Tag: Nexus coma corrector

B33 HORSEHEAD NEBULA

Horsehead nebula is IMHO the most beautiful deep space object. It is located in the constellation Orion. Everybody knows this constellation because it can be easily identified by three aligned stars (Alnitak, Alnilam, and Mintaka), which forms the belt of the Orion.

The nebula is very dim. Therefore, visual observation is nearly impossible, unless you have a telescope, having at least 1 meter in diameter. To photograph it, one needs a very long exposure time. I used 5 minutes per image and I took 36 of them. The nebula complex is visually very large, so the optimal focal length should be shorter than 750 mm. I used a Newtonian telescope with a focal length of 1000 mm but reduced to 750 mm by the Nexus coma corrector. It turns the Newtonian into a light-collecting bucket, but the quality suffers from that. The stars in the corners are everything, but round. Moreover, I used dual-band filter Optolong L-eXtreme, which increased the contrast of the nebula, but also made the asymmetric halo around the bright stars. I played a bit with the white balance and pushed the colors into the orange tint, to reach the warmer feeling in cold February.

TelescopeNewton 254/1000 mm
Aperture254 mm
Focal length750 mm
MountGemini G53f
AutoguidingZWO 174MM, TS 60/240 mm
CameraZWO 071 Pro @-10°C
CorrectorNexus coma corrector
FiltersOptolong l-eXtreme
Exposure36x300s, Gain 95, bin 1x1,
Date2022-02-09

IC443 Jellyfish nebula

Jellyfish Nebula is a supernova remnant in the constellation Gemini. A very long time ago a supermassive star exploded and emitted a lot of material into space. It is not clear when exactly it happened, but the latest research dates the explosion between a few thousand years and 30’000 years. The shape definitely resembles a jellyfish, having the head at the top and tentacles at the bottom and overall it looks like it floats in the space. It’s interesting how many nebulae have names related to an animal. For example the Seagull Nebula, the Elephant Trunk Nebula, the Eagle Nebula, the Lobster Nebula, the Horsehead Nebula, etc.

TelescopeNewton 254/1000 mm
Aperture254 mm
Focal length750 mm
MountGemini G53f
AutoguidingZWO 174MM, TS 60/240 mm
CameraZWO 071 Pro @-10°C
CorrectorNexus coma corrector
FiltersOptolong l-eXtreme
Exposure48x300s, Gain 95, bin 1x1,
Date2022-02-06