Two "Quickies" from last night - NGC7635 and IC1805

[Paramount]

Hi all
Later this year I have been planning to do some 30 minute sub frames to see how deep I can go with some of the emission nebula so last night I thought it was about time that I tweaked my polar alignment and gave it a go. Using TPoint I managed to get the polar alignment to 6 arc seconds beyond which you can't measurably adjust the Paramount by the alt/az adjusters. I was using the Starlight Xpress H9 camera as its quick 1 second downloads make TPoint mapping a breeze. I had planned to use the H9 anyway and had taken a series of 30 minute darks a couple of evenings ago albeit at a different temperature as they were taken indoors.
My main target for the evening was the centre of IC1805 but as I had to wait about 2 hours for it to clear my neighbours tree it gave me time to do some work on the bubble nebula. Both of these targets I tried last year with the BRC-250 and H9 but I was plagued by halo problems, these efforts can be seen on the Nebulae 2 page of the image gallery on my website http://www.imagingtheheavens.co.uk (http://www.imagingtheheavens.co.uk/) the difference is like the difference between chalk and cheese.
Equipment for last night was
Paramount ME
Takahashi FSQ106ED at f5
Starlight Xpress SXVF H9
Auto guided by Lodestar and OAG using 2 second guiding exposures and dithering
Exposures were 4x30 minutes for NGC7635 and 10x30 minutes for IC1805, the "Quickie" comment wasn't in relation to the exposure length but more in relation to the processing time taken which was about 10-15 minutes each including callibration and stacking.
Each frame was callibrated with dark subtracted flats (32 of each), bias frames (32) and dark frames (15x30 minutes)
The only processing was a combination of levels, curves and contrast and shadows and highlights adjustment. No noise reduction was used in either image
I will be adding to both of these next outing to eventually complete a HST rendering of each

Here are links to the full size high resolution images on my pbase site

http://www.pbase.com/imaging_the_heavens/image/128347428/original

http://www.pbase.com/imaging_the_heavens/image/128347432/original

Thanks for looking
Best wishes
Gordon

[h0ughy]

the sructure detail is amazing - love the result

[TrevorW]

Great shots Gordon

[spearo]

Nice and crisp
frank

[Bassnut]

The bubble thing image is impressive, and the detail in the other one is too.

Your an odd fellow. 30 min exposures, an obsessive calibration routine (32 flats/bias and 15 darks?) and only 10 mins processing time :lol:, sheesh, what a mess ;) :thumbsup:.

[gregbradley]

Excellent images. Fabulously sharp. Are these luminance or Ha?

How did you find 30 minutes versus your normal exposure length?

Greg.

[Alchemy]

Off to a good start, never tried 30 min subs. Looks like you pulled it off nicely.

[Paramount]

Hi Guys
Thanks for the comments, there definitely is an improvement in signal with the 30 minute subs but there are a few things that have to be considered and taken care of first
1. The polar alignment has to be spot on
2. Guiding and tracking have to be working smoothly
3. The weather, if there are any clouds about then be prepared for disappointment, only one cloud came across in the whole evening which just meant me stopping the imaging run for 5 minutes.
These were taken with a 5nm Ha filter, 30 minutes with a luminance filter from where I live is imaging suicide.
The resulting calibrated and stacked frames were so high in signal and detail that the processing was very simple and quick, hence all the calibration frames, long exposure time and very short processing time. From a personal point of view the less processing you have to do the better the image
Best wishes
Gordon

PS Now that I have a very accurate polar alignment I may try some 40 minute subs later in the year depending on the subject and clear sky