Another NGC 7000 with new Antlia 2.8nm Ha filter

[SamAndrew]

Thought I'd share this as we've had a few clear nights in the UK and it's good to show something for the effort!

Four pane mosaic shot through the FSQ 106 with recently acquired 0.73 reducer and the 2.8nm Ha filter from Antlia. 30 minutes each pane, taken in the early hours of the morning during nautical/civil dark from London (not that I notice the lack of darkness given the light pollution). I kept going until the guide camera lost the guide stars, yet the data was still passable. The narrow bandpass and high transmission looks like it will work nicely during these summer months where it doesnt get dark. I haven't got another Ha filter at the moment, so I can't do a quantitative analysis.

I Haven't had chance to play with tilt or spacing since getting the 0.73 reducer, so stars are less than perfect, but passable; I'll wait till the moon is up before delving into that refinement.

I will continue to get more data for each pane at the next opportunity.

[Roy Foreman]

Nice capture for this time of year !

[robertm]

Not too shabby for 30 minute panes,  the filter seems to be working well at that focal ratio so thats great news.  I'm not familiar with the 294 - presumably the horizontal pattern noise will calibrate out easily with a bit more data?

Have been interested in moving to the 106 myself but my wallet keeps rebelling.

PS. I know what you mean about never getting dark in London.  BB targets are a real pain and getting worse by the year!  <rant>I wish something would improve in this country - the French seem to have worked out that turning streetlight off at night saves money, all we do is try to make daytime last 24 hours!</rant>

Robert

[SamAndrew]

39 minutes ago, robertm said:

I'm not familiar with the 294 - presumably the horizontal pattern noise will calibrate out easily with a bit more data?

Have been interested in moving to the 106 myself but my wallet keeps rebelling.

PS. I know what you mean about never getting dark in London.  BB targets are a real pain and getting worse by the year!  <rant>I wish something would improve in this country - the French seem to have worked out that turning streetlight off at night saves money, all we do is try to make daytime last 24 hours!</rant>

Robert

Thanks. It's been a while since I processed a narrowband image with such little data, so the horizontal banding is not something I'd seen before with the 294; it's not noticeable in my broadband frames, so it does look like a lack of data. I'm not dithering, so if it persists then I'll try dithering to tackle it. I'll now have to budget to get the SII and O3 filters as well.

I do love petzval telescopes; not having to worry about spacing is nice, but now that I've added the reducer it has added that hassle back in. I'll see how I get on with it, I may drop it and switch to a camera with a larger chip instead. Having owned an Esprit 100 I can't see a difference optically, but my Esprit did seem to suffer with internal reflections and some focuser flex which the 106 doesn't have.

The problem we've got with the LED lights is they are soo cheap to run compared to the old sodium lamps, there's little incentive to turn them off, but you'd think with tight council budgets any little saving would help. My plan is to get my rig setup remotely in Spain, so hopefully I'll be away from all this light pollution before too long.

[robertm]

That's interesting what you say about the Esprit.  I had a 150 and it seemed, at least to me, optically excellent but I haven't had anything similar to compare it against.    Was this image in the binned 4.6um or 2.3um pixel mode?

 

[SamAndrew]

On 26/05/2023 at 22:53, robertm said:

That's interesting what you say about the Esprit.  I had a 150 and it seemed, at least to me, optically excellent but I haven't had anything similar to compare it against.    Was this image in the binned 4.6um or 2.3um pixel mode?

 

The above image is in bin 2x2 mode, I've now got about 6 hours of data for a 4x4 mosaic of Sadr and the Crescent nebula in bin 1 which is looking good, I will get some more data before processing and posting that one.

I'm up to 5.5 hours on NGC 7000 now as well, the horizontal banding cleared up after dithering between subs.