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Wednesday, November 16, 2011

How to capture a dancing planet

When Jupiter dances, you may need GRGB !
Since two years I capture the planets by using a powerful one shot color webcam, the TIS DBK21USB. It produces regular avi video files. After stacking the avi files with the software Registax, I produce FITS files, need sharpening. The sharpening step is done by using the wavelets function in Registax. Finally, I split the best FITS image in its three separate channels R,G, and B in order to use one of them as luminance, since my seeing conditions from my roof observatory are usually bad.

I need a luminance! But which one?
Depending on what kind of details you want to visualize on a specific planet (i.e. cloud or surface details), a suitable channel should be used as luminance. See below:

Jupiter and Saturn
I extract the G (green) channel in order to set it as a luminance.  It has a higher resolution than red or blue because of the RGGB mask placed on the camera sensor. Two of the four pixels in the RGGB matrix are green.

Examples on other planets:

Mars
I extract the R (red) channel in order to set it as luminance to bring out more albedo details under my poor seeing conditions.  The red channel does not suffer from seeing so much as the green and blue channel. It has a low resolution, since only one of the four pixels in the RGGB matrix is red.
If you want to visualize the orographic cloud structures on Mars you will want to use the B (blue) channel as luminance. You need very good seeing to get a sharp blue channel. These are very rare especially from roof observatories, where the local seeing also plays a role. Perhaps once a year? I think so.

Venus
I extract the B (blue) channel in order to set it as luminance as the cloud structures on Venus are visible in the blue/UV channel. As I said before, the blue channel suffers more from the seeing than the red or the green channel. Its resolution is also low.

NOTE: If your seeing conditions are excellent, the most accurate method for planet photography is simply RGB. You prevent sacrifying details both in the cloud structures and on the surface of the planets using the classic RGB method. See my latest results on Jupiter at http://dark.astrodigital.net.
If you are interested on how to process a RGB planet photos with the software GIOTTO and MaximDL please visit my homepage at: http://www.astrodigital.net

Photo shooting with IC Capture.AS
This is the software package I use with my DBK21 webcam. One of the advantages it provides is the live display of the RGB values. I pay special attention during the image acquisition, not to exceed the max. values of 255 in each RGB diagram. The screenshot above shows the settings, I always use. When the values tends to exceed the limits (255) during the session, I reduce immediately both the gain and the exposure time.

Jupiter rocks :-)
Jupiter rotates fast! Its rotation is easily noticeable at 3850mm focal length I use. I keep the time window for each avi video file short enough to prevent smearing due to its fast rotation. I developed an application to calculate the allowed time window to capture a given planet, taking into account your telescope/camera system! You can download it here for free. See also a screenshot of it:
Figure: My telescope, eyepiece and CCD calculator
/Panagiotis

Wednesday, November 09, 2011

I wonder (a poem)


I wonder

I wonder how come the angels fly high
while we are forced to walk

I wonder how come the stars always shine
but we see them only by night

I wonder how come six senses we've got
but we use only the eye

I wonder how come people don't ask
what's beyond the deep blue sky


---
(c) Copyright 2003 by Maria Kafritsas, all rights reserved.
Email: Maria.Kafritsas(@)gmail.com
Please replace the (@) with a @ to contact the author.

Saturday, October 29, 2011

Weltenrausch - ein Gedicht (a poem)





Ich springe zwischen den Welten
Lange bleibe ich selten
Ich singe und tanze und taumle vor Glück
Über solche Vielfalt einfach entzückt.


Jeder Mensch ein neuer Planet
Wie er lebt, liebt, wie er geht
Was er glaubt, sagt, weiß über sich
Was ich lerne mit ihm über mich.


Zurück bei mir zuhause
Froh über die Pause
Atme durch von früh bis spät
Denke zurück so viel es geht.


Kein Spiegel mehr, kein du, kein da
Alles ist anders als es mal war
Mein Stern ist einsam ohne dich
Erinnerungen halten mich.


Die Zeit verfliegt in der Ferne
Ich lebe dort aber gerne
Ein Gast bei mir, spaziert umher
Als er ankommt glaubt er sich leer.


Nun singt er und tanzt er und taumelt vor Glück
Über solche Vielfalt einfach entzückt
Ich bin erfüllt
Geh nicht.




Copyright 2011 by Maria Kafritsas, all rights reserved.
Email: Maria.Kafritsas(@)gmail.com
Please replace the (@) with a @ to contact the author.

Wednesday, October 05, 2011

A Canon 7D under the stars

Please, sit down and keep cool. We are talking about a hot stuff tonight.


The system consists of a Canon 7D and a telephoto lense on a Losmandy G11 mount with the Gemini GoTo system. The system is guided with a Starlight Lodestar on a small Astro-Professional ED triplet refractor. This camera is a hell of quality. Magnesium alloy, hermetically sealed against dust and moisture, the large display, a professional long life shutter (150'000 cycles!), agile knobs everywhere and a beautiful body containing 18 million pixels. If you are an astrophotographer, you will never need more pixels in a APS-C format chip. We normally use the 7D at ISO800 for 7 min. integrations during the german summer. A handful shots are usually enough to capture faint nebulas of the Milky Way. We stack them with a freeware called DeepSkyStacker. Note, the software Aperture or Photoshop are excellent to process Canon's raw CR2 files. Oh yes, we are always working with 7D's 14 bit CR2 files to keep the dynamics high. When further processing with other software packages unable to read CR2 files is required, we use 16 bit TIFF files.


Did you know? A Canon 7D is upgradable to Da (a=astrophotography) in several shops here in Germany. Additionally, an IDAS LPS v2 filter can be attached on it, to block out the light pollution.
The clip version of his filter can be attached internally in the 7D. However, there is a normal 2" version  to attach it in the 48mm thread of your Canon<->WideT adapter! 

That's a hot deal, since the 7D with its small 4.3mu pixels is an ideal match for short focal length refractors and telephoto lenses. Since, the achieved resolution isn't trivial, we use a separate small telescope to guide the system. The guiding camera can be controlled by the software MaximDL or CCDSoft, the de facto standards in astrophotography.


A handmade "Hartmann Mask" (the mask having three holes in the photo above) is used for focusing. The micrometer screw at the left side of the telephoto lens facilitates precise focussing. Note, the 7D is remotely controlled from the laptop by using the supplied USB cable. The excellent "Canon 200mm f/2.8L USM II" telephoto lens is used at f/3.5 to take breathtaking wide field photos of large celestial objects (e.g. dark nebulas). This is the best 200mm camera lense for astrophotography, we have ever used so far, no donuts at the corners, no vignetting. Yes, why not, this dream lense could be also used on a full frame camera (e.g. Canon 5D MkII).

If you carefully look at the photos, you may find numerous parts being special customtailored products manufactured only on request.


This is the region around the star Tarazed in Aquila. Note, this is a crop of a 9 stacked (median) photos at ISO800 with 7 minutes each. No darks have been used.


Discover more details of this setup at dark.astrodigital.net

Thanks for reading.

Panagiotis Xipteras

Monday, October 03, 2011

Pleiades - The Seven Sisters

These are the Seven Sisters, the Pleiades complex, an open cluster in the Taurus constellation containing several blue giant stars. The most prominent of them, the Seven Sisters, are visible even with the n.aked eye.
See this photo in higher resolution at: dark.astrodigital.net. It's a single 13 minutes exposure with ISO400, at 385mm focal length (f/3.65) under suburban light pollution with an unmodified Nikon d3100 DSLR camera without any LPS filter. The photo processing has been entirely done in Aperture v3.1 (Mac).

It gets even better..
However, we experienced it get's even better if you stack many photos instead of using only one. So I did it, and I was astonished about the high quality the stacking can produce.
See my ultimate Pleiades (M45) photo in highest resolution at: dark.astrodigital.net

Data:
Median of 772+240+276+325+386+330 seconds
Nikon d3100 unmodified
FL=385mm, f/3.65, ISO400, No CLS filter
Urban light pollution

Exposure: Nikon d3100 unmodified in NEF (raw format)
Stretching & Histogram of each NEF photo: Aperture (Mac)
Alignment: MaximDL (2 stars manual)
Stacking: MaximDL (Media filter, default settings)
Histogram: Aperture (Mac)
Convert to JPG: Aperture (Mac)

Tuesday, September 27, 2011

It's Jupiter Time!

Jupiter, the largest planet in our solar system reaches its opposition to Earth in October, 29th 2011. On that day, Jupiter will reach its max. apparent size, making it ideal for observation even through small amateur telescopes. Its galilean moons and its Great Red Spot are attractive targets. Their movement is obvious during long observation sessions.
Find more Jupiter photos in my gallery at: dark.astrodigital.net

Thursday, September 01, 2011

The supernova SN 2011fe in the Pinwheel Galaxy M101

This is the supernova, I didn't discover ;-) The SN 2011fe in Messier 101, also called Pinwheel galaxy.

Yesterday, it was possible to observe it even through my small 4 inches telescope from my light polluted suburban area in Stuttgart, Germany. In order to prove my observation, I attached my DSLR camera and I shot this photo, where the supernova is visible. This unguided, 30 second exposure reflects my visual experience through my 18mm TakLE eyepiece. This is the brightest supernova I've ever observed.

At the moment (Sep. 1st, 2011), the ongoing supernova SN2011fe is brighter than the entire Pinwheel galaxy! It has a brightness of 10,5mag, that means it became 4 mag brighter in only 5 days, since on Aug.25th, 2011 it was significantly fainter with 14.8mag and thus only visible with bigger instruments. Note, each magnitude is about 2,5times fainter than the previous one, e.g. 11mag is 2,5 times fainter than 10mag!
I've heard from other colleagues in my astronomy club the detonation of this distant star could be strong enough to destroy everything in a radius of 30 light years around it. However this star is in a distant galaxy 19000000 (nineteen million) light years away from the Earth! So, don't worry about it. If you have a small telescope go out in the garden and don't miss this unique chance to watch a real supernova with moderate equipment. Note during your observation, you are watching a star in another galaxy! Normally, all stars you can watch with an amateur scope are in our Milky Way. But not this one.
/px

PS: New observation five months later on January 25th, 2012. Read more at: http://xipteras.blogspot.com/2012/02/pinwheel-galaxy.html
--
See also a wikipedia article about it: http://en.wikipedia.org/wiki/SN_2011fe
Learn how to find it at: http://www.astronomind.com
Watch it blinking in high resolution at: http://www.capella-observatory.com

Thursday, August 25, 2011

Sun spots in a hot afternoon

This photo has been taken at 820mm focal length using a Nikon d3100 DSLR camera. A Baader astrosolar foil has been used. This cropped image almost expresses the visual experience through the scope. It captured in Nikon's NEF (RAW) format to prevent data loss, a well known problem of JPEG files. The software Aperture v3.1 (Mac) has been used for further processing.
See a high resolution photo at http://dark.astrodigital.net
See also the same sun spots few days ago at http://www.astrovox.gr

Wednesday, July 20, 2011

M63 .. four years ago

This is an old unpublished photo of the Sunflower galaxy Messier 63 I made four years ago. I discovered it today on .. my harddisk, and I decided to upload it on this blog. This was the last photo I made with my Losmandy G11 mount at that time. It was a hard job, since I had to stay awake three nights, till my SBIG ST-7XME and the FS-102 (f/5.9) telescope encountered enough of the 37.000.000 years old photons arrived from these distant worlds.

Monday, July 04, 2011

The Wild Duck Cluster

This is the open cluster M11 in the constellation of Scutum. Messier 11 somehow looks like an globular cluster but it isn't. It consists of many middle aged stars.
This is the full field version 3° 25' x 2° 15'. Notice the dark nebulas around M11.

Tuesday, June 28, 2011

Diamonds in the sky

This is the double cluster in Perseus. It is called h + chi and it contains over 600 blue giant stars. More information at: http://en.wikipedia.org/wiki/Double_Cluster
See my astrophoto in high resolution at www.astrovox.gr or at dark.astrodigital.net

When I am working on such delightful celestial objects, I sometimes think astrophotography is a pre-stage of poetry. The astrophotographer, invests all his experience trying to interpret a fact into a shapes and colors, so a poet tries to interpret his emotions after looking that pictures into wonderful words.

/px

Tuesday, June 21, 2011

My autoguiding settings are here :-)

Yes, it works! These are the settings for my autoguider. The graph is smooth (if nobody is jumping next to the mount ;-) and I could expect good photographic results with it.
..and now live during the download of the light frame ... (hertzklopf klopf klopf :-)))
The software "Point An Object" can be download here for free.

Thursday, June 16, 2011

Moon eclipse - Mondfinsternis 2011

June, 15th 2011 - 22:23 MEST
You are also welcome to visit my Moon Eclipse 2011 gallery at:

Clear skies from Germany
Panagiotis

Sunday, April 17, 2011

Trying to capture Saturn with a color webcam

The planet Saturn has currently a brightness of 1.04 mag and an apparent size of 19.2". I tried to capture it using my TIS DBK21 One-Shot-Color webcam on my 21cm (f/11.5) Dall Kirkham cassegrain telescope in order to find out the most appropriate focal length for this application. The DBK21 cam uses the same chip as the popular Philips ToUcam 840k Pro. However both the electronics and the mechanical construction are excellent on the DBK21. Considering the low brightness of Saturn (compared to Jupiter, the Moon or the Sun) and the permanent bad seeing at my roof observatory, it was useful to get some experience on using this webcam to capture Saturn with my telescope. The goal is to find the "golden ratio" between the focal length and frame rate to get best possible results on Saturn.

f/11.5


Image 1: a single unprocessed frame

f/11.5 @ 27 frames per second. Focal length was 2415mm. No extenders. Notice: Quick enough to freeze the seeing. Too small planet disc but very bright. No problem to increase the frame rate.

The following data have been calculated with the free software AstroDigital.Net
Model: Takahashi Mewlon 210 (f/11,5)
Focal length [mm]: 2415
Critical Focus Zone [mu]: 290,95
Model: DBK 21AF04
Pixel size [x*y]: 5,6 x 5,6
Chip size [x*y]: 640 x 480
Chip diagonal [mm]: 6,08
Chip surface [qmm]: 18,26
Wavelength [nm]: 550
Telescope illumination power: 1,102345E-05
FOV: 0° 5' 6'' x 0° 3' 50''
Image scale: > 0,48 x 0,48


f/18.4

Image 2: a single unprocessed frame

Image 3: 5000 frames added and processed (AVIStack, Giotto, MaximDL)

Image 4: The setup

f/18.4 @ 19 frames per second. Focal length was 3864mm. The ExtenderNQ (1.6x) of a FSQ-106ED was used. It works excellent on the Mewlon! The planet disk is large and bright enough to show details under good seeing conditions. The frame rate is high enough to freeze the seeing.


Model: Takahashi Mewlon 210 (f/18,4)
Focal length [mm]: 3864
Critical Focus Zone [mu]: 744,83
Model: Takahashi Extender 1.6x
Model: DBK 21AF04/21BF04
Telescope illumination power: 4,306035E-06
FOV: 3' 11'' x 2' 23''

f/28.7
Image 5: a single unprocessed frame

f/28.7 @ 9 frames per second. Focal length was 6037mm. Televue Powermate 2.5x. Notice: Too dark on Saturn, too slow to freeze the seing. Big planet disk.

Model: Takahashi Mewlon 210 (/28,8)
Focal length [mm]: 6037
Critical Focus Zone [mu]: 1818,44
Model: Televue Powermate 2,5x
Multiplier [times]: 2,5
Model: DBK 21AF04/21BF04
Telescope illumination power: 1,763752E-06
FOV: 2' 2'' x 1' 32''
Image scale: > 0,19 x 0,19

Tuesday, April 12, 2011

Backnang's star party 2011

Dear guest, welcome to the photo gallery of our Star Party 2011 ..
..in Backnang, Germany.
The moon is still up and running
Vixen ED102 on a green Vixen GP
Two SkyWatchers are gazing the night sky
Happy faces, good scopes
Most of the guests were observing the planet Saturn at that night. The photo above corresponds to a typical view of Saturn through a big dobson telescope. It has been taken some hours after the event.
A 20cm f/5 newton telescope. Mike said, he had the best view of M42 in his life, as he observed it with this scope on the Alps/Austria 10 years ago.
A Meade LX10 ready to go.
Markus the APOD guy as he sets up his INTES 18cm Maksutov telescope.
Two Lightbridges look the sky.
Gerd at the 76cm dobson telescope. This was once the biggest portable telescope in Europe! John Dobson signed it during his stay in Fellbach/Germany a couple of years ago. It belongs to the Backnanger Sterngucker. You can observe some deepsky objects in color with it! (I'm not kidding!)
The eye of the tiger: a 400mm dobson telescope.
Mike is setting up his unbelievable 30cm dobson telescope.
Dennis with his fine tuned 37cm Dob.
An apple a day ... catches light at night! :-))))

Oh yes! My Nikon and me were also there ;-)

Kind regards and clear nights to the world wide astronomy community from Backnang, Germany. /Panagiotis