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New build 6" f/4.5 newtonian

Started by Greg Shaffer, 04/25/2016 06:37PM
Posted 04/25/2016 06:37PM Opening Post
So I acquired a Mark Harry 6" mirror about 3 years ago that has been bugging for an OTA for a while now smile

Started fiddling with it in earnest a few months ago whenever the notion struck me. Have decided on making it a spiderless newt using an optical window to mount the secondary and contacted several glass houses for a quote to my specs for a window. Have the 8" tube, 2ndary, mirror cell etc all ready to go, starting on the cell for the window. If I like the way this turns out a 6.9" f/10 will be next with a window. Disregard the spider in the pic....Having read up on Ed Turco's windowed newt I am going that route.






Attached Image:

Greg Shaffer's attachment for post 60206

20" MidnighTelescopes f/5
8" f/16 Muffoletto Achro
Meade 6" AR6 f/8.0 Achro
Celestron C11
Parallax PI250 10" F/5 Newt
Vixen FL102S,NA140SS,R200SS
80mm Stellarvue Nighthawk with WO APOupgrade lens, 90mm f/16.67 Parallax Achro
LXD75/LX200, Mini-tower, GP-DX, CG5 ASGT, LXD650, GM-8, G11, GM-100, GM-150EX, GM-200 and a Gemini G40
4" portable AP convertable 44" or 70" pier
Stellarvue M7 Alt-Az, TSL7 Pier/Tripod
12.5" f/5 MidnighTelescopes DOB Swayze optics
Statham GA
Posted 04/25/2016 06:38PM #1
Turned the square mirror cell to fit the 8" tube.

Attached Image:

Greg Shaffer's attachment for post 150679

20" MidnighTelescopes f/5
8" f/16 Muffoletto Achro
Meade 6" AR6 f/8.0 Achro
Celestron C11
Parallax PI250 10" F/5 Newt
Vixen FL102S,NA140SS,R200SS
80mm Stellarvue Nighthawk with WO APOupgrade lens, 90mm f/16.67 Parallax Achro
LXD75/LX200, Mini-tower, GP-DX, CG5 ASGT, LXD650, GM-8, G11, GM-100, GM-150EX, GM-200 and a Gemini G40
4" portable AP convertable 44" or 70" pier
Stellarvue M7 Alt-Az, TSL7 Pier/Tripod
12.5" f/5 MidnighTelescopes DOB Swayze optics
Statham GA
Posted 04/26/2016 08:42AM #2
Exported the pptx file as a jpg....should be able to upload the specs now....

Have heard back from 6 requests for a quote now, one turned it down and 5 are working it up. Going to be interesting to see how much variation there is in the quotes.



Attached Image:

Greg Shaffer's attachment for post 150681

20" MidnighTelescopes f/5
8" f/16 Muffoletto Achro
Meade 6" AR6 f/8.0 Achro
Celestron C11
Parallax PI250 10" F/5 Newt
Vixen FL102S,NA140SS,R200SS
80mm Stellarvue Nighthawk with WO APOupgrade lens, 90mm f/16.67 Parallax Achro
LXD75/LX200, Mini-tower, GP-DX, CG5 ASGT, LXD650, GM-8, G11, GM-100, GM-150EX, GM-200 and a Gemini G40
4" portable AP convertable 44" or 70" pier
Stellarvue M7 Alt-Az, TSL7 Pier/Tripod
12.5" f/5 MidnighTelescopes DOB Swayze optics
Statham GA
Posted 04/28/2016 03:42PM | Edited 04/28/2016 03:50PM #3
So the 1st of 3 known to be willing to quote (based on communications) out of about 9 houses came in today, about 5 or 6 turned it down or have not responded.

I know I am getting quotes from 3 sources so far, Esco Optics, R L Cumberland and United Lens not in order of quoting.

The 1st quote is $1150.00 uncoated $1910 coated. Obviously coating is quoted based on a solo run and I have inquired about waiting on them to do a production run to lower the cost....another $150 for interferometer testing.

Leaving out the coating cost this is actually a little better than I was expecting so it looks like this is going to happen smile

I may actually forgo coating since I am mounting the window at about a 3 degree angle to the light path ghosting wont be a factor and I doubt a 3% gain in light transmission would even be noticeable.

20" MidnighTelescopes f/5
8" f/16 Muffoletto Achro
Meade 6" AR6 f/8.0 Achro
Celestron C11
Parallax PI250 10" F/5 Newt
Vixen FL102S,NA140SS,R200SS
80mm Stellarvue Nighthawk with WO APOupgrade lens, 90mm f/16.67 Parallax Achro
LXD75/LX200, Mini-tower, GP-DX, CG5 ASGT, LXD650, GM-8, G11, GM-100, GM-150EX, GM-200 and a Gemini G40
4" portable AP convertable 44" or 70" pier
Stellarvue M7 Alt-Az, TSL7 Pier/Tripod
12.5" f/5 MidnighTelescopes DOB Swayze optics
Statham GA
Posted 04/29/2016 02:33PM #4
Just heard back from a 4th company LaCroix Optical out of AR today that they will be providing a quote next week so that's one in and three more potentials so far.

20" MidnighTelescopes f/5
8" f/16 Muffoletto Achro
Meade 6" AR6 f/8.0 Achro
Celestron C11
Parallax PI250 10" F/5 Newt
Vixen FL102S,NA140SS,R200SS
80mm Stellarvue Nighthawk with WO APOupgrade lens, 90mm f/16.67 Parallax Achro
LXD75/LX200, Mini-tower, GP-DX, CG5 ASGT, LXD650, GM-8, G11, GM-100, GM-150EX, GM-200 and a Gemini G40
4" portable AP convertable 44" or 70" pier
Stellarvue M7 Alt-Az, TSL7 Pier/Tripod
12.5" f/5 MidnighTelescopes DOB Swayze optics
Statham GA
Posted 05/01/2016 04:46AM #5
OK, Greg, we've humored you long enough on this mere distraction. What is the latest on your 8" f/15? Have you been able to finish it? Please post an update to that thread (with pictures), too.

Have you started making a bracket or rings so you can mount this 6" f/4.5 on your 8" f/15?
Posted 05/09/2016 03:00PM #6
So the idea of having the window made uncoated and reaching out to coating houses instead of having it down at the same time has proven to be worth it.

So far I have two window quotes in (not counting the $15k ridiculous one)

$1300 and $1500 with IF reports. Coating house said $125 per side which is roughly 1/3 of what the fabricators were wanting.

20" MidnighTelescopes f/5
8" f/16 Muffoletto Achro
Meade 6" AR6 f/8.0 Achro
Celestron C11
Parallax PI250 10" F/5 Newt
Vixen FL102S,NA140SS,R200SS
80mm Stellarvue Nighthawk with WO APOupgrade lens, 90mm f/16.67 Parallax Achro
LXD75/LX200, Mini-tower, GP-DX, CG5 ASGT, LXD650, GM-8, G11, GM-100, GM-150EX, GM-200 and a Gemini G40
4" portable AP convertable 44" or 70" pier
Stellarvue M7 Alt-Az, TSL7 Pier/Tripod
12.5" f/5 MidnighTelescopes DOB Swayze optics
Statham GA
Posted 05/25/2016 01:44PM #7
Greg Shaffer said:

So I acquired a Mark Harry 6" mirror about 3 years ago that has been bugging for an OTA for a while now smile

Started fiddling with it in earnest a few months ago whenever the notion struck me. Have decided on making it a spiderless newt using an optical window to mount the secondary and contacted several glass houses for a quote to my specs for a window. Have the 8" tube, 2ndary, mirror cell etc all ready to go, starting on the cell for the window. If I like the way this turns out a 6.9" f/10 will be next with a window. Disregard the spider in the pic....Having read up on Ed Turco's windowed newt I am going that route.





So now that I fully understand the costs involved with building using a window I have decided the 6" f/4.5 will be built using a curved spider and relegated to superfinder status on my Dob mirrorbox. I am however moving ahead with a windowed 6.7" f/9.2 Spooner mirror build. Cant see spending the bucks for more than one of these.

Also getting the window uncoated....all the glass pushers want too much for coating, minimum $500 for coating both sides. Majestic will coat both sides with MgF2 for $125.

I have 4 quotes in hand now. $1300.00, $2000.00, $5000.00+ and $15,000+ lol....I think one can guess who is winning....It appears Cumberland Optics is the clear choice given they were all given the same exact specs.

20" MidnighTelescopes f/5
8" f/16 Muffoletto Achro
Meade 6" AR6 f/8.0 Achro
Celestron C11
Parallax PI250 10" F/5 Newt
Vixen FL102S,NA140SS,R200SS
80mm Stellarvue Nighthawk with WO APOupgrade lens, 90mm f/16.67 Parallax Achro
LXD75/LX200, Mini-tower, GP-DX, CG5 ASGT, LXD650, GM-8, G11, GM-100, GM-150EX, GM-200 and a Gemini G40
4" portable AP convertable 44" or 70" pier
Stellarvue M7 Alt-Az, TSL7 Pier/Tripod
12.5" f/5 MidnighTelescopes DOB Swayze optics
Statham GA