astrocatinfo Posted December 21, 2016 Share Posted December 21, 2016 Good morning, I'm close to purchase the ASI1600 with the filter wheel and OAG. I have a couple of questions about the filters: Is it worth to go for the Baader LRGB? Or can I go for the ZWO ones (maybe are Optlong?). Some bad reports on the L filter on the later. For narrow band I was thinking on the Astrodons: 5nm Halpha, 3nm OIII and SII. I don't want to go for the 3nm Halpha and the same NII... not high polluted area, less filters. Am I right? Always looking for a balance price-caracteristics. About the size, 31mm unmounted. Thanks so much for your help, Aleix Link to comment Share on other sites More sharing options...
DaveS Posted December 21, 2016 Share Posted December 21, 2016 If you want to save money and you don't have much LP then 5nm [OIII] and [SII]. get a 3nm HII for now and add a [NII] later. If you buy a 5nm HII and then decide you *would* like to try [NII] as well, you'd have to get a 3nm HII after all. Of course, if you have no intention of ever exploring [NII], and your LP isn't bad then 5nm for all filters makes sense (At least to me). Just a thought, 3nm [OIII] would be a bit more resistant to moonlight, which is LP to an astrophotographer. 2 Link to comment Share on other sites More sharing options...
astrocatinfo Posted December 21, 2016 Author Share Posted December 21, 2016 4 hours ago, DaveS said: If you want to save money and you don't have much LP then 5nm [OIII] and [SII]. get a 3nm HII for now and add a [NII] later. If you buy a 5nm HII and then decide you *would* like to try [NII] as well, you'd have to get a 3nm HII after all. Of course, if you have no intention of ever exploring [NII], and your LP isn't bad then 5nm for all filters makes sense (At least to me). Just a thought, 3nm [OIII] would be a bit more resistant to moonlight, which is LP to an astrophotographer. That's why I was considering 3nm OIII. Because of the moon effects... is it the same with SII? Worth going to 3nm? How good or bad would be to stay only with Halpha 3nm? Which deep sky objects have important signal in the NII band? Link to comment Share on other sites More sharing options...
DaveS Posted December 21, 2016 Share Posted December 21, 2016 The further towards the blue the worse the moon will affect your images, so H N & S will be less affected. As for suitable targets for N part of the fun is looking for them. The Rosette is s good target as is M27 and possibly other planetary nebulae. Might be worth looking at other pure emission nebulae. 2 Link to comment Share on other sites More sharing options...
ollypenrice Posted December 21, 2016 Share Posted December 21, 2016 I'm not sure that I'd use an OIII in the moon. I've never found them terribly moon proof. I have both the Baader 7nm and the Astrodon 3 in Ha. The Astrodon is vastly more moon proof and gives tiny stars, which is great either for combining with LRGB, where they don't affect the star colour, or for standalone narrowband images where tiny stars are just nice of themselves. I've never tried the AD 5 Ha which admits the N11 line. We went for the 3 because of its higher contrast which is good for adding to natural colour images. If I shoot Baader 7nm in the TEC 140 at 1015mm FL the detail is comparable with that of the 3nm AD shot in the Tak 106 at 530mm. In any other comparison the Tec massively out resolves the Taks, so the Astrodon is in another league. It is also incredibly easy to process. Olly 3 Link to comment Share on other sites More sharing options...
Gina Posted December 21, 2016 Share Posted December 21, 2016 I started with Astrodon 5nm Ha, 3nm OIII and 5nm SII. More recently I've bought 3nm Ha and found it much better for tighter stars and keeping a full moon at bay To match I bought the 3nm SII (already having 3nm OIII). Now it seems I could do with NII. Fortunately, the ASI1600MM-Cool works fine with the cheapest Astrodon size of 1.25" mounted filters and the ZWO EFW mini with negligible vignetting. But the diminishing value of the pound has forced the price up to nearly half a grand I think I should have bought the 3nm NII filter instead of the SII. 1 Link to comment Share on other sites More sharing options...
DaveS Posted December 21, 2016 Share Posted December 21, 2016 Agree with Olly that [OIII] isn't very moon-proof, but up here we have to take any clear night on offer, and sometimes that might mean getting [OIII] data with some moon (No more than half moon, and 90deg or so away), so the narrower the bandwidth the better. Regarding [SII] vs [NII] I've found [NII] to be more use, often with a stronger signal. But that's just my personal experience, YMMV as they say. 2 Link to comment Share on other sites More sharing options...
DaveS Posted December 21, 2016 Share Posted December 21, 2016 Just for the fun of it here is an image of M42 from a couple of years ago in the "forbidden" lines of [SII], [NII], and [OIII], mapping sulphur to red, nitrogen to green and oxygen to blue, I think there was an hour of each in 10 min subs. To reiterate, there's no hydrogen in this image. In my defence, and because I know it's a pretty poor image, I *was* still learning the art and craft of NB imaging. If we ever get another clear night this winter I may revisit M42 (Visiting it with fire and sword ) 2 Link to comment Share on other sites More sharing options...
Gina Posted December 22, 2016 Share Posted December 22, 2016 I can see I'll have to get an NII filter and hope for some time to use it Watch out for some of my lesser used kit in the sales section after Chrimbo 3 Link to comment Share on other sites More sharing options...
astrocatinfo Posted December 27, 2016 Author Share Posted December 27, 2016 (edited) Any information about the Baader Halpha 3,5nm? Edited December 27, 2016 by astrocatinfo Link to comment Share on other sites More sharing options...
astrocatinfo Posted January 10, 2017 Author Share Posted January 10, 2017 As I've been researching not yet in the market for 31mm. I hope they realesed it soon together with the NII SII OIII... Link to comment Share on other sites More sharing options...
libraryman Posted January 10, 2017 Share Posted January 10, 2017 The 3nm are good to be sure, however..signal can be very very weak, I've run 20 x 20 mins on a target recently without much to show for it, be prepared to take long and lots of subs. Ray 1 Link to comment Share on other sites More sharing options...
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