Return to the Cloudy Nights Telescope Reviews home pageAstronomics discounts for Cloudy Nights members
· Get a Cloudy Nights T-Shirt · Submit a Review / Article

Click here if you are having trouble logging into the forums

Privacy Policy | Please read our Terms of Service | Signup and Troubleshooting FAQ | Problems? PM a Red or a Green Gu… uh, User

Equipment Discussions >> ATM, Optics and DIY Forum

Pages: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | (show all)
seryddwr
Innocent Bystander
*****

Reged: 02/19/10

Loc: La-la land.
Re: 70 inch Dob sneak peek new [Re: Chuck Hards]
      #6147754 - 10/20/13 01:20 AM

I remember talking to Mike shortly after he got the mirror. I am still amazed, a 70" scope just boggles the mind!

Post Extras: Print Post   Remind Me!   Notify Moderator  
Mirzam
Post Laureate
*****

Reged: 04/01/08

Loc: Lovettsville, VA
Re: 70 inch Dob sneak peek new [Re: seryddwr]
      #6147956 - 10/20/13 07:14 AM

Do you think one of the folks involved could do an article? A lot of ATM's would like to have more details I expect.

JimC


Post Extras: Print Post   Remind Me!   Notify Moderator  
Mark Harry
Vendor
*****

Reged: 09/05/05

Loc: Northeast USA
Re: 70 inch Dob sneak peek new [Re: Mirzam]
      #6147988 - 10/20/13 08:25 AM

Grab&Go
(a -WHOLE- new meaning!)
M.


Post Extras: Print Post   Remind Me!   Notify Moderator  
BigC
Carpal Tunnel
*****

Reged: 09/29/10

Loc: SE Indiana
Re: 70 inch Dob sneak peek new [Re: seryddwr]
      #6148179 - 10/20/13 10:38 AM

I think "looking through the 70" scope" just got added to my list of "what I want to do"!

That is an amazing project .It shows that dreams can be achieved with hard work.


Post Extras: Print Post   Remind Me!   Notify Moderator  
alancygnusx2
professor emeritus


Reged: 11/25/08

Loc: CA
Re: 70 inch Dob sneak peek new [Re: Chuck Hards]
      #6148325 - 10/20/13 12:20 PM

Thanks for sharing your observations through this scope. Its a landmark event in amateur astronomy, very exciting!

Post Extras: Print Post   Remind Me!   Notify Moderator  
Chuck Hards
Post Laureate
*****

Reged: 05/03/10

Loc: The Great Basin
Re: 70 inch Dob sneak peek new [Re: Mirzam]
      #6148344 - 10/20/13 12:31 PM

Quote:

Do you think one of the folks involved could do an article? A lot of ATM's would like to have more details I expect.

JimC




Mike and I are talking about writing an article at present.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Chuck Hards
Post Laureate
*****

Reged: 05/03/10

Loc: The Great Basin
Re: 70 inch Dob sneak peek new [Re: Chuck Hards]
      #6148357 - 10/20/13 12:40 PM

OK, I've got last nights images WELL BELOW the CN size limit, but it won't let me post them. I'll see what I can do to work around it. Stay tuned. Grrr....

Post Extras: Print Post   Remind Me!   Notify Moderator  
Edward E
scholastic sledgehammer
*****

Reged: 03/26/06

Loc: Tucson, Arizona
Re: 70 inch Dob sneak peek new [Re: Chuck Hards]
      #6148401 - 10/20/13 01:04 PM

That is one big scope! My 20" would make a nice finder for this monster.

It must have a GOTO system on it and tracking. I cannot image star hopping with such a behemoth.

I tried to view the video but it was not functional .


Post Extras: Print Post   Remind Me!   Notify Moderator  
Chuck Hards
Post Laureate
*****

Reged: 05/03/10

Loc: The Great Basin
Re: 70 inch Dob sneak peek new [Re: Chuck Hards]
      #6148427 - 10/20/13 01:20 PM

Steve Dodds (L) and Mike Clements (R) standing in front of the 70-inch.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Chuck Hards
Post Laureate
*****

Reged: 05/03/10

Loc: The Great Basin
Re: 70 inch Dob sneak peek new [Re: Chuck Hards]
      #6148429 - 10/20/13 01:21 PM

Steve Dodds (L), myself (R) next to the 70-inch.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Chuck Hards
Post Laureate
*****

Reged: 05/03/10

Loc: The Great Basin
Re: 70 inch Dob sneak peek new [Re: Chuck Hards]
      #6148431 - 10/20/13 01:22 PM

The 70-inch primary mirror. f/6.1 Mike silvered the mirror in quadrants, and has masked-off the borders, in line with the secondary supports. The central shadowed area of the secondary is also masked-off. Note the streaks of condensation which formed on the steel structure and dripped onto the mirror. Mike is working on a fix for that.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Chuck Hards
Post Laureate
*****

Reged: 05/03/10

Loc: The Great Basin
Re: 70 inch Dob sneak peek new [Re: Chuck Hards]
      #6148433 - 10/20/13 01:22 PM

Looking up at the secondary mirror from the observing postion. From left to right are a sight tube (no optics), a conventional finderscope, and an empty refractor OTA aimed at the secondary, which holds the focuser. A 2-inch star diagonal serves as tertiary mirror.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Chuck Hards
Post Laureate
*****

Reged: 05/03/10

Loc: The Great Basin
Re: 70 inch Dob sneak peek new [Re: Chuck Hards]
      #6148434 - 10/20/13 01:23 PM

Rear view. 9 point mirror cell. Steve said it supports the cellular mirror adequately. At the eyepiece, star images were nicely round, no hint of astigmatism, and displayed a textbook diffraction pattern. Note the hanging barbell weights, which must be changed depending on the scopes altitude. Mike is still working on fine-tuning balance.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Chuck Hards
Post Laureate
*****

Reged: 05/03/10

Loc: The Great Basin
Re: 70 inch Dob sneak peek new [Re: Chuck Hards]
      #6148435 - 10/20/13 01:24 PM

Note the multiple sight tubes used for initial aiming, spaced all along the back end. You can also see the hanging weights in the rear (a temporary work-around)


Post Extras: Print Post   Remind Me!   Notify Moderator  
Chuck Hards
Post Laureate
*****

Reged: 05/03/10

Loc: The Great Basin
Re: 70 inch Dob sneak peek new [Re: Chuck Hards]
      #6148436 - 10/20/13 01:25 PM

Right side. The azimuth ring is blocked-up on timbers at present.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Chuck Hards
Post Laureate
*****

Reged: 05/03/10

Loc: The Great Basin
Re: 70 inch Dob sneak peek new [Re: Chuck Hards]
      #6148438 - 10/20/13 01:26 PM

Bearing detail.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Chuck Hards
Post Laureate
*****

Reged: 05/03/10

Loc: The Great Basin
Re: 70 inch Dob sneak peek new [Re: Chuck Hards]
      #6148440 - 10/20/13 01:27 PM

Another view of the observing station.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Chuck Hards
Post Laureate
*****

Reged: 05/03/10

Loc: The Great Basin
Re: 70 inch Dob sneak peek [Re: Chuck Hards]
      #6148441 - 10/20/13 01:29 PM

That's all the photos for now. It wouldn't let me post them all in a single post.

Remember that this telescope is a work in progress. It's only been operational for several weeks and Mike has many adjustments and changes to make before it can hit the road next year. He plans to add motorized tracking as well.

He has no email or online presence, but I will be happy to forward questions as long as it doesn't become overwhelming.


Post Extras: Print Post   Remind Me!   Notify Moderator  
gatorengineer
Carpal Tunnel
*****

Reged: 02/28/05

Loc: Hellertown, PA
Re: 70 inch Dob sneak peek new [Re: Chuck Hards]
      #6148542 - 10/20/13 02:54 PM

I cant see any means of stray light control. A low rider with that amount of angle I would think would get drowned in stray light. What am I missing? I have a 36 in the works and this is the second steep angle low rider recently seen, its a great idea.... I am just not understanding how it works. Kinda like a cass or SCT without a baffle tube.

Post Extras: Print Post   Remind Me!   Notify Moderator  
Chuck Hards
Post Laureate
*****

Reged: 05/03/10

Loc: The Great Basin
Re: 70 inch Dob sneak peek new [Re: gatorengineer]
      #6148574 - 10/20/13 03:17 PM

The long tube that the focuser is attached to, aimed at the secondary, is an effective baffle.

As I said above though, it is very much incomplete and a work in progress. I'll ask Mike about it next time I see him. Probably next weekend.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Pages: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | (show all)


Extra information
13 registered and 19 anonymous users are browsing this forum.

Moderator:  ausastronomer, richard7, Starman81 

Print Thread

Forum Permissions
      You cannot start new topics
      You cannot reply to topics
      HTML is disabled
      UBBCode is enabled


Thread views: 13310

Jump to

CN Forums Home


Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics