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L-enHance Filter w/ EdgeHD

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#1 Richard Bell

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Posted 25 August 2019 - 09:01 PM

First, it's been a LONG time since I've last posted on Cloudy Nights!

 

Second, I recently got an Optolong L-enHance 2-inch filter. Adapting it to my Stellarvue 130mm (with the focal reducer/field flattener) is no problem. The same cannot be said with my Celestron 9.25-inch Edge HD.

 

I've got the #93646 T-adapter, #94295 0.7x Reducer, and a Canon 600D. I have been unable to find a way to include the filter with this arrangement.  Stepper rings would seem to introduce vignetting (assuming they'd work at all).  Anyone I've contacted hasn't been able to help, so I thought I'd throw it out to the masses.

 

Thanks!

 

Richard



#2 tonyt

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Posted 25 August 2019 - 09:49 PM

Replacing the T-adapter with custom manufactured parts to enable inclusion of an m48 filter shouldn't introduce vignetting with an APSc chip.

 

Something like this for example: https://www.teleskop...ngth-15-mm.html

.. placed in front of the camera with a shortened T adapter between the filter holder and reducer wouldn't vignette an APSc chip.

 

My next camera will be mirrorless to allow room for a filter holder in front of the camera. 



#3 Iamhondo

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Posted 26 August 2019 - 04:32 PM

Richard, 

 

First, the 93646 adapter is not for and EdgeHD scope. It's for conventional SCTs. It's the wrong length and width.

 

Celestron sells one for the 9.25" EdgeHD, and you could use that adapter with a T-ring for your 600D. (https://www.celestro...dgehd-925-11-14) The larger adapter seems to have a wider (and longer) body than the older one you have. That girth might prevent vignetting that the smaller adapter might produce.

 

The problem comes when you want to squeeze your filter into the light path. The adapter for 9.25 and larger EdgeHDs seems fixed-length. (The one for 8" EdgeHDs has two lengths.) So your filter would thread onto the adapter and the camera onto the filter, but the sensor would be too far for sharp corners. 

 

If the adapter (can't find a manual for it) has some interior 2" threads, it could hold the filter inside the adapter with no cost in spacing, but that seems unlikely. And even if you switched to a t-threaded filter or an SCT-threaded filter, you'd face the same complications with the reducer/adapter/camera spacing.

 

The radical option for perfect spacing is to build your own adapter from scratch using parts. Start from the back of the scope with an SCT-48mm adapter, a 48mm extension (length TBD), the filter, a 48mm-t-mount adapter, your t-ring and your camera. You'd need to calculate the extension length to leave your sensor at the right distance from the reducer. (There are some variable 48mm extensions so you have some fudge spacing for other filter depths.) But those bits start adding a lot to the cost if you don't have a few to start out with.

 

HTH,

Joe

 

...Celestron 9.25-inch Edge HD.

 

I've got the #93646 T-adapter, #94295 0.7x Reducer, and a Canon 600D....

 



#4 Richard Bell

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Posted 28 August 2019 - 10:00 PM

The #93646 is definitely for Edge HD 'scopes. It's MUCH larger than a conventional SCT T-adapter.  Celestron does offer another version (#93622) for full-frame DSLR cameras.  I'm guessing that's the version you're thinking of.

 

My astrophoto camera has an APS sized chip, so my current T-adapter is fine.  I've imaged with the T-adapter with and without the focal reducer and have seen no vignetting.  I just post this in case any beginners read your post and get confused.

 

It looks like I have a few options.  #1) Wait for a version of the L-enHance filter that clips into my DSLR.  #2) Have a custom adapter built (pretty pricey).  #3) Remove the filter from its mounting and use Baader's specialized T-mount.  Guess I'll just have to use the filter when imaging with the Stellarvue only.

 

Too bad Celestron didn't have the foresight to build T-adapters with threads for 2-inch filters.

 

- Richard

 

Richard, 

 

First, the 93646 adapter is not for and EdgeHD scope. It's for conventional SCTs. It's the wrong length and width.

 

Celestron sells one for the 9.25" EdgeHD, and you could use that adapter with a T-ring for your 600D. (https://www.celestro...dgehd-925-11-14) The larger adapter seems to have a wider (and longer) body than the older one you have. That girth might prevent vignetting that the smaller adapter might produce.

 

The problem comes when you want to squeeze your filter into the light path. The adapter for 9.25 and larger EdgeHDs seems fixed-length. (The one for 8" EdgeHDs has two lengths.) So your filter would thread onto the adapter and the camera onto the filter, but the sensor would be too far for sharp corners. 

 

If the adapter (can't find a manual for it) has some interior 2" threads, it could hold the filter inside the adapter with no cost in spacing, but that seems unlikely. And even if you switched to a t-threaded filter or an SCT-threaded filter, you'd face the same complications with the reducer/adapter/camera spacing.

 

The radical option for perfect spacing is to build your own adapter from scratch using parts. Start from the back of the scope with an SCT-48mm adapter, a 48mm extension (length TBD), the filter, a 48mm-t-mount adapter, your t-ring and your camera. You'd need to calculate the extension length to leave your sensor at the right distance from the reducer. (There are some variable 48mm extensions so you have some fudge spacing for other filter depths.) But those bits start adding a lot to the cost if you don't have a few to start out with.

 

HTH,

Joe



#5 Iamhondo

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Posted 11 September 2019 - 12:27 PM

Richard,

 

Clearly my bad on the 93646. Not sure how I muddled that one.

 

Joe




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