Tuesday, October 18, 2016

Codename Sh2-124

Not much can be said or read about Sh2-124 molecular hydrogen cloud in the north-east Cygnus frontiers. It is pretty large but not too bright. The whole area is filled with the hydrogen, so every place you look you can see red. Not much science work has been done there, it is even not certain which stars are responsible for exciting hydrogen to shine in red. Pretty mysterious nebulosity.
Pictured from my backyard with 130mm refractor and Atik383 camera. 420 minutes of H alpha and 180 minutes total RGB.

Sh2-124 hydrogen cloud in hydrogen alpha band
Sh2-124 enriched with RGB star signal
Clear skies!

Friday, October 14, 2016

QHY163M a few more pictures

Weather is far from being perfect, so I am not really able to shot any pretty pictures with new camera. Plus I had a little miscollimated refractor (fixed by now) and the distance to the flattener is too short (will be fixed soon). Nevertheless I managed to take a few longer exposures, so here you will find them.
NGC6888 single 600s shot with Baader Ha filter. GAIN=0
M31, M32, M110 galaxy triplet, 180x10s luminance, unguided on EQ6. GAIN=10
Sh2-235 area, 12x600s stack, Baader Ha, nasty conditions (high clouds + Moon), 75% crop
13.10.2016 Moon with 130mm refractor and Baader G filter, 10x0.006s stack
So far, so good. Camera seems to be pretty much like many-in-one - good for long exposure "classic" DS picturing, good for short few seconds many frames stack for unguided LRGB imaging, and of course good for planetary imaging as well.

Waiting for darker nights. Without Moon.
Clear skies!

Thursday, October 13, 2016

Enchanting hydrogen

Today's gem nickname is Wizard, due to its shape that resembles medieval magician. The official nebula symbol is Sh2-142 at Sharpless catalog, and embedded open star cluster is NGC7380. Its pretty young cluster, stars age is estimated for 4-5 million years. The surrounding molecular cloud is excited to shine by DH Cephei binary eclipse system of two super hot stars of spectral types O5.5+O6. O type stars are very rare, it is estimated to be only 0.00003% of whole stars population. 
Also a few carbon stars have been recorded, you can try to look for them at enlarged picture. These will be as very red small spots.
Shot from my backyard with 130mm refractor. 500 minutes of Ha and 180 minutes of RGB.
Wizard with 180 minutes of RGB
Wizard with 500 minutes of H alpha

Combined HaRGB view

Clear skies!

Monday, October 10, 2016


Nope, no M97 this time. Its NGC457 star open cluster in Cassiopeia. Plus NGC436 little sister. Both are relatively young clusters - first one is about 20 millions year old, smaller one is four times older, nothing impressive though :)
First one is called Owl, E.T. or Kachina Doll cluster, second one is anonymous.
Pictured from my backyard with 130mm refractor and Atik383 camera on EQ6 mount. 2 hours total exposure time
NGC457 Owl (bottom) and NGC436 (top right) open clusters in Cassiopeia
Clear skies!

Saturday, October 8, 2016

Caroline's Rose

This open cluster has been called after the Caroline Herschel. It is also known as The White Rose or Caroline's Haystack (according to Interstellarum atlas). NGC7789 star open cluster is in the Cassiopeia constellation and can be spotted with naked eye under perfectly dark sky. Pretty large (over 15 arc minutes) and rich is an elegant view with any optical instrument. 
11.09.2016 it has been viewed with my 130mm refractor and Atik383 camera through RGB filters. Almost 2 hours of total exposure time with 3 minutes subframes.
NGC7789 Caroline's Rose open cluster
Clear skies!

Friday, October 7, 2016

Cave in the sky

Cepheus attacks again - this time with the Cave nebula (aka Sh2-155 or Caldwell 9). It is beautiful object in LRGB, but requires dark sky for this technique. My backyard sky is not so fortunate, so I decided to picture it with HaRGB filter set. There is 12 hours of exposures total with 130mm triplet refractor and Atik383 camera. 
Sh2-155 Cave nebula with vdb155 at lower right
At the lower right part there is vdB155 reflection nebula. And little bit to the left - faint, but evidently red carbon star.
Clear skies!

Monday, October 3, 2016

QHY163M first light, first impressions

A few days ago I have received one of the first QHY163M cameras. This is the one http://www.qhyccd.com/QHY163.html . That is a direct competitor to ASI1600 camera. Differences are as follows: QHY163 has two stage cooling that allows to reach temperature drop 40*C below ambient (I have checked and it is true). It also has built in 128MB memory buffer and heated chamber front window. 
Camera has come in the plastic case:

After installing drivers from QHY webpage all has been detected without any problem (Lenovo T420s laptop with Windows 10). Camera is working well controller with EZCAP and MaxIm DL 6.13. When cooling is switched on the sensor reaches temperature drop about 30*C within a minute, and within another minute it reaches maximum drop of 40*C. Cooling fan works pretty quiet (it makes less noise than for example the one in Atik383 camera), and the camera case becomes little warm after some time due to the heat collected from the sensor and from the front window. 

Here are the two frames at -10*C sensor temperature: 60s dark and bias. PixInsight autostretch:

I have measured camera linearity and it looks very good (gain=0, offset=40):
Basically up to 60000 ADU plot is perfectly linear:
Then using method described for example here http://www.phy.cuhk.edu.hk/djwang/teachlab/projects/CCD/CCD%20Camera%20Gain%20Measurement.pdf I have measured real camera gain and the value is g=0.26e/ADU.
Having this it was pretty straightforward to calculate full well depth that is 17100 electrons assuming the response is linear till the max ADU. But the plot drops at the end, so for further calculations I assumed the pixel depth is 18000 electrons, and it gave following calculated results:

First column is gain set in the camera driver settings. Second column is measured signal for 1s exposure. Then third columns is real gain in dB, and in the next column real gain in electrons / ADU. Then we have camera read noise, saturation and dynamic range both in EV and dB. Last row is Atik383 values for comparison.
Read noise is pretty impressive in my opinion. 

First lights have been made during star party in Zatom, Poland. I used SCT8" with Alan Gee Mark II telecompressor and CG5GT mount without guiding. I have shot 5 seconds exposures, and camera settings were: gain=20, offset=100, sensor temperature -25*C.
NGC891, 80x5 seconds stack
M1, 200x5 seconds stack
M15, 100x5 seconds stack
M76, 100x5 seconds stack
I am pretty happy with this first results of QHY163 mono. Now time for long exposures.

Clear skies!