P.S.T with uhc ?

[part timer]

Has any one else tried putting a UHC filter on the eyepiece of a PST?

I've done it before but never really been sure if it helped. Yesterday and today however leave no doubt. The view is quite a bit sharper and many surface features in particular are MUCH easier to see.

Prominences are easier to, although the effect is not so marked. I have a Baader filter by the way.

Are there any other cheap tricks people have used with Ha viewing?

Luke

[Solar B]

Mmmmm thats very interesting i thought that id tried everything there was possible with a pst

but a uhc is a new one on me.....im gonna have to give that a go.

Cheers Brian

Oh....no other cheap tricks for ha viewing.....you could try a nd filter as well....it does improve contrast

slightly but robs you of light.

[part timer]

I am not sure how it's working but it is! Since my last post I've had another go and the filter again made things clearer. I don't see as much gosting etc as without, so it seems the filter is blocking some of the unwanted 'stuff'.

LUKE

[Solar B]

That does sound very promising Luke....i will get a hold of one to try....one question are you

using a new or original type pst ? Brian

One other trick is to make or buy a shade.

[part timer]

Mine was original type but was 'repaired' by telescope house for the rust problem. It's never been the same since it came back from repair. The rust was affecting the view however and was getting thicker so it had to be done.

Luke

[Astroman]

Well, first you say you're using it on a PST, then you say you have a Baader filter. Which one is it? A PST is strictly H-Alpha, while the Baader is white light. I'd be surprised if a UHC worked at all with a PST, as the UHC filters all but H-Beta and OIII. It shouldn't affect the very narrow H-A band at all.

Now, if you're using a Baader film white light filter, which I've done too, it does help quite a lot with contrast, for the same reason it works on nebulae. It filters out wavelengths other than two relatively narrow ones.

Which scenario is it?

[part timer]

You've misunderstood,

I use a PST. I then screw a UHC (made by baader)(for deepsky!) filter into the eyepiece. This should make zero difference, as you say. The difference is not zero. It is large.

I never tried this with the original optics so i don't know if it made a difference then.

I will try to explain what I see.

With the filter (on the eyepiece placed in the PST) fainter Prominences can be seen, brighter prominences are sharper and disc detail is much more defined. In addition detail on disc and prominences is easier to see at the same time.

I don't know why all this is so. When i have time in about 3 weeks I'll try to figure it out.

Luke

[Astroman]

Hmmm. I'll have to try this myself when I next get the Coronado HA setup. I suppose it could make prominences along the edge stand out more, but the narrow band of HA makes me skeptical. Very odd. Not that I don't believe you, I just don't see how it could work. :? :scratch:

[part timer]

Believe me I wouldn't waste my time posting If It wasn't doing something.

since my PST came back from Telescope house for it's rust fix there has been LOTS of scattered light all around the solar image with ghost images on either side. This was not the case with the old optics. The uhc filter in place reduces this which is what I think is improving the image.

the problem (as you point out) is that the PST has such a narrow bandwidth that The image (scattered or not) should show no difference. Now I am wondering if my PST is is entirely lightproof. I use it a lot and I still have my retinas so I don't think un filtered focused light is reaching the eyepiece but it's got me thinking :insects1:

LUKE

[Mark at Beaufort]

Luke

I have an original PST so I found your statement very interesting. Today is the first sunny day that I have been able to test the suggestion. Some good prominences and bright areas on the surface. I tried the Baader UHC-S and it made no difference - I am sorry to say. At least it was worth the try and allowed me to do some solar observing this morning. I hope your PST is safe and okay.

Mark

[part timer]

Never mind,

Mine seems safe i.e. I'm not blind . But there's something wrong some where. The optics were changed when it got rusty. It came back unable to see any prominences at all and with the tuning ring wobbly and loose. Luckily it was fixable (Eyepiece end) were different as well and I,m thinking maybe this is where any problems may be. I'll try and see if i can take a picture of the difference the next chance I get weather permitting .

Luke

[blinky]

I had a loan of a glass solar filter and when I stuck in the UHC 3 tiny sunspots popped out at me! I removed the UHC and although they were still visible they were much less obvious.

[part timer]

Thats pretty much my pst experience. The only difference is it shouldnt happen in such a narrow band :? .

Not to worry summer is coming and I'll figure it out then.

Luke

[scotastro]

The PST has a wider passband than the more expensive Coronado models so the enhancement you are seeing could be because the H alpha bandwidth of the UHC filter has a narrower bandwith or a least a complimentary one.

Scotastro

[part timer]

I'm going spend some time investigating this in a few weeks when I have chance. I was sort of wondering about the passband width. It is certainly true that not all PST's are equal. Some (very few) do have a lower passband due to the inherent variability of mass production. These give a better view than most. Possibly I am at the other end of the scale and I've just got a particularly poor example thus giving scope for improvement.

Thanks for the idea.

plenty to mull over!

Luke

[part timer]

Couldn't help but look at this today even though I do not have time :nono: .

Anyway measurements of band pass of the uhc filter (about half way down link)

http://www.astrosurf.com/~buil/filters/curves.htm#Protocol

show that the band pass of the PST 'may' be complemented by the UHC. The Transmition curve around this wavelength is not at maximum and so in a Poor PST such as mine the filter may help a bit.

Luke

[part timer]

Alright,

before any one looks I was looking at the meade graph underneath .

The baader one does peak at the Ha wavelength. More investigation required

Most transmittion graphs I have found are not identical however and it would not take much for the filter to make a difference to the view.

[Paxo]

Luke,

I think the important thing here is that if it works for you then go for it, and don't get too hooked up in working out the bandwidths and physics, just enjoy the views.

Steve..

[part timer]

Actually I enjoy working it out Besides its cloudy here anyway

[Paxo]

Actually I enjoy working it out Besides its cloudy here anyway

Good luck as the physics are definately against you on this one !

Steve..

[part timer]