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Solar imaging questions


jambouk

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I can't stand the processing side of imaging, it doesn't interest me and I'm not very good at it. Is processing solar images taken in Ha any easier than processing images of DSOs and the like, or just as tedious but in a different way?

Is there a simple guide to understanding Ha solar scopes on the web, as I can't find one. What I've learnt so far is to get as much aperture as possible, and ideally less than 0.5A. We'd be looking at imaging with either a DSLR or a mono QHY5ii. Budget under £2000.

Thanks for any help.

James

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IMO much more straight forward.

I run the avi through Registax, this doesn't take long. I have a preset file for the wavelets (this give me a good starting point, and in fact is usually all I do), this is also handy for mosaics as they are all processed to exactly the same point.

In Photoshop I have an action saved which performs the same amount of unsharp mask (only a subtle change), and turns the image to a nice colour.

A few minutes per image tops. If I have a nice image that I want to process differently then I can. Have a look at my images (www.emberson.org), almost all my images are processed in this way. I'm happy with them.

Ant

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Processing solar images is closer to planetary, I find. I find it more predictable, as you are focusing on a single object, rather than a huge variety of objects. Capture us far faster, and photons are plentiful.

I was thinking about writing a tutorial. Maybe I can make time for that the next cloudy period.

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I find solar more straight forward and quicker, I spend from about 2 minutes per image up to maybe at most a couple of hours. DSO I was looking at about ten hours I think :-o The couple of hours I sometimes do on solar is not that common, it's more if I am not quite happy with how an image has come out, I might reprocess it two or three times. I love that you have a lot of flexibility with the processing, invert the image, do light contrast, heavy contrast, false colour, it's all up to you. I personally much prefer the processing of solar images to DSO, I find it fun adding the false colour and not worrying about "correct colours."

I also like the fast data capture, 60 seconds to get an image, I was looking at four plus hours data capture last time I tinkered with DSO's. I hated DSO data capture, lack of an obsy didn't help. Solar I actually quite enjoy the data capture apart from the cold windy days. Summer is great fun capturing the images, I sort of "observe" on the laptop screen while it captures. I also prefer the solar accessories like sun hat, ice cream, suntan lotion, cold drinks :D That said, DSO imaging had whisky :D

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I also like the fast data capture, 60 seconds to get an image, I was looking at four plus hours data capture last time I tinkered with DSO's. I hated DSO data capture, lack of an obsy didn't help. Solar I actually quite enjoy the data capture apart from the cold windy days. Summer is great fun capturing the images, I sort of "observe" on the laptop screen while it captures. I also prefer the solar accessories like sun hat, ice cream, suntan lotion, cold drinks :D That said, DSO imaging had whisky :D

Very nicely summed up!

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Ok, thanks all. So it sounds like the processing side of things is more like the stuff I can handle and not get totally irate with :) And the idea of sitting in the sun shine with a glass of Pimms helps...

Now, what scope? Could get bits to convert the Skywatcher ED80, but would really like a stand alone solar scope. Any suggestions? I like the look of the 60mm Lunt with the BF1200 blocking filter:

http://www.altairastro.com/lunt-60mm-h-alpha-telescope-crayford-focuser-bf1200-blocking-filter-ls60tha-b1200c.html

Or is there something else?

Will there be issues focusing with either a DSLR or a QHY5ii?

James

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The Lunt is a great piece of kit, a Quark in your ED80 would get more detail, however (but not full without misaics). A Quark in your ED80 will get results close to my APM 80/Solar Spectrum set-up. The LS60 will be a slight step up from my Coronado SolarMax-II 60 with BF15 set-up. That is pretty good but cannot match the Solar Spectrum.

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10 hours on DSO processing, blimey I usually spend an hour at most. Perhaps I should take longer but then life is getting shorter. I too wish to try solar and I had guessed that it would take me the same time as my planetary so about an hour or so. Looking forward to giving it a go over a few chilled ciders.

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The Quark looks nice; shame one has to decide on either one for prominences or chromosphere:

http://www.teleskop-express.de/shop/product_info.php/language/en/info/p7049_Daystar-Instruments-QUARK---H-Alpha-eyepiece-filter-system-for-Prominence.html

So with the Quark, no energy rejection is done until the light has passed through the scope? What filter would be used?

James

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So with the Quark, no energy rejection is done until the light has passed through the scope? What filter would be used?

I was beginning to think that maybe that aspect was never going to be highlighted on the forum.

Well done James.

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The Quark looks nice; shame one has to decide on either one for prominences or chromosphere:

http://www.teleskop-express.de/shop/product_info.php/language/en/info/p7049_Daystar-Instruments-QUARK---H-Alpha-eyepiece-filter-system-for-Prominence.html

So with the Quark, no energy rejection is done until the light has passed through the scope? What filter would be used?

James

Prominences show nicely in the Quark, and even with my Solar Spectrum filter at even narrower passband. Scopes no bigger than 80 mm do not require an ERF, just a UV/IR filter in front of the Quark (in my APM 80mm the Herschel wedge never gets hot, after all). Bigger scopes do require ERFs (as does my Solar Spectrum filter).

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The Quark looks nice; shame one has to decide on either one for prominences or chromosphere:

http://www.teleskop-express.de/shop/product_info.php/language/en/info/p7049_Daystar-Instruments-QUARK---H-Alpha-eyepiece-filter-system-for-Prominence.html

So with the Quark, no energy rejection is done until the light has passed through the scope? What filter would be used?

James

If going Quark I would say go Chromosphere unless Proms are your massive thing, proms still look very good with the Chromosphere, they will be even better in the Prom version, but really they are still very impressive in the Chromo. A bit like when I used my SolarMax 60 double stacked (0.5A) I didn't feel a desperate need to take the front filter off and use it single stack too (0.7A), proms still looked very good at 0.5A and disc contrast was much better :)

re: the light entering the scope, the same is true of course for many of us who are using Herschel wedges. I personally prefer using a Herschel wedge to using Baader solar film over the font of the scope, but that's just me, with solar only ever do what you personally feel comfortable with and of course it's essential to thoroughly read the manual for these solar products before using them.

I use a Herschel wedge with my Equinox 120 and like several others I know of I use UV/IR cut with the Quark in a 120mm scope (I use a 2 inch Astronomik L). You can download the manual here that covers it all in some detail:

https://www.daystarfilters.com/downloads/QuarkManual.pdf

I suspect that I would get slightly better performance with my 120mm if I used a front energy rejection filter, e.g. on cold winter days it seems to need some time for the view to stabilize (no such issue with my 85mm scope), my best guess - and it's only a guess - is that thermal currents are at play, that a front ERF would address. That said, I am more than happy with how it performs in my 120mm, even without front ERF. For the price it takes some beating.

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The front end ERFs are pretty expensive, several hundreds of pounds! So I think it's a 2" IR/UV filter job.

Looks like it can be used with a reducer too, so maybe a full disc would be possible with an ED80:

http://blog.astroshop.de/wp-content/uploads/2014/07/quarkkonfig2.jpg

Not sure how the reducer-spacing issue would affect image capture.

James

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Not sure about the reducer spacing, James. For imaging I use a 1.25 inch 0.5x reducer on the camera nosepiece, i.e. after the Quark (about £20 from Telescope House). A downside to my reducer setup is that with a larger camera chip I may have to use quite a bit less reduction to avoid vignetting.

I get about 0.55x reduction with my 1/1.8 camera (Grasshopper 3, ICX687) and had to nudge things up to about 0.72x with my larger 1/1.2 camera (ZWO ASI174) to avoid strong vignetting. I still get a touch of vignette at 0.72x, but a flat sorts it out. I think other ways may allow less of a vignette issue, like running through a 2 inch reducer, but I can get by with my setup, the ASI174 has larger pixels anyway than my Grasshopper 3.

And for visual I get easy full disc with my Tele Vue 60 so don't really need a reducer there. I think Stu (BigSumorian) uses a reducer before the Quark?

Yes, front ERF's are pricey! :eek:  I think I would be close to matching the Quark price if getting an ERF for my 120mm.

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A reducer in front of the Quark is the only way to increase the maximum field of view. However, this turns your scope effectively into a Petzval type. I would not use such a design with a Quark, because of the heat build up in the rear lens. You might be able to use it with a full aperture ERF, but the Petzval set-up does not work in an ideal fashion with the tele-centric lens in the Quark. It is better to get an ST80 to cater for full disk views

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A reducer in front of the Quark is the only way to increase the maximum field of view. However, this turns your scope effectively into a Petzval type. I would not use such a design with a Quark, because of the heat build up in the rear lens. You might be able to use it with a full aperture ERF, but the Petzval set-up does not work in an ideal fashion with the tele-centric lens in the Quark. It is better to get an ST80 to cater for full disk views

That image looks exact same style as a different one in the manual, Michael, and on this page they seem to be suggesting this is a recommendation from Daystar?:

http://www.astroshop.de/blog/?p=18473

It hadn't initially entered my mind that reducer could be okay before Quark, and I would also have thought it would lower the performance, but I know not!

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