M51 - Basic LRGB Short Session

[daemon]

A short session - a total of about 2 hours on M51 - LRGB (an hour of Luminance and 15 mins each of RGB).

Calibrated with flats, darks and dark flats using my trial version of Astro Pixel Processor - still deciding whether or not to buy this.

Final tweaks in GIMP.

Imaged with S/W Evostar ED72 with a 2.5x Barlow - mounted on EQ6R-Pro - ASI1600MM. Not guided.

Cheers,

Daemon

 

 

[Tommohawk]

That's great especially for relatively little data and no guiding. Can I ask what gain and exposure settings your using for LUM. ? I'm still experimenting with mine.... Even though I've had it a couple of years.

[daemon]

Thanks Tom! I'm using Unity Gain (139) on the ASI1600 for LUM- I believe this is pretty much a default and I have not had a chance to try anything else yet. I have had the camera for about a year but it saw little use last year.

As far as exposure is concerned I was shooting 60 second subs. I could maybe have gone to 90 seconds before the stars begin to trail but 60 seconds seemed to make sense for this session. My biggest problem was that 60s seemed to0 short when using the filters (especially Green for some reason). With hindsight I should have increased the gain for R,G,B - rookie mistake probably. Deep Sky Stacker could not find enough stars with 60s, hence the reason I downloaded APP which stacked them without an issue - although insisted on me shooting flat darks! Clear skies!

[Tommohawk]

Ok thanks. And I'm also using unity gain and 60s. I'm amazed DSS couldn't find enough stars... that's odd. I routinely use DSS with 139 gain and 60s for L R G and B and it's never a problem. 

There's a setting somewhere for star numbers. You can test to see how many star's it'll find. I think I have it set to 10 per cent and median filter on. 

[daemon]

Yep, I varied the star threshold various times before registering the coloured channels. I lowered it all the way to 2% and the maximum it could find was 4 or 5 stars. I believe it needs a minimum of 8. I also tried to use the star editor to select other stars but could not make that work either. I really like DSS but for that dataset I just could not make it work. APP seemed kinder with my data, but not sure if it offers enough to buy it. I will test it over the next 30 days and see. Maybe I should just take the plunge into the Pixinsight world!

[Tommohawk]

Well TBH I used DSS extensively for many years and was very pleased with it. However I now use APP  - I liked the free trial and so bought it. I do find it more reliable and also easier to do LRGB integrations in one go without having to worry about reference frames etc.

I just did a star count on a random green sub in DSS with 10% threshold and median filter and it only found 50 stars so maybe it is a bit marginal.

[daemon]

Fully agree on the LRGB integration. It is straightforward and I Iike the workflow of APP.

I have another integration running right now on some Needle Galaxy data. Let's see! 😉