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#1401 Stargazer3236

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Posted 01 April 2019 - 12:16 AM

 

So, what is it?



#1402 Dave Bush

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Posted 01 April 2019 - 07:12 PM

LX90 10"attachicon.gif 10lx90.jpg

Baader Clicklock & FeatherTouch Focuser

attachicon.gif back.jpg

I’ve always loved the clean design of the LX90s.  


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#1403 rik ter horst

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Posted 03 April 2019 - 02:43 AM

Some time ago, I wanted to build a 250 mm F/15 SCT for myself (I've build some for customers in the past) and I wanted it to be as simple as possible without sacrificing performance. Back in 2013 I ordered a Carbon tube from Klaus Helmerichs (Germany) and due to a lot of other interesting projects and obligations I only finished the instrument at the start of this year . But it's there! A brief description: Primary mirror made from AstroSitall with conical back, primary F/ratio = 2.5 for improved correction of spherochromatism, BK7 corrector with BBAR-coating, linear obstruction 26% and 4 fans for internal air circulation to discharge thermal gradients (these still have to be installed, they just arrived).

I'm totally happy with it, easy to transport, easy to use and very pleasant images. From what I've experienced so far, this could easily become my favorite CAT ;-)

20190215_165734klein.jpg

COPERNICUS2019-02-14-small.jpg
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#1404 Joe1950

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Posted 03 April 2019 - 04:55 AM

Wow! That is amazing rik!



#1405 luxo II

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Posted 03 April 2019 - 06:14 AM

And it shows what Celestron/Meade could have produced if they'd adopted f/15 and a small CO. Very, very nice, Rik.

 

So how did you make the corrector ?


Edited by luxo II, 03 April 2019 - 06:15 AM.

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#1406 rik ter horst

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Posted 03 April 2019 - 06:41 AM

Thanks Joe and Luxo! How I make the Schmidt-corrector:

My process is a bit time consuming:  I start with a fine-ground plane-parallel BK7 window, with one side polished on a lapmaster to be sure that there is no astigmatism whatsoever… This is the side which is attached to a concave vacuum tool of which the edge has been flat polished, again on a lapmaster (edge width about 5 mm). Instead of air, I use liquid, so I suck liquid out of the vacuum tool untill it has the right deflection. Then the surface is polished spherical and tested with a very long radius test sphere to ensure that there are no zones or other irregularities present. I do this for both sides. Basically it is the vacuum technique used by Bernard Schmidt, which still works fine, but some small modifications were made to optimize the process.


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#1407 Stargazer3236

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Posted 03 April 2019 - 07:38 PM

Your OTA is very unusually shaped. How did you do that? Or was it manufactured that way?

 

I need to save up for the Vixen 260mm Cassegrain...I am so jealous of you!



#1408 MrRoberts

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Posted 04 April 2019 - 09:10 AM

My renewed love affair with my C-8/Eflowerred.gif 

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#1409 rik ter horst

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Posted 04 April 2019 - 10:18 AM

Your OTA is very unusually shaped. How did you do that? Or was it manufactured that way?

 

I need to save up for the Vixen 260mm Cassegrain...I am so jealous of you!

Hi Stargazer, the Carbon tube is manufactured that way by Klaus Helmerichs, who is able to make tubes with a flat side for easier mounting of the telescope onto a mount. No rings, no extra mass…. 

 

Here's another pic showing this unusual shape a bit better. Maybe round looks better, but I just wanted to try this, and I'm happy I did :-)

 

20190203_164546 klein.jpg

 

By the way, I think  you can have a lot of fun with that Vixen 260 mm Cas too!


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#1410 Dave Mitsky

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Posted 04 April 2019 - 01:06 PM

Here's a shot of my  6" f/10 Celestron NexStar Evolution.  I've owned many Newtonians and refractors over the years but this is my first SCT.

 

Dave Mitsky

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#1411 Stargazer3236

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Posted 04 April 2019 - 09:07 PM

I just purchased a brand new Nexstar 6SE w/Fastar for $400. Apparently the woman I bought it from received this as a gift from her employers as a Christmas gift. It was an impractical gift, she didn't know how to use it, so I found it on Craigslist this past weekend and emailed her and offer of $400, down from $500. When I got there to pick it up, it was still all wrapped up. Not even taken out of the box. The tissue paper was still on the OTA, the dovetail had the protective plastic still on it and all the accessories were still all wrapped up and boxed.

 

I ordered the usual accessories: Bahtinov mask, Bob's Knobs, Dew Shield. My next major purchase is for the Hyperstar C6. Since I only do EAA and some AP with my telescopes, I no longer have the need for eyepieces. Visually observing is so yesterday.

 

I prefer an SCT over a refractor, although I own one, soon to be getting a second, no newts and maybe a 3rd or 4th SCT and straight Cassegrain in the future. I find an SCT to be the perfect point between a refractor and newt, giving refractor like images with no CA or SA and no collimation fuss with only 3 bolts to use to collimate the secondary and they are all so darned compact too!


Edited by Stargazer3236, 04 April 2019 - 09:08 PM.


#1412 bbqediguana

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Posted 04 April 2019 - 09:47 PM

...Visually observing is so yesterday...

foreheadslap.gif


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#1413 Freezout

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Posted 05 April 2019 - 08:19 AM

Hi Stargazer, the Carbon tube is manufactured that way by Klaus Helmerichs, who is able to make tubes with a flat side for easier mounting of the telescope onto a mount. No rings, no extra mass…. 

 

Here's another pic showing this unusual shape a bit better. Maybe round looks better, but I just wanted to try this, and I'm happy I did :-)

 

attachicon.gif 20190203_164546 klein.jpg

 

By the way, I think  you can have a lot of fun with that Vixen 260 mm Cas too!

This makes look the telescopes with rings or dovetails like prehistoric or steam-punk items...



#1414 yellobeard

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Posted 10 April 2019 - 03:39 PM

My home build 16" SCT with flexible primary mirror..

With swappable secundaries capable of configurations from F/6 to F/20 (with 17% obstruction at F/20)

 

20190410_223148.jpg


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#1415 yellobeard

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Posted 10 April 2019 - 03:40 PM

Picture of that beautiful schmidt corrector plate:

 

20190410_223104.jpg


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#1416 jdupton

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Posted 10 April 2019 - 03:56 PM

yellobeard,

 

Picture of that beautiful schmidt corrector plate:

   That is quite impressive.

 

   The corrector appears to be coated. What type of coating is it and where did you find a place that could / would coat such a large lens?

 

 

John



#1417 yellobeard

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Posted 10 April 2019 - 04:39 PM

Thanks John,

 

My work is my hobby, and my hobby is my work.

I have the abillity to provide my optics with optical thin layers at my work. That 16" corrector has a 3 layer high efficieny anti reflex coating at both sides.

 

Edit: Forgot to mention: The thickness of that corrector plate is 5,6mm (0.22 inch)


Edited by yellobeard, 10 April 2019 - 04:46 PM.

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#1418 MalVeauX

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Posted 12 April 2019 - 02:38 PM

My C8 Edge HD this morning with a full aperture D-ERF and Daystar Quark doing some high resolution solar imaging.

 

https://www.cloudyni...pril-12th-2019/

 

SolarSetupB_04122019.jpg

 

SolarSetupA_04122019.jpg

 

Very best,


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#1419 vicg

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Posted 15 April 2019 - 05:44 AM

Skywatcher Skymax 127 an ebay find for $200. Optics are excellent, just the odd scratch on the dovetail. Now...the hunt for the perfect mount for Dso AP..

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#1420 Kunama

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Posted 17 April 2019 - 12:36 AM

My new Astronomy Outreach setup:  Tak Mewlon 210 and TSA102S Binoculars 

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#1421 DJ N

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Posted 17 April 2019 - 01:56 AM

My new Astronomy Outreach setup:  Tak Mewlon 210 and TSA102S Binoculars 

Hi Matt

 

That is nice......... the Mewlon that is!!!

 

Cheers

 

D


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#1422 luxo II

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Posted 17 April 2019 - 04:04 AM

My new Astronomy Outreach setup:  Tak Mewlon 210 and TSA102S Binoculars 

Interesting configuration Matt, I would have put the scope on the dovetail rather than trust where you've put it. But it looks like the bino's must be rather heavier than the Mewlon.

 

BTW what is the counterweight ? I could use one like that.



#1423 Kunama

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Posted 17 April 2019 - 04:43 AM

Interesting configuration Matt, I would have put the scope on the dovetail rather than trust where you've put it. But it looks like the bino's must be rather heavier than the Mewlon.

 

BTW what is the counterweight ? I could use one like that.

Nick, the binoscope is double the weight of the Mu 210.  I have a spare Casady saddle somewhere but will need to make a puck on the lathe.  The counterweight is a Casady 10Kg unfortunately no longer made since Robin retired.



#1424 Justin Fuller

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Posted 17 April 2019 - 11:42 AM

My new Astronomy Outreach setup:  Tak Mewlon 210 and TSA102S Binoculars 

You're a good man to trust the public around such nice equipment! How do you like the AZ-EQ6 by the way?



#1425 Kunama

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Posted 17 April 2019 - 04:39 PM

You're a good man to trust the public around such nice equipment! How do you like the AZ-EQ6 by the way?

I only let their eyes near the scope, everyone is told to keep hands in their pocket !!! 4.gif rulez.gif

The AZ-EQ6 is the best mount for what I do.  It does have a little hiccup every now and then but overall an excellent mount. I have never used it in EQ mode so can't give an opinion on that.

The weakest link is the stock tripod, when the mount is fitted onto a decent tripod the difference is like chalk and cheese waytogo.gif


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