Splendid Leo !
The 9 micron pixel is a perfect match for your setup. Well done !

It is beautiful !!

Splendid Laszlo !

Marvellous set of images Marty !

Amazing. Well done !

Very nice. Thanks for sharing !

OK, did a bit of reading and if I am not mistaken, FSR divided by FWHM gives finesse, so this one would have excellent finesse, right? Yes, this is true. But it would have been better to have the same finesse with a smaller FSR, giving a smaller FWHM as a result. I am going a test another Quark. Ju...

Very interesting! Is the FSR of 40A in line with other mica filters you have tested? My quark is more like 30A. I was really surprised by the FSR value. Other mica-spaced etalons I measured have a FSR in the range of 18 to 26 A. So, rather close to your 30 A. I used two different approaches to meas...

Thanks guys ! Pedro, I used the ASI 1600 with binning 2x2, otherwise the "pixel" size is too small. Accordingly, I got 47 fps. This is not very large, but better than nothing in order to have a field large enough. The alternative would have been to use the Basler 1920-155 (at a much larger...

Great ! Thanks for sharing.

Well done Filip ! Thanks for sharing.

Thanks to all !
So it was an M-class. Good to know.
Great animation Filip. It is quite dramatic in spite of the seeing condition.

This TS Triplet seems to be quite convincing. Your Quark is quite good too.
You're gone have fine when seeing conditions are good !

Thanks !
Indeed, my concern with the usual M42 focusers we can find in astro (Borg, TS or others), is that they are not strong enough to support the weight of the SHG (in my case Sol'Ex, which is not very heavy, but still ...).
Maybe I have some old macro focusing tubes somewhere.

Thanks to all !

Hello Laura,
This is quite good !

Hello,
Could you post a picture of the M42 focuser arrangement for the collimating lens ? Currently, I just use a spacer to change focus between Ha and Ca II. Still, it is not very practical.
BTW, the quartz slit is a great idea !

Hi, Still processing belated images ... Here are two images of the flare visible on April 18 in the group near to the east limb : http://astrosurf.com/viladrich/astro/soleil/wl/2022/AR2993-4-18April2022-9h31UT-C8EdgeHD-B1920-PE06A-SMN35.jpg http://astrosurf.com/viladrich/astro/soleil/wl/2022/AR2993-...

Very interesting! Is the FSR of 40A in line with other mica filters you have tested? My quark is more like 30A. I was really surprised by the FSR value. Other mica-spaced etalons I measured have a FSR in the range of 18 to 26 A. So, rather close to your 30 A. I used two different approaches to meas...

Great shots Marty !

Here is the FWHM broadening with f-ratio for a mica-spaced etalon :

http://astrosurf.com/viladrich/astro/in ... spaced.jpg

and for an air-spaced etalon :
http://astrosurf.com/viladrich/astro/in ... spaced.jpg

Hi Rainer, Sensationalism in order to “popularize” science where facts get distorted doesn’t sound like a good idea to me. I doubt Carl Sagan, Neil deGrasse Tyson, Sir Patrick Moore, Brian Greene, or Bill Nye would engage in such a level of what appears to be deliberate misrepresentation to popular...

Excellent images Stu. The aluminium rail is a great idea.

I've got the same seat :-)

The difference is stricking. Filaments are much dark in DS, and the double limb effet is minimal.
Very illustrative !

It seems that some activity is coming back on the east side.
Thanks for sharing.