Setting up filters in a Solar Herschel wedge?

[900SL]

Hi

 

My TS 1.25"  wedge has arrived, with no instructions..

It has a separate dual lens filter (not annotated) which looks like it is the ND3 and 40nm continuum filter 

There is also a circular polarising filter (labeled)

I assume (dangerous with solar, hence the post):

 

 

ND3/continuum comes after the wedge (seems obvious..)

The circular polariser wont fit double stacked, So I have added it to the barlow thread (see diagram)

For good measure I have retained a L2 UV/IR filter as a backstop in case of any UV/IR off band leakage

Q:

Should the ND3 be placed in front of the Continuum (one is dark and one is silvered and I don't know which is which)

I assume the circular polariser will interact with the ND3 and by rotating the camera I should improve contrast?

Many tanks

 

Edited May 16 by 900SL

[900SL]

Found this thread, same set up so looks good. I'll try both w.ith and without the polariser, with the SC and ND3

 

Edited May 16 by 900SL

[Littleguy80]

Beat me to it. I was going to say I posted some pics over my TS optics wedge showing how the filters are screwed in. 

[Louis D]

With my 1.25" Hercules Herschel wedge, I generally put a Meade UV/IR filter on the front of the wedge.  Being an interference type filter that reflects rather than absorbs rejected energy, it doesn't heat up that I've ever noticed.

The Hercules comes with an integrated ND3 filter below the eyepiece holder.  I don't even know if it can be removed.  After all, why would I want to remove it?

I generally set the variable polarizer it came with to about an ND1 to ND2 level, and attach it to the bottom of the eyepiece.  I can then rotate the eyepiece to darken the image more because the wedge itself partially polarizes the sun's light.

If I use another filter, I stack it ahead of the polarizer so I can swap it more easily to try other filters.

The Hercules even comes with an integrated variable iris, but all it does is decrease the effective aperture, which might be useful for an achromat, but not for an APO.

[Vroobel]

I also have the Hercules 1.25" wedge. I've replaced the original ND3 filter (inside the eyepiece holder) with 1.25" Solar Continuum 10nm. Also, I screwed the 1.25" variable polarizing filter into my ASI 678MC camera nosepiece, because it's much easier to adjust the filter there than if it's elsewhere. 

https://www.astrobin.com/f3sum2/

 

Edited May 16 by Vroobel

[John]

My Lunt 1.25 HW seems to work in the same way as the Hercules one ie: an ND filter fitted at the bottom of the eyepiece drawtube. I use a single polarising filter on the end of the eyepiece and turn the eyepiece to adjust the final brightness of the image. The light coming through a HW is already polarised on one plane so the single polarising filter is all that is needed on the eyepiece.

I'm not keen on green solar observing so I don't use a solar continuum filter. 

 

[900SL]

Thanks all

 

Contrary to the norm, my wedge arrived with blazing sun. So after a frantic assembly of bits, I have my first solar image!

GT71, Baader hyperion barlow, TS wedge and filters, 533MM, 100 FITS files with best 15% stacked. I'm dead chuffed with this for a first-out-of-the-box I-have-no-idea-what-I'm-doing thing. Finding the damn thing took ages, I ended up using a stick on the scope on the top and sides to get it aligned (when the shadow disappeared I was in line)

 

[John]

That looks a nice result 🙂

I only observe through my HW. To find the sun I usually remove the eyepiece and look into the empty HW eyepiece tube moving the scope until the sun illuminates the prism. Popping the eyepiece back in usually finds the sun to be in the field of view.

[900SL]

1 minute ago, John said:

That looks a nice result 🙂

I only observe through my HW. To find the sun I usually remove the eyepiece and look into the empty HW eyepiece tube moving the scope until the sun illuminates the prism. Popping the eyepiece back in usually finds the sun to be in the field of view.

Only problem being this could be a gateway drug into the bottomless pit that is Ha solar 🤑

[John]

22 minutes ago, 900SL said:

Only problem being this could be a gateway drug into the bottomless pit that is Ha solar 🤑

I've owned a couple of Ha scopes but not found them engaging enough to keep. I'm a lightweight dabbler in solar observing - mostly for outreach with my astro society really 🙂

If you get in deep though, the costs can quickly mount up. I'm currently minding a 60mm double stacked Lunt Ha scope for my society which I believe would cost over £5K to replace 😲

[Louis D]

I think I looked through an Ha scope once at an outreach event, but I found the deep, dark red color too difficult to make out any details.  Is that what Ha scopes view like?  For me, I'd probably only use one for imaging rather than visual.

[Stu]

Interestingly Baader recommend the Continuum filter being closer to the scope and then the ND3.0, both on the eyepiece side of the wedge of course. This minimises reflections from the shiny Continuum.

The filter in my Mark II is a 7.5nm and I also have a polariser fitted which can vary brightness by moving the lever on the Wedge. I generally prefer it towards the brighter end of the scale, although sometimes granulation is easier to see with it a bit darker.

[Paz]

My white light setup has changed a lot over time, but currently it is...

Objective

2" uv/ir cut (with kg3 which absorbs any ir that is not reflected)

Wedge

Glass path corrector

Continuum filter

ND3 filter

Polarising filter

Filters are on a nosepoece that I can rotate independently of the wedge and the binoviewers to enable use of the polarising filter.

Binoviewers 

Eyepieces

 

The nd3 filter was previously "fixed" on the wedge but I finally worked out how to detatch it as I also use the wedge sometimes for observing Venus, hence the nd3 is how it is now.

[900SL]

On 16/05/2024 at 21:20, Stu said:

Interestingly Baader recommend the Continuum filter being closer to the scope and then the ND3.0, both on the eyepiece side of the wedge of course. This minimises reflections from the shiny Continuum.

The filter in my Mark II is a 7.5nm and I also have a polariser fitted which can vary brightness by moving the lever on the Wedge. I generally prefer it towards the brighter end of the scale, although sometimes granulation is easier to see with it a bit darker.

Thanks Stu.

 

The TS wedge 'Continuum' filter is fairly wide, I think 40nm from memory.

Would I see any improvement (for imaging) using my 4.5 nm Oiii narrowband filter?  

[Stu]

On 18/05/2024 at 07:08, 900SL said:

Thanks Stu.

 

The TS wedge 'Continuum' filter is fairly wide, I think 40nm from memory.

Would I see any improvement (for imaging) using my 4.5 nm Oiii narrowband filter?  

Worth trying I should think. May be a bit too narrow but I’ve not tried one so don’t know.