天文望远镜观察摄影山林山鸟---林月笙香港天文台

[MANDII]

NO.38 )

[MANDII]

Cloudy Nights


azure1961p : 01/06/11 09:23 PM from USA

delete, delete , delete, delete...

If there is any astronomy happening in those images let me know. Im obviously missing it.

Pete
Post Edit: Wait, you listed RA and Dec for terrestrial locations of botanical subject matter. OK - I get it.



MANDII : 01/06/11 11:09 PM
Ha Ha !
Astronomy can be much , much thing to do .
Not only the objects hanging up the night sky .
If that is the case , there is too little we can do something . Or otherwise we will not come to this cloudy night Forunm , we all come here to fight away the clouds ( our enemy ) . Ha ha .
And one of the practical way to fight it , is to expand our usage of telescope , to expand the use of a telescope imaging system , for anything that we can use it , and the meaning to use it .

You had noted the visual position value , that is a critical point !
To find the same object at night time ! Efficeintly !

Ha Ha !

[MANDII]

NO.39)

TREE10 竹 (18h15m,+2) 2011/01/22晚_NO.39

[MANDII]

NO.40 )

TREE11 白树径 (18h30m,+5) 2011/02/05午_NO.40

[MANDII]

NO.41 )

FLOWER 08  (18h15m,0) 2011/02/12午_NO.41

[MANDII]

NO.42 )

TREE10 竹 (18h15m,+2) 2011/01/22晚_NO.39 |  2011/02/12午_NO.42

[MANDII]

NO.43 )

LEAVE06 (18h20m,0) 2011/02/18晚_NO.43

[MANDII]

NO.44)

TREE12 (18h38m,+11) 2011/02/19晚_NO.44

[MANDII]

US ASTRONOMY

sxinias : 02-19-2011, 02:17 AM from Marathon Greece
Getting a good focus is one of my biggest difficulties. Nice to hear that the Hartman mask works for you. Here, nothing but clouds and more clouds.... had two nice nights last week on the day my new telescope arrived and since then, clouds and more clouds.

Joe




MANDII : 02-19-2011, 11:28 AM
Dear Joe , yes the mask did work before when I was using it with my MIZAR newtonian , for these kind of territorial pictures . But I still haven't succesfully make better focus when I was taking Moon pictures , and the stars of DSO pictures as well . I am not sure my self made Hartnman mask is a good one or not actually . But the idea of Hartnman mask that invented by Hartnman should be very great ! Recently , I am ordering a Bahtinov mask from the net , it's very cheap one only costing 30 RMB .

2ndly about focusing , for this picture last night , I didn't use any mask yet . The new Orion newtonian has better focuser than the previous one (MIZAR) , I can control the focusing movement much more smoothly and steadily , that is much better than before , and at the same time check the image sharpness on the computer screen . However , one point is that I still cannot control the focus movement in more precise . I always thought about to change the current focuser by using some kind of gear box , let say the gear ratio around 1: 20 , somehow it can be DIY by adding a gear box externally . In such case I can have much better controlling on the focus sharpness and accuracy . Anyway , at first looking forward the new Bahtinov mask can helps in focusing .

[MANDII]

NO.45 )

BIRD01_2011/02/27_午

ORION 6" Newtonian
EQ3
DSI-1( 0.0087s X 1)

Observe : 2011/02/27_午

[MANDII]

I forgot to say something on feeling to shoot birds . Because that day I was very tired in writing this report , the photo was not yet processed as well .

My point on that day's experiment is :
Using newtonian to shoot birds , is very difficlut , But at same time very exciting and challenging to me . The FOV of the photo is about half degree only . Plus the image in Newtonian is rotated to some degrees , it's not the same 180 degree inverted image as a refractor do , so even find the target is not easy . And in order to shoot it down onto picture , my action had to be very fast . Or the bird fly away in the mean time .
Very excited !

[蕭同學_Skywatcher]

I forgot to say something on feeling to shoot birds . Because that day I was very tired in writing this report , the photo was not yet processed as well .

My point on that day's experiment is :
Using newtonian to shoot birds , is very difficlut , But at same time very exciting and challenging to me . The FOV of the photo is about half degree only . Plus the image in Newtonian is rotated to some degrees , it's not the same 180 degree inverted image as a refractor do , so even find the target is not easy . And in order to shoot it down onto picture , my action had to be very fast . Or the bird fly away in the mean time .
Very excited !

不好意思, 在下的經驗感覺, 用天文望遠鏡拍地面景物,
對比 contrast 都不怎麼好, 不知是什麼原因?
不知前輩們是否有解答? 謝謝 !

[MANDII]

不敢当前辈啦,照片也不是很漂亮。
你提到的對比(contrast)的问题，我觉得这是照片素质上的一个问题。
素质包括 對比，明暗度，画面有没有发虚，色彩是否丰富，等等因素，整体来说，就是感觉好不好看了。

而我认为,照片素质，与采用的照像机的品质，和图像处理方面有关，多于望远镜。
那也不是说望远镜完全没关系，但相对地影响要小。
当然要看个别情况，我指的是在我上面拍出来的照片而言。


照像机的品质，这个好与不好，因人因情况需要而异。
图像处理，我感觉每次要叠加越多越好看，越多就会出越多细节。
我不太会说理论上（signal/noise raito)的是怎么样，小看书,反正我每次处理都是那样感觉。
景物图因为构图复杂，变化大，叠加得够不够精确是重点所在，每张图叠加的方法都不一样。
它不像天文照那样是有规则的图（比如按星点来叠加就可以了）。
不过这些鸟都是单张的 ,没法叠加，1秒不到的时间就要拍下，因为它是在动的，不像天体那样是不动，或者有规则地动，它是不规则地动，因此无法多张叠加。加了效果也不怎么样，因此这些照片我今回也没处理就放上来了。

[MANDII]

NO.46)

LEAVE07 (18h32m,+4) 2011/03/10晚_NO.46

[蕭同學_Skywatcher]

NO.46)

LEAVE07 (18h32m,+4) 2011/03/10晚_NO.46

歐, 抱歉, 原來是晚上拍的, 這樣應該非常厲害了!
大概是利用月光當照明的吧?
在下用 Photoshop 處理一下, 或許更好看一些?