White Light Images on May 12

[johnpd]

I tried some white light images with my 5" refractor and the Player One Apollo-M Mini camera. I did a couple of AR groups but had a lot of trouble getting a good focus. It is getting very hot down here in Southern AZ and I am wondering if it is getting too hot for solar imaging. I have the scope set up just outside the house with a long USB cable feeding inside and powered hubs at each end. The mount is on patio stone. It is either that or rocks. Any suggestions for improvement.

JohnD

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[Rusted]

Are you saying the ground is getting too hot and causing thermals? Which affect the performance of your scope?

You could lay a white lightweight tarp [tarpaulin] over the area under the front of the telescope.
Weigh it down if wind lift is a problem. I discovered these cheap tarps are thermally neutral.
If left in place during the day the tarp would shield the ground from the sun.
Uncover at night to let the ground cool by radiation to the night sky.
Some solar observers spray water to cool the ground locally.
Or observe over a pond, lake or the sea.
Early morning imaging might be best in a hot climate.
Before the ground has a chance to heat up.

[Montana]

These are great John and a very warm and happy welcome

What equipment are you using? Baader astro solar film / Hershel wedge? Continuum filter?

To get good clear images yes you do need good seeing and this is number one, but you also need to have good optics and only Baader ND3.8 film or Herschel wedge is good for that. You need fast shutter exposure (hence ND3.8) and you need to eliminate UV/IR out of focus light. Therefore a good Herschel wedge or ND3.8 film + UV/IR cut filter and if possible a Continuum filter or O III filter for more contrast.

I hope this helps
Alexandra

[johnpd]

Are you saying the ground is getting too hot and causing thermals? Which affect the performance of your scope?

You could lay a white lightweight tarp [tarpaulin] over the area under the front of the telescope.
Weigh it down if wind lift is a problem. I discovered these cheap tarps are thermally neutral.
If left in place during the day the tarp would shield the ground from the sun.
Uncover at night to let the ground cool by radiation to the night sky.
Some solar observers spray water to cool the ground locally.
Or observe over a pond, lake or the sea.
Early morning imaging might be best in a hot climate.
Before the ground has a chance to heat up.

I was considering getting an astroturf mat/carpet but it appears they can get hot. I will look around for something.

JohnD

[johnpd]

These are great John and a very warm and happy welcome

What equipment are you using? Baader astro solar film / Hershel wedge? Continuum filter?

To get good clear images yes you do need good seeing and this is number one, but you also need to have good optics and only Baader ND3.8 film or Herschel wedge is good for that. You need fast shutter exposure (hence ND3.8) and you need to eliminate UV/IR out of focus light. Therefore a good Herschel wedge or ND3.8 film + UV/IR cut filter and if possible a Continuum filter or O III filter for more contrast.

I hope this helps
Alexandra

Thanks Alexandra,

I have an Explore Scientific ED127mm refractor as well as a Stellarvue SV80 refractor for full solar disk. I was using the 127mm for these images along with a Thousand Oaks SolarLite filter which apparently has a ND 5 rating. I might consider a Herschel wedge but would I need a ERF filter for the big scope? The Player One Apollo-M Mini has an optional accessory (Photosphere 10mm filter) which enhances contrast and I am using that.

JohnD

Edit: I found out that I do not need an ERF. I would need the 2" HW for my 5" which is OK since it has a 2" focuser. The 80mm also has a 2" focuser so it would work on both. So I am looking at probably a Lunt Solar Wedge.

[johnpd]

I also noticed that no matter what resolution I tried (1944x1472, 1104x1104, 800x600, 640x480), the frame rate was the same (about 6fps). Not sure why that is. I was using a long USB cable to connect from the scope to my computer inside. I connected the camera to a small powered USB hub on the mount, the hub to a 32ft USB 3.0 extension, that connected to a second powered USB hub inside, which then connected to the computer. I was using SharpCap for capturing.

JohnD

[Montana]

John, you will struggle to get clear WL images if you are only getting 6fps. Ideally you need to be getting 26-150fps for lucky imaging, hence the short exposure time needed (and hence ND3.8).

I use my Herschel wedge on a TEC140 no problem for hours, so no need for a front ERF.
Kind regards
Alexandra

[marktownley]

Hi John!

Nice results! My tips for improvement; throw the thousand oaks filter away - it is optically junk (you'll get the same results with a beer bottle). Fafr better and on a budget is the Baader solar film, better still a herscchel wedge.

To get better fps you need to lose USB extensions, that is a data bottle neck.

Mark

[johnpd]

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Well I took Mark's suggestion and dumped the Thousand Oaks W/L filter. I purchased a Lunt W/L Solar Wedge and Wow what a difference it made. I was able to easily get a decent focus. With the Thousand Oaks I was constantly struggling. Unfortunately I was fighting wind and clouds and was only able to get some quick snapshots. I processed one with ImPPG. Using a small ROI, it shows several groups of active regions at one end of the Sun. This image was taken with my Explore Scientific ED127mm refractor and the Player One Apollo-M Mini camera including the Photosphere 10nm filter.

Regarding the USB extension. I don't have much of a choice. With the extreme heat down here in southern AZ I can't stay outside next to the scope as I would bake. I got a new slightly shorter "active" extension that I can plug into AC power. It worked perfectly. No drops of devices. When the weather calms down a little, I will try some videos. I did try the new extension inside and there was not a substantial drop in FPS as with the other extension. I processed one of the snapshots with ImPPG.

JohnD

[marktownley]

That's quite an upgrade

[nicspenceryork]

Hi John, brilliant result with your new wedge 👏
Nic

[johnpd]

Thanks,

Sunday I was able to get some videos but the Sun was still bouncing around. I processed one. The Player One camera with that higher contrast filter is working out great not to mention the Lunt Solar Wedge. Fortunately my local astronomy shop up in Tucson had one wedge left. I want to try to use a Barlow and get some higher resolution shots. My focuser is at about 7mm from the end of infocus. Hope I can get the Barlow to work.

JohnD

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[johnpd]

I finally tried a Barlow (2.5x) with my setup to get some closeups of the big groups. The wind is still a problem down here and I will probably stop imaging for a while until the wind situation subsides. I grabbed the big AR3310 in one image and the multiple group AR3311 and 3313 in a second. I really wanted to try SharpCap's "Feature Tracking" tool, but with the gusting winds that was not a possibility.

JohnD

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[marktownley]

Great results!