Wednesday, May 25, 2016

Coma Cluster

It's been over three years since I pictured Coma Cluster in the astrojolo Deep Field One entry. This cluster is about 320 million light years away and is dominated by two supergiant elliptical galaxies. This to the left is NGC4889 - real monster. Its central part is about 240 000 light years in diameter, that is a size of whole Milky Way. However outer faint halo extends to 1.3 million light years, and NGC4889 mass is estimated to be a thousand times more than our Galaxy.
This time is in the wider context. TS130/910 0.79x, Atik383, EQ6, suburban sky:
Coma Cluster, 580 minutes LRGB
Coma Cluster, 400 minutes L inverted
Clear skies!

Monday, May 23, 2016

Imperfect Sun

AR12546 is the symbol of sunspot group (Active Region) that has been passing over sun disk since one week. It is pretty huge and can be spotted without any optical instrument but WITH some kind of solar filter (never look directly to Sun). Last weekend eventually I have been able to take a look at this monster and also take some pictures. 
Sunspot is quite dynamic, it's possible to notice changes within 1 hour. Below two pictures of this region made with SCT8", ND5 + Baader SC filter and ASI290MM camera (Earth picture is for size comparison):

AR12546 on May, 21st
AR12546 on May, 22nd
You can easily notice Sun cellular granules, a photospheric feature of size about 1000km that cover whole Sun surface except the areas occupied by sunspots.

Clear skies!

Friday, May 20, 2016

ASI290MM - hot stuff

It's been already over one week since ASI290MM camera arrived to me directly from Shangai. It is a new ASI product, very low noise, 2.13Mpx back illuminated CMOS sensor mono camera https://astronomy-imaging-camera.com/products/usb-3-0/asi290mm/ . 
ASI290MM camera with 2.1mm wide lens and 1.25" nosepiece
In the box there is standard ASI equipment - camera, nosepiece, 2.1mm lens, ST4 cable and USB3.0 cable - more about USB cable later.

Camera IMX290 sensor is panoramic, 6.5mm diagonal, and pixel size is 2.9um. Despite its small size pixel has quite a lot of place for signal - full well depth is 14500e. Read noise is 3e with gain set to 0 and drops to 1e for gain 30dB. It gives pretty well dynamic range - 12EV for low gain and still over 8EV for 30dB gain. 
Camera panoramic 2.13Mpx back-illuminated sensor
Very low read noise comes together with high sensitivity. Absolute QE value is about 70%, but the camera is very sensitive in red and infrared range. Its sensitivity drops to half at 860nm - for example for ASI120MM it is 670nm. 
Camera drivers installed without problems and at Toshiba Satellite L50 ASI290MM reached maximum full resolution speed 172fps / 8bit and 78fps / 16bit with SharpCap 2.8 and FireCapture 2.5.
At Lenovo T420s there was a problem with USB3.0 Renesas driver, so connected to USB3.0 port camera camera randomly hanged. After removing driver and installing Microsoft 0.96 driver version and replacing the USB3.0 cable camera works also at my Lenovo laptop.

Below a few recently made pictures with SCT8" and TVx2:
Tycho lunar crater - IR pass filter

Montes Alpes HD full resolution - IR pass filter

Jupiter with two moons

Jupiter - first light of camera

Camera has met my expectations - its very low noise, pretty sensitive in wide range up to 900nm, fast and has reasonable resolution 2.13Mpx, so it is possible to create lunar panoramas and picture quite a lot of Moon and Sun surface at once. It also helps to find a target :)
Comparing to my previous ASI gear - ASI120MM, new camera has obvious less noise and is more sensitive in IR - it is visible when imaging Moon with IR pass filter. Low noise and high dynamic range allows to extract subtle details when imaging Moon with 12 bit resolution, and for planets we can shorten exposure to freeze seeing or decrease gain to lower the noise.

Clear skies!

Tuesday, May 17, 2016

Moonwalk May 14-15

First lights of ASI290MM camera with SCT8" - getting used to the new gear and preparing for mosaic. Filters Baader R610nm and Baader IR pass 685nm, barlow TVx2.
May, 14, lunation 8.16 days
Archimedes, Sinus Lucinus

Alpes

Aristoteles, Rima Hyginus, Alphonsus, Albategnius
May, 15, lunation 9.10
Alphonsus, Arzachel, Alpetragius

Alpes

Eratosthenes

Tycho

Tycho and Clavius HD - open full size

Alpes and Caucasus HD - open full size
Clear skies!

Saturday, May 14, 2016

Whale plays hockey again...

It's already been three years when I pictured the same galaxies with Atik314 camera http://astrojolo.blogspot.com/2013/04/whale-plays-hockey.html. Now a little larger sensor, a little bit more exposure time, refractor instead of reflector, but the same backyard.
TS130/910 0.79x, Atik383, EQ6, LRGB 250 + 3x40 minutes
NGC4631 and NGC4656 galaxies
In the same frame also almost 12 billion light years away distant quasar has been recorded:

z=3.131 quasar next to Whale galaxy
Whole frame, luminance channel, annotated.
Clear skies!

Sunday, May 8, 2016

Whole bunch of stars

M92 globular cluster has been discovered by Johann Elert Bode in 1777. He wrote then:

"A nebula. More or less round with pale glow. On this occasion, I also want to announce that on December 27, 1777 I have discovered a new nebula in Hercules, not known to me, southwest below the star s in his foot, which shows up in a mostly round figure with a pale glimmer of light. Its longitude is about 11 deg [Sgr] [251 d] and its latitude 66d north.Together with two small [faint] stars, which don’t occur at Flamstead, it appears in the reversing telescope as shown in fig k (in the following volume)."

It is an easy target for binoculars and small scopes, and magnificent view in large instruments. Contains about 330 000 stars and is one of the oldest globular clusters in the Milky Way.

M92 globular cluster in Hercules
Picture shot with Atik383 camera and TS 130/910 refractor. LRGB frames, 370 minutes total exposure time.

Clear skies!