Cygnus Loop Mosaic with Esprit 80ED and 460EX - WIP

[Gina]

Just got the Esprit 80ED mounted on top of the MN190 and using OAG on the MN190 with Lodestar X2 for guiding.  This is the first pane containing the Eastern Veil Nebula.  Not quite finished the remote focuser yet so focussing was manual and not perfect so this is binned 2x2.

6x6m Ha, 7x6m OIII and 8x6m SII subs all binned 2x2, stacked in DSS, aligned with RegiStar, combined and Hubble processed in Photoshop.  Resized to 1200px wide and saved in PNG and JPEG file formats.

EQ8, MN190 with OAG and Lodestar X2 guide camera - with PHD for guiding.

Esprit 80ED with field flattener, EFW2 with Astrodon NB filters, and 460EX for imaging.

[peter shah]

great result I love those little ED80's they do pack a punch

[Gina]

Thank you Peter

[Gina]

I now have the Arduino focus controller working so I've been looking at how best to cover the Cygnus Loop in a matrix with fewest panes.  I thought I could do it with 4 as the diagram in CdC would indicate but there's more to the Loop than that as can be seen in one of my widefield images from last year.

Try as I may, it seems like 6 panes are needed to do a decent job of it.  This covers the area easily with plenty of overlap and plenty of room for misplaced images.

This image was a screenshot from the TeamViewer screen showing the Cygnus Loop area in CdC with the coverage of MN190, 460EX and DSLR shown as rectangles.  The DSLR (eg. debayered EOS 450D) would cover the Loop in two panes with approximately the same resolution.  The coverage with the 460EX is shown by the blue rectangular overlays.

[Gina]

I think I'm ready for an imaging run tonight - forecast is good.  I have rebalanced the mount and set up on the distant tree so the pointing should be almost spot on (saves time in AT getting it exact).  Focussing seems to be working pretty well.  As an example, here is a crop of part of the view below the tree I use for setting up.  This is unbinned with Ha 5nm filter 0.1s exposure.  Pixel for pixel.

[Gina]

Good imaging run last night.  In setting up I got an FWHM figure of around 1.7 unbinned using 10s exposures but when I went to 20m the FWHM was around 4 so I decided to go for binning 2x2 with 10m exposures.  That enabled me to get 6-8 subs in each colour.

Here are 8x10m Ha + 7x10m OII + 6x10m SII subs stacked in DSS, aligned with RegiStar and Hubble processed in Photoshop.  Resized to 1200px wide and saved in PNG and JPEG file formats.

[astro mick]

You do some amazing work Gina,and your Tech Knowledge leaves me baffled.

I just sort of point and shoot,and post.

Your descriptions are second to none,and your passion really shows through.

Always a good read.

Mick.

[Gina]

Thank you very much Mick

[Knight of Clear Skies]

Looking good, I look forward to seeing the finished article.

[Gina]

Thank you   So am I

[james_screech]

There's a lot of detail in there Gina, well done.

[Gina]

Thank you

[Gina]

Next pane is middle right.  Had to reduce exposures due to bloating of the star 52 Cygnus and ended up choosing a compromise between bloating and amount of data and went for 5m subs.  So this is 17x5m Ha + 15x5m OIII + 13x5m SII processed as before.

Next, I'll start matrix building.  Unfortunately the Veil Nebula as a 2 pane matrix with the MN190 does not quite overlap the right hand matrix panes so that will want capturing again.  Anyway, the top right and middle right Esprit panes do overlap and I'll join those up.

[Gina]

Slowly slowly catchee monkey   Here's the top right and middle right Ha panes merged and resized in PNG and JPEG file formats.

[Gina]

I've now processed a Hubble Palette version of the two panes captured that overlap.  I need to do a lot more practicing with the processing to get the panes to match properly.  With 2 panes there are 6 sets of curves to match up - goodness knows how the matrix experts manage with 6 panes or more    I think I'm probably making things more difficult for myself with the Hubble palette.  I'll try the "natural" HOO version I think - only 4 sets of curves to match up

[Gina]

Another go at the Hubble Palette version.  May be no better - just different

[WaveSoarer]

Apart from your wonderful, as ever, astro photos, I really like the setup picture of the cow. It has a touch of contemporary art about it.

[Gina]

Can't say I'm satisfied with this lot   But I know what the trouble is - the Witch's Broom pane needed more exposure for each sub.  The 10m subs I used on the other pane were just about right but I reduced the exposures for this pane because of bloating of 52 Cygnus, the star near the middle of the Broom.  I think I'll probably repeat this pane and use 10m subs and use a star mask and other techniques to deal with the star.  But I'll do it after I've collected data for the other panes.

I tried the HOO version and had dire problems trying to match that up too.

[Gina]

Had a pretty good night's imaging last night, brought to a halt around 3am by (I think) dew on the scope lens.  So I'll see if I can make up a dew heater for it.  Anyway I managed to get 7x10m Ha and 6x10m of OIII and SII all binned 2x2.

Here is the result processed as before but only as far as matching up the histograms of the 3 colours and before applying Selective Color (sic) to produce the Hubble Palette.  This is the top left pane of the mosaic.  Resized to 1200x960 and saved in PNG and JPEG.

Taking advice from others and from my own experiments I've come to the conclusion that the best way of tackling matrices is to take the data for each pane, align and process to match up the histograms while applying curves in Photoshop using Histogram view to check colour matching.  Then to take all the panes and merge with RegiStar in Union mode.  I have wide angle images from last year and can use one of these to register with to counteract field curvature.

Tonight if the weather forecast is right I'm hoping to capture the middle left pane in the same way.

[Gina]

Made a booboo on the pane above so redid it.  Have now captured 3 panes successfully having had another go at the middle right pane containing the Witch's Broom last night - I'll pist details shortly.  But here is a matrix of the merged panes to date, before applying Hubble selective colour processing.  As usual PNG and JPEG

[Fordos Moon]

Great work Gina and a fascinating read - loving this one!

[Gina]

Here is the redo of the top left pane.  I had used the wrong file set for the SII   This is SII, Ha, OIII stretched and histogram matched (before applying selective colour).

[Gina]

Now to last nights imaging run.  Mostly a good night but with a bit of passing high cloud that spoilt two or three subs of each colour.  I ended up using 7 Ha subs, 8 OIII subs and 5 SII subs all 10m binned 2x2.  Seeing was exceptionally good for the most part and I was getting FWHM values down to 1.2   Much better than previous nights.  I used a bit of jiggling with curves to lessen the halo around 52 Cygnus which seems to have been moderately successful.

[ianaiken]

Hi Gina,

That's looking real good, unusual colours but good.

[Gina]

Here is a redo of the merging operation using just the three panes rather than using the widefield image as the pattern.  I had forgotten to scale up the widefield image so the result was matched to that (idiot)   The redone merge produced an image size of 2493x2181 which I have resized to 1200x1050 for upload here.  This is pretty basic processing in Photoshop using curves, layers and a little sharpening plus fuzzy clone stamp to smooth the edges of the panes.