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Images 11-21-18

Posted: Fri Nov 23, 2018 1:19 am
by BlackWikkett
Hi Team,

Since I've been having problems with flats and live stacking thought I'd Image in Live Stack and capture the individual frames for DSS stacking post processing in Photoshop.

Equipment: RC 6, ZWOASI294 MC Pro, AP CCDT67 Reducer, IDAS D1 Filter

All images stacked in DSS with 20 darks and flats, processed in Photoshop.
I'm not the best at processing images but here are my results for 2018-11-21

ImageB33 Horsehead Nebula by Black Wikkett, on Flickr
80 x 30 sec 300 Gain 20 Offset

ImageM42 Orion Nebula NGC1977 Running Man by Black Wikkett, on Flickr
311 x 8 sec 300 Gain 20 Offset

ImageM81 Bodes Galaxy M82 Cigar Galaxy by Black Wikkett, on Flickr
211 x 30 sec 300 Gain 20 Offset

ImageNGC2174 MonkeyHead Nebula by Black Wikkett, on Flickr
104 x 30 sec 300 Gain 20 Offset

ImageM101 Pinwheel Galaxy by Black Wikkett, on Flickr
100 x 30s 300 gain 20 Offset

Thanks for having a look, Wikkett

Re: Images 11-21-18

Posted: Fri Nov 23, 2018 8:11 am
by turfpit
A good collection there Wickett. M42 came out well at 8s. Horsehead is always a tricky object sitting so close to Alnitak.

I bought a 2" IDAS P2 filter off AstroBuySell based on your other posts - waiting for weather now to understand the effect.


Re: Images 11-21-18

Posted: Mon Nov 26, 2018 2:22 am
by BlackWikkett
Thanks Dave!

IDAS P2 is a good filter, Don on NSN has had some great live shots with it. When I picked up the IDAS D1 it was from reviews I found using this filter with several different OSC and DSLR cameras. Keep in mind that these LPS filters really cut down your red channel and can at times double the required exposure time. Trade off being your cutting down the light pollution and get much better contrast. Best of luck with your filter.


Re: Images 11-21-18

Posted: Mon Nov 26, 2018 9:26 pm
by turfpit
Useful info Wickett - thanks.

I did a quick bench test with and without the IDAS filter using flat frames with an Altair 183C and 183M. I set the histogram to the same % saturation for both with and without the filter. Gain and black level were kept the same for the mono & colour test.

Exposure times:
no IDAS with IDAS exp. increase
MONO 25.9ms 39ms 50%
COLOUR 51ms 67ms 12%

Given that the flat frame is a much brighter object than those we are imaging, I can see that doubling exposure, as you state, can be expected. probably a crude test but at least I go into it prepared. My usual M31 at 120s will be tested at 240s - as I recall you had some 240s in your gallery post.

As for the red (notice it drops off 5%), that means using the IDAS with LRGB will mean some adjustment to LRGB ratios.

The screens from the tests are below.

mono-flat-with-IDAS.JPG (19.46 KiB) Viewed 917 times
mono-flat-no-IDAS.JPG (19.88 KiB) Viewed 917 times
colour-flat-with-IDAS.JPG (19.86 KiB) Viewed 917 times
colour-flat-no-IDAS.JPG (20.26 KiB) Viewed 917 times