Search found 99 matches

by DavidG
Tue Apr 10, 2018 10:01 pm
Forum: Solar Scope Modifications
Topic: Maier ITF - first failure?!
Replies: 12
Views: 4278

Re: Maier ITF - first failure?!

Both of my Maiers filters are still perfectly clear and my two are the first two he made.

- Dave
by DavidG
Wed Feb 22, 2017 9:18 pm
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: Baader Halpha Coronagraph (prominence viewer)
Replies: 21
Views: 6532

Re: Baader Halpha Coronagraph (prominence viewer)

With it being 24 years old the odds are very good that it has drifted off the CWL of 656 and is also cloudy. It should look perfectly clear so if you see any hazy it has problems.

- Dave
by DavidG
Wed Feb 22, 2017 4:34 pm
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: Baader Halpha Coronagraph (prominence viewer)
Replies: 21
Views: 6532

Re: Baader Halpha Coronagraph (prominence viewer)

Have you checked the narrow band filter ? If your unit is 10 years old then the filter might have aged and is no longer on band.

- Dave
by DavidG
Thu Feb 16, 2017 3:21 pm
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: Baader Halpha Coronagraph (prominence viewer)
Replies: 21
Views: 6532

Re: Baader Halpha Coronagraph (prominence viewer)

You can assembly the unit minus the narrow band filter and see if you can get an eyepiece to focus of the edge of the cone. Since the Moon is about the same diameter as the Sun you can try the unit out again without the narrow band filter in place to see if you can get the Moon and the occulting con...
by DavidG
Wed Feb 15, 2017 3:16 pm
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: Baader Halpha Coronagraph (prominence viewer)
Replies: 21
Views: 6532

Re: Baader Halpha Coronagraph (prominence viewer)

The key is that H2 that contains the Iris is located at the aperture stop of the system So V2 might not be in the correct position. Here is a link to my math that shows how to calculate the spacing for all the elements in a solar coronagraph. http://considine.net/dgroski/promscope/prom3.gif so you c...
by DavidG
Tue Feb 14, 2017 10:51 pm
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: Baader Halpha Coronagraph (prominence viewer)
Replies: 21
Views: 6532

Re: Baader Halpha Coronagraph (prominence viewer)

The main parts should be the tube with the lens and occulting disk, with the occulting disk facing the focuser of the telescope. Next, what screws on the back of that tube ( end without the lens/disk) is the tube with the iris, and screwed on to that is the tube with the second lens without the disk...
by DavidG
Tue Feb 14, 2017 3:53 pm
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: Baader Halpha Coronagraph (prominence viewer)
Replies: 21
Views: 6532

Re: Baader Halpha Coronagraph (prominence viewer)

Hi, Having designed and built coronagraphs from scratch I'll be happy to try to happy. http://considine.net/dgroski/promscope/ The first issue you might have are the occulting cones. The diameter is determined by the size of the solar disk produced by the telescope. The Sun's disk is approximately 1...
by DavidG
Mon Aug 31, 2015 8:25 pm
Forum: Solar Scope Modifications
Topic: I have a PST (40mm)... Need to clean scope
Replies: 5
Views: 1911

Re: I have a PST (40mm)... Need to clean scope

A Q-tip that is only slight damp with isopropyl alcohol can be used to clean the surface of the filters without any damage. It is possible that the spot your seeing are on the ITF filter and the coating are known to go bad. The ITF filter is not the small 5mm that you see when you remove the eyepiec...
by DavidG
Sat Aug 22, 2015 4:07 pm
Forum: Solar Scope Modifications
Topic: Etalon reconnecting, Success !!!
Replies: 5
Views: 2036

Etalon reconnecting, Success !!!

Last weekend I was in Vermont at the 80th Stellafane convention. Stellafane has a legendary Swap meet on Saturday morning and you'll never know what you'll find. In the piles of treasures was a PST that the owner stated gave a sharp image but the Etalon needed adjusting since his kids had dropped it...
by DavidG
Sun Apr 13, 2014 3:30 pm
Forum: Solar Scope Modifications
Topic: What is it and for what is it to use ?
Replies: 8
Views: 1242

Re: What is it and for what is it to use ?

Walter,
I think it is some type of artifical star. Light is reflected off the big mirror onto the little mirror, then back off the big mirror and then brightly illuminates the pin hole.

- Dave
by DavidG
Sat Apr 12, 2014 8:46 pm
Forum: Solar Scope Modifications
Topic: Appenzellersun, first light in the hand, Schiefspiegler/Kutt
Replies: 41
Views: 5178

Re: Appenzellersun, first light in the hand, Schiefspiegler/

Walter,

You need to do the final alignment on a defocused star. You most likely only need to adjust the primary in the "M" plane so the primary mirror is tilted a little bit more away from the secondary. Remember to recenter the star in the eyepiece after each adjustment.


- Dave
by DavidG
Sat Apr 12, 2014 8:35 pm
Forum: Solar Scope Modifications
Topic: Appenzellersun, modding an old SPV
Replies: 4
Views: 1060

Re: Appenzellersun, modding an old SPV

Walter, You might consider this filter from Omega on Ebay. It is cheaper then the Andover filter and narrower in bandwidth. - Dave http://www.ebay.com/itm/Optical-Interference-Filter-656-3-H-Alpha-0-15nm-Band-Pass-Double-Pass-/310516117756?pt=Educational_Toys_US&hash=item484c33f0fc#ht_1173wt_1074
by DavidG
Tue Apr 08, 2014 8:30 pm
Forum: Solar Scope Modifications
Topic: Appenzellersun, first light in the hand, Schiefspiegler/Kutt
Replies: 41
Views: 5178

Re: Appenzellersun, first light in the hand, Schiefspiegler/

Hi David step four done. I'm not far of the 62.5 mm depending on where I hold the ruler on. Looking up the tube I see nothing but the primary. I wonder how that looks on the moon ;-) . I guess I have to wait a couple of days. the laser still points to the middle of the primary give or take a Millim...
by DavidG
Tue Apr 08, 2014 5:58 pm
Forum: Solar Scope Modifications
Topic: Appenzellersun, first light in the hand, Schiefspiegler/Kutt
Replies: 41
Views: 5178

Re: Appenzellersun, first light in the hand, Schiefspiegler/

Walter, Excellent alignment so far. You just need to tilt the primary away from the secondary so it is no longer is visible in the when you look up the focuser. In your picture, showing what you see when looking up the tube, your at Step 3 in my drawing. The primary mirror is looking at the secondar...
by DavidG
Tue Apr 08, 2014 1:51 pm
Forum: Solar Scope Modifications
Topic: Appenzellersun, first light in the hand, Schiefspiegler/Kutt
Replies: 41
Views: 5178

Re: Appenzellersun, first light in the hand, Schiefspiegler/

Walter, When the primary is aligned correctly, the laser being reflected off it should be around 62.5mm (125/2) from the edge of the secondary. It may be much more depending on the design. So if you taped a piece of paper off the back of the secondary mirror cell you can use that as a target to alig...
by DavidG
Mon Apr 07, 2014 8:18 pm
Forum: Solar Scope Modifications
Topic: Appenzellersun, first light in the hand, Schiefspiegler/Kutt
Replies: 41
Views: 5178

Re: Appenzellersun, first light in the hand, Schiefspiegler/

Walter, I added more information to your picture. Once you tilt the primary so the laser spot falls back on the center of the secondary you should be able to move the primary in the plane shown by the red lines and the laser should hit the spot marked as red dots. If you continue to increase the til...
by DavidG
Mon Apr 07, 2014 5:53 pm
Forum: Solar Scope Modifications
Topic: Appenzellersun, first light in the hand, Schiefspiegler/Kutt
Replies: 41
Views: 5178

Re: Appenzellersun, first light in the hand, Schiefspiegler/

Walter, In your picture looking up the focuser I can still see the edge of the tube so your primary mirror is still not adjusted correctly. It looks to me that your primary is both out of adjustment in the plane that the mirrors moves when you turn the screws for the "M" plane and also the "S" plane...
by DavidG
Sun Apr 06, 2014 9:24 pm
Forum: Solar Scope Modifications
Topic: Appenzellersun, first light in the hand, Schiefspiegler/Kutt
Replies: 41
Views: 5178

Re: Appenzellersun, first light in the hand, Schiefspiegler/

Walter, When you look up the focuser, the only thing you should see is the primary mirror and with nothing in it. If your seeing part of the tube or the secondary mirror then the tilt of the primary is not great enough. Here are some pictures that show what you should see when you use the laser and ...
by DavidG
Thu Apr 03, 2014 6:49 pm
Forum: Solar Scope Modifications
Topic: Appenzellersun, first light in the hand, Schiefspiegler/Kutt
Replies: 41
Views: 5178

Re: Appenzellersun, first light in the hand, Schiefspiegler/

Walter, Here is how I align my Schief using a laser collimator 1) Place the laser collimator in the focuser 2) Adjust the tip and tilt of the focuser so the laser beam hits the center of the secondary 3) Adjust the the tip and tilt of the secondary so the laser beam hits the center of the primary 4)...
by DavidG
Thu Apr 03, 2014 1:24 pm
Forum: Solar Scope Modifications
Topic: Appenzellersun, first light in the hand, Schiefspiegler/Kutt
Replies: 41
Views: 5178

Re: Appenzellersun, first light in the hand, Schiefspiegler/

Walter, If you have any questions on the optical performance, or collimation I maybe able to help. I'm the designer of the Delmarva Schief in which I improved the optical performance over the Kutter design. We also have Yahoo Group for 'SchiefBuilders' https://groups.yahoo.com/neo/groups/schiefbuild...
by DavidG
Tue Apr 01, 2014 6:31 pm
Forum: Solar Scope Modifications
Topic: Reducing Spherical Aberration In Our Scope Mods
Replies: 45
Views: 5907

Re: Reducing Spherical Aberration In Our Scope Mods

It is actually very simple to test a lens for spherical aberration at any wavelength you want ie check for spherochromatism. You setup the lens a double pass autocollimation mode us an optical flat. Since we are taking about small lenses, a good quality flat optics are available for not much money. ...
by DavidG
Tue Feb 18, 2014 12:58 am
Forum: Solar Scope Modifications
Topic: Appenzellersun, Polar Coelostat arrived , now in maintenance
Replies: 47
Views: 4805

Re: Appenzellersun, Polar Coelostat arrived , now in mainten

Hi Joe,
Thanks for jogging my memory about the Helio vs Ceolostat. I should have remembered the difference since I 'm restoring an original Hale spectrohelioscope that uses a Ceolostat.

- Dave
by DavidG
Mon Feb 17, 2014 5:19 pm
Forum: Solar Scope Modifications
Topic: Appenzellersun, Polar Coelostat arrived , now in maintenance
Replies: 47
Views: 4805

Re: Appenzellersun, Polar Coelostat arrived , now in mainten

Hi Walter,
I'm interested in the clock drive. The two brass gears attached to the clock look to give a ratio of 1:1 so that means the clock motor itself needs to turning at 1 revolution in 48 hours to track the Sun. Have you measured it's speed ?


- Dave
by DavidG
Mon Feb 17, 2014 2:24 am
Forum: Solar Scope Modifications
Topic: Appenzellersun, Polar Coelostat arrived , now in maintenance
Replies: 47
Views: 4805

Re: Appenzellersun, Polar Coelostat arrived , now in mainten

Hi Walter,
I think what the symbols mean is that if the Sun is drifting downward then you want to move the slow motion control in the direction the arrow is pointing to recenter the image.


- Dave
by DavidG
Mon Feb 03, 2014 10:35 pm
Forum: Solar Scope Modifications
Topic: Appenzellersun, Polar Coelostat arrived , now in maintenance
Replies: 47
Views: 4805

Re: Appenzellersun, Polar Coelostat arrived , now in maintenance

Walter, The light source ( your lamp) and the reflection off the mirror were it comes to sharp focus must be next to each other and you need to move them as unit until the reflection comes to a sharp focus. Please see the website I provide a link to. Think of it this way, when a you look at a star t...