PixInsight "LearningFlow"

[DaveLeeNC]

I am brand new to AP and have decided to go 'all in' with PixInsight (will be using BYEOS for camera control). I have defined a 'simple strategy' to get into the image acquisition process of AP.

1) Canon 1100D DSLR (Baader mod)

2) Initial imaging limited to the use of prime focus 50mm/f1.8 and 200mm/f2.8 lens'. I can borrow the 200mm from a friend = still trying to convince him that he needs a 400mm/f2.8 as well :-)

3) While I have a G11 (non-Gemini) and a C11, I will be starting out unguided (permanent pier so should be able to achieve good alignment) using the short focal lengths stated in #2. FWIW, I live in moderate light pollution (Milky Way visible but definitely washed out).

4) Given #3 I am just going to do all my initial imaging with 30 second subs. I should be able to get good enough tracking at that duration/focal length. This was a relatively arbitrary choice made, in part, to simplify the application/generation of dark frames. Maybe this is irrelevant in PixInsight - not sure.

5) I currently have a 'library' of 30 second darks and (separately) bias frames for the sensor temps (as reported to BYEOS) that I expect to encounter over the next several months (16*C to 28*C). For each temp there are 25 to 50 raw files (bias separated from darks).

6) I will do that same for light-flats but have not yet done it (or even defined a procedure or built a light box).

Given that as a starting point, I'm struggling trying to figure out how to get started with PixInsight. Should I just start with Harry's tutorials and start to 'do work' as I gain knowledge and expertise (and some lights to work on)? Or

My second question is that there appears to be many 'batch scripts' that will automate much of what needs to be done. My inclination is to mostly avoid those initially as (I think) they will tend to hide stuff that I need to learn. Or are there some that for my set-up that should just be used (without understanding what is happening under the covers).

Thanks.

dave

[astropixel]

You could start with the calibration tutorial. The DSLR_RAW workflow has been updated and gives an overview of the tools used by the BatchPrepocessing script, which has adequate control and setting options in most cases. As to the nitty gritty, Harry's videos. There are a number of links in the DSLR_RAW workflow that point to some very good background info as well as advanced processing, calibration presentations - several below.

I use a 200mm prime Canon lens almost exclusively, with a 1000D and more recently a 5DMKII with an Astrodon Inside mod. You must get hold of one...

http://pixinsight.com/tutorials/master-frames/en.html

http://pixinsight.com/forum/index.php?topic=1167.msg29098#msg29098

http://jordigallego.fotografiaastronomica.com/articles.html

http://pixinsight.com/forum/index.php?topic=2570.0

[DaveLeeNC]

Astropixel, thank you. It is appreciated.

dave

[pfile]

at 200mm you can probably do more than 30 seconds with the G11 as long as the polar alignment is good. the image scale a new-ish canon sensor + 200mm lens is about 5 arcseconds per pixel. you can tolerate a lot of error at that focal length. that being said my G11 has 30arcsec pk-pk periodic error.

the rule of thumb for DSLRs is that you want the histogram peak of your exposures to be "well detached" from the left hand side when viewed on the back of camera (or BYE's display). 20-30% over is a good target. you may find that at 30s your histograms are still stuck against the left hand side. the problem with this is that you will lose signal to the readout noise of the sensor.

rob

[astropixel]

30  seconds is possibly a little short. Exposure time is a balance between the best ISO for the conditions, depending on the sensor characteristics and lens performance; aperture vs resolution.

The 200mm f2.8L USM II is best at f5.7. More lines/mm. The 1000D at ISO400 with moderate light pollution retains star colours across a reasonable dynamic range. The 5DMII at ISO800. Early days with this camera.  Exposure times 150 - 210 seconds. Usually 180, which is a temperature limitation for the MKII sensor, avoiding a steep temperature rise in excess of 180 seconds.

There are a number of factors to consider, aside from polar alignment and periodic error, which are also limiting.