Solar Viewing w/refractor

[Moonshane]

I'd appreciate confirmation but suspect a good white light full aperture filter (either home made or bought) would work well with any design of scope? I use them for my newtonians so I assume there's little/no heat in the system.

[Stu]

I'd appreciate confirmation but suspect a good white light full aperture filter (either home made or bought) would work well with any design of scope? I use them for my newtonians so I assume there's little/no heat in the system.

I think that's right Shane, any full aperture solar filter such as Baader film or Thousand Oaks which prevent the heat entering the tube should be useable on any type of scope including maks etc

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[Mark at Beaufort]

I used an Orion glass filter at the front of my 5" SCT for many years which gave great views. A front solar filter will work on any scope although you need to check it each time to make sure that there is no damage - cracks, pinholes etc etc.

Nate -  a front solar filter will work with any of your refractors. I looked at the Stellarvue website and I am not sure about direct solar viewing (no front filter) through a carbon fibre scope plus its been flocked with velvet. Plus as Stu mentioned its not recommended to use a triplet which has a cemented front objective if you are thinking of a Herschel Wedge or Quark. Somewhere on the forum is a photo of a new cemented triplet that was badly damaged by direct solar viewing. So sending an email to Stellarvue is sensible but if in doubt use a front filter over the objective.

I know that many members use the Baader film and make their own filter because the view is very neutral.

However, if you are not certain about anything keep asking - your eyesight is very important.

[Stu]

http://stargazerslounge.com/index.php?/topic/217759-Quark-and-cemented-Triplets-%2A%2AA-Warning%2A%2A

!!!

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[Qualia]

Nate, in an issue of such importance regarding health and safety, I'm basically going to repeat what our colleagues have already said, but figure the more voices saying the same thing, surer will be your decisions. Secondly, I can only talk about white light, for I have no experience with Ha dedicated scopes, filters or eyepieces etc.

I find the Herschel Wedge with filters, that is, the absolutely necessary ND 3,0 filter and the optional variable polariser and continuum, provides the best white light solar views obtainable in terms of visual use.

But the Herschel Wedge is not recommended with any type of reflecting telescope, NOT Schmidt-Cassegrain, Maksutov, Newtonians etc. It is also necessary to make sure your refractor scope hasn't got cement or oil in it's internal works. It is also a good idea to make sure you have no plastic bits on your scope that could warp, melt etc whilst viewing the sun. 

Baader's Mylar film, for example, can be used with any type of scope and will also give you outstanding white light images, that is, you will also see sunspots, faculae and surface granulation. This is an excellent, cost effective, safe performer if used correctly.

A Herschel Wedge will only work with refractors as they replace the diagonal whereas the Baader film fit's over the front of a telescope and can be used on any type of telescope.

To see the sun with prominences etc you need to use a very expensive Ha filter or Quark eyepiece (fitted on a suitable frac - see above) or a Coronado or Lunt dedicated solar telescope.

Going back to the Herschel Wedge, you use the frac in the same manner as you would at night, except you either remove the finders or keep them absolutely capped at all times. It also makes very good sense to remove the large dust-dew shield thingy stuck on the objective end of fracs. Effectively, then, when viewing the Sun in white light with a Herschel Wedge, 100% of the Sun's light is raining down into your frac's lens, the objective end.

The Lunt wedge itself is a solid and very sturdy diagonal which passes about 5% of the light towards the eyepiece. The rest goes into the wedge's heat sink which in the summer months here in Spain can get quite warm to the touch but there’s nothing to worry about. Needless to say, this 5% is still too bright for the eye, so there’s an ND 3.0 filter which is inside the Wedge.

The ND 3,0 reduces the sun's brightness by something like a factor of 1000. Some wedges don’t have this filter built in so you need to purchase it separately. Again, even with the ND 3 in place the Sun is still too bright for visual observing, so you use a variable polarising filter fitted in the eyepiece’s barrel to reduce it even further. By rotating the eyepiece you adjust the brightness to the optimum level of the day. It is also very useful to use a green colour filter or the continuum to reduce the light just a tad further and also to augment white light solar features.

If you use Myler film, you make for yourself or you buy a suitable holder for it and place it over the objective end of the scope. This seems to me a perfectly safe way of viewing the sun in white light, but you need to check the film each time you use it to make sure there is no damage. This is also good advice for the Herschel Wedge. I have never used objective end solar glass filters, so really cannot comment on them.

In terms of safety, I feel the wedge is about as good as it is going to get and personally speaking, although not exactly based on any sound logic or reasonable argument, I have more peace of mind using it than I did with the Baader film.

I have included a little diagram of the Herschel Wedge set which I hope says more than my jumble of words and a randomly picked white light sketch that highlights the kind of thing seen:

[Liquid360]

Awesome/helpful reply Q! Thanks. Were you referring to any of these?

[Uplooker]

Liquid360,

NO, you should not use ANY of those filters you have pictured for looking at the sun.

Ian

[michael.h.f.wilkinson]

The drawing in Qualia's post is not correct. There should NOT be a lens between objective and wedge! The wedge is designed to take the heat, any other optics should be behind the wedge (hiding )

I think Mylar was the older material for films, modern ones are different, AFAIK.

[Moonshane]

agreed you should not use the filters shown as the main filtration but you could substitute the baader continuum with your Oiii.

good spot by Michael - looks like a petzval type design in the schematic.

[Liquid360]

I'm unsure what the forum guidelines have to say about high jacking ones own thread, but I just wanted to make sure I have my equipment hooked up correctly?

[Liquid360]

Also, there are three autoguiding ports, the guidecam, the CCD, and the mount. Obviously one won't be used. I'm assuming the guidecam goes to the mount leaving CCDS blank, but wanted to be sure.

Thank you!!

[allcart]

That's a nice looking setup Liquid360.

What type of filter have you decided to use?? Baader solar film or a Herschel wedge.  If you are going to use your setup as it is, then any scope or finder that has NO solar filter fitted, must have the objective end covered. Pointing any open ended scope directly at the sun with NO solar filter in the optical train will destroy the eyepiece or camera chip.

If you are viewing/ imaging through the SV, then keep the Tak objective covered.