I am afraid sunspots are the effect of localized strong magnetic fields in the photosphere (and in the layer below).
They have nothing to do with comets.

Interesting info Raf :-)
I didn't know they have these small size Cassegrain scopes.They have quartz mirrors which is very nice. I have no idea of the optical quality.

Hello Bob, Here are the simulations for a re-spaced classic C8 : http://astrosurf.com/viladrich/astro/instrument/sensitivity/sensitivity-analysis-SC8-Plate.htm The diffraction limited flat-field increases by a factor of four when the Schmidt plate position is set 230mm ahead its nominal position. ht...

Hi Bob,
Is this the C8 or the C8 EdgeHD ?

Hi Bob,
I have done some simulations there for a re-spaced C14 :
http://astrosurf.com/viladrich/astro/in ... -Plate.htm
I can run some more for the C8 if it is helpfull.
Christian

Hi,
We will keep you informed when the English version is ready.

Thanks Ralf and Pedro for your kind comments :-)

This give us even more motivation to get the English version ready ASAP.

Best regards
Christian

40 nm FWHM in both Ca K and Ha is amazing. What far goes the blockage in IR ? 1000 nm ? 1200 nm ?

Any idea of the optical quality (P-V or rms wavefront) ?

Looks good !
Any idea of the optical quality ? Any transmission curve available ?

Very interesting :-)
I am planning a visit there in January.
Christian

Hello Bob,
Thanks for the valuable information.
What is the orginal source of information for these figures :
download/file.php?id=34786
Thanks !

Hello Apollo
Could you give data / hour of observation ?
Best regards
Christian

You can use Autostakkert. It can correct the rotation of images taken with an altazimutal mount.

Thanks to all for your messages :-)

Marvellous !!

Back to the C8 Edge-HD, the optical quality is much better than the optical quality of these vintage SC...I started a long time ago with an orange tube C8 ... The C8 Edge-HD is an excellent balance between portability, ease of use, optical quality and resolution. The only drawback is that you need a...

Hello Marty, Thanks for taking the time of takin in/out focus images. This is helpfull. We can see the following things : - There is a very significant level of spherical aberration. It could be because the thermal balance of the optics was not reached, or the optics are really bad, or both. - The t...

So, finally there are two filters : - Number 2 at the rear. Actually it consists in two parts (glued ?). - Number one at the front (behind the lens ?), this one is a GG395 according to the information given by Apollo. Is this correct ? No filter at the front of the eyepice ? BTW, the lens seems to b...

Hello Apollo,
Here is a full disk movie of the event :
https://gong2.nso.edu/products/scaleVie ... uctIndex=0
Your movie is much more impressive !

Hello Marty, A a comparison, here is an image of Copernic region taken by Gerard Therin with his 260 mm telescope : http://www.naturepixel.com/as/2017_09_14_0402_stadius_copernic_hortensius_kepler_vmc260l_asi178mm_g_as3_r6_cc_copyright.jpg To be honest, Gérad is among the best lunar imagers. My poin...

Just wondering whether you could apply some heat arround filter n1 ? Maybe there is some glue ?

Thanks a lot Bart !!

Hello Marty, This is an interesting case :-) Let's start with the resolution of the lunar and planetary images. They are far from beeing on pair with what a 10" telescope can give. This leads us to the question of seeing and / or optical quality of the telescope. The simple question is do you see th...

Thanks guys :-)

So, we have to get working to get this English version available ASAP ;-)

Thanks !