Tips for shooting the entire solar disk in H alpha

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Arrakis97
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Tips for shooting the entire solar disk in H alpha

Post by Arrakis97 »

Hi all :)
In the last few weeks I have been testing the Daystar Imaging Focal Reducer 0.5 - 0.3 X, on my Tecnosky 80/480 with Daystar Quark Cromosphere. The goal was to film the entire solar disk with the ASI 174 MM camera. The results were far from expectations; in the combination with a 0.3 X spacer ring, a strong vignetting is obtained at the edges and in any case only a part of the disc; even removing the spacer, the image quality is degraded at the edges (see attached image).

Image2021 11 28 - 10h 31' 03 sec CET Sun H alfa cromosphere NOAA 12898 e 12900 by Carlo Casoli, su Flickr

I am therefore still looking for a solution to capture the full disk of the sun in H alpha;

A solution could be to use a larger CCD, even if the small size of the filter does not allow to use much larger CCDs; furthermore, the recovery times would increase excessively.

A second solution could be to diaphragm the Tecnosky to 60 mm, mount a 2x Barlow (already available) and buy a Daystar Combo filter; in this way the filter would work at 480 X 2/60 = F 16. With a focal length of 960 mm and the ASI 174 mm I should be able to shoot the full disk. I am not able to assess whether this solution can be efficient.

I also tried to get a photo of the entire solar disk by processing a mosaic of several images; the first results were quite poor since each image has an excess of exposure at the edges and at the time of assembling the mosaic the edges have different exposures.

Finally, the alternative could be to buy a new small aperture solar telescope such as a 50 or 60 lunt or a 40 mm or 60 -70 mm coronado. In this solution I would try to buy a solution in DS for better contrast. I would use this lens only to shoot the full solar disk in H alpha since for high detail shots I already have the TEC 140 APO available.
The coronado 70 solution with the 60 mm front filter could be useful for use in visible light with the Baader Wedge Filter and in Ca K with the Lunt B600, a solution available by removing the frontal etalon, an operation that I imagine is simple.

I have never owned one of these optics and would be grateful for any suggestions for this choice.
Thank you in advance for the valuable suggestions you will want to provide me from the top of your great experience.
Transparent skies
Carlo


Carlo Casoli
https://www.flickr.com/photos/carlocasoli/
TEC140 Apo with Baader D-ERF 160 mm, Beloptik Telecentric 5x, Coronado PST, Solar Spectrum S.O. 0.5 A
LUNT Tha 80 D.S.
Tecnosky 80/480 Apo
Daystar Quark Cromosphere H alfa Filter
Lunt B600 Ca K filter
Baader Herschel Wedge
Ioptron CEM70-G & Tripier
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Re: Tips for shooting the entire solar disk in H alpha

Post by Radon86 »

Hi Carlo,
I tried mosaics with a ED70mm refractor, Quark chromosphere and ASI120mm-S camera. I found this possible but need very good weather and stable seeing conditions.
To get a full disc is a lot of effort but can be done. I recommend FireCapture with flats applied. You will need to get very good at making flats and get a good exposure with flat calibration.

I also had used ASI174mm and this much easier to get a full disc and ED70 (F6 refractor, 420mm=focal).
In fact I got a full disc with a 60mm guidescope using only 2 panels and the ASI174mm

I am not expecting the best quality detail, but I am satisfied with things. I think you have to put a reasonable expectation of the quality you can get.

I can always go to the Parker Solar Probe for best images of sun close up....and the SDO website as well.

Best wishes,
Magnus


Solar: H-alpha": Quark Chromosphere filter; Baader white light filters
Scopes: Altair Astro Travel ED70mm (F 420mm, D=70mm);; Skywatcher 90mm (F 910mm D=90mm); GSO focuser;;Altair Astro 60mm guidescope (D=60mm,F=225mm)
Cameras: ASI120mm-S,ASI174mm
Mount: SW HEQ5 Pro, SW EQ3 Pro Synscan (SW = Skywatcher),Vixen Polarie tracker (portable setup)
Accessory: SW Auto-focuser
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Re: Tips for shooting the entire solar disk in H alpha

Post by Radon86 »

Hi Carlo,
Have you got the Solar Astronomy book by Christian Vladrich ? There is a section on solar imaging and a part of it is dSLR and full discs. It is not the answer you want, but there is useful ideas to take a look there. I may have a try using one of my Canon APS-C cameras. A challenge. Of course mono high speed cameras is necessary for best quality.
I am sure one of the more experienced forum users will explain better than me..like Montana.

Magnus


Solar: H-alpha": Quark Chromosphere filter; Baader white light filters
Scopes: Altair Astro Travel ED70mm (F 420mm, D=70mm);; Skywatcher 90mm (F 910mm D=90mm); GSO focuser;;Altair Astro 60mm guidescope (D=60mm,F=225mm)
Cameras: ASI120mm-S,ASI174mm
Mount: SW HEQ5 Pro, SW EQ3 Pro Synscan (SW = Skywatcher),Vixen Polarie tracker (portable setup)
Accessory: SW Auto-focuser
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Re: Tips for shooting the entire solar disk in H alpha

Post by Radon86 »

Hi Carlo,

A focal reducer will be hard to get good images. This is because the Quark gives a high focal ratio. You may have to crop your image to eliminate the areas affected. You can get tips from Montana, but with Quarks, maybe it is not so easy...?

Magnus


Solar: H-alpha": Quark Chromosphere filter; Baader white light filters
Scopes: Altair Astro Travel ED70mm (F 420mm, D=70mm);; Skywatcher 90mm (F 910mm D=90mm); GSO focuser;;Altair Astro 60mm guidescope (D=60mm,F=225mm)
Cameras: ASI120mm-S,ASI174mm
Mount: SW HEQ5 Pro, SW EQ3 Pro Synscan (SW = Skywatcher),Vixen Polarie tracker (portable setup)
Accessory: SW Auto-focuser
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Re: Tips for shooting the entire solar disk in H alpha

Post by marktownley »

Hi There,

With the setup you have a full disk is just not possible. I would recommend getting a Lunt50/60 and then a suitable camera to get a full disk in one. The 174 and it's large pixels really is only suitable for use with the Quark on close ups.

Mark


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http://brierleyhillsolar.blogspot.co.uk/
Solar images, a collection of all the most up to date live solar data on the web, imaging & processing tutorials - please take a look!
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Re: Tips for shooting the entire solar disk in H alpha

Post by Arrakis97 »

Boso36 wrote: Wed Dec 08, 2021 8:42 pm Hi Carlo,
In fact I got a full disc with a 60mm guidescope using only 2 panels and the ASI174mm
I am not expecting the best quality detail, but I am satisfied with things. I think you have to put a reasonable expectation of the quality you can get.
thanks Magnus for the suggestion regarding the use of a finder scope with a focal length of 200-250 mm; I'll do a test with my finderScope and i will post the results.
Best regards
Carlo


Carlo Casoli
https://www.flickr.com/photos/carlocasoli/
TEC140 Apo with Baader D-ERF 160 mm, Beloptik Telecentric 5x, Coronado PST, Solar Spectrum S.O. 0.5 A
LUNT Tha 80 D.S.
Tecnosky 80/480 Apo
Daystar Quark Cromosphere H alfa Filter
Lunt B600 Ca K filter
Baader Herschel Wedge
Ioptron CEM70-G & Tripier
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Arrakis97
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Re: Tips for shooting the entire solar disk in H alpha

Post by Arrakis97 »

marktownley wrote: Wed Dec 08, 2021 9:19 pm Hi There,

With the setup you have a full disk is just not possible. I would recommend getting a Lunt50/60 and then a suitable camera to get a full disk in one. The 174 and it's large pixels really is only suitable for use with the Quark on close ups.

Mark
Thx a lot Mark for ur recommendation for Lunt 50/60 :) ; do you suggest looking for an old model, with tilted etalon, or one of the new models with pressure tuned etalon? Regarding the camera, what about ASI 178 MM with 2,4 micro pixel?
Carlo


Carlo Casoli
https://www.flickr.com/photos/carlocasoli/
TEC140 Apo with Baader D-ERF 160 mm, Beloptik Telecentric 5x, Coronado PST, Solar Spectrum S.O. 0.5 A
LUNT Tha 80 D.S.
Tecnosky 80/480 Apo
Daystar Quark Cromosphere H alfa Filter
Lunt B600 Ca K filter
Baader Herschel Wedge
Ioptron CEM70-G & Tripier
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Re: Tips for shooting the entire solar disk in H alpha

Post by marktownley »

Hi Carlo,

I would recommend the PT model. Those cameras with 2.4um chips can show a fixed pattern noise, some are susceptible, some are not. If you can buy from somewhere where you can return with no quibbles then all good. Failing that the ASI1600 is a decent option.

Mark


Image
http://brierleyhillsolar.blogspot.co.uk/
Solar images, a collection of all the most up to date live solar data on the web, imaging & processing tutorials - please take a look!
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Re: Tips for shooting the entire solar disk in H alpha

Post by fedele »

"IT IS IMPOSSIBLE...."

No IS NOT impossibile:

viewtopic.php?f=9&t=34181&fbclid=IwAR2p ... YPmq_Y4Zn8


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