Thursday, October 31, 2013

Quick Orion test

Just to present quick five minutes test picture of Orion Nebula M42. It is one of the brightest nebulae in the sky and is placed about 1340 light years away. It is also the closest to Earth region of active star formation. 
Picture below is single 5 minutes photo through hydrogen alpha filter.

Clear skies!

Tuesday, October 29, 2013

Bubble hydrogen attack

Not so long time ago I shot Bubble Nebula with modded Canon 450D. Total exposure was 6.5h and I was pretty happy with the outcome. But the time has come for narrowband exposures. Hydrogen alpha is the first filter used and this black and white result I present today. As you probably remember this filter passes the light that corresponds to the hydrogen presence in the space, so all cloudies in the picture are actually massive hydrogen regions. At the upper right border you can see fragment of M52 open star cluster (about 5000 light years away).

Bubble nebula (NGC7635) is actually hydrogen II region emission nebula placed about 11,000 light years away. The bubble shape is created by stellar wind from massive blue central star. 

In the right part of the picture you will find NGC7538 nebula which is the region of active star formation. This one is placed a little bit closer - about 9100 light years away from us. 

There is actually very little of dark sky in this area - the hydrogen is almost everywhere. That's why the whole picture is filled with some haze.
The picture itself has been shot with my current setup - GSO 6" F4.5 newtonian with Atik383L+ camera and Baader hydrogen alpha filter. Total exposure time was 5.5h. Next in the queue are Oiii and Sii images of this region, so finally I am going to greate HST palette image of Bubble nebula.

Clear skies!

Sunday, October 27, 2013

Morning comet triplet

There are always at least few comets visible in the sky. Usually there is one large enough comet to be visible in binoculars and others tha can bee seen with telescope. Once every few years there can be comet visible with naked eye. 
At the moment we have also a little bit unusual  scenario - in the morning sky in northern hemisphere we can see three comets with binoculars! These are comets: C/2012 S1 (ISON), 2P/Encke and C/2013 R1 (Lovejoy). Last night (actually today morning) I spent some time on imaging all of them.

2P/Encke has the shortest period of any known comet - it completes the orbit every 3.3 year. Its nucleus diameter is 4.8km. Encke comet orbit is unstable and evolves over time due to perturbations and outgassing. The picture has been shot at 04:27 CET and the exposure time was 5x60 seconds. The comet in this moment was about 80mln km from Earth and its velocity was 46km/s. At this distance the pixrel scale is about 950km/px (when enlarged).

C/2013 R1 Lovejoy is quite new comet discovered on September, 9th. This comet will pass its perihelion on December, 25th. The picture below was shot at 3:55 CET and exposure time was 5x90 seconds. The Lovejoy comet was 110mln km away at this moment and traveled across Solar System with velocity 38km/s. Piksel scale is about 1300km/px (when enlarged).

C/2012 S1 ISON comet is probably the most famous comet this year. It was discovered on Septermber 21st, 2012. The comet will pass its perihelion on November 28th, 2013 in a distance only 1.9mln km from the Sun center that is only about 1.2mln km over the Sun surface! At the end of this year the comet may become visible with naked eye under the dark sky. Currently its magnitude is about 9mag, so it is binocular target. The picture belowe has been shot at 4:11 CET with total exposure time 10x120 seconds. The comet was at this time about 200mln km away from Earth, so the picture pixel scale is about 2400km/px when enlarged.
One may wonder what the heck are these lines at photos? These are star trails - during the exposition time the comets moved significantly across the sky. So we could track the stars and have comet blurred or we could track the comet and have star trails. In this case the answer was simple :)

Clear skies!

Wednesday, October 16, 2013

Autumn tulips

Sharpless Sh2-101 or Cygnus Star Cloud are the alternative names for the nebula presented here today. Although it is much better known under the name Tulip Nebula. It is classic emission nebula that shines (faintly) in deep red hydrogen hue. The Tulip itself can be seen in the right part of the picture. This hydrogen cloud lies about 6000 light years away and its apparent size is 16'x9' so about half apparent size of the Moon.
The picture below is enlarged part of the Tulip itself. The exposure has not been long enough to record some more details, probably I will get back to this nebula some day.
And the last one is color HaRGB version with some star hue added to the stack.
You can see for comparison the same nebula shot with modded Canon 20D about one year ago.

Clear skies!

Showcase

Some people ask me to create a one place when one can view all the images I present in the blog. I found it actually to be a good idea and reviewed a few solutions, also some well known galleries like flicker or picasa. But eventually created ultra simple page by myself. My idea was to make it

  • all in one place
  • readable 
  • easy to navigate
  • not processing uploaded images (like blogspot or picasa do)
  • able to show image in full size
  • present a short description with link to the blog entry
And thats all. The gallery is available at http://astrojolo.fotojoler.net/ web address. 

Have fun!

Monday, October 14, 2013

Bloody sky

Not so long time ago I presented Crescent Nebula in hydrogen alpha emission line. The picture was black and white, but in fact the color that corresponds to hydrogen alpha line (656nm) is deep red. So this time I have made a few more exposures in RGB colors to catch some star hue and mixed it with hydrogen alpha signal using HaRGB technique. The result is as follows:

The Crescent Nebula (NGC6888) is placed about 4000 light years away and is formed by stellar wind from Wolf-Rayet star colliding with slower moving wind ejected by the star.

Clear skies!

Friday, October 11, 2013

Dust and blue

There is another piece of beautiful nebulosity in the Cepheus constellation - it is Iris nebula (NGC7023 or Caldwell 4). It is typical reflection nebula lit by the 7 magnitudo star SAO 19158 placed in its center. Actually the NGC7023 symbol does not denominate the nebula itself, but the star cluster placed immediately to the west of the nebulosity region. The correct designation of the nebula is LBN487. Dust particles that shines in the Iris nebula are leftovers from when the star was formed. 
The whole complex is about 1300 light years away and its radius is about 3 light years. There are also faint hints of red color surrounding the central star - this is evidence that some hydrogen emission takes place.
The photo above has been exposed during three nights - 10h total exposure of luminance and 5h total RGB channels. Processing took me more less the same amount of time - I started all over again four times from scratch. Iris nebula is quite demanding target and requires dark sky (not at my site), fast optics (I am almost there) and large aperture (not really me :) )
Below cropped nebulosity center:
Clear skies!

Thursday, October 10, 2013

NGC7822 star nursery

There are many hidden astrophoto treasures in the constellation of Cepheus (although not so many for visual observations). One of them is nebulosity called NGC7822. It is a young star forming complex. The complex is about 3000 light years away, and younger components are believed to be 'only' few million years old. The complex also contains the hottest star within the distance 3000 light years from Sun. It is  BD+66 1673 star - an eclipsing binary that one member is about 100 000 times more luminous than Sun and its surface temperature is about 45 000 K.
The picture above is a resized full frame stack of 10 minutes subexposures made with Hα filter, so only the light emitted by excited hydrogen atoms have been recorded. You can notice many of so called pillars of creation where stars are formed.
Below is the enlarged part of the picture.

Clear skies!

HEQ5 on steroids

HEQ5 equatorial mount is not top quality. It is build in China, often requires some adjustments when you receive it. But on the other hand the price is very acceptable, and you can start your astronomy adventure with not really astronomical investments. 
Due to its flaws many amateurs wanted to improve HEQ5 - mainly for astrophotography purposes. There are two popular modifications made for HEQ5 mount:

  1. replacing original Chinese bearings with some better ones made by more reputable companies (EZO, Timken, FAG)
  2. replacing original gears with belts and pulleys
The first modification I already made some time ago. Now the time has come for second one :) There are two types of belt mod kits - one changes original gear ratio so it can be controller only using laptop and EQMOD interface. Another type keeps the original ratio, so there is no limitations to future use of the mount. These second type requires some fancy small 9 tooth pulley and usually are a little bit more expensive. Me and few other astro amateurs have chosen belt mod kit manufactured in Rowan Astronomy company located in UK. This one keeps the original 9:47 gear ratio so it is transparent to any controller.
The kit has come well wrapped. It contains four pulleys, two belts, acrylic cover spacer, two steel pins for idlers and two idler rollers, three different allen keys and 6 head screws for cover. Additionally one can order pinion extractor to remove the pinion gear - I can recommend this tool. This gear sits tight on the motor shaft and is not so easy to remove.
There is also very detailed instruction provided for the whole process. It took me about one hour to replace the original gears with the belt kit mod. Un-twisting motor wires can take some significant amount of time.
Above there is declination motor with plate and two gears. The larger one will be replaced with idler roller. The good news is that there is no need to move the main worm gears, so you do not need to adjust it again. This worm gear adjustment process can be time consuming.
Stepper motor with pinion gear removed. The extractor did its job perfectly :)
New 9 tooth pulley on place and idler roller fixed to the plate.
Declination belt mod on place. Now the right ascension part to go.
Voila! All kit elements fit precisely and there is no more annoying noise during mount moves. Unfortunately weather forecast says that I will need to wait few days for real test :( 
There are few advantages when using belt mods:
  1. quiet mount work :)
  2. smoother guiding (especially important for the astrophotography with longer focal lengths like over 400mm)
  3. more regular periodic error correction (PEC) so it can be recorded now and can work better when making unguided photos
Some real life tests to come...
Clear skies!

Friday, October 4, 2013

Andromeda by the way

Andromeda Galaxy (aka M31 or NGC224) is a spiral galaxy approximately 2.5 million light years away from Earth. It is the nearest spiral galaxy to our Milky Way, although there are some other galaxies closer to us, but not spiral (like Magellanic Clouds). As one can easy guess the galaxy can be seen in Andromeda constellation. SST observations revealed that M31 contains over one trillion stars (1012) - this is the largest galaxy in our Local Group. Andromeda Galaxy is moving towards us and in about 4.5 billion years both galaxies will collide and eventually merge into large elliptical galaxy.
The galaxy itself can be viewed with naked eye. Its apparent magnitude is about 3.5, but it covers quite a large area in the sky. The galaxy core is quite compact - core apparent diameter is the same as the Moon apparent diameter. But the external arms are spread 3 degrees wide, so it is 6 times more than Moon diameter. However only the core is visible with naked eye, to view the arms you will need good bino or telescope. 



Picture above is only one 10 minutes exposure I made last night. The galaxy has not been my target, but I needed to rotate telescope through the whole sky and decided to spend few minutes in this place. In the picture bottom there is M110 galaxy, and above M31 there is NGC206 star cloud. NGC206 is the richest and largest star formation region in our Local Group of galaxies.  Below you will find the crop of the galaxy center.


Clear skies!

Thursday, October 3, 2013

Incandescent Crescent

Crescent Moon is an easy target for any stargazer. However not many know that we have another crescent in the sky. This one is well hidden in constellation Cygnus and cannot be viewed with naked eye - the Crescent Nebula (NGC6888) shines faintly somewhere there and can be spotted with medium sized telescopes using filters. Nebula is placed about 4000 light years away and is formed by stellar wind from Wolf-Rayet star colliding with slower moving wind ejected by the star when it become a red giant star a few hundreds of thousands years ago. The result of this collision is a sheel and two shock waves. The red giant center star will some day (in about one million years) explode as supernova, and then whole this space region will be changed.
Picture at the top is enlarged crop of the full frame (below). It has been shot through Hα Baader filter with total exposure time of 3 hours and single exposition of 10 minutes.
Clear skies!