Crescent Nebula DSLR Woes

[imakebeer]

I've been thinking about these light leaks and I'm wondering why does they matter? 

There's no question they're there - I did a quick experiment last night in a dark room with a torch. You can clearly see light leaking in around the focuser, and I can literally see my torch shining through the semi-opaque primary mirror at the base. 

But when I'm imaging it's dark. I live (I think) a Bottle 4 area. I've taped over the power lights on my gear, the house lights are off, no direct line of sight to street lamps, and my new neighbours generally seem to keep their lights off so they're not shining into my garden either.

I'm not needing do take darks or biases. I'd have thought flats taken during the day are quick enough that light leaks aren't hugely significant.

I'm not debating that these are worthwhile mods to make (i.e. dealing with light leaks, not the other ones) I'm just wondering what I'm missing? What light sources would be leaking in?

[AstroMuni]

1 hour ago, imakebeer said:

I can literally see my torch shining through the semi-opaque primary mirror at the base. 

Many of us use a shower cap or equivalent to prevent this. I prefer a cloth bag as that lets in air and should help with cooling. Thats my theory anyway 🙂 

Edited 3 hours ago by AstroMuni

[Elp]

1 hour ago, imakebeer said:

I'd have thought flats taken during the day are quick enough that light leaks aren't hugely significant.

You'd be very wrong. Light intensity during the day is far higher and you have a lot of ambient light around (reflected/bounced off other surfaces). I use perspex sheets to diffuse my LED light panel at night, if I try it during the day even indoors the flats come out all sorts due to light transmitting through the sides of the perspex.

[alacant]

1 hour ago, imakebeer said:

lights off so they're not shining into my garden

Hi
You took 76 x 3 minute frames. Now take 76 x 3 minute frames under the same conditions. but with the dust cap on the telescope. Process as you did the light frames.
In fact take just a few 3 minute frames and process. You can then decide for yourself whether light intrusion is a thing with low-end reflectors. I think I know what the answer will be😉

Cheers, CS and have a great weekend.