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GavStar

H alpha vs white light

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GavStar    759

I'm sure this topic would have been covered before but I've done a search and can't find a comparison between h alpha and white light observing.

Ive got a 60mm Lunt and had fantastic views of the sun on Saturday afternoon. I got very detailed views of the main activity but also observed a large prom emerging from the limb of the sun. First it looked like an orange pimple on the limb l, then a loop and then finally it detached one end - all in 30 mins or so. An aircraft flew past the sun as I was observing when was fun to see as well.

I haven't done much solar observing but yesterday showed me how good it can be. However the Lunt only really was able to take magnification up to around 70x - once I moved to 100x the views broke down. In fact my favourite view was at 25x which gave a very well framed sun but with lots of detail there.

I was wondering if using a Herschel wedge on my 100mm frac would enable higher magnification views of sun spots etc. Are there any other benefits of white light viewing over Ha?

Edited by GavStar

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Davey-T    8,876

I use LS60 for full disc views and Quark for close ups but I don't think you can beat WL  for super sunspot detail, so you really need all three :evil4:

Dave

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Stu    14,146

I use up to x200 with binoviewers in my Tak Gavin. I think the limit would be lower using a single eyepiece due to floaters (fore certainly), but the binocular views when seeing is good are amazing. At high power you do have to wait longer for the good seeing spells, but these days I always use x100 as a minimum.

I find that the brightness available with white light is higher and so the resulting contrast means that features are more clearly defined. With Ha, even with a 100mm PST mod there is a greater need to shield yourself from glare with a hood in order to get the necessary contrast. I'm not sure, but believe Ha is more susceptible to poor seeing, particularly on surface detail.

As you have seen, the activity in Ha is significantly more dynamic than in white light. Features can and do change within minutes, although not all the time. There is also generally something to see in Ha, whereas white light can be quite literally a blank disk.

I do love white light solar though. The high power views when the seeing is good are better than all but the highest quality images on the forum. Observing the granulation cells changing is fascinating and the detail available in large active areas can literally take your breath away. Petal-like structures in the penumbra, tiny pores, lovely areas of faculae, it's really amazing stuff!

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GavStar    759

Very helpful. Thanks. So next question I need to think about is baader Herschel wedge or new lacerta Brewster angle Hershel wedge.

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Stu    14,146
24 minutes ago, GavStar said:

Very helpful. Thanks. So next question I need to think about is baader Herschel wedge or new lacerta Brewster angle Hershel wedge.

I've only had experience of the Lunt 1.25" and Baader CoolWedge. I'm very happy with the Baader, to me, knowing I've got the optical figure of the Tak and Zeiss prism quality is an assurance that I'm getting the best quality high power views.

Then again, you could always get the Lacerta and see me weep if it's better! :(

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Piero    2,671

I've never observed the sun in h-alpha but regularly do in white light. In the beginning I was using a 1.25" Lunt wedge but didn't feel comfortable with heat dissipation. I also didn't like filter placement, and that I could not use 2" eyepieces directly (è.g. my zoom).

The Baader wedge solved all these issues and I feel the image shows more contrast, particularly at high power. I also agree with Baader that the placement of the SC filter before the ND3 reduces reflections. My eyes don't have many floaters and under good seeing I managed to push the magnification above 300x successfully. Really great views. All all, I'm very happy with this filter and I've never regretted this purchase. Aesthetically, it fits with the Tak too! 

20170816_174831.thumb.jpg.9296fc731ab2f9dd75c954e8a226e503.jpg

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AdeKing    138

I'm a recent convert to solar observing and love the white light views I get with a ST102 and Lacerta wedge.

I opted for the Lacerta wedge as I couldn't stretch to the 2" Lunt or the Baader Cool Ceramic and I haven't been disappointed.

The Lacerta wedge has been fantastic, though is a bit of a lump weighing in at about 750g.  I was viewing continuously for about 3 hours on Saturday with an EQ5 tracking the sun and the back of the wedge was still cool to touch at the end of my session.

The wedge certainly improves contrast more than the solar film that I previously used.

I don't have my own Ha scope yet, but have borrowed a Coronado PST from our Astro Group and whilst Ha gives excellent detail I find the WL views more rewarding as I find that i pay more attention to the sunspots as there is less surface detail to distract me.

Ade

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xtreemchaos    9,279

thay both have there merits, my eye says HA but my heart says Whitelight, I find Whitelight the harder of the two for imaging, HA gives you so much detail that it makes easyer processing. I'm glad I cut my teeth on WL because if id started with HA I might of found WL too hard.  charl.

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spaceboy    1,518

WL for me, especially when you get sunspots like we have on the sun at present. It is worth noting 2" wedges do eat up more inward travel than a 2" astro diagonal as I unfortunately found out recently. A quick comparison showed an additional 14mm of back focus was required in the coolceramic over my SW/WO diagonal. I have the Lunt 1.25" which tbh I have always been happy with but the Baader does seem to offer up marginally better contrast and, I want to say deals with seeing better but in truth I think this is probably more a matter of the coolceramic dealing with the heat better both through design and the larger heat sink. The 1.25" Lunt is no slouch though and is far better than solar film.

I enjoy Ha and I do get those wow moments when considering just how massive some of those proms can get but more often than not my eye is all over the place and not really settling in on one feature making the best of it. When you do get real-time activity like lift offs and flares Ha really comes in to it's own though. It's moments like these when a PST mod of 4"+ really shines.

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Highburymark    894

Glad you've had some great views with your Lunt. If you do get a chance to view with a second etalon the scope will deliver stunning detail.

As for white light, I have always used an ETX105 or 80ED - I would not have dreamt about using my Tak for WL observing until I started reading Stu's reports. Even now I'm nervous about trying - but sounds like the views are amazing.

 

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Stu    14,146
57 minutes ago, Highburymark said:

I would not have dreamt about using my Tak for WL observing until I started reading Stu's reports.

Go on, do it! You know it makes sense :) 

Seriously, my Tak gets used ALOT for white light observing, probably more that astro and I have had no problems. As I've said elsewhere, I'm sure it gives away some resolution to a 120ED but it doesn't half take mag well when conditions allow and is so much more compact.

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Paul73    2,407

Don't worry Stu the views through Tak and ED120 are pretty close.😊😀😊😀

It is worth noting that, at high mags, the Baader offering is noticeably better than the Lunt 1 1/4". But, I guess that this is reflected in the price. The Baader Solar Continuum filter is worth the money too (use with the wedge).

To my mind, the Lunt 1 1/4" wedge is the best value for money kit  buy in astronomy.

I have the Ha scope parallel mounted with an ED120 + Lunt Wedge. Best of both worlds!!! Why compromise?

Paul

PS. In my limited experience, seeing/turbulence effects Ha more than WL. This difference is exacerbated as you up the aperture.

Edited by Paul73
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timwetherell    565

I do a bit of both. Interesting to compare the views of sunspots in different scopes - I guess one is looking at the photoshphere in one and chromosphere in the other with many km between. One thing I've noticed is that the "umbra" of sunspots appears smaller in Halpha than white light. I've tried to confirm this using a graticule eyepiece and though the error bars are quite big, does seem to be a real phenomena :) This is a sketch of a very nice sunspot group visible yesterday (and presumably today too)

59bce04ad9d51_solarobservationssunspot.jpg.067594ed14632bceb32662a67e068599.jpg

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jetstream    3,898
On 9/3/2017 at 16:52, GavStar said:

So next question I need to think about is baader Herschel wedge

:thumbsup:

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GavStar    759

Thanks for all the comments. I've decided to go for the tried and trusted Baader which I've now got but of course it's raining! Looking forward to doing a side by side comparison soon.

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Piero    2,671
7 hours ago, GavStar said:

Thanks for all the comments. I've decided to go for the tried and trusted Baader which I've now got but of course it's raining! Looking forward to doing a side by side comparison soon.

Congratulations! It's a great tool! 

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Stu    14,146
On 13/09/2017 at 21:37, Paul73 said:

I have the Ha scope parallel mounted with an ED120 + Lunt Wedge. Best of both worlds!!! Why compromise?

Yep, agreed.

IMG_0244.JPG

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