What is the best approach to stacking data from multiple sessions

[Phil Crompton]

Hi Han,

I have two lots of data captured on separate nights of the same target but with differing camera orientations and therefore differing sets of flats and dark flats. What is the best approach to use for combining this data into a single stacked file ready for post processing?

I assume that I cannot simply pile all the images, darks, flats and dark flats into a single stacking run as the software would have no idea which flats and dark flats went with which images. Is this a correct assumption?

Kind regards,

Phil

[han.k]

Hello Phil,

Coincidentally, I created an option a few weeks ago just for that (throwing all together) . There is a new option to create master flats and darks for each day. See screen shot below. If check-marked, it will make masters of all input flats or darks of each day. While stacking it will then select the master flat and dark with a date closed the date of the light.

This option was created a few weeks ago.

Rotation should not be a problem but landscape and portrait orientation will not fit very well.

I would suggest you try it. It is good moment to field test this option. I like to hear any problem you face.

Han

[Phil Crompton]

Hi Han that's great. How timely. I only have two data sets because I forgot I had already imaged M3 in April. When I got a clear night last weekend I did M13 and M3. It wasn't until I got home and downloaded the data the next day that I realised I had duplicated targets! Oh hum.

I will download the latest version and give it a go.

What I have noticed though is that satellite trails are showing even though I choose Sigma Clip Average. Is this normal? Attached in fits file loaded in StarTools and initial AutoDev.

[Phil Crompton]

Hi Han, the new check boxes for grouping the flats and darks by date work great. Thanks.

Phil

[Phil Crompton]

Hi Han, the new check boxes for grouping the flats and darks by date work great. Thanks.

Phil

[han.k]

SigmaClip will work well if you have ten or more images. Secondly if you set the sigma setting to about 2.0., the filtering of outliers will be stringent. The default for sigma was previously set at 2.5 but in the latest versions it set it at 2.0 or 2.2.

Sometimes if the satellite track is very very bright, it is better to remove that image. You can scroll with the arrows in the right top of the light tab. Hit ESC when you see a very bright track and remove that frame

See below

Han

[matthew]

same target but on multiple nights with different times, 60s , 180s, etc.., and different flats & flat darks. This is a game changer for me if we can do it all in one shot preprocessing.