Recent content by Bill Richards

The "Dark Shark Nebula" (aka LDN 1235) is a dark/reflection nebula made up of interstellar dust which is so thick it hides most of the light from behind it. Just behind the dorsal fin, you can see a distant spiral galaxy (PGC67671). This is the result of 6-1/4 hours of exposure time taken on...

The North America Nebula (aka NGC7000) is a huge emission nebula, a vast region of mostly hydrogen gas, so named because its shape resembles North America. It’s part of the same interstellar cloud as the Pelican Nebula (IC 5070), which is to the right in this image. They are separated by a...

A LONG TIME AGO IN A GALAXY FAR, FAR AWAY… About 40 million years ago, in a galaxy known as NGC 7331, a very large star (at least 8 times larger than our sun) exhausted enough of its nuclear fuel that the energetic pressure from the fusion process could no longer counter the immense...

The Tulip Nebula (aka SH2-101) is an emission nebula about 6000 light-years from Earth. It's close to microquasar Cygnus X-1, one of the first suspected black holes. Cygnus X-1 is orbited by a blue supergiant star (21 times as massive as our sun) which feeds a spinning accretion disk around...

This globular cluster known as Messier 5 is ~25,000 light-years away and contains hundreds of thousands of stars. Stars in globular clusters are believed to form in the same stellar nursery and grow old together. The most massive stars age quickly, exhausting their fuel supply in less than a...

Jim Fox asked me to post some photos of my new mount - a 10Micron GM1000HPS. I finally got a chance to take some decent photos and annotate them, so here they are. Although pricey, this mount has incredible tracking accuracy, as shown in the PHD2 guide plot following the photos. I can't wait...

#1 - Bode's Galaxy (M81): #2 - Cigar Galaxy (M82): #3 - Hamburger Galaxy (NGC3628): #4 - Solar Eclipse Totality: #5 - Solar Eclipse Prominences: #6 - Sunflower Galaxy (M63): #7 - Rho Ophiuch Cloud Complex: #8 - Omega Nebula (M17): #9 - Dumbbell Nebula (M27): #10 - Helix Nebula...

Hi Jim, These adapters thread into the face of the lens where a filter would go. There are intended to enable you to use a filter that is smaller than the lens supports. So they do not affect your backfocus at all. They have the effect of reducing your aperture using a perfect circle, so no...

Get youself a few step-down rings and you won't have those diffractions spike. This $13 ring will reduce your aperture by 51% (so, F2 to F2.8) - that should eliminate most of the distortion from the outer perimeter of the lens. I doubt you really need (or want) to go to F4 or F5/6. That just...

Yep, I saw that - 18 radial spikes (or 9 spikes that bisect the star), confirming 9 blades in that lens. Some find the affect appealing, some don't. It's an artistic choice.

Yeah - those aperture rings are implemented using a set of blades (in the case of your Samyang, I believe it's 9 blades), which approximate a circle using straight edges which create diffraction spikes. If you use a step-down ring, you get the exact same effect without any spikes.

Hi Jim, Just FYI - if you stop down a camera lens, the blades will often generate diffraction spikes on bright stars. I'm not sure if you have encountered that or not (or care about it). If you want to stop down your lens without diffraction spikes, use a filter adapter instead. I have the...

The Christmas Tree Cluster is a young open cluster which contains the Cone Nebula, the Fox Fur Nebula, and the Snowflake Cluster. The stars in the cluster formed within the emission nebula NGC 2264. They are still heavily obscured by the thick dust clouds that keep producing new stars...

A stunning face-on spiral galaxy, M74 is a perfect example of a grand-design spiral galaxy. Symmetrical spiral arms reach out from the galaxy’s central nucleus and are traced by winding dust lanes. The arms are dotted with clusters of young, blue stars and pink regions where the ultraviolet...

Just in time for the "Rings of Power" season 2 finale, I bring you the "Eye of Sauron" (officially known as the Helix Nebula or NGC 7293). It's a colorful planetary nebula about 650 light-years away, formed by a star which shed its outer layers near the end of its life. The remnant central...