Crescent Nebula

The Crescent Nebula

The Crescent Nebula (also known as NGC 6888, Caldwell 27, Sharpless 105) is an emission nebula in the constellation Cygnus, about 5000 light-years away from Earth. It was discovered by William Herschel in 1792.[2] It is formed by the fast stellar wind from the Wolf-Rayet star WR 136 (HD 192163) colliding with and energizing the slower moving wind ejected by the star when it became a red giant around 250,000[3] to 400,000[citation needed] years ago. The result of the collision is a shell and two shock waves, one moving outward and one moving inward. The inward moving shock wave heats the stellar wind to X-ray-emitting temperatures.

It is a rather faint object located about 2 degrees SW of Sadr. For most telescopes it requires a UHC or OIII filter to see. Under favorable circumstances a telescope as small as 8 cm (with filter) can see its nebulosity. Larger telescopes (20 cm or more) reveal the crescent or a Euro sign shape which makes some to call it the “Euro sign nebula”.

What’s nice on this image is that the external shell is visible.

Crescent Nebula
Crescent Nebula

It took me a couple of weeks on a good clear night to capture the object.  The total time for capturing was about 16 hours and only 9 hours of good data are registered and stacked.

Western Veil Nebula Reprocessed

Removed some of the stars and did a little bit of clean up in the Ha, S2 and O3 channel before combining into an SHO pallete.

The Western Veil Nebula is a supernova remnant about 2400 light years away from Earth.  This image was captured using Explore Scientific ED127 with Explore Scientific 3″ 0.7x FF/FR with the ASI 1600MM camera.

Reprocessed the Western Veil Nebula out of boredom waiting for the capturing the Tulip Nebula.

Western Veil Nebula

Discovered something odd – Cannot focus!!!

Woke up early in the morning just to discover that all of my captures are out of focus and decided to figure out a bit of what went wrong.  It was me, I adjusted and tightened the focuser lock and it affected electronic motor to return to the previous state.  That’s why when I discovered it, the focuser was in the maximum range.  Anyway time to get back to printing the bracket again to clean things up a little bit and test it tonight.

The Dumbbell Nebula

The Result

About the Dumbbell Nebula

It is also known as the Apple Core Nebula.  It is a planetary nebula in the constellation of Vulpecula at a distance of about 1227 lightyears.

The Dumbbell Nebula was one of my earliest favorite because of the color especially when you look at it from the eyepiece of the telescope.

This image is captured using the Celestron 11″ SCT with the 0.63X flattener/reducer and with the ASI 1600MM camera with ZWO 8 positions filterwheel.  The filters I use are the Astronomik Ha, O3 and S2.

It took me over 2 weeks to capture and almost 2 weeks to process.  I thought that this will be an easy on because of the brightness but i was wrong.

The Hydrogen Alpha channel

The Oxygen 3 channel


Some of my old captures of the Dumbbell Nebula

Dumbbell Nebula
Dumbbell Nebula
Dumbbell Nebula

Auto Guiding Problems


Last night was a good night as it was not so windy, but still alignment is challenging.  Spent a lot of time trying to figure out what’s happening so I started aligning the mount using PoleMaster then I used SharpCap 3.2 Pro version.  Using PoleMaster is not enough since I’m using C11 with .63x reducer/flattener with the ASI 1600MM camera.  Tried tirelessly until I was able to get to the “EXCELLENT” alignment in SharpCap.  Well the result was definitely better than the other day.

I used to have a very good guiding with my usual setup but have faced a difficult challenge when I started using my C11 for long exposures.  Before, I have this kind of chat in my guiding with PHD2

A total of RMS Error of 0.10 and with this number I was able to get very long exposure and sharp images.

With my C11 and a 0.63x reducer and ZWO ASI 1600MM camera, I can only get 30 secs of meaningful exposure or else I’ll have an elongated star.  Also loosing 2/3 of my images which is a waste of time.

Guiding shows it’s okay as I also use PoleMaster for polar alignment.  From the chart above the DEC seems to have a problem in guiding.  Perhaps another problem could be the weight of the scope.  I’m using the Orion EQ-G Atlas mount rated for 40lbs but I’m pretty sure that my telescope, camera, filter wheel, focuser are way below that mark.

My guess here is PoleMaster is not enough to provide a good alignment and hopefully SharpCap can help if I use the Polar Alignment method using the Orion 80mm with ASI 120MM camera.


Galaxy Season

I’ve decided to use the Celestron 11″ for capturing the galaxies.  I have a lot of galaxy pictures that was taken by the Explore Scientific 127ED.

C11 from my surveillance camera and me.
C11 from my surveillance camera and me.

I usually use this scope for planetary targets and I have a couple that has a very good quality specially that they are raw videos.

This one is pretty good as it clearly shows the Great Red Dot in Jupiter

And Saturn here

And of course Mars