Quick question when taking flats

[evltoy]

Hi All,

I'm planing to use my baader moon & sky glow filter on some objects soon.

After my session when I do my Darks and Flats (white T-Shirt), do I require to keep my filter on when doing them?

Thanks
Wayne

[brisen]

Hi Wayne

You will need to keep the filter on and also not rotate the camera before taking the flats. This will ensure any dust spots and vignetting are the same as the lights you took.

Brian

[evltoy]

Thank you very much Brian for the clarification

[multiweb]

+1 same focus as well and temperature.

[evltoy]

Yeah. focus and camera position I can do for both Darks and Flats, but Temp is a no go for me with Flats. Darks on the other hand gets done after right after a session, so temp would be roughly the same as the lights.

[multiweb]

I meant as long as you take your light flats and dark flats at the same temp you'll be alright.

[evltoy]

Sorry for bringing up this topic again... I'm still learning the ropes.

If I was using a dew shield on my scope (SCT) do I need to leave it on when doing flats?

I also stumbled on this item https://www.officeworks.com.au/shop/officeworks/p/triumph-a3-led-light-pad-with-stand-ssod8119a3 and was wondering if this would help take flats after a session in the dark?

[AdamJL]

Hi Wayne

I would leave the dew shield on, not because it's necessary to match your lights, but anything to keep extra light out is good :) You want even illumination. But to be honest, this is one of the things you can do with or without. An even, white field is what you're after.

For the second question, yes that's great. I recently made something to hold something almost identical (ordered from Amazon, not Officeworks) for my refractor.

Here are some images, and with it being used last night.

[Craig_]

How does focus work when using an AF unit? That will naturally refocus automatically throughout the night. Is this sort of tiny temperature-induced focus changes "close enough" for flats? Becuase you wouldn't want to be shooting flats before every autofocus run.

[evltoy]

Thanks for the info.. going to get me one of these light pads :D



Very interesting.

[multiweb]

Yes it's fine. If the focus is close enough the dust motes will match up.