A very elementary question Re DSS

[lensman57]

Hi,

Could someone please tell me how to combine and stack data from two or more nights of capture in DSS. Would it be possible to register and stack data with different FOVs in DSS and if so how?

Regards,

A.G

[earth titan]

As long as the exposure times and ISO are the same, then DSS should just work through them with no problems.

I've previously thrown in many nights of work, even lights that were taken after mount flip and it still worked through them.

Just pick one frame and nominate as the reference frame.

[Bizibilder]

You can process several "batches" in DSS quite easily. Load all the first batch of lights, darks, flats etc and then look at the bottom of the screen where you will see a tab has appeared called "group 1" (next to the original "main group" tab). Click on this tab (group 1) and load your second batch of images etc. A group 2 tab will appear should you need it for a third batch. DSS will then stack everything automatically. You only need to load your darks and bias, if used, into the main group and these will be used to calibrate all the groups. Lights and flats must be loaded into their own seperate groups.

Unfortunately DSS cannot resize images in order to stack batches taken with fifferent focal lengths. I believe the software for this is called "Registar" and is commercial ie paid for.

[lensman57]

You can process several "batches" in DSS quite easily. Load all the first batch of lights, darks, flats etc and then look at the bottom of the screen where you will see a tab has appeared called "group 1" (next to the original "main group" tab). Click on this tab (group 1) and load your second batch of images etc. A group 2 tab will appear should you need it for a third batch. DSS will then stack everything automatically. You only need to load your darks and bias, if used, into the main group and these will be used to calibrate all the groups. Lights and flats must be loaded into their own seperate groups.

Unfortunately DSS cannot resize images in order to stack batches taken with fifferent focal lengths. I believe the software for this is called "Registar" and is commercial ie paid for.

Hi,

Many thanks to both Tom and Roger for the replies. May I ask one more question please? Do the lights need to have been taken with the same orientation in the camera or a little deviation could be corrected by DSS?

Reagrds,

A.G

[Bizibilder]

DSS is quite happy for the orientation to be different - part of the stacking process is to match the image orientation. The downside of a mismatch is that you will have to crop a lot of "junk" from around the edges if the orientation between frames is a long way out. Generally you should try and keep the camera in the same position from session to session - (I sometimes put a felt tip pen mark on the scope and camera to help alignment). If you can keep to a degree or two either way then you will have a stack that properly covers 95% of the frame and few "junk" edges.

Flats must match their own lights perfectly (which is why they are taken at the same time as your lights with identical optical train, including focus). Darks and bias are for calibrating the sensor and therefore can be taken at any time (but should be taken at the same temperature as your lights/flats - at least within +- 5°C if using a DSLR).