HH 555... well, OK, it's actually IC 5070

[AKB]

The Pelican.  20 x 20 seconds on a windy and somewhat cloudy evening at 20:30.  This is white light (no filters at all.)

FL 540, f2.3 (C9.25 Hyperstar + Atik 460EX CCD.)  No sign, actually, of HH 555 itself, but you can see where it should be! 

Does anyone do EEVA with Ha filters?  It seems counter to the 'quick results' theme.

Tony.

 

[tooth_dr]

Pretty amazing, 400s 😮

[Mike JW]

I tried Ha filter once - as you say it ups the integration time (not keen on that) and also I found I had to re-focus in the middle of a session, as well as remove camera to add the filter. Gave it up as a bad idea.

Re pelican - once again the benefit of the wide fov, low f-ratio.  Lovely to see what you achieved.

Mike

[Martin Meredith]

Agreed, wonderful image and FOV in short exposures.

I've used Ha in an EEVA setting, but not for a while. There are some objects with plenty of signal, but the best time I had was adding it to luminosity data 'live' (using SLL). This animation shows the effect of adding Ha to a L base can be quite informative.

I'm planning to add a L+Ha mode to Jocular in addition to the LRGB and mono, using the saturation slider to modulate the effect of Ha. It helps of course to have an electronic filter wheel for multispectral work during a live session.

Martin

[AKB]

2 hours ago, Mike JW said:

I tried Ha filter once - as you say it ups the integration time

 

1 hour ago, Martin Meredith said:

I've used Ha in an EEVA setting, but not for a while.

 

Oh, interesting.  Earlier in the week I was experimenting with some old data (from my beloved Quattro and the same 460EX camera I'm using currently.)  Here's 3x60s L and 12x5m of Ha (I know, too long) and some HLL combination...

 

 

 

 

1 hour ago, Martin Meredith said:

I'm planning to add a L+Ha mode to Jocular in addition to the LRGB and mono, using the saturation slider to modulate the effect of Ha.

That would be interesting.  And yes, the problem with the Hyperstar is that I have to use a filter slider, rather than a wheel.

 

Tony

[Martin Meredith]

The other thing to add regarding refocusing is the importance of acquiring a set of parfocal filters which include a clear (C) or a luminosity (L) filter. This way, there is no need to refocus when adding narrowband, at least for EEVA purposes. I have the Baader LRGBC set which includes both L and C. The difference is one of passband: L covers pretty much the same as RGB combined, while C is much wider and therefore better for making use of the near-IR sensitivity of modern cameras. The 3 members of the Baader narrowband set are parfocal with these too, so I just pack my 9-slot filterwheel with the lot of them, plus a piece of flocking for a dark filter, and a spectral grating (which almost certainly isn't parfocal!).

https://www.baader-planetarium.com/en/blog/the-baader-l-rgb-c-ccd-filters/

In fact, all of my luminosity captures are taken through a C filter (so I guess I lose a tiny fraction of transmission). I do this so that if I'm observing something in mono that turns out to be potentially interesting enough to add a quick colorisation, I can simply add some RGB to the end. Or vice versa, if I'm doing an LRGB capture and want to improve spatial resolution and depth, I can add more L (actually C) without refocusing.

Martin