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Shawn
31-10-2007, 05:46 PM
Still a little bit of an issue with not quite round stars, this is a stack of 4 200 second exposures. lousy seeing and more an attempt to improve guiding and tracking. the drift is both axis and consistant across all images, Ive drifted this scope to the best of my ability, but Im still getting this slight drift at full FL. I can tolerate it if I have too, but if anyone can suggest something I have not maybe thought of it would be appreciated..Also does anyone have any info on the stars that are not Alcyone and its three buddies in terms of magnitude. Im just after a frame of reference...

Thankyou all

Shawn

...

Dennis
31-10-2007, 10:46 PM
Hi Shawn

For prime focus work at +3500mm I’d be very happy with that – well done! I just had a look at the DSS image and yours is much nicer.

Cheers

Dennis

RB
01-11-2007, 12:28 AM
Like Dennis said, that's great work Shawn, I'd be very happy with it too.
As for your drift problem, just an obvious suggestion but have you carefully balanced the scope?

You may want to try something like Starry Night to find the magnitudes in the star-field.


:thumbsup:

saberscorpx
01-11-2007, 01:18 AM
Nice shot.
Ally's three brighter buddies are mag 6.3 @ 117", 8.3 @ 181", and 8.7 @ 191".


SJS

citivolus
01-11-2007, 02:03 AM
The limiting magnitude as far as I can tell from USNO-A is 1125-01276336 with a red magnitude of 17.7. It is just barely visible above the noise threshold in a stretch. Several 17.5 magnitude stars are clearly visible.

This was checked in Cartes du ciel with USNO-A.

ballaratdragons
01-11-2007, 02:05 AM
Shawn, those stars look round to me :thumbsup:

Shawn
01-11-2007, 04:23 PM
Thankyou Dennis, I thought I was probably asking too much of the gear. cheers for the compliment.

Thankyou Andrew, You may be onto something Ive overlooked it may need a bit of bias to the East...

Thanks for the info Stephen & Citivolus, appreciated..

And no they are not quite round Ken close but not round, its really noticable on the faint stars,Im sure if tracking were spot on the fainter ones would be more prenounced and maybe even reveal some that are not visible, but then, maybe Im am asking too much of the gear :) and seeing was a bit mucky. Im going to use this little area to tweak and fiddle, with this as a frame of reference...

Thanks Guys....

Shawn

citivolus
01-11-2007, 04:28 PM
Meade claims an 18.5 limiting photographic magnitude, so theoretically you could get twice the signal per pixel in perfect seeing & with perfect guiding. You're not far off there.

gbeal
01-11-2007, 05:54 PM
Crikey Shawn, if that is at 3500mm plus, then stop complaining and rejoice. I find it difficult enough at 800mm.
Gary

Shawn
02-11-2007, 06:43 PM
Thanks guys, what Im going to attempt over the next week or so Is a montage of the Plieades, since every one is a guide star...then make it smaller. I have no idea how to do this but Im keen to try. If anyone can give me any tips, I would appreciate it...

S