Well i feel as thought it is the dogbowl shot with the curvature in the field. Still working on the 8" so i stuck with the 127Ed and the Wo 0.8 reducer. I really need to sort this out - somehow this must work? Anyway it is of 3 hours and 32 minutes duration of wasted effort from last night and this morning guiding and pushing the camera at 4 degrees and iso400 - and not using a LP filter the shots were 3minutes each.
so i did two versions processed in pixinsight and a tweak with special herbs and spices- not happy with either to be honest
Dog tucker indeed Huff, LOL.
What is the issue? There must be enough of you guys with this Gilman Special to have worked out what is needed to keep it all flat?? Surely?
In my case a while back with an 80mm triplet I used an MPCC, so if you have access to one of them, try that. Be prepared to try differing spacings, like Marc MultiWeb did.
A great project for the full moon period, instead of barking at it, LOL. Sorry couldn't help myself.
Gary
Well i feel as thought it is the dogbowl shot with the curvature in the field. Still working on the 8" so i stuck with the 127Ed and the Wo 0.8 reducer. I really need to sort this out - somehow this must work? Anyway it is of 3 hours and 32 minutes duration of wasted effort from last night and this morning guiding and pushing the camera at 4 degrees and iso400 - and not using a LP filter the shots were 3minutes each.
so i did two versions processed in pixinsight and a tweak with special herbs and spices- not happy with either to be honest
David - which WO flattener are you using? I have a FLAT2 and 3 and find neither of them works very well on the 127 - in fact the Canon20D works better with no flattener in line.
I think there is under correction as your corner stars are
\ /
/ \
If I have this right this means the sensor needs to be further from the corrector - try a small spacer. If you get stars in the corners like this:
/ \
\ /
you are over corrected and you need to get closer unfortunately that is tricky to achieve with a DSLR.
How do your images look with no corrector in line? (BTW it is not a crime to crop a little if your field is not flat all the way to the corners)
Finally you may also get a better result by focusing on a star 1/2 way to the corner not one dead centre on the CCD as this will balance the focus better.
As Gary pointed out you're going to have to try different spacing to find the sweet spot. If you can't then you'll need a different reducer/corrector. It's all part of the fun. Nothing wrong with that shot though. The center field looks great. You just need to tidy up the edges.
David - which WO flattener are you using? I have a FLAT2 and 3 and find neither of them works very well on the 127 - in fact the Canon20D works better with no flattener in line.
I think there is under correction as your corner stars are
\ /
/ \
If I have this right this means the sensor needs to be further from the corrector - try a small spacer. If you get stars in the corners like this:
/ \
\ /
you are over corrected and you need to get closer unfortunately that is tricky to achieve with a DSLR.
How do your images look with no corrector in line? (BTW it is not a crime to crop a little if your field is not flat all the way to the corners)
Finally you may also get a better result by focusing on a star 1/2 way to the corner not one dead centre on the CCD as this will balance the focus better.
John thanks for your reply - it is version 3 i have. The information is great - and i will have a try at the spacers. have a look at a sample image i have withought a spacer http://www.iceinspace.com.au/forum/s...ad.php?t=59765
As Gary pointed out you're going to have to try different spacing to find the sweet spot. If you can't then you'll need a different reducer/corrector. It's all part of the fun. Nothing wrong with that shot though. The center field looks great. You just need to tidy up the edges.
Do you have CCD Inspector? If not post a link to one raw sub and give us your sensor pixel size and the FL the picture was taken at. I'll send you back the graphs. Might help in checking what's off and you'll get there faster.
Nothing wrong with that one Houghy, well done mate, stay with it.
Leon
thanks Leon
Quote:
Originally Posted by Vanda
Great shots!
Ta
Quote:
Originally Posted by duncan
Hi David,
That bit of curvature gives it a 3D effect. I know you want rid of it so i'll not say anmore,Lol.
Looks good to me.
Cheers,
Duncan
thanks for the opinion
Quote:
Originally Posted by sheeny
OK, a little bit of curvature, but it's far from a dog's breakfast!
Al.
Sorta like Mydog
Quote:
Originally Posted by telecasterguru
I can't see too much wrong with the image at all. I think it is a fine effort.
Frank
Frank i couldnt post a larger image due to file size - but it is bad
Quote:
Originally Posted by gbeal
Dog tucker indeed Huff, LOL.
What is the issue? There must be enough of you guys with this Gilman Special to have worked out what is needed to keep it all flat?? Surely?
In my case a while back with an 80mm triplet I used an MPCC, so if you have access to one of them, try that. Be prepared to try differing spacings, like Marc MultiWeb did.
A great project for the full moon period, instead of barking at it, LOL. Sorry couldn't help myself.
Gary
Do you have CCD Inspector? If not post a link to one raw sub and give us your sensor pixel size and the FL the picture was taken at. I'll send you back the graphs. Might help in checking what's off and you'll get there faster.
I like the one with special herbs and spices.
I did some tests on the weekend (in between the clouds up at Heathcote) and I recon the Astro-Tech 2" field flattener is a perfect match for the ED127 and a DSLR. The images comes out very flat in CCD Inspector, and the spacing seems spot on when it is screwed directly into a canon t-ring.
I like the one with special herbs and spices.
I did some tests on the weekend (in between the clouds up at Heathcote) and I recon the Astro-Tech 2" field flattener is a perfect match for the ED127 and a DSLR. The images comes out very flat in CCD Inspector, and the spacing seems spot on when it is screwed directly into a canon t-ring.
LOL
