Search found 457 matches

by christian viladrich
Wed Mar 20, 2019 6:55 pm
Forum: Solar Scope Modifications
Topic: 150 mm Solar Newton
Replies: 26
Views: 360

Re: 150 mm Solar Newton

Bart, the idea of removing the coating of the secondary, or of having an MCM-like coating on the secondary, is not a good idea. This is because the secondary mirror support would get all the heat load. There would be no mechanical problem. This is just you will have the equivalent of a 40 Watts heat...
by christian viladrich
Tue Mar 19, 2019 7:19 pm
Forum: Solar Scope Modifications
Topic: 150 mm Solar Newton
Replies: 26
Views: 360

Re: 150 mm Solar Newton

Hi Bart,
Testing the concept with a 200 mm F/8 mirror (indeed a 300 / F5.5 stopped to 200 mm) is on my to-do list. I think it should be OK.
Before that, I am working on another project related to very narrow band Ca K imaging.
by christian viladrich
Mon Mar 18, 2019 7:31 pm
Forum: Solar Scope Modifications
Topic: 150 mm Solar Newton
Replies: 26
Views: 360

Re: 150 mm Solar Newton

Hello Bart, This is an interesting project ! This being said, and for Ca K - H imaging, and considering you have an F/8 mirror, another option would have been to keep the primary mirror coated. The setup would have been a litlle bit more complex because you have have needed the addition of a subaper...
by christian viladrich
Sat Feb 23, 2019 8:05 pm
Forum: This is SolarChat !!
Topic: Finding Scopes That Are Well Corrected For Ca-K Imaging
Replies: 5
Views: 170

Re: Finding Scopes That Are Well Corrected For Ca-K Imaging

Maybe a 150 mm F/8 (or 10) Newtonian telescope with a sub-aperture ERF in front of the secondary mirror is the way to go.
by christian viladrich
Fri Feb 22, 2019 9:28 pm
Forum: This is SolarChat !!
Topic: 2017 Feb 17. Dark filament through a 6" aperture.
Replies: 12
Views: 302

Re: 2017 Feb 17. Dark filament through a 6" aperture.

Nice images Valery ! There is a very distinct 3-D effect with the spicule field.
by christian viladrich
Mon Feb 11, 2019 8:25 pm
Forum: This is SolarChat !!
Topic: 1.25" Filter Tilt Adapter. Who is interested?
Replies: 4
Views: 145

Re: 1.25" Filter Tilt Adapter. Who is interested?

It is custom made starting from Baader 42 mm thread tube.
by christian viladrich
Mon Feb 11, 2019 6:52 pm
Forum: This is SolarChat !!
Topic: 1.25" Filter Tilt Adapter. Who is interested?
Replies: 4
Views: 145

Re: 1.25" Filter Tilt Adapter. Who is interested?

Hi Bart,
I have two of these tilt adapters (from Beloptik). I used them for testing Omega Ha filters. They work fine.
The tilt is rather easy to adjust. They stay tuned (there are two screws which can be tightened more or less).
Christian
by christian viladrich
Wed Jan 23, 2019 9:27 pm
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: What camera?
Replies: 23
Views: 1089

Re: What camera?

Hello Alexandra, The first question is what is your Ha filter ? Indeed, the Ha solar filter sets the F/D, which in turn sets the size of the pixel, which in turn sets the sensor. If your Ha filter need F/30 or more, the short answer is the IMX174. Smaller pixel sizes won't make the job. In a nutshel...
by christian viladrich
Wed Jan 23, 2019 9:14 pm
Forum: This is SolarChat !!
Topic: What does 656.281 nm look like?
Replies: 12
Views: 414

Re: What does 656.281 nm look like?

BTW, the Televue X2.5 is not telecentric. It is much better to use a telecentric system.
by christian viladrich
Wed Jan 23, 2019 9:12 pm
Forum: This is SolarChat !!
Topic: What does 656.281 nm look like?
Replies: 12
Views: 414

Re: What does 656.281 nm look like?

Hello phil, There are 3 criteria which may help to find the center of the band : - measure the average intensity of the image => the darkest image is the one on the center of the band ; - the short dark "little things" coming in bunches are groups of spicules seen from above. They are at the border ...
by christian viladrich
Sun Jan 06, 2019 11:10 am
Forum: This is SolarChat !!
Topic: Ca K and G band images take on July 1 and 8, 2018
Replies: 12
Views: 481

Re: Ca K and G band images take on July 1 and 8, 2018

Thanks Pedro :-) Mark, regarding the ASI290, the S/N max is 6.9 bits while it is 7.5 bits for the IMX174. So, in situations where there is a lot of light (e.g. use of an Hershel wedge), the IMX 174 will give better results. In Ca K, light could me missing. I had some good results with the ASI290 on ...
by christian viladrich
Sun Jan 06, 2019 10:51 am
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: Multiple aperture off axis mask with white light film on dob
Replies: 6
Views: 333

Re: Multiple aperture off axis mask with white light film on dob

As explained by Mark, this is a bad idea. Make it simple and go for only one aperture. Here is a simulations comparing the effect on the figure of diffraction of full aperture, two and four holes : http://astrosurf.com/viladrich/astro/instrument/sensitivity/planche-obstruction.jpg http://astrosurf.c...
by christian viladrich
Sat Jan 05, 2019 5:23 pm
Forum: This is SolarChat !!
Topic: Ca K and G band images take on July 1 and 8, 2018
Replies: 12
Views: 481

Re: Ca K and G band images take on July 1 and 8, 2018

Hello Mark,
The focal length is close to 3000 mm.
by christian viladrich
Sat Jan 05, 2019 5:23 pm
Forum: SPoD Archive
Topic: Ca K and G band images take on July 1 and 8, 2018
Replies: 8
Views: 365

Re: Ca K and G band images take on July 1 and 8, 2018

Hello Mark,
The focal length is close to 3000 mm.
by christian viladrich
Fri Jan 04, 2019 8:42 pm
Forum: This is SolarChat !!
Topic: Ca K and G band images take on July 1 and 8, 2018
Replies: 12
Views: 481

Ca K and G band images take on July 1 and 8, 2018

Dear All, I still have some images taken on 2018 waiting for processing. Here are some of them. The solar activity was not much higher than now :-( The seeing was quite good on July 1, 2018 : http://astrosurf.com/viladrich/astro/soleil/2018/CaK-1July2018-9h34mnUT-TOA150-IDS3370.jpg Here are close-up...
by christian viladrich
Fri Jan 04, 2019 8:42 pm
Forum: SPoD Archive
Topic: Ca K and G band images take on July 1 and 8, 2018
Replies: 8
Views: 365

Ca K and G band images take on July 1 and 8, 2018

Dear All, I still have some images taken on 2018 waiting for processing. Here are some of them. The solar activity was not much higher than now :-( The seeing was quite good on July 1, 2018 : http://astrosurf.com/viladrich/astro/soleil/2018/CaK-1July2018-9h34mnUT-TOA150-IDS3370.jpg Here are close-up...
by christian viladrich
Fri Nov 23, 2018 1:25 pm
Forum: This is SolarChat !!
Topic: Hawk Repurposed My Solar Scope
Replies: 9
Views: 559

Re: Hawk Repurposed My Solar Scope

Beautiful !
by christian viladrich
Fri Nov 23, 2018 8:09 am
Forum: This is SolarChat !!
Topic: Citizen Science
Replies: 24
Views: 1499

Re: Citizen Science

This is a great idea ! Here are the links to some images. Newton 300 mm, G band, K-line, filigrees, faculae http://astrosurf.com/viladrich/astro/soleil/wl/2018/AR2720-25August2018-9h25min-N300-B1920-430nm.jpg http://astrosurf.com/viladrich/astro/soleil/wl/2018/AR2719-24August2018-11h43mnUT-N300-396n...
by christian viladrich
Mon Nov 12, 2018 7:21 pm
Forum: This is SolarChat !!
Topic: I told ya so... Comets causing sunspots.
Replies: 2
Views: 423

Re: I told ya so... Comets causing sunspots.

I am afraid sunspots are the effect of localized strong magnetic fields in the photosphere (and in the layer below).
They have nothing to do with comets.
by christian viladrich
Sun Nov 11, 2018 8:31 pm
Forum: This is SolarChat !!
Topic: Mg II in UltraViolet
Replies: 31
Views: 2115

Re: Mg II in UltraViolet

Interesting info Raf :-)
I didn't know they have these small size Cassegrain scopes.They have quartz mirrors which is very nice. I have no idea of the optical quality.
by christian viladrich
Sun Nov 11, 2018 7:16 pm
Forum: This is SolarChat !!
Topic: Mg II in UltraViolet
Replies: 31
Views: 2115

Re: Mg II in UltraViolet

Hello Bob, Here are the simulations for a re-spaced classic C8 : http://astrosurf.com/viladrich/astro/instrument/sensitivity/sensitivity-analysis-SC8-Plate.htm The diffraction limited flat-field increases by a factor of four when the Schmidt plate position is set 230mm ahead its nominal position. ht...
by christian viladrich
Fri Nov 09, 2018 7:46 pm
Forum: This is SolarChat !!
Topic: Mg II in UltraViolet
Replies: 31
Views: 2115

Re: Mg II in UltraViolet

Hi Bob,
Is this the C8 or the C8 EdgeHD ?
by christian viladrich
Thu Nov 08, 2018 8:08 pm
Forum: This is SolarChat !!
Topic: Mg II in UltraViolet
Replies: 31
Views: 2115

Re: Mg II in UltraViolet

Hi Bob,
I have done some simulations there for a re-spaced C14 :
http://astrosurf.com/viladrich/astro/in ... -Plate.htm
I can run some more for the C8 if it is helpfull.
Christian