filter removed) is a IR-cut filter. Also, most likely you would need a minus-violet filter of some sort as the colour correction of EDs isn't great. If you see blue bloating in stars you'd most definitely need one. I'd venture to suggest the Baader Semi-APO which also serve as IR/UV cut.

Thanks Andrea.  I am an astro beginner and the info you are providing is very helpful. I really appreciate it.  

In addition to a full frame D750 I also use crop sensor D7100, so I certainly have the flexibility to play around and test things out.  Do you think that something like the ELIM-T 2" Prime Focus Camera Adapter (https://bit.ly/2WOMPJo) would work (and is this what you meant when you suggested a 2" push-fit adaptor with a M42/48 flange)?

Neither camera is modified and I have been hesitating to do so as a CCD is on my wish list and a probably purchase early next year. In the mean time I have just been using an Optolong L-Pro light pollution filter.
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bluespeck avatar
bluespeck avatar
Stuart Taylor:
I have borrowed an old Sky-Watcher ED-100 refractor (circa 1980s)

I (for one) would be interested in seeing a photo of this scope (if you can be bothered). I own a new SW scope and I'd like to see how the old ones looked.

Hi Stuart.  Excuse the mess in my office and all the stuff in the background... Here is a quick pic of the old ED-100.  It is a borrowed unit and didn't have a dovetail bracket or any parts to attach the scope to the mount so I've temporarily MacGyvered something using parts from another rig. 

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andrea tasselli avatar
andrea tasselli avatar
andrea tasselli:
It depends. If you're using the D750 in DX mode then probably not. In FX mode I wouldn't be too sure. I'd start without and see how it goes. One thing you'd need if the D750 is modded (i.e., with the front filter removed) is a IR-cut filter. Also, most likely you would need a minus-violet filter of some sort as the colour correction of EDs isn't great. If you see blue bloating in stars you'd most definitely need one. I'd venture to suggest the Baader Semi-APO which also serve as IR/UV cut.

andrea tasselli:
It depends. If you're using the D750 in DX mode then probably not. In FX mode I wouldn't be too sure. I'd start without and see how it goes. One thing you'd need if the D750 is modded (i.e., with the front filter removed) is a IR-cut filter. Also, most likely you would need a minus-violet filter of some sort as the colour correction of EDs isn't great. If you see blue bloating in stars you'd most definitely need one. I'd venture to suggest the Baader Semi-APO which also serve as IR/UV cut.

Thanks Andrea.  I am an astro beginner and the info you are providing is very helpful. I really appreciate it.  

In addition to a full frame D750 I also use crop sensor D7100, so I certainly have the flexibility to play around and test things out.  Do you think that something like the ELIM-T 2" Prime Focus Camera Adapter (https://bit.ly/2WOMPJo) would work (and is this what you meant when you suggested a 2" push-fit adaptor with a M42/48 flange)?

Neither camera is modified and I have been hesitating to do so as a CCD is on my wish list and a probably purchase early next year. In the mean time I have just been using an Optolong L-Pro light pollution filter.

The Optolong L-Pro should be fine. As well as the prime focus adapter you mentioned above.