CMSimple.dk - Template
 
 
 
 
 

Home > hobbies > astronomy

astronomy

 
current night sky over Cagliari
Sky map by AstroViewer®
Get the HTML code for thƒis sky map



CURRENT MOON


All of the picture posted here are full resolution frames without any reduction. Most of amateur astronomers post reduced, lower resolution pictures. In doing so, they hide most of the defects but they also loose most of the beauty.


I am a particle physicist, but one of my favorite hobbies is astronomy at amateur level. I used so far three telescopes:

  • Celestron Schmidt-Cassegrain 200 mm f10
  • Televue 102 refractor 100 mm f8.6
  • Astrophysics EDF130 Starfire 130 mm f5.6

For 10 years my scopes were mounted on a computerized GP-DX mount on top of a Baader wooden tripod. Recently I acquired an Avalon Linear mount.

The telescope I use most is the astrophysics, which is a real piece of art. Its star test is quite interesting because the inside and outside out-focus star images are quite different! After having spent one month thinking about it - the conclusion is: don't trust most of the stupidities written in magazines on symmetric inside and outside out-focus star tests as a mandatory condition for a perfect optics! The in-focus start test of the astrophysics is simply perfect and that is what matters. It outperforms by far the Televue (which is also a very good telescope) and the Celestron.

When I got a Canon digital camera I started also taking pictures. I have been using also ccd cameras: audine and atik 383.

Below you can find some of my pictures. Long exposures were taken first by manual guiding with a little refractor mounted on top of the astrophysics (M13 and M31 with the 200 mm telefoto lens).

I don't find they are super high quality (considering that the scope is super high quality) and I think the reason is the following. Taking a good picture requires a lot of exposure time (I mean many many hours, not minutes) with an excellent tracking system first of all.  Optics, at this level, is less important. If you have to dismount the scope every night then this is a problem because a single picture can require several nights (since I have also to sleep to work properly during the day). If the tracking system is not authomatic, this is
another big problem. So, even with my equipment, taking a decent picture without an autoguide is a pain in the neck.

For that reason in 2011 I acquired the avalon linear mount which has a much higher load capacity than the gp-dx and a very smooth tracking with zero backslash. 

The guide is now performed with a starlight express lodestar coupled to a TS OAG9 offaxis guide. This is system is much lighter and more precise than the guidescope. It is insensitive to differential flexures - in particular with the C8 it is the only choice because of the primary mirror flop. First pictures are starting to come - but, still, getting good pictures is still quite some work.

Below a flat taken with the astrophysics 130, OAG9, field flattener and the canon 5d mkii is shown. The vignetting in the corners is evident. The prism of the oag is mounted very close to the border in order to reduce the vignetting as much as possible (it is the right upper corner). Details: raw, iso 400, 1/13 s.

flat field



Comet Holmes 17 

15 min exposure with 200 mm f6.3 canon lens+eos20d on top of the astrophysics scope. Sum of unguided 30 s exposures. Taken on nov 18 2007 in Cagliari.

comet Holmes-17



M13 and M3 Globular clusters

The M13 picture taken with the Canon digital rebel shows a >14th magnitude galaxy and it was taken on two nights from the center of Cagliari where I live (a rather high polluted town). 

M13 globular cluster - Audine CCD camera
M13 - 1

M13 globular cluster -
AP130 EDF + field flattener + LPS filter with canon 300D - 82 min total
integration under moderate/heavily light polluted site (Central Cagliari area)
Processed with IRIS for darkframe subtraction (not perfect - some hot pixels still present) / background flattening +
wavelet filter / RGB balance (not flat field)
DDP + unsharp mask

M13 globular cluster - 2


Same as before, but further processing with photoshop: residual hot pixel eliminated - new RGB balance to get redder colours
M13 globular cluster - 3


Beside the cluster, Two galaxies ery close to M13 are clearly visible:

- NGC 6207. This small 11.9 magnitude galaxy is located less than a half degree away from M13. In fact many observers never notice this small galaxy and are surprised to find it located so close to such a prominent galaxy.
Locate NGC 6207 1/2 degree from the center of M13 to the northeast. NGC 6207 is oriented north to south, is very faint and may suggest some structure within the halo of the galaxy.

- IC 4617. By the way; on your star-hop to NGC 6207, did you happen to notice a VERY (!) faint (magnitude 15.5) galaxy about half way between NGC 6207 and M13? You might have noticed it next to a parallelogram of 4 stars which remind me of the parallelogram in Lyra which locates the "Ring Nebula," M57. IC 4617 isn't even charted on Uranometria!

details about M13 

M3 globular cluster - Audine Camera 



eta and chi clusters


eta and chi clusters - canon 300D




M57 - The ring nebula

M57 ring nebula - Audine Camera

M57 ring nebula canon digital rebel

2011: M57 ring nebula - canon 5d mkII
This is the first shot taken with the linear mount and the C8 at f10 (2000 mm f lenght). Guiding performed with a guidescope mounted on top of the C8. Tracking is not perfect due to mirror flop (the phd graph was perfect with rms below 0.2 and osc index 0.4-0.5)

details about M57

ngc6939 canon digital rebel first trial


                                  
The Andromeda Galaxy

2011.


Andromeda galaxy canon 20d with 200 f/4L zomm lens

2011: Andromeda galaxy canon 5d mkii with 200 f/4L zoom lens

2011: Andromeda galaxy canon 5dmkii with astrophysics 130

this pictures is a stack of 5/10 min subs for a total of almost 6 hours at 400 iso. 100% of the subs were well guided. A track from an airplane is visible.

The following pictures are stacks of 5/10 min subs. The full moon stacks were 200, 320, 400 ISO and taken in part from the center of Cagliari. The new moon were taken from Capitana at 800 ISO. The "average" is an average of -1 and -2.

8 hours stack full moon 3 hours stack new moon-1 3 hour stack new moon-2

3 hours stack new moon-average

The subs were acquired in three different nights (7,8,9 september 2011): 4, 3 and 2 days before full moon. One third of the subs were in addition acquired from the center of Cagliari. Is it is an example of what one can reasonably get in heavily light polluted situations? It is interesting to inspect a single sub taken the third night with the moon already very high in the sky:

m31 sub (5 min) with almost full moon




M33 - Triangulum galaxy

2011. Canon 5d mkii Two hours at 1000 ISO. Astrophysics 130 edf + canon tele-extender 1.4x. 10 min subs. Dark frames and flat field. Seeing poor. Two different processing settings:




M45 - The Pleiades

2011. Canon 5d mkii Two hours at 400 ISO (Cagliari center) + 20 min at 800 ISO (20 km outside Cagliari). Astrophysics 130 edf. 5 min subs. Dark frames and flat field. Seeing poor. Canon 5d mkii




M27 - The Dumbell nebula

Canon 5d mkii + C8. Approximately 2 hours, 5 min subs (20 km outside Cagliari). Dark frames and flat field. Seeing poor. 

m27 canon 5d mkii



IC443 - Jellyfish nebula

14/01/2011 ATIK 383 monochrome + baader H alpha 6 nm filter cooled af -15 C

135 min (9 x 15 min sub)

8 dark, 9 bias, 9 flat, 9 dark flat

IC443-1

IC443-2

IC443-3


18/01/2011 ATIK 383 monochrome + baader H alpha 6 nm filter cooled af -15 C

125 min (11x10 min sub + 1x15 min sub)

14 dark, 22 bias, 22 flat (30 s), 22 dark flat

IC443-group-2_filtered-third-proc

IC443-group-2_filtered-hdr-5


Sum of 14/01 and 18/01 exposure (frame cropped because exposition fields were quite different)

IC443-prova-crop_filtered-3

IC443-prova-crop_filtered-hdr-3

IC443-prova-crop_filtered-hdr-4


NGC6888 Crescent Nebula


02/06/2012 4 hours (20 min subs) from Cagliari

crescent-02-06-2012-ddp-4.jpg


6 hours (4 hours 02/06/2012 Cagliari + 2 hours Capitana with bad seeing)

Borders cropped. 2 hours aquired with nebulosity and dithering

ngc6888-02-june-09-june-ddp-4.jpg


24/07/2012

9 20 min sub - 140 min total acquired with canon ef1.4x tele-extender (1080 mm focal length)

ngc6888-calib-7-files-1-unsharp.jpg



SH2-115

Sharpless 115

13/06/2012 SH2-115 (nebula close to Deneb)

160 min (8 subs) from Cagliari

sh2-115-all-correct-calib-ddp-6



NGC 6992 (the eastern part of the veil nebula)


17/06/2012 180 min (9 subs) from Capitana


ngc6992-all-calib-3-1

ngc6992-all-calib-3-2

ngc6992-all-calib-3-3


NGC 6960 (the western part of the veil nebula)


24/06/2012 180 min (9 subs) from Capitana

ngc6960-all-calib-4-masks.png




The Moon

Moon total eclipse march 2006
Full moon just before eclipse beginning full moon
Moon during total eclipse moon eclipse




Moon 4 days after first quarter 22/12/2004
Canon Digital Rebel + Astrophysics 130 f/6
Exposure: 1/250 s at ISO 100
processing: unsharp mask

Moon one day after first quarter - 18/03/2005
Canon Digital Rebel + Astrophysics 130 f/6 prime focus
Exposure: 1/160 s at ISO 100
processing: van cittert 7 iterations

Moon 2 days after first quarter - 18/03/2005
Canon Digital Rebel + Astrophysics 130 f/6 + barlow 2x vip baader
Exposure: 1/60 s at ISO 100
processing: van cittert 30 iterations

Moon 3 days before first quarter - 18/03/2005
Canon Digital Rebel + Astrophysics 130 f/6 + barlow 2x vip baader
Exposure: 1/50 s at ISO 100
processing: unsharp mask + histogram stretch + gray tones only
Picture taken with moon quite low in the sky


Moon first quarter - 12/07/2005
Canon Digital Rebel + Astrophysics 130 f/6 + barlow 2x vip baader
Exposure: 1/50 s at ISO 100
processing: unsharp mask + histogram stretch + gray tones only
Picture taken with moon quite low in the sky


Solar corona - 18/03/2005
Canon Digital Rebel + sky watcher 500 mm + barlow 2x vip baader + Coronado Halpha filter (4 cm)
Exposure: 1/60 s at ISO 100

 

 

 
 
 
 
 
 
 
   

Powered By CMSimple.dk | Design By DCWD