Skywatcher ED72R - A Quick First Light

[Virgoman]

I haven't posted on here for quite a while - continuing ill-health being a major factor but I took delivery on Tuesday of the new Skywatcher ED72R from the guys at First Light Optics (superb service as ever). What's more it was actually clear and I managed to get out and got first light on the bright afternoon moon - lovely sharp view. I attached my ASI224MC  and managed the attached image ( 2 pane mosaic ). Very pleased.

 

                                       Best regards,

                                                           Ralph

[Ben the Ignorant]

Nicely chiseled craters and mountains. Have you imaged its inside-focus and outside-focus patterns? 

[Virgoman]

Thanks. No I haven't - just a quick first light. 

                         

[Knighty2112]

53 minutes ago, Ben the Ignorant said:

Nicely chiseled craters and mountains. Have you imaged its inside-focus and outside-focus patterns? 

As a newby to imaging, what would this achieve please? 

[Knighty2112]

Sorry, nice image! Well done!  

[Ben the Ignorant]

2 hours ago, Knighty2112 said:

As a newby to imaging, what would this achieve please? 

It would assess optical quality and chromatic correction. The ideal defocus pattern is a set of concentric rings with the outside ring brighter than the others because the defocused image is the opposite of the focused image. An ideal focused star has almost all the light in the center, and as little as possible in the diffraction rings. When you blur it, the center becomes the outside and vice-versa, so now the brightest part has to be the outside.

In reflectors all colors come to the same point, but refractors spread them a bit. Full-apos spread them so little it's not visible, the defocus disks are white. In semi-apos the disk is a pale uniform color and the rim can be another color. In achromats colors are vivid and strongly different.

Great scopes have barely different brightness in their inside-focus and outside-focus rings, showing negligible spherical aberration. And other aberrations deform the rings. I love to see star tests because they reveal a lot about optics at a glance. Well-shaped, finely polished optics have nice patterns to look at.

Edit: get a feel for the ideal star test viewing lots of them, achromats, apos, semi-apos, reflectors of all types with obstructions big and small:

https://www.teleskop-spezialisten.de/shop/Astro-Blog-Erfahrungsberichte-Testaufnahmen/Testaufnahmen:::73_119:2.html

Click on a small picture, it will be shown on another page; click on the small image again and it will be enlarged.

[Ben the Ignorant]

2 hours ago, Virgoman said:

Thanks. No I haven't - just a quick first light. 

                         

Too bad, not that I intend to buy a 72 now, but I am a telescope review addict. 

[Virgoman]

2 hours ago, Knighty2112 said:

Sorry, nice image! Well done!  

Thank you very much and clear skies! 

[MilwaukeeLion]

Nice lunar image with blue sky, nicely captured!