Gonna Try DSLR, whats my best non mask focus routine

[TheDecepticon]

I was gonna delve into a bit of DSLR tonight, just for something different. I have MaxIm DSLR I can use with a focus routine built in, also Nebulosity with a Canon 40d. If I don't use a Bartinhov mask(which I haven't got) and focus on a bright star, is that going to get me close enough for DSO's? I also live in light polluted Adelaide and don't have a light pollution filter, what is going to be my best exposure and ISO setting for M42, NGC3372 etc. What light pollution filter and coma corrector will work best on a 200mm F/5 reflector?

[gbeal]

Hmmm, lotsa questions.
Use MaxDSLR, it has a great focus routine once you get used to it, and it will stand you n good stead for when you use Maxim DL with a CCD, if you do got past the DSLR.
Focus by eye on a bright enough star, using the viewfinder first, then switch to a dimmer star and use the pixel count with MaxDSLR.
Can't help with the light pollution filter I luckily haven't needed one.
ISO depends on a lot of things. Brighter object would work K with something like ISO400, but the dim stuff needs 1600 perhaps, depending on how the noise is with the camera. 800 is another good all round ISO setting.
If you need a coma corrector, and until you establish you DO sit tight, the Baader MPCC is the best all rounder.
Gary

[leon]

Ok, this will probably not go down with some, but focus is achieved by your eye.

I use a Modded, Canon 5D, and have it attached to a Takahashi FSQ-106, I do not, and never have used any focus software to achieve focus.

I am nearly sixty, and the results talk for them self.

Leon

[Matty P]

You could also use Live view with your 40D through EOS Utility. I use Live view with my 450D to focus. Makes focusing really quick and easy.

Just an alternative to using MaxDSLR or nebulosity.

:thumbsup:

[spearo]

Hi Deception,

Not sure why you wouldn't use a mask.

While the Bahtinov mask does take time to make yourself (free) you can whack togehter a super cheap and effective "emergency field Hartmann mask" in a matter of 2 to 4 minutes (seriously I've done it several times including recently for a friend who came to visit with ihs scope.

I'd also use this in combination with Live view, especially if this camera offer additional functions in the bulb range of magnification (the 20Da does)

Nevertheless, take any piece of carboard (rip out a side from any carboard box) that can fit over the aperture of your scope, cut to a rough circle bigger than aperture and leave a couple of flaps that can be bent so the tig doesnt slide off the front of your scope.
Cut out 2 circular holes opposite ends of the circle (or 3 in a tringular arrangement) about the size of a can of Coke (product placement - not...i just like it with my Rum...) for your 8 and 10 inch scopes or about the diameter of a 20 cent piece for your 100mm.

looking into your liveview, adjust focus until the multiple (2 or 3) stars merge into one.

Of course this can be improved by spending more than 2 minutes on the whole process but this is very quick and easy, free and you can pop out as many of these as you have cardboard at home!
frank

[Tandum]

You got a 40D, just point it at a star and zoom in with live view to focus.

As for sky fog, all you can do is take some exposures and see the limit. I use the EOS software to capture and am lucky enough to do 20 minute subs to the east of here. I don't use filters. I have no idea how long you'll get there.

I do have a mask here and it makes focusing with live view easier, not sure about better :)

[TheDecepticon]

Cool, thanks for all the replies!!:thumbsup: