Orpington Astronomical Society

Astronomy => Astrophotography => Topic started by: spendrey on Jun 09, 2004, 18:08:00

Title: My transit
Post by: spendrey on Jun 09, 2004, 18:08:00
Hi everyone, what a great day it was yesterday. I was up until 1 the night before making my filter but had to wait until the sun was above the surounding trees before beginning viewing from my garden. But the first glimpse through the finderscope was quite exciting.

I've seen some great photos on here so far and am in the process of putting a montage of mine together similar to John's. One thing that I experienced though was that earlier in the morning I was able to view via the toucam on a high shutter speed but by about 11 I could not see Venus with a shutter speed above 1/500 or below 1/250. Therefore all my photos are saturated unlike John's. I had the gain set to 0. Should I have altered anything else to avoid the saturation?

One other question, what's the easiest way to pull single frames out of a video file as a jpg?
Title: My transit
Post by: Rocket Pooch on Jun 09, 2004, 18:38:00
if you are using k3ccd, select a single frame and then save it as a jpg, sor registax, load the avi, click show frame list, de-select all, select the one you want then press align and stanck and eventually save the single file.
Title: My transit
Post by: spendrey on Jun 09, 2004, 18:52:00
Thanks Chris. Registax is a bit long winded isn't it.

I didn't see a black drop effect on 3rd contact. Did you?

Title: My transit
Post by: Rocket Pooch on Jun 09, 2004, 19:06:00
By that time my eye's wern't upto much so I'll have a look through the 190 avi's I took and let you know tonight.
Title: My transit
Post by: Ian on Jun 09, 2004, 19:16:00
As with Johns image, changing the gain alone may not cure saturation. It depends on what part of camera is saturating. The approach I take is to set gain to around 50% and adjust exposure time until I get a detailed image, rather than a saturated one. Then use gain as a fine tune.

To extract a single frame of an AVI use K3CCDTools and use the export frame option.
Title: My transit
Post by: JohnP on Jun 10, 2004, 05:50:00
What setting did you have brigtness & Gamma set to? This both make a big difference as to how bright the image is

John
Title: My transit
Post by: spendrey on Jun 10, 2004, 19:35:00
I had the gamma at about 25% and the brightness at about 50%. In fact if I had it any lower I couldn't see anything.
Title: My transit
Post by: JohnP on Jun 10, 2004, 19:59:00
Hi,

I'm a little confused - You say that with Gain 0% & shutter between 1/250 & 1/500, brighness 50% you could get a saturated image but if you changed anything outside of these settings you couldn't see any image? Is this correct. Perhaps you could try imaging it again to see if it is still behaving strangely.

John.
Title: My transit
Post by: spendrey on Jun 11, 2004, 16:23:00
Venus disappeared when I altered the shutter speed, and everything disappeared when I lowered the brightness. Does that sound right?
Title: My transit
Post by: spendrey on Jun 19, 2004, 07:49:00
I've finally got round to uploading my images...

http://homepage.ntlworld.com/simon.pendrey/transit_of_venus.htm