Dream come true!

Use this section to discuss "standard" Baader/Coronado/ Lunt SolarView/ Daystar, etc… filters, cameras and scopes. No mods, just questions/ answers and reviews.
User avatar
Marcello
Im an EXPERT!
Im an EXPERT!
Posts: 375
Joined: Sat Dec 28, 2013 5:06 pm

Re: Dream come true!

Post by Marcello » Tue Mar 01, 2016 3:54 pm

Hi Bob,
congratulation for the happy of this long story, and to Mr. Andy for the excellent assistance!

The image looks great, I can only guess how wonderful is the view at the eyepiece!

cheers
Marcello
Play in the sunshine, we're gonna get over !!

https://www.flickr.com/photos/87718267@ ... 5844277683

Solar B
Ohhhhhh My!
Ohhhhhh My!
Posts: 139
Joined: Mon Jul 27, 2015 9:29 am
Location: Dunfermline , Scotland

Re: Dream come true!

Post by Solar B » Wed Mar 02, 2016 8:19 pm

Fantastic news Bob and it does appear to be onband in the image even giving
the poor seeing :cool:

Brian
" Gentlemen only ever use Refractors "

User avatar
marktownley
Librarian
Librarian
Posts: 24116
Joined: Tue Oct 18, 2011 5:27 pm
Location: Brierley Hills, UK
Contact:

Re: Dream come true!

Post by marktownley » Wed Mar 02, 2016 9:18 pm

Brilliant! Bring on spring!
Image
http://brierleyhillsolar.blogspot.co.uk/
Solar images, a collection of all the most up to date live solar data on the web, imaging & processing tutorials - please take a look!

User avatar
Valery
Way More Fun to Share It!!
Way More Fun to Share It!!
Posts: 2878
Joined: Sun Nov 18, 2012 3:13 pm

Re: Dream come true!

Post by Valery » Thu Mar 03, 2016 5:32 pm

Congratulates, Bob!

Looking for your DS images full disk and high res.


Valery
"Solar H alpha activity is the most dynamic and compelling thing you can see in a telescope, so spend accordingly." (c) Bob Yoesle.

Largest full size 185 - 356mm Dielectric Energy Rejection Filters (D-ERF) by ARIES Instruments.

Derek Klepp
Way More Fun to Share It!!
Way More Fun to Share It!!
Posts: 12595
Joined: Wed Oct 19, 2011 10:02 am

Re: Dream come true!

Post by Derek Klepp » Sat Mar 05, 2016 8:58 am

Good to hear Bob.

User avatar
Bob Yoesle
Im an EXPERT!
Im an EXPERT!
Posts: 417
Joined: Thu Mar 08, 2012 7:24 pm

Re: Dream come true!

Post by Bob Yoesle » Thu Oct 13, 2016 5:05 pm

I have a bit of progress to report on this seemingly endless project - a lot of time and effort which is turning out to be worth it in the end.

Views through the scope in the early spring were good, but not quite what I had hoped for. While I had hoped the mechanical internal etalon tuning would work, it proved to be impractical - as once the setting was chosen, the telescope then became fixed with the internal etalon tuning, and would require complete disassembly to adjust further. Changing atmospheric pressure and temperature seemed to prevent optimum performance.

So I decided the only way to go would be pressure tuning. Once again I relied on the wonderful help of Dan Steinmetz and his students at Perry Technical Institute.

I didn't want to disassemble the etalon from its housing, and Dan advised there was plenty of clearance around the etalon to drill and tap an access for a vacuum fitting. A bit nerve racking waiting for the process, but all went well!
20160727_131959(0) SM.jpg
20160727_131959(0) SM.jpg (163.99 KiB) Viewed 5978 times
20160727_132826 SM.jpg
20160727_132826 SM.jpg (153.61 KiB) Viewed 5978 times
Next was determining how to seal the etalon collimator module. I decided on a silicone gasket and vacuum grease approach. Here's my dining room table workbench. I purchased the gasket material, and Perry Tech cut custom gaskets for both the collimator and refocusing lens cells, and the cell mounts themselves.
IMGP3898 SM.jpg
IMGP3898 SM.jpg (284.13 KiB) Viewed 5978 times
Applying vacuum grease to the lens cell:
IMGP3900 SM.jpg
IMGP3900 SM.jpg (240.93 KiB) Viewed 5978 times
My look of disappointment when seeing the vacuum would not hold:
IMGP3905 SM.jpg
IMGP3905 SM.jpg (300.78 KiB) Viewed 5978 times
I tried redoing the seals several times, and in the end all I had were sore wrists from the multiple assembly and disassembly tries (silicone grease is thick - and quite messy) -- and no sealing. A quick call to Lunt, who advised sealing the lens itself with clear RTV silicone applied inside the cell, and applying the same to the outside of the lens cells to achieve the best seal possible. This did the trick:
IMGP3914 SM.jpg
IMGP3914 SM.jpg (207.16 KiB) Viewed 5978 times
Here's the completed internal module, with a Lunt IR blocking ERF ahead of the negative collimator lens, the vacuum fitting, and OTA positioning bolts:
IMGP3916 SM.jpg
IMGP3916 SM.jpg (253.38 KiB) Viewed 5978 times
Perry Tech cut longitudinal slots along the OTA which were necessary to allow adjustment/optimizing the position of the internal module, and passage of the vacuum fitting. Note the nice brass setting bolts on the curved aluminum pressure blocks (which I faced with felt to protect the OTA finish):
IMGP3917 SM.jpg
IMGP3917 SM.jpg (285.07 KiB) Viewed 5978 times
The completed OTA with a Ralston Instruments precision vacuum/pressure hand pump attached:
IMGP3921 SM.jpg
IMGP3921 SM.jpg (235.18 KiB) Viewed 5978 times
Here's the OTA in place, with the ball check valve and disconnect. The OTA is quite heavy at 40 pounds with both etalons:
IMGP3929 SM.jpg
IMGP3929 SM.jpg (215.55 KiB) Viewed 5978 times
A close up of the Ralston Instruments pump, showing the days optimum vacuum of -4.5 PSI. The level of pressure is roughly set by the hand pump on the right side, and the fine adjustment is accomplished by the threaded fine-tuning knob of the left side -- very fine adjustment is possible. I found this preferable to the pressure tuners I have used, due to the fact that the adjustment is accomplished off-scope and no movement of the image is involved during tuning.
IMGP3924 SM.jpg
IMGP3924 SM.jpg (237.25 KiB) Viewed 5978 times
Initial evaluation was performed yesterday just before the weather deteriorated here in the Pacific Northwest. Despite poor transparency, everything was perfectly on band! I first viewed the image single stack with the internal 90 mm etalon, and tuned it up perfectly. Adding the SM140 removed the double limb and showed much improved contrast. But boy is the seeing aperture-limiting. Therefore no imaging was attempted. Additional fine tuning of the collimator position, OTA finish details, and possible addition of a 105 mm B+W Kaesemann circular polarizer behind the ERF lie ahead - weather dependent and it might be spring until these issues can be optimized.

And being somewhat OCD, I'm looking to adapt a defunct Helios etalon assembly as an internal triple stacking module for use within the AP 2.7 inch focusers I use for my H alpha scopes:
IMGP3938 SM.jpg
IMGP3938 SM.jpg (157.18 KiB) Viewed 5978 times
Looking forward to some steady clear weather for my first real observation and imaging attempts. Might have to get down to California for the winter shake down.
IMGP3933 SM.jpg
IMGP3933 SM.jpg (284.95 KiB) Viewed 5975 times
IMGP3936 SM.jpg
IMGP3936 SM.jpg (307.84 KiB) Viewed 5974 times
Diagonally parked in a parallel universe.

Curiosity is the father of knowledge; uncertainty is the mother of wisdom.

Dark-Sky Defenders

christian viladrich
Im an EXPERT!
Im an EXPERT!
Posts: 357
Joined: Sun Jun 14, 2015 4:46 pm
Location: France
Contact:

Re: Dream come true!

Post by christian viladrich » Thu Oct 13, 2016 7:03 pm

What a beautiful and amazing work !
I am delighted you start having good results paying back your effort.

BTW, if I run the math, I find you will have a 0.67° sweet spot (in diameter) with the 140/90 etalons. This is if we allow a CWL shift of only 0.25 A at the edge of the sweet spot.
Christian Viladrich
Co-author of "Astronomie Planétaire"
http://www.astroplanetes.com/

User avatar
marktownley
Librarian
Librarian
Posts: 24116
Joined: Tue Oct 18, 2011 5:27 pm
Location: Brierley Hills, UK
Contact:

Re: Dream come true!

Post by marktownley » Thu Oct 13, 2016 9:34 pm

It's looking fantastic Bob!
Image
http://brierleyhillsolar.blogspot.co.uk/
Solar images, a collection of all the most up to date live solar data on the web, imaging & processing tutorials - please take a look!

User avatar
Bob Yoesle
Im an EXPERT!
Im an EXPERT!
Posts: 417
Joined: Thu Mar 08, 2012 7:24 pm

Re: Dream come true!

Post by Bob Yoesle » Fri Oct 14, 2016 7:18 pm

Thanks Mark and Christian - and thanks Christian for the sweet spot calculation ;-)
Diagonally parked in a parallel universe.

Curiosity is the father of knowledge; uncertainty is the mother of wisdom.

Dark-Sky Defenders

george9
Oh, I get it now!
Oh, I get it now!
Posts: 24
Joined: Tue Jan 26, 2016 1:28 am

Re: Dream come true!

Post by george9 » Fri Oct 14, 2016 8:06 pm

Amazing, Bob! Good luck on the tuning. George

User avatar
MapleRidge
Way More Fun to Share It!!
Way More Fun to Share It!!
Posts: 4957
Joined: Fri Jan 13, 2012 11:58 pm
Location: Cambray, ON Canada

Re: Dream come true!

Post by MapleRidge » Fri Oct 14, 2016 11:10 pm

The scope looks great Bob...eager to see how the refinements work out.

Brian
Brian Colville

Maple Ridge Observatory

Cambray, ON Canada

User avatar
Montana
Way More Fun to Share It!!
Way More Fun to Share It!!
Posts: 19465
Joined: Mon Oct 17, 2011 5:25 pm
Location: Cheshire, UK

Re: Dream come true!

Post by Montana » Mon Oct 17, 2016 7:15 am

Wow! I'm looking forward to the first image through it :hamster:

Alexandra

Solar B
Ohhhhhh My!
Ohhhhhh My!
Posts: 139
Joined: Mon Jul 27, 2015 9:29 am
Location: Dunfermline , Scotland

Re: Dream come true!

Post by Solar B » Mon Oct 17, 2016 6:51 pm

In Awe of your fastidious work as ever Robert :bow

Now that's one Bino view I'd like to take :cool:

Oh and triple stack ... that should cut down on leakage !!

Brian
" Gentlemen only ever use Refractors "

User avatar
Bob Yoesle
Im an EXPERT!
Im an EXPERT!
Posts: 417
Joined: Thu Mar 08, 2012 7:24 pm

Re: Dream come true!

Post by Bob Yoesle » Wed Oct 19, 2016 4:34 pm

Thanks everyone! I have learned to be patient with this endeavor. I've also heard from Bill Dean that there may be additional 140/90's in existence somewhere, and that indeed the Vatican's was one of the first 90/60 DS scopes.

As it turns out the Helios might be totally unsalvageable - not only won't it come on-band in it's current state - it's put together with some kind of Loctite material. I will have to apply a hack saw or C4 to it to get it apart.

In the meantime, I'm also going to play around with a 105 mm Schneider (B+W) Kasemann circular polarizer for both the new telescope and the DS 90's. My previous experience with a smaller Kasemann for the CaK module indicates these appear to have very good optical quality. The advertised specifications show high quality components for an off-the-shelf photography CP:

"The Kasemann circular polarizer filter is completely edge-sealed for maximum durability under extreme climatic conditions. Lesser non-sealed circular polarizer filters can suffer from foil separation at the filter edges when used in these conditions. Käsemann polarizing foils are neutral in color, have a higher efficiency than conventional polarizing foils, and are cemented between high-grade plano-parallel optical glass, using a special cementing technique that resists delamination in humid climates. The resulting sandwich is then precision-polished again to achieve highly accurate plano-parallel surfaces... They are well suited for applications that require the highest possible imaging quality, especially with high-speed telephoto lenses and apochromatic lenses. " [Schneider Optics]

We'll see if they live up to this level of quality for solar telescope use. Hoping the weather may soon cooperate.
Diagonally parked in a parallel universe.

Curiosity is the father of knowledge; uncertainty is the mother of wisdom.

Dark-Sky Defenders

User avatar
marktownley
Librarian
Librarian
Posts: 24116
Joined: Tue Oct 18, 2011 5:27 pm
Location: Brierley Hills, UK
Contact:

Re: Dream come true!

Post by marktownley » Wed Oct 19, 2016 6:50 pm

Thanks Bob, very interesting about the CP filter, i've just been googling them.
Image
http://brierleyhillsolar.blogspot.co.uk/
Solar images, a collection of all the most up to date live solar data on the web, imaging & processing tutorials - please take a look!

User avatar
Spectral Joe
Ohhhhhh My!
Ohhhhhh My!
Posts: 118
Joined: Wed Mar 14, 2012 4:34 am
Location: Livermore, California

Re: Dream come true!

Post by Spectral Joe » Thu Oct 20, 2016 2:37 am

Bob

Before getting violent with the Helios (not that I have anything against C4 in the proper place, having used hundreds of pounds of it in a previous career) I can try getting the relevant parts out without damaging them. If you're heading down to California in the future it would be a good thing to attempt together. I'm also working on some new equipment for bandpass measurement that you might find interesting.

Joe
Observing the Sun with complex optical systems since 1966, and still haven't burned, melted or damaged anything.
Not blind yet, either!
Light pollution? I only observe the Sun, magnitude -26.74. Pollute that!

antonello
Ohhhhhh My!
Ohhhhhh My!
Posts: 58
Joined: Tue Mar 24, 2015 12:34 pm

Re: Dream come true!

Post by antonello » Thu Oct 20, 2016 7:11 am

Hello Bob

Also I have had a dream for a long time and I worked for achieve it. For this purpose I have built a slight Truss (see picture 1)
1.jpg
1.jpg (88.16 KiB) Viewed 5764 times

for a 150 mm H-alpha Istar lens. After, I have purchased a Lunt Etalon, the model for 60 mm Double stack, for to put it inside the telescope. For this purpose, I have designed and made a 65 mm lenses collimator with a negative lens and a positive lens, to be used as shown in the second image (all this is attached to the end of the truss ....).
2.jpg
2.jpg (91.44 KiB) Viewed 5764 times
The whole system works perfectly, but my real dream was to have an Etalon of type "pressure" from 60 mm, promised for years by Lunt, but never realized.
My dream was to make (easily) a sealed cylinder for my Etalon (the two lenses help much) and to get the same H-alpha tuning not by inclination, but through the reduction in pressure within the cylinder sealed Etalon.
I thought it was a difficult thing because I've never seen him do this ... but then I saw your solution and I think that my dream It could be achieved. I saw that you are using a Hand vacuum pump Ralston
This pump is very expensive ($ 400). Is it necessary to such a precise pump? Would not be enough a more simpler pump, by that very Lunt used in "Etalon pressure type" (type syringe) used not for pressure, but for to create a vacuum?
Last thing. You or anyone is reading, know a formula that allows to calculate the shift of the frequency as a function of pressure?

Many thanks

Antonello

christian viladrich
Im an EXPERT!
Im an EXPERT!
Posts: 357
Joined: Sun Jun 14, 2015 4:46 pm
Location: France
Contact:

Re: Dream come true!

Post by christian viladrich » Thu Oct 20, 2016 8:15 pm

Hello Antonello,
I was just wondering where did you find the 65 / 400 mm lenses ?
BTW, in your case the diameter of the sweet spot is 22 arcmin, if you accept a max 0.25 A CWL shift at the edge of the sweet spot.
I've got an EXCEL file from Gert Gottschalk which calculates the CWL as a function of pressure. If you don't find it on the web, you can drop me a message.
Christian Viladrich
Co-author of "Astronomie Planétaire"
http://www.astroplanetes.com/

User avatar
Bob Yoesle
Im an EXPERT!
Im an EXPERT!
Posts: 417
Joined: Thu Mar 08, 2012 7:24 pm

Re: Dream come true!

Post by Bob Yoesle » Thu Oct 20, 2016 8:27 pm

Hi Mark - the Kasemann should arrive today and I'm looking forward to seeing what it can do and how much the decrease in image brightness occurs... unfortunately it might be a week or more until some sun arrives :-(

Hi Joe - would love to visit you again sometime for some "demolition" :) - I'll PM you...

Hi Antonello - what a beautiful telescope implementation!
You or anyone is reading, know a formula that allows to calculate the shift of the frequency as a function of pressure?
I think you can get to it by the formula's on these pages - get the air pressure and resultant refractive index put into the etalon wavelength formula:

https://www.gribble.org/cycling/air_density.html

and

http://emtoolbox.nist.gov/Wavelength/Documentation.asp

This graphic shows the relationship between refractive index and pressure, temperature, and humidity:
Effects of temperature pressure and humidity on refractive index of air.jpg
Effects of temperature pressure and humidity on refractive index of air.jpg (91.9 KiB) Viewed 5733 times
Depending on how high the etalon is tuned, I don't think you'd need more than - 5 PSI or so of vacuum - right now I'm finding about - 2 PSI is ideal for my internal 90.

You could first try one of these type of Mityvac automotive vacuum hand pumps to see if it would work:
MV8000.jpg
MV8000.jpg (121.33 KiB) Viewed 5733 times
Diagonally parked in a parallel universe.

Curiosity is the father of knowledge; uncertainty is the mother of wisdom.

Dark-Sky Defenders

Solar B
Ohhhhhh My!
Ohhhhhh My!
Posts: 139
Joined: Mon Jul 27, 2015 9:29 am
Location: Dunfermline , Scotland

Re: Dream come true!

Post by Solar B » Thu Oct 20, 2016 11:40 pm

That's a wonderful assembly you've got going on there Antonello !!
Loving the adonized red features to :cool:

If I may I think etalons that exhibit good finesse do/would benefit from pressure tuning ... however a regular
or average etalon perhaps not so and tilting would suffice ... this just from my rudimentary understanding.

Brian
" Gentlemen only ever use Refractors "

User avatar
Bob Yoesle
Im an EXPERT!
Im an EXPERT!
Posts: 417
Joined: Thu Mar 08, 2012 7:24 pm

Re: Dream come true!

Post by Bob Yoesle » Mon Oct 24, 2016 8:20 pm

Update.

I had some good weather and decent seeing for a couple of hours this past weekend, and finally had the views I have hoped for.

First single stacked; the internal SM90 etalon is quite uniform and superb in contrast, and is only slightly off-band high. About - 2.0 PSI of vacuum was required to bring the filter on-band (maximum filament density), and the range of adjustment is quite generous: +/- 0.5 PSI or greater. The increased aperture is awesome in good seeing!

Next: double stacked with the SM140 was a delight, no double limb, and the full-disc contrast was quite good, though not quite up to the DS SM90's - apparently nothing can touch them - DS ghosting required more tilt than I preferred to remove the ghost completely from the FOV.

Next I added the Schneider B+W 105 mm Kasemann circular polarizer - and solar Nirvana has been achieved! Though the image is dimmer, using my BelOptik KG3 BF30 still provided good image brightness, I could see no degradation in image quality at the 90 x magnification I used, and I couldn't get the grin off my face with binoviewing :-)

Some final tweaks and refinements are underway, and when I have good seeing I'll grab some images to post for the community.
Diagonally parked in a parallel universe.

Curiosity is the father of knowledge; uncertainty is the mother of wisdom.

Dark-Sky Defenders

User avatar
robert
Way More Fun to Share It!!
Way More Fun to Share It!!
Posts: 2361
Joined: Fri Oct 14, 2011 1:49 pm
Location: Isle of Skye, Scotland
Contact:

Re: Dream come true!

Post by robert » Tue Oct 25, 2016 6:34 am

Amazing journey to this point. Thanks for sharing it.
Robert
images and animations http://tinyurl.com/h5bgoso
2018 images https://www.flickr.com/photos/69734017@ ... 1234171714
2017 images http://tinyurl.com/gvk9k3k
ED80. SW200. ES127. Celestron-150mm-PST mod
LS60PT-LS60F-B1200. B600-Cak. PGR-Ch3-IMX265

george9
Oh, I get it now!
Oh, I get it now!
Posts: 24
Joined: Tue Jan 26, 2016 1:28 am

Re: Dream come true!

Post by george9 » Wed Oct 26, 2016 5:24 pm

Great to hear, Bob. George

User avatar
marktownley
Librarian
Librarian
Posts: 24116
Joined: Tue Oct 18, 2011 5:27 pm
Location: Brierley Hills, UK
Contact:

Re: Dream come true!

Post by marktownley » Thu Oct 27, 2016 8:02 am

Fantastic news Bob!
Image
http://brierleyhillsolar.blogspot.co.uk/
Solar images, a collection of all the most up to date live solar data on the web, imaging & processing tutorials - please take a look!

antonello
Ohhhhhh My!
Ohhhhhh My!
Posts: 58
Joined: Tue Mar 24, 2015 12:34 pm

Re: Dream come true!

Post by antonello » Thu Oct 27, 2016 11:37 am

Hello Christian

I designed the collimator with OSLO and optimized with Zemax so that none of the surfaces of the lens was flat, then I built the lambda/10 lenses from an important national industry. The system is expensive, but it is perfect.

This is the spots diagram with a perfect 150 mm f:10 lens
1_150mm_f10_perfect_lens_with_satta_collimator .jpg
1_150mm_f10_perfect_lens_with_satta_collimator .jpg (41.32 KiB) Viewed 5551 times
and this is the spots diagram with a commercial achromatic (150 mm f: 10)
2_150mm_f10_achromatic_with_satta_collimator .jpg
2_150mm_f10_achromatic_with_satta_collimator .jpg (42.34 KiB) Viewed 5551 times
The project was created for commercial purposes, but the result is still good when using catalog lenses with a flat side, as in this drawing
img010.jpg
img010.jpg (14.37 KiB) Viewed 5551 times
In this case, the quality is however still inside the diffraction
3_1_150mm_f10_perfect_lens_with_plano_concave_plano_convex_collimator .jpg
3_1_150mm_f10_perfect_lens_with_plano_concave_plano_convex_collimator .jpg (43.72 KiB) Viewed 5551 times
4_150mm_f10_achromatic_with_plano_concave_plano_convex_collimator .jpg
4_150mm_f10_achromatic_with_plano_concave_plano_convex_collimator .jpg (44.32 KiB) Viewed 5551 times
The important thing is that the two lenses are placed exactly as in the drawing above

You are right about the sweet spot, but I have realized the 150 mm to see details of the sun. To see the full surface of the sun I use the same Etalon and the same collimator system in a 100 mm f:10 telescope (Tal 100).
Here it is
tal_100_modified.jpg
tal_100_modified.jpg (89.78 KiB) Viewed 5551 times
The block collimator with etalon is universal and fits on all telescopes F: 10 or more, just put the first lens to F- 400 mm from the lens obiectiv (the precise value is achieved with Oslo (or ZEMAX).

Hello Bob
Thank you for all your interesting graphics. Thanks also to the information on the necessary pressure. Less 0.2 Bar, are a very small value. much smaller than I thought. Thanks also to the photograph of the economical aspirator vacuum. I had already thought of use one such tool that is used to suck oil from the brakes of cars, but you must change the tool for fine adjustment of the pressure. Precisely for this reason now I'm following a new road, testing a simply small piston for vacuum with adjustment by screw self made. I will experience everything as soon as the sun comes out.
Many thanks

Post Reply

Who is online

Users browsing this forum: No registered users and 3 guests