video mode canon 550D

[mymoon]

diantara ciri2 terbaru canon 550D ialah video crop mode.

using the center 640×480 pixels of the sensor for recording so that a C8 telescope becomes  effectively about 15,000 mm focal length (7x 2032mm focal length)

video of jupiter recorded using canon 550D and C8 and MT mount

and the still image from the video align and stack using registax



Thanks to sifu shahgazer for the conversion of canon native .mov to .avi suitable for registax.

cheers

[shahgazer]

ASW

Really nice detail. I'm sure for GRS can be easily seen hanging in the 'empty' SEB area. 

[redzuan]

Gambar ni diproses bersama dark frames juga atau distack sahaja?

[mymoon]

Gambar ni diproses bersama dark frames juga atau distack sahaja?

no dark frames used. align and stack in registax sahaja.

berjalan dulu sebelum belari 


Focus nearly there sebab this time focus guna live view using computer screen. senang focus sebab image besar .

C8 tu pun baru collimate.

model 550D boleh adjust speed, iso dan aperture(fix to f10 for the C8) in the video manual mode.

Soalan untuk sifu2 atau bakal sifu: Jupiter berputar. Kalau lama sangat ambil video tentu akan detect rotational motion. Mungkin menyebabkan surface features jadi blur.

Jadi ada rule of thumb atau teori yang boleh diguna pakai ke berapa lama kah boleh expose video sebelum jadi blur surface features

untuk jupiter, saturn and mars 

cheers

[shahgazer]

Soalan untuk sifu2 atau bakal sifu: Jupiter berputar. Kalau lama sangat ambil video tentu akan detect rotational motion. Mungkin menyebabkan surface features jadi blur.

Jadi ada rule of thumb atau teori yang boleh diguna pakai ke berapa lama kah boleh expose video sebelum jadi blur surface features

untuk jupiter, saturn and mars 

cheers

ASW

Interesting you asked this. There are some good articles relating to this.

Check out HERE , and scroll down to 7.0 The planets rotation . Some nifty math formula to use too...

[mymoon]

Thank you sifu shagazer. The lost in detail is like comparing shooting handheld and with a camera on a tripod.

From that website based on his calculation
worst case scenario:

t max=(206265*dPixel*T)/(2Pi*F*R)

substituting for change of equipment

dPixel = 4.3 microns = 0.0043mm for canon 550D

F = 7 X 2032mm for C8 crop mode

number crunching

t max = (206265*0.0043*35430)/(2*(22/7)*7*2032*22.55)

         = 15.6sec

say 16 sec

According to him this is a "worst case" calculation. So he reckons that in real live you can exceed this calculated "max. duration time" by the factor 2 and still have a good final image.

so t max= 30 sec for jupiter using Canon 550D crop video and C8 telescope.

Weather permitting have to shoot jupiter at 30sec and at 60sec and compare.

BTW my earlier video stream is for 1 min.

cheers