Moon / ND filter for Ha scope (PST)?

[Moonshane]

Has anyone ever tried this? I ask as whilst using my PST today, I noticed that the detail visible had a little more contrast as thin cloud wandered across the field.  I wondered if a ND/Moon filter would have the same effect? If nobody has then I may try my polarising filter tomorrow (or when the clouds lift) as a start.

[Stu]

Shane, I noticed exactly the same thing using the Quark soon after I got it.

I did try a polarizing filter in it, and was able to tune the brightness by rotating the eyepiece.

I think I was using the 60 at the time, and overall I didn't end up thinking it added much. I will try it again on a larger scope to see what happens. I did wonder whether the effect was as much to do with my eye not adjusting fast enough when the clouds were passing in front of the sun and then clearing ie it could almost be a false effect so that once your eye has fully adjusted to the brighter image the contrast ends up being the same.

Does that make any sense at all???

Stu

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[Moonshane]

it does actually mate. in fact I was also noticing that the longer you look and roll your eye around (in its socket I mean) the more you see.

really enjoying the pst as standard. just need to get or make some tube rings for the Tal and then the increased aperture if the pst mod will be more noticable I should think.

[Stu]

it does actually mate. in fact I was also noticing that the longer you look and roll your eye around (in its socket I mean) the more you see.

really enjoying the pst as standard. just need to get or make some tube rings for the Tal and then the increased aperture if the pst mod will be more noticable I should think.

Shane, I now have a vision of you popping an eyeball out and slowly rolling it around on the table whilst assembling your PST mod. Disturbing!

Stu

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[Peter Drew]

I've tried many ways to replicate the thin passing cloud effect with little success so far. It seems as though the cloud narrows the band pass width as this can be produced usually only by double stacking or a narrower native band pass. Expensive!. Maybe a cloud chamber in front of the telescope is the way forward. 

[Stu]

I've tried many ways to replicate the thin passing cloud effect with little success so far. It seems as though the cloud narrows the band pass width as this can be produced usually only by double stacking or a narrower native band pass. Expensive!. Maybe a cloud chamber in front of the telescope is the way forward.

Interesting Peter. So it is a real effect then, not just a trick of the eye?

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[Peter Drew]

Seems to be a real effect. Interestingly, a hazy day doesn't give a similar appearance, only thin moving cloud. ?!! 

[spaceboy]

I have noticed in white light that on regular occasions the seeing becomes crystal clear once a cloud has just passed. I also noticed windy days seem to offer the best seeing more than calmer days. My best views are in the evening which it recently dawned on me it is because it's over clear land which has nothing but trees and fields for some way. Despite the sun being low the views are excellent.

[Peter Drew]

I have also noticed that approaching cloud seems to be preceded by a bow wave of turbulence, followed as you say, by a period of better seeing. I don't do a great deal of white light observation but Ha seems to be less affected by atmospheric turbulence, I get excellent results around an hour or two before sunset, particularly when in Tenerife where my horizon is the sea. 

[Moonshane]

I have also noticed that approaching cloud seems to be preceded by a bow wave of turbulence, followed as you say, by a period of better seeing. I don't do a great deal of white light observation but Ha seems to be less affected by atmospheric turbulence, I get excellent results around an hour or two before sunset, particularly when in Tenerife where my horizon is the sea. 

you can fall out with people you know Peter. 

[Pig]

Peter I find just after sunrise and an hour before sunset are the best times to observe

[JB80]

I have noticed in white light that on regular occasions the seeing becomes crystal clear once a cloud has just passed. I also noticed windy days seem to offer the best seeing more than calmer days. My best views are in the evening which it recently dawned on me it is because it's over clear land which has nothing but trees and fields for some way. Despite the sun being low the views are excellent.

That's interesting as I find the complete opposite to most of that but then it must come down to regional and like you say even more localised differences like your surroundings. When it is windy here seeing is not great at all and I wont even bring the scopes out after 3pm as the seeing starts heading south around lunch time. That is why I have been waiting on the cooler weather because not only does the atmospheric seeing effect me but the ground based heat turbulence is a real killer.

I often wonder if using an obs would help.