Moon 15.11.2010 8pm 250px 1000D

[Revs]

Just managed to get a couple of hours in last night before the cloud rolled in. These are single shots at ISO100, the second is with the Ultima Barlow..

Full res.. http://img266.imageshack.us/img266/1335/lrpic4.jpg

[themowgli]

Great pics, great quality.

For the whole moon pic, did you use a mosaic, or focal reducer to get the whole thing in?

Intrigued as my first time using a webcam with my Skywatcher 8" was last night, and I couldn't get the whole moon in field of view so was advised I probably need to go down the mosaic route, as a focal reducer probably wouldn't work on my size dob.

[oldfruit]

Really good pictures. Nice capture.

[jgs001]

Very nice results. The full image is actually a crop of the original picture file, the 250px is 1200mm which is what I've been using for the moon, single frames.

[Revs]

Cheers peeps

For the whole moon pic, did you use a mosaic, or focal reducer to get the whole thing in?

Just a single shot with a direct-to-scope connection. As a rule, web-cams have a far small sensor than D-SLR's. With this Dob and the 1000D you could prolly just about fit the moon in twice, side by side. Even with the Mak (1500mm FL) the Moon fits in shot no problems

In case anyone's interested, I'd say the Dob produces a better quality image than the Mak, but obviously tracking is the issue. I tried imaging Jupiter with the webcam, but without the barlow it was just too small to get any decent detail, and with the barlow it didn't stay on sensor long enough to get enough frames.

Horses for courses, as they say

[themowgli]

Cheers peeps

Just a single shot with a direct-to-scope connection. As a rule, web-cams have a far small sensor than D-SLR's. With this Dob and the 1000D you could prolly just about fit the moon in twice, side by side. Even with the Mak (1500mm FL) the Moon fits in shot no problems

In case anyone's interested, I'd say the Dob produces a better quality image than the Mak, but obviously tracking is the issue. I tried imaging Jupiter with the webcam, but without the barlow it was just too small to get any decent detail, and with the barlow it didn't stay on sensor long enough to get enough frames.

Horses for courses, as they say

So what you're saying is that as you used a dsl-r and not a webcam, you could fit the whole moon on FOV, as its got a bigger sensor, even though you're still using a dob. Because webcams have a smaller sensor, it can't fit the whole image on there. Is that right?

Cheers

[Revs]

Yup, that is correct

This is a resized, but not cropped image...

EDIT: Download yourself CCD Calc... http://www.newastro.com/downloads/ccdcalc/ccdcalcfull.exe

[jgs001]

As a very rough and approximate guide, if you look at focal lengths in terms of a full frame camera 1000mm is 1000mm. a crop sensor dslr like my 450d and the majority of slr's on here you multiply by the crop factor of 1.6x so the slr makes the 1000mm 1600mm equivalent. This means you'll need 960mm on the full frame camera to get the same fov as the 450d. A webcam has a crop factor of 8.5x so that's 8500mm compared to the full frame and a much much tighter fov. Hope that makes sense, I got used to visualising in those terms from a photography forum.

[themowgli]

Yup, that is correct

This is a resized, but not cropped image...

EDIT: Download yourself CCD Calc... http://www.newastro.com/downloads/ccdcalc/ccdcalcfull.exe

Thanks for the link to the program @REVS, very handy tool. Also thx for the info @jgs001. I guess from this info re 8500mm you're saying that having the webcam attached is like having a focal length of 8500mm. Is that right?

Playing around with that handy program, says that you cant get the whole moon in a FOV for 8" dob unless you have a focal reducer of about 0.25. Guess they don't make them that small, and also someone else said that on a dob not sure it will rack back far enough to be able to get into focus with a focal reducer of approx. 0.5. Guess the only way is to do it with a webcam and the size dob i have is to mosaic and stitch together.

Thanks for the info. Sorry to hijack your thread. Original point was great pics @REVS.

[Revs]

No worries

TBH I think unless you do a mosaic or the webcam is a HD one, you don't really have the res to get enough detail to do the Moon justice.