SolarChat!

I am wondering what people might consider to be their best current solar set up of all the configurations they have tried. I think there is a lot of useful information inherent in the collective experience. I mean, all the things we have tried are good, but after all the tweaking and tinkering what do we like best? E.g., Bob Y has tried different large front mounted, internal, rear, different forms of DS, etc.

After owning a decent Quark on many refractors, a pre-Meade Coronado ASP-60 DS, and a Lunt LS80 DSII, here is my choice:

For full disk H-alpha, it is my LS80 with DSII (purchased normally, not hand selected), with the two etalons made parallel with thin shims, with a circular polarizer that I rigged up between the etalons, with a home mod for a brighter B1200 blocking filter, and a Denk II binoviewer with a Denk OCS and Denk 21mm or TV Delite 11mm eyepieces. I prefer it to the Coronado (more aperture, more contrast, bigger sweet spot with binoviewer) or the full-disk Quark.

For high-power H-alpha, it is my chromosphere classic Quark on a 155mm f/7 refractor in series with a DSII unit (from my LS80) and my same binoviewer. (Slowly looking into a classic Cassegrain.)

For CaK, it is my Lunt B1200 CaK on a 70mm f/6.8 TV Pronto or on my 155mm f/7 stopped down to 100mm. But I am only using an R2 video camera, so hard to tell good from great. I have a PST #1 yellow filter that seems to add contrast, but not a huge difference in the R2. Currently testing a 92mm f/6.65. (Probably will get a better camera.)

George

Hi George,

You definitely need a better camera for observing CaK at the screen. And the less noisy and as more sensitive your camera will be, the better images on the screen you will get. This is especially important if you like to see spiculaes at the limb and prominences in a DS mode. You will need to use high gain and average camera will show a lot of noise.
I see these features best with large telescope at medium scale - in such way I get much less photon noise and better S/N ratio.

Such a camera will allow you to obtain images easier and light years ahead vs your images R2 camera.

Hope this helps.


Valery

Thanks, Valery. Agreed. I was thinking of starting with an ASI 174MM mono as an efficient next step, which should cover the large refractor well enough. Then can decide what to move on to.

George

george9 wrote: ↑Sun Dec 16, 2018 4:11 pm Thanks, Valery. Agreed. I was thinking of starting with an ASI 174MM mono as an efficient next step, which should cover the large refractor well enough. Then can decide what to move on to.

George

ASI174MM is a noisy enough camera. I get rid of it. For CaK one of the best camera now is ASI290MM.

Even old cameras by PGR on the ICX445 chip is very good for visual, but too slow for imaging.


Valery

Ok thanks. I will check. George

Interesting...
I find the performance of the ASI 174MM pretty good in my set up. the 5.86 micron pixel and 11.34 x 7.13mm frame size, read noise (at unity gain) 3.8e, QE 50% At longer fl, and ROI I still get good frame rates.

The ASI 1600, 3.8 micron pixel, 23.6 x 15.6mm frame size, read noise (at unity gain) 1.6e, QE approx 50% (@ Ha) gives full disk opportunities.

I think the ASI 290 with 2.9 micron pixel and a small 5.6 x 3.2mm frame size is limiting. Yes, I agree the read noise (@ unity) of 1.4e, and QE around 57% (@ Ha) is interesting.

Thanks. So obviously I am new to this part. Hard for me to judge noise. On pixel size, I guess the 174 makes more sense for H-alpha, where you are likely at f/30 (say with a Quark). For CaK, where you are f/7, the 290 pixels are likely to make more sense. And the 1600 has intermediate pixels, low noise, and large imaging area; presumably the only limit would be frame speed for so many pixels.

George

One size of pixels does not fit all. I use a 174 for f30, proper power supplies (not USB power) makes a big difference to noise - that's why I like the PGR / FLIR cameras as they allow external power options. I am getting a 290 for f10-15 imaging next year - nice for CaK! I use a different camera for full disks more suited to the f20 I work at.