Lunt 80tha & Lunt 50DS unit how to front mount

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Peterm
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Lunt 80tha & Lunt 50DS unit how to front mount

Post by Peterm »

Howdy,

I have my Lunt 80Tha and I have a Lunt 50mm Double Stack tilt tune unit. Has anybody else front mounted this 50mm DS unit on their 80mm? Does it work ok? Sure, it becomes a 50mm DS scope but the point is I already have these items and it will take some time (and $) to obtain an 80mm DS. Is there an existing mod / adaptor / plans / links that will allow me to screw fit the DS to the front of my 80Tha? Has anyone already been there done that and have the specific thread sizes to fashion such an adaptor?

I am able to have a part 3D printed if needed but am also thinking of asking an Astro friend who is a machinist to fashion one from metal as the DS unit is quite heavy.

All feedback and thoughts would be greatly appreciated.

Ta,
Peter


Solar observation/imaging: Lunt 80mm S/S & 60mm D/S, P/T, B1800 & B1200; Moonlite focusers; Orion ED80; Coronado BinoMite 10x25 binoculars
Mounts etc: Celestron AVX; Celeston 6" SE; ZWO174MM & ZWO432MM & ZWO533MM; Lunt Solar Wedge; Hinode Solar Guider; Airy Labs SSM, Sharp Cap 4 Pro; AutoStakkert 3; ImPPG; Pixinsight; GIMP; Affinity Photo 2; Topaz Denoise

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Re: Lunt 80tha & Lunt 50DS unit how to front mount

Post by MapleRidge »

Hi Peter...

I have mounted my Lunt 75mm front mount etalon on my LS80T as a double stack and it does work very well.

You will have to find others to get a dimension on the threads...I can't remember the specs but the original 50mm and the
75mm units fit the same threaded adapter I bought from Lunt when they were first released. I had a local machine shop make a custom adapter by cutting the threads to match the thread on dust cap from the 75mm since they were same. We used an ABS pipe fitting to make the adapter.

I removed the dew shield so that the etalon mounted to the main tube...a lot of weight to keep the etalon assembly from sagging on the dew shield...difficult to get tuned with the sag ;)

Brian


Brian Colville

Maple Ridge Observatory
Cambray, ON Canada

Photos: https://www.flickr.com/photos/185395281@N08/albums

10'x15 Roll-off Roof Observatory
Takahashi EM400 Mount carrying:
C14 + Lunt 80ED
Deep Sky Work - ASI294MM+EFW 7x36/Canon 60D (Ha mod), ONAG
Planetary Work - SBIG CFW10, ASI290MM/ASI462+ADC

2.2m Diameter Dome
iOptron CEM70G Mount carrying:
Orion EON 130ED, f7 OTA for Day & Night Use
Ha Setup: Lunt LS80PT/LS75FHa/B1200Ha + Home Brew Lunt Double Stack/B1800Ha on the Orion OTA + Daystar Quantum
WL & CaK Setup: Lunt WL Wedge or B1800CaK Wedge
ASI1600MM, ASI294MM, ASI174MM, ASI290MM, PGR Grasshopper Express
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Re: Lunt 80tha & Lunt 50DS unit how to front mount

Post by Peterm »

This is very handy info Brian thanks indeed.

Yes, screwing the DS to the dew shield had me concerned. So does your adapter/pipe slide over the lens and is just a pressure fit onto the tube. How long is the ABS pipe fitting over the tube? Do you have pic you could please post.

Best,
Peter
Last edited by Peterm on Tue Jan 17, 2023 11:26 am, edited 1 time in total.


Solar observation/imaging: Lunt 80mm S/S & 60mm D/S, P/T, B1800 & B1200; Moonlite focusers; Orion ED80; Coronado BinoMite 10x25 binoculars
Mounts etc: Celestron AVX; Celeston 6" SE; ZWO174MM & ZWO432MM & ZWO533MM; Lunt Solar Wedge; Hinode Solar Guider; Airy Labs SSM, Sharp Cap 4 Pro; AutoStakkert 3; ImPPG; Pixinsight; GIMP; Affinity Photo 2; Topaz Denoise

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Re: Lunt 80tha & Lunt 50DS unit how to front mount

Post by marktownley »

Hi Peter, if it is a 'white' lunt50 the threads are M90, if it is the 'red' one it is M80.


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Re: Lunt 80tha & Lunt 50DS unit how to front mount

Post by Peterm »

marktownley wrote: Tue Jan 17, 2023 6:43 am Hi Peter, if it is a 'white' lunt50 the threads are M90, if it is the 'red' one it is M80.
Thanks Mark, it is the white one. This helps a lot. Really appreciated.
Peter


Solar observation/imaging: Lunt 80mm S/S & 60mm D/S, P/T, B1800 & B1200; Moonlite focusers; Orion ED80; Coronado BinoMite 10x25 binoculars
Mounts etc: Celestron AVX; Celeston 6" SE; ZWO174MM & ZWO432MM & ZWO533MM; Lunt Solar Wedge; Hinode Solar Guider; Airy Labs SSM, Sharp Cap 4 Pro; AutoStakkert 3; ImPPG; Pixinsight; GIMP; Affinity Photo 2; Topaz Denoise

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Re: Lunt 80tha & Lunt 50DS unit how to front mount

Post by MapleRidge »

Hi Peter...

The ABS fitting I used is a reducer, specifically a BOW 4" x 3" reducer. The narrow end ID was close to the diameter needed to thread it to mount the etalon and the larger end that cover the scope has adhesive felt installed to take up the bit of slack. I added tapped holes for 3 nylon locking screws to hold it on place and to keep it from sagging. I've used it for 10 years or so (forget really) and it works fine. I did add a bot of lube to the threads to keep the metal threads on the etalon from setting tight.
601617.jpg
601617.jpg (16.32 KiB) Viewed 217 times
20230117_133449.jpg
20230117_133449.jpg (524.45 KiB) Viewed 217 times
My original mount was a custom machined adapter that threaded into the front of the Lunt dew shield and it did hold the etalon very securely it wasn't designed to hold that much weight and sagged a bit even when the dew shied was retracted all the way. to keep this snug, I removed the dew shield completely and the black ring behind the ABS in the pic is the threaded ring that it would be mounted to. This leave the OTA clear and I can slide about 3 inches of the ABS onto the tube before it bottoms out and then snugged up wit the nylon set screws.

The scope is piggybacked on top of the Orion 130ED, held by an ADM Max Guider (alt/az adjustments) and the sensor for the SSM is mounted on the plate below the etalon.

I hope this makes sense...let me know if you have any questions,
Brian


Brian Colville

Maple Ridge Observatory
Cambray, ON Canada

Photos: https://www.flickr.com/photos/185395281@N08/albums

10'x15 Roll-off Roof Observatory
Takahashi EM400 Mount carrying:
C14 + Lunt 80ED
Deep Sky Work - ASI294MM+EFW 7x36/Canon 60D (Ha mod), ONAG
Planetary Work - SBIG CFW10, ASI290MM/ASI462+ADC

2.2m Diameter Dome
iOptron CEM70G Mount carrying:
Orion EON 130ED, f7 OTA for Day & Night Use
Ha Setup: Lunt LS80PT/LS75FHa/B1200Ha + Home Brew Lunt Double Stack/B1800Ha on the Orion OTA + Daystar Quantum
WL & CaK Setup: Lunt WL Wedge or B1800CaK Wedge
ASI1600MM, ASI294MM, ASI174MM, ASI290MM, PGR Grasshopper Express
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Re: Lunt 80tha & Lunt 50DS unit how to front mount

Post by Peterm »

Thanks so much Brian,

This is brilliant, well constructed. The pics are very helpful. I will toddle off to the big hardware store plumbing department later and see what they have similar.
Peter


Solar observation/imaging: Lunt 80mm S/S & 60mm D/S, P/T, B1800 & B1200; Moonlite focusers; Orion ED80; Coronado BinoMite 10x25 binoculars
Mounts etc: Celestron AVX; Celeston 6" SE; ZWO174MM & ZWO432MM & ZWO533MM; Lunt Solar Wedge; Hinode Solar Guider; Airy Labs SSM, Sharp Cap 4 Pro; AutoStakkert 3; ImPPG; Pixinsight; GIMP; Affinity Photo 2; Topaz Denoise

Astrobin: https://www.astrobin.com/users/PeterM/
BOSS team: www.bosssupernova.com
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Re: Lunt 80tha & Lunt 50DS unit how to front mount

Post by MapleRidge »

Hi Peter...

Hope you can get an adapter setup...keep us posted on your progress too.

Brian


Brian Colville

Maple Ridge Observatory
Cambray, ON Canada

Photos: https://www.flickr.com/photos/185395281@N08/albums

10'x15 Roll-off Roof Observatory
Takahashi EM400 Mount carrying:
C14 + Lunt 80ED
Deep Sky Work - ASI294MM+EFW 7x36/Canon 60D (Ha mod), ONAG
Planetary Work - SBIG CFW10, ASI290MM/ASI462+ADC

2.2m Diameter Dome
iOptron CEM70G Mount carrying:
Orion EON 130ED, f7 OTA for Day & Night Use
Ha Setup: Lunt LS80PT/LS75FHa/B1200Ha + Home Brew Lunt Double Stack/B1800Ha on the Orion OTA + Daystar Quantum
WL & CaK Setup: Lunt WL Wedge or B1800CaK Wedge
ASI1600MM, ASI294MM, ASI174MM, ASI290MM, PGR Grasshopper Express
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