Am I wasting my time and money? Anything goes · Vinny Vent · ... · 57 · 924 · 2

Vinny Vent:
I was in fact completely ignorant of this until just an hour or two ago! This is really helpful to know!

Jon Rista:
I would offer that, the key benefit with mono under light polluted skies, ironically (given I'm not entirely a fan of the L channel under dark skies!), is that the L filter can suck down a lot of light in short order. Its spectrum spanning, so its gathering red, green and blue light all at once. You could use an LP filter with OSC. That will decimate your color, and IMO makes the data even harder to work with (its effectively impossible to get good color with an LP filter, even a multi-bandpass one that passes a little bit of green). 

Pretty much every LP filter out there, will filter out about HALF the visible spectrum. There are some pretty clever ones these days, trying to pass little bits and notch out the key LP emitters. But as LP becomes more and more broadband anyway, these filters become less and less effective. And they will always introduce color issues (I mean, if you don't capture a color, you just don't have it, and no amount of color correction is going to fix that.) Some LP filters, filter out more than 50% of the visible spectrum. A "dual-band" or "multi-band" narrow band "LP" filter, is going to filter out most of the spectrum, and only pass the key narrow band emissions from nebula (Ha, OIII and maybe SII and/or NII). The more light an LP filter cuts out, the more the filter is going to be useful for NB and not so useful for broadband. By the time you get to the narrow band stuff, just stick to emission and planetary nebula. 

An L filter, on the other hand, passes the whole spectrum. Some may even pass more than the standard red, green and blue channels pass, making it around three times better, OR MORE, from a "photon collection rate" standpoint. 

Now, the knee-jerk reaction is "your gonna collect all that LP as well!" Well, yes, but you are collecting most of it anyway with so much of it being LED these days, which is broadband, and cannot really be filtered out. The benefit of an L filter is it sucks down ALL the light in the spectrum. Signal grows faster than noise, so even though you are picking up LP, most of the time you should find that after nuking the LP gradient, the contrast you get with an L filter is actually better than with an LP filter. I used to have a bunch of this kind of data, but over the years of my haiaitus and the loss of some hard drives, its either been backed up to some unlabeled (or poorly labeled) bluray disc, or is simply gone. Lot of my older data is just gone. Otherwise I'd share, as I had some good demonstrations of the differences at one point. 

So, get a bunch of L data, get some good time on the RGB channels, and you can make do under light polluted skies pretty well. You just need a mono camera to make the most of it.

Vinny Vent:

You have a 8SE. Just buy a hyperstar v4. 30s or 15s. i guess it should be ok to capture some good image.

I’ve looked into it, so a hyper star with filter drawer is going to run me around the $1,200 mark. But that’s not even the part turning me off. It’s the collimation and focusing. Everything I’ve read thus far or videos I’ve watched either rave about it or have sold it off. I had a bear of a time learning to collimate the 8 SCT to begin with, using a Defocused star in almost permanently poor seeing conditions is a total pain. I can’t imagine having now tackle doing the hyper star as well. I also read shooting at F2 means your focus and collimation better be perfect, me being an amateur it’s almost surely not going to be. Plus it still gives me a pretty narrow FOV. 

Also the alt / az mount will be the limiting factor again on top of all the of the above. This is what turned me off from the hyper star up to this point.