California Neb from SG Balcony - Tampines

[PETER LOO]

Friday night the sky was opened intermittently, as my balcony has only limited usable FOV, only manged to collect 2 subs of ISO 800 at 4 mins with UHC filter. 50mm guider was guiding fine for RA but record large swing for the DEC. Not sure whether it was caused by the seeing condition.
To improve, i think this object needs ISO 800 4 mins X 5 plus ISO 1600 2 mins X 20 to produce low noise result. It is thought that When n number of shots exceed 20, Gaussian noise will be reduced much. This arrangement would help to balance the realizable shooting time & end quality.

(n.b. trying hard to quit but find shooting is much easier instead)

[kimo]

Very nice. DSLR has large sensor. I have to learn more then I can buy a large sensor CCD cam.

[cataclysm]

Nice work Peter!

[PETER LOO]

Thank Kimo, i saw yours too (NGC1499), very smooth, like you said, need a larger sensor though to cover the area. Thanks Kelvin, the DEC guiding is a a bit large, not sure is due to the seeing condition or not (sometime can go down to +/- 2.5) not sure need a stronger star or need to increase the guide scope Focal Length to 480mm @ F6.0 to make the DEC guiding more robust ? Please advice

[kimo]

I am not exp. why you need to guide DEC? you should be guiding RA, DEc don't require actually if your polar alignemnt is good enough. may i know your PHD setup and your guide scope ,main scope FL?

[PETER LOO]

Hi Kimo and Kelvin

Main scope = TS-65, aperture 65mm, FL at 420mm, F6.2
Guide Scope = Orion 50mm with SSAG , FL 162mm, F3.5
Mount = GPD2, Guided by PHD, Selected DEC Guide Mode to Auto for DEC guiding (i also ever off it - but just for testing)

The RA Guiding was always quite good, it is the DEC that fluctuate, hence, is highly possible that my Lagi Simple Polar alignment is out too, thinking of trying out yours & Orly's method: IS-WCS. as we are doing it indoor before changing guide scope. See RA graph for the same guiding session:

[orly_andico]

I have a Cali Neb lying around. At my FL (600mm) the 8300 chip is still too small.... FYI.

BTW I now use AstroTortilla for rough polar alignment, then PemPro to refine.

Dsi Wcs is just too unreliable.

[Gary]

Nice shot Peter! Thanks for sharing. Never let clear enough skies get away scott free.

[kimo]

look like it is polar alignment problem.

[PETER LOO]

Thanks Orly and Gary