Comet Lovejoy QHY8 / SLR (film) lens

[kinetic]

Reposted here , for the benefit of the dabblers.

This was posted in the main Lovejoy thread also. (http://www.iceinspace.com.au/forum/showpost.php?p=803673&postcount=358)
I think this setup has potential for the coming week of Lovejoy
nearing the SCP.
Nothing new about this idea, inspired by Marc (multiweb) and his
QHY9 / lens / Ha work. (http://www.iceinspace.com.au/forum/showthread.php?t=83226)
Love the FOV, and as you can see from test set #1 (near Crux/Coalsack)
the stars are pretty good out to the edges. 80-200mm lens set at 80mm.

Set #2 is the tail (head off screen to right), extending all the way to
almost Alpha Cent (far left)

Steve

[renormalised]

I've been thinking about someone doing this at some stage...nice shots, Steve:)

It would be interesting to see if someone tries this with one of the big SBIG cameras on a tripod.

[kinetic]

Here is set 1 of 2 with the setup from this morning (29th)
Better seeing, better transparency.


It needs to track accurately Carl, these were 30 sec exposures.

Steve

[kinetic]

And set 2 (03:22 to 04:32 LT)
Dark smudge at far right is a tree, blurred by the tracking.

[kinetic]

A mosaic of set 1 and 2 done in Autostitch.
Comet head is just off the view far right.
Tail extends right across image! :)
Beta and Alpha Cent. at far left.

Steve

[renormalised]

Well done, Steve:)

I especially like the mosaic:)

[zardos123]

its interesting to see just the tail detail with out the distraction of the head
great shot

brad

[jjjnettie]

You've done really well with that set up Stee. Nice sharp stars.

[kinetic]

Thanks all,

prelim sets from this morning (30th)

now for some sleep.........

[kinetic]

Sleep is underated..can't believe I'm saying that:P

Here is a mono version of the pano-stitch...a smidge under 200k.
Not sure what is bending the images in auto-stitch (that tail should
be pencil straight).

I think it might be crops of 2 different sizes on the 2 originals-then
resized by the same 33%...that would make auto-stitch have to skew each image where it joins maybe?

I think the 29th produced better results overall due to better seeing
and transparency than this set

Steve

[Lester]

Nice set-up Steve, producing good views.

All the best.

[DavidU]

Thats a great result Steve.

[kinetic]

thanks for the comments guys,

While waiting for Lovejoy hour, my son and I swung it
over to Orion to check out how well it would frame the hunter.

pic one...crop of the good stuff.
Pic two...close to a full frame.

30 sec x100, QHY-8, lens set at 80mm

Steve

[kinetic]

Finally the comet head comes within reach of the
QHY-8 setup in the observatory!! A special morning for me.
It might be the last chance for a few days.
This is set 4 of 4, this one spanning 04:15 to 04:35am LT Adelaide.
Twilight had started at the end of this set.

Steve

[Quark]

Top Stuff Steve, most impressive effort with Orion, even the companion to Rigel and very nice job with the comet. Applying the QHY9 to a SLR lens seems to be a winner for sure.

[multiweb]

Very cool shot of the comet's head. :thumbsup: I missed it by thaaat... much last Thursday due to high winds in the morning.

[kinetic]

Thanks Trev and Marc,

Marc your threads with the Q-9 were the inspiration for this
little test...and I have you totally to thank for the results I
have obtained so far.

set 2 of 4 with the setup.... I'll try a mosaic next...

Steve

[kinetic]

31st Dec mosaic added.
Very distorted due to autostitch still doing something weird.
Steve

[kinetic]

A comparison of two stack methods on the same data.

My usual QHY8 routine is:

1. subtract the darks (mono raw darks from mono raw frames)
2. debayer the calibrated frames (7.8x7.8 pixels, 1x1 grid)...back to colour
3. stack using translation /rotation (just in case something rotated)

4. crop to remove things that throw off the histogram
5. a gentle 1st curve ending linearly.
6. aggressive/moderate curve to suit seeing/data quality
7. colour adjustment/colour background adjustment.
8. sharpening to suit stars/ nebulosity (in layers if necessary.)

This time I used everything in the list except the rotate,
used fine star align ,and I resampled the debayered data before the stack.
It seems to have got better stars and nucleus on even a bad
data set (this was only 26 frames)
Some of my better sets were before twilight with 100frame sets .

I keep saying it...there is SO much in even mediocre data!

Steve

[kinetic]

Comet this am from the obs.

very dim now as others are reporting.
No longer visual from suburban Adelaide for me at least.
Purely photographic for many more nights hopefully.

Scott (http://www.iceinspace.com.au/forum/showthread.php?t=85029)sure shows how beautifully you can still get this comet
with the right technique.

Steve

[kinetic]

Apologies for rabbiting on in my own thread to myself but
this is worth documenting too. If only for my bad memory :)

I previously had little faith in using DSS to get the best registering
of frames. I'm not sure what I based this on ages ago, but I do
believe I did some thorough comparisons to other progs.

Well...Today I put my most recent set of the head of Lovejoy
thru DSS, initially to try something else that Neb wouldn't do.

That is, to attempt to register on the very faint comet head
in the first and last frames, and let DSS interpolate movement
of the comet in the set. DSS does this apparently. News to me.

Well , alas, that bit isn't sorted yet, but as a bonus, the basic register
did better than Neb. Way better.

Here is this morning's result thru the QHY-8/ SLR lens in D.S.Stacker:
(a gradient, but Iris can deal with that)

Steve

[kinetic]

What a difference a week and a half makes...and a moon.
Last night's result with a 3/4 full moon risen.
This is my first window of opportunity since the first days of
January. Clewds, mainly.
Same capture routine: 100 x 30 sec frames, stacked.
Comet tail is just visible in the full frame shot.
Rob, Lester, Gordon and Greg did way better than me.
Suburban skies FAIL :)

Steve

[gregbradley]

You got some good captures there.

Catching an image of the comet isn't that easy is it?

Luckily at least, it seemed to be a very slow moving comet and being so large a widefield approach seemed to work the best so it didn't move much between subs. Plus it virtually had no nucleus (perhaps that's why it faded so quickly it was already virtually spent from going around the sun).

It was a very different beasty to Garrad which moved very fast.

Greg.

[kinetic]

30 sec set from tonight, the 15th. 60 sec set still to process.

Edit: added 60 sec set.

No moon up this time.

Steve

[Lester]

Good one Steve, looking forward to the processed view.

[kinetic]

becoming a real challenge now from LP Adelaide skies.

Jan 16 evening set: 30sec x 100 frame set, QHY8/lens

Steve