First ever sub with my G2-8300 and Astrodon Ha 3nm

[kirkster501]

At last got my autofocuser fixed and an hour of clear sky.  No processing or preprocessing whatsoever, just one 20 minute sub and stretched to be none-linear. Much less noisy a sensor than I expected.

FSQ85 at native FL.

Very pleased with the potential of this combination.

[ian_bird]

Those 3nm Astrodons are rather good aren't they!

Nice capture.

Cheers

Ian

[michaelmorris]

Gorgeous

[kirkster501]

12 minutes ago, ian_bird said:

Those 3nm Astrodons are rather good aren't they!

Nice capture.

Cheers

Ian

...and rather expensive as well Ian!

[Davey-T]

Looking good Steve, I've had my Astrodon 3nm HA chuntering away for the last few hours on the Flaming Star Nebula in the moonlight, sky is better than last night here but can't do much except gather HA

Dave

[swag72]

Looks great Steve.. well done for persevering with everything...... satisfying when it all works ?

[kirkster501]

Thankyou for the words of encouragement guys. As you know, there are a lot of moving parts to get working with a new camera, adapting it to the scope, new OAG, new guide cam and a Lakeside to get up and running. Not to mention the weather and Christmas season and it only ever being seemingly clear on the nights when I am out.... ?  This was the first time I got it all going.  My guide graph is a tad worrying with occasional 2" spikes at the shorter FL of the FSQ.  I need to investigate that.

No signs of the infamous FSQ focuser tilt other than a teeny-weeny bit bottom right, but that could be do to field rotation at this exposure length and I do need to re-do my PA next clear night.  The acid test will be when I get the adapter for the 0.73 reducer.....

[sloz1664]

Nice one Steve. Yes you've had a major refit to deal with, but boy, aren't the rewards satisfying.

Steve

[tomato]

Very nice indeed. I was not really going to venture into narrowband but have been a bit frustrated by the number of clear nights 'lost' to the moon.

By coincidence I got first light on my 7nm Baader Ha filter last night on the same subject, same exposure time, same mount, same camera running at -30. Here is a single stretched 20 min sub. Not a fair comparison of the filters as the optics and location are different, (my scope is an Altair 102 mm APO) but it maybe gives an idea of what improvement you can expect for the extra spend on the premium quality filter.

 

[kirkster501]

Thanks Tomato.  Fantastic that your image is, the Astrodon 3nm reveals finer structures to my eyes. But for the cost differential between the Astrodon and the FSQ I used, is it that much better?

[tomato]

For sure, the Baader  is a fine value for money filter and gives me what I am looking for from narrowband imaging, but I can fully appreciate why you want the best... 
 

[ollypenrice]

Great sub, Steve. The 3nm Ha filter data needs very little post processing since it delivers what you normally have to work for in software: that's small stars, sharp detail and high local contrast.

The price is eye watering, even more so when you need the blessèd 2 inch, but I do think it's worth it. Last year I was doing a composite widefield using both TEC140 and Tak 106 for Ha. The 7nm data from the TEC was less highly resolved than the 3nm from the TEC despite a near doubling of focal length. In similar filters there is no comparison, the TEC clearly trounces the Tak on resolution. (Same cameras all round.) So this is a filter that will allow a smaller or otherwise lesser scope beat a bigger or better one. On top of that, the 3 is far more moon-proof than the 7. And it isn't slower. For whatever reason or reasons, it just isn't. We've seen this using both filters side by side in the dual rig.

The difference is somewhat target specific, some objects producing a greater quality difference than others. But if I could afford it I'd have a second Astrodon 3.

Olly

 

[Mick J]

very nice - both   and very nice to compare, thanks.

[kirkster501]

The 3nm Astrodon Ha is VERY expensive for sure.  £470!  That is a lot of money for a small piece of glass and when screwing the filter into the 31mm receptacle on the filter wheel we do not want any mishaps with the philips screwdriver now do we... ? ???!!!     Complete concentration whilst handling the filter with a pair of Marigolds on my hands lest the oil from my fingers get on the glass!  Ha is number 5 below.  Not much to it is there for nigh on half a grand!

I also got the LRGB Astrodon's as well whilst I was at it.  I treated myself to these with the 8300 camera after extensive research and being mindful that whilst the 16000 chip would be nicer still a line has to be drawn somewhere and that 2" Astrodons are not going to happen at Kirkster towers (not until I strike my first gas and oil field in my back yard at any rate..... ).

Rosette will be my first project with this combination so grabbing the Ha first. 

[tomato]

Steve, you got a good deal, I thought they were £496!

[kirkster501]

42 minutes ago, tomato said:

Steve, you got a good deal, I thought they were £496!

I’m a very good negotiator ...... ??

[kirkster501]

Can't wait to get more data for this and do more testing of the G2-8300 and Astrodons.  The weather is not playing ball at all.......

[Droogie 2001]

Great result with your new 3nm Astrodon, the Rosette looks stunning even with just a single RAW sub.
I have the same camera as you but I elected to go with Chroma's Ha 3nm. Also purchased the Chroma OIII 3nm but managed to only use this the once since purchasing it a couple of months back.

Here is a single 25min RAW stretched sub at -30C on my WO Star 71. As I am undersampling this makes my stars look a bit square before I carry out drizzling which brings them back inline.
Like you I have only managed to capture a short amount of data (2.5 hours) which I posted on my Flickr page, desperately trying to capture more data before it disappears behind my neighbours roof.

I really, really like my G2-8300 despite it being 'old' tech 

[wimvb]

On 2017-12-29 at 17:41, ollypenrice said:

On top of that, the 3 is far more moon-proof than the 7. And it isn't slower. For whatever reason or reasons, it just isn't. We've seen this using both filters side by side in the dual rig.

Should it be? If the only light that is captured comes from the emission line H-alpha, the transmission width of the filter shouldn't matter. What should matter is the maximum transmission in % at the H-alpha wavelength. Otoh, blocking unwanted (white) light should be more efficient with the narrower filter.

[kirkster501]

Great result Doogie, Yes I looked long and hard and for me, to get the FoV, nothing seems to beat the 8300 chip cameras.  The demise of QSI seems to default the choice to the Moravian.  I though this was a "second best" but I was mistaken, it is superb.

[ollypenrice]

3 hours ago, wimvb said:

Should it be? If the only light that is captured comes from the emission line H-alpha, the transmission width of the filter shouldn't matter. What should matter is the maximum transmission in % at the H-alpha wavelength. Otoh, blocking unwanted (white) light should be more efficient with the narrower filter.

Well, you might expect more light to come through an 8nm than a 3nm because, for instance the NII line is blocked by the 3. However I find the 3nm Astrodon to be a remarkably productive filter in terms of signal to time.

Olly

[kirkster501]

... I gasped with amazement at the sub I posted in the top post when it came off the camera.  Astonishing filter.  Outrageous in cost, formidable in performance, outstanding at what it can do.  Yes, you need to gulp hard at shelling that much out for a 31mm diameter piece of coloured glass.  But, from what I have seen so far (which I readily confess is very little) it certainly does perform and live up to its stratospheric billing..........

[RayD]

6 minutes ago, kirkster501 said:

... I gasped with amazement at the sub I posted in the top post when it came off the camera.  Astonishing filter.  Outrageous in cost, formidable in performance, outstanding at what it can do.  Yes, you need to gulp hard at shelling that much out for a 31mm diameter piece of coloured glass.  But, from what I have seen so far (which I readily confess is very little) it certainly does perform and live up to its stratospheric billing..........

You should have the 16200 sensor like me Steve, needing 2" filters, and then look at the price!  If my Mrs doesn't ask where her Mulberry handbag has gone for another 2 weeks, then it goes up for sale and I may then be able to afford one 

[kirkster501]

6 minutes ago, RayD said:

You should have the 16200 sensor like me Steve, needing 2" filters, and then look at the price!  If my Mrs doesn't ask where her Mulberry handbag has gone for another 2 weeks, then it goes up for sale and I may then be able to afford one 

That was a key reason why I stayed with the 8300 chip Ray.  2" NB Astrodons is not going to happen at kirkster towers.  Gee whiz, the 31mm are expensive enough....

[RayD]

5 minutes ago, kirkster501 said:

That was a key reason why I stayed with the 8300 chip Ray.  2" NB Astrodons is not going to happen at kirkster towers.  Gee whiz, the 31mm are expensive enough....

With your results there, well worth every penny though Steve.  That's a great single sub.

I'm planning selling some stuff so hopefully can raise enough to get one, but only the HA I'm afraid