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Paz

2nd Feb solar - first outing in a while

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I made the effort to set up for a look at the sun yesterday. I know the sun isn't doing much spot-wise in white light but it is still good for other things and I was keen to get out and have a go regardless. It's sometimes fun to set up not knowing if you will even see anything as when you do it is more rewarding.

My set up was an ST120 with a Brewster angle Herschel wedge on an EQ5. I took out a 8, 6, and 4.5mm Delos hoping one of those would hit the best magnification somewhere from 75x to 133x.

Unfortunately it was 1pm so the air was moving a lot but in the good spells I spotted some faculae north of the equator on the trailing limb with an orange filter and tuning the brightness down quite a bit with a polarising filter. I tried other filters and never got a better view. My guess it it was more likely a good spell of seeing and good luck with getting the focus spot on that resulted in the good views.

The 8mm was the best, the shorter focal lengths were too much for the seeing. I probably should have taken out 12mm, 10mm, and 8mm.

I either saw the faculae change shape a little over the space of half an hour, or maybe I just saw more details over the period and so a shape formed in my head.

A check of the solar imaging forum helpfully confirmed I wasn't imagining it.

No granules seen, but then I've only ever seen granules twice.

It was really good to be out observing again. The peace and quiet is something I have missed. Oddly, my main memory of this session will be that whilst observing I was listening to birds tweeting to each other in the trees and realised I could tell individual birds and they seemed to take it in turns to speak  - the kind of thing you never notice most of the time in life.

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Thanks for sharing your observations.  It was just like being there but with more birds than us. :thumbsup:

Did you try a solar foil filter before getting your prism? And why choose a Brewster wedge in particular?

Is it really worth the much larger investment in a solar wedge, instead of solar foil, in your own experience?

I'm suffering from blank sun syndrome and hoping for a bit more.  :blush:

 

 

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12 hours ago, Rusted said:

Thanks for sharing your observations.  It was just like being there but with more birds than us. :thumbsup:

Did you try a solar foil filter before getting your prism? And why choose a Brewster wedge in particular?

Is it really worth the much larger investment in a solar wedge, instead of solar foil, in your own experience?

I'm suffering from blank sun syndrome and hoping for a bit more.  :blush:

 

 

I did white light with a solar foil for a few years before getting a wedge.

I found foil doesn't eat up so much light path like a wedge does which allows more eyepiece options, and foil works with my maksutov whereas a wedge can't.

The wedge shows up slightly more detail, it's safer than foil, and you can tune the brightness to suit the feature you are looking at which is great. Not only can you dim an image if you want, you can for example put on a narrow band colour filter and jack the brightness up to whatever level necessary.

i don't think a wedge is absolutely  necessary, and I think film is better value for money, but a wedge is better and if you are keen and have a frac they are worth a go.

I got a Brewster wedge as that allows a wider range of dimming control with a polarising filter.

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Thank you for your very helpful and thoughtful response to a hotly debated subject.
You covered details which would never have occurred to me never having tried a wedge.
I've read lots of online discussions and websites but you have clarified areas where I still had questions.

The one remaining doubt is the ability of any particular wedge to cope with [literally] whole days of being toasted by my 7" refractor.
I rather like the look of the more sensibly priced Lacerta 2" Brewster and glass path length is not an issue for me.
A full frame DSLR might become an option one day. So I might as well cater for one.
Peter has mentioned using his 8.5" with a wedge but didn't mention how many hours the heat sink was tortured.

Thanks again. :thumbsup:

 

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I have a Lunt 1.25" HW, the last time I used it I was doing a comparison with a Lacerta version. If I was buying new it would be the lacerta. I don't observe in white light for more than perhaps 15 minutes at a time, enough to note changes, I can't see any good reason to leave a telescope tracking the Sun for longer periods for visual use.   🙂

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3 hours ago, Peter Drew said:

I have a Lunt 1.25" HW, the last time I used it I was doing a comparison with a Lacerta version. If I was buying new it would be the lacerta. I don't observe in white light for more than perhaps 15 minutes at a time, enough to note changes, I can't see any good reason to leave a telescope tracking the Sun for longer periods for visual use.   🙂

Thank you, Peter.
15 minutes hardly qualifies for the attention span of a wotsit in my [glacial] terms. :laugh2:

If, like me, you suffered from endless clouds AND had your H-a telescope mounted alongside the white light jobby,
then you might well want to leave both tracking [together] to make instant comparisons over the course of the day.  :wink2:

This morning, for example, the number of clear moments could be counted in mere seconds.
So I left them both tracking and pottered around the obs. doing odd jobs.
As soon as I saw the light I would dash across to the eyepiece.

Edited by Rusted
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14 hours ago, Rusted said:

Thank you for your very helpful and thoughtful response to a hotly debated subject.
You covered details which would never have occurred to me never having tried a wedge.
I've read lots of online discussions and websites but you have clarified areas where I still had questions.

The one remaining doubt is the ability of any particular wedge to cope with [literally] whole days of being toasted by my 7" refractor.
I rather like the look of the more sensibly priced Lacerta 2" Brewster and glass path length is not an issue for me.
A full frame DSLR might become an option one day. So I might as well cater for one.
Peter has mentioned using his 8.5" with a wedge but didn't mention how many hours the heat sink was tortured.

Thanks again. :thumbsup:

 

On the topic of heat dissipation I recall reading that a 2" wedge will disperse heat better than a 1.25" but mine is 1.25" and has never had a problem with my 120mm frac which I've observed with for long periods at a time (certainly over half an hour many times).

I stick a UV/IR filter in the chain but I don't know quantitatively how much heat this might deal with. I only do this for personal peace of mind about my eyes, I would not claim that it is necessary. I think these are more for imagers, but I don't know much about imaging.

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Thanks, Paz.  All good advice. :thumbsup:

It follows that the heat sink area of the 2" is considerable larger. LxW, so area rises as the square of the heat sink dimensions.

The same holds for the aperture of the telescope, of course. Bigger lens = considerably more heat!

Lacerta recommend a serious UV/IR cut filter for larger instruments. Though it must always follow the prism, on the eyepiece side and never in front.

Their 2" recommendation https://teleskop-austria.at/KG3-IFIRUV2_Optolong-IF-IR-UV-Sperrfilter-2-auf-KG3-Glasmaterial--#m is seriously pricey in 2"!

As is the 2" Solar Continuum! Each cost as much as the complete 1.25" prism! :crybaby2:

The single Baader 2" polarizing filter is more affordable and can be fitted in the rotating collar and left there for visual use.

The wedges, with adapters fitted, have a built in ND3 but Lacerta clearly state that it is still not enough on its own for visual use.

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