Saturn 17/05 from Bembridge

[SnakeyJ]

Not happy with my Mars runs and processing tonight, but the Saturn looks pretty good to my tired eyes.

The usual F20/4000mm with the SW Exp 200P and QHY5L-IIM.    Frame rates were between 35 for R, 30 for G and in the low 20's for B (despite cranking up the gain).

Possibly a little over done on the post processing - I'll take another look tomorrow

[SnakeyJ]

Here's a question for any QHY5L-II owners out there using Firecapture - Why do I need to boost gain or exposure to maintain same histogram, when I drop from full frame down to a smaller ROI?   I would say 30-40% drop in histogram, which is a significant loss of brightness - especially on an already dim Saturn!

[red dwalf]

i like the capture, sorry can`t help with the question

[zedds]

That's a cracking image!!

What capture software do you use?

[Space Cowboy]

Great image Jake especially for an 8" scope! I get the same dimming when changing ROI too not sure why that is.

[Christopher Davenport]

Cracking image jack, loving the banding and clarity of gaps on the rings.

I don't use firecap, rather the buggy ezcapture, which doesn't dim my subject when decreasing the frame size. ROI

It may be the way the histogram is measured, it is picking up the sky glow across the extra fov?

[si@nite]

Very nice Jake looks ok to me, more to come out of that image I think!

[NorrinRadd]

That's a terrific capture Jake. The rings are full of detail, nicely done :-)

[SnakeyJ]

That's a cracking image!!

What capture software do you use?

Thanks Zedds - Firecapture.

[SnakeyJ]

Great image Jake especially for an 8" scope! I get the same dimming when changing ROI too not sure why that is.

Cracking image jack, loving the banding and clarity of gaps on the rings.

I don't use firecap, rather the buggy ezcapture, which doesn't dim my subject when decreasing the frame size. ROI

It may be the way the histogram is measured, it is picking up the sky glow across the extra fov?

Thanks Stuart and Chris - rather odd issue and one that's been niggling for quite a while.   Full credit to Chris for sticking with EzCap - mine went out of the window within about 5 mins, though in all fairness I was trying to do some LX at the time.    Interesting to here that it doesn't have the same affect here and I might have another go with this.

I think it's more than the histo calculation, there is perhaps 30-40% loss in signal on anything below full frame.    1280x960 is limited to around 35FPS @ 8bit, so perhaps the exposure lies a little at max res?

[SnakeyJ]

Very nice Jake looks ok to me, more to come out of that image I think!

Thanks Simon - I thought I'd pushed it within an inch of it's life last night, but will take a fresh look tonight.

[theo]

For the aperture that's really very good Jake. Nice work!! 

Pete

[zedds]

Thanks Zedds - Firecapture.

Just noticed on your second post Jake, sorry. :-)

[Space Cowboy]

I use EZ Capture Jake and its just the same with the dimming. I've always assumed its the slower frame rate of the larger ROI that increases the signal. You can clearly see how much brighter the planet is when going up from 640x480 to 800x600.

[simmo39]

Brilliant.

[Christopher Davenport]

I use EZ Capture Jake and its just the same with the dimming. I've always assumed its the slower frame rate of the larger ROI that increases the signal. You can clearly see how much brighter the planet is when going up from 640x480 to 800x600.

Aah, good point never thought of the decrease in the frame rate. Does make you wonder about what exposure timing really does?

Anyway, apologies, I should have stated that I target a FPS of between 30 to 50 fps, as I find with my small aperture (5inch), this to be my sweet spot.

(I use the USB setting, fast frame rate boost and hard disk write speed, to control my frame rate,  between ROI changes.)

I used to just up my frame rate up as high as possible, but I find it degrades the image.

This may have something to do with the dimming effect you are speaking of.

Never really thought about it in detail though.

[Space Cowboy]

Higher frame rates certainly increase noise levels but if seeing is poor its worth it for the faster shutter speed to get a sharper image and in theory stacking extra frames to reduce the noise.. One thing I have considered is using the larger ROI to have a fast shutter speed with a slower frame rate. Problem is you need a very large HDD.

[astroman001]

Great image with the 200P. The polar banding has come out well.

regards

Peter

[robbie c]

Great image Jake well done 

[leelee970]

Great capture Jake, looking really good.

Have you tried Sharpcap.

I've used both Sharpcap and Firecap (as well as Ezcapture - but like you didn't get on with it)

I must get off my ...... and process what I've captured - been out 5 night in a row until past 1am so I must have something decent.

Lee

[Alan]

Excellent shot Jake with good colour balance and detail

[SnakeyJ]

Thanks Peter, Robbie, Lee and Alan - great support and comments, thanks!

[SnakeyJ]

Great capture Jake, looking really good.

Have you tried Sharpcap.

I've used both Sharpcap and Firecap (as well as Ezcapture - but like you didn't get on with it)

I must get off my ...... and process what I've captured - been out 5 night in a row until past 1am so I must have something decent.

Thanks Lee - I have used Sharpcap, though not recently or with my QHY5L-IIM, but it is loaded on my imaging laptop so no real excuse!   More a case of being most familiar with Firecap and not wanting to waste time when conditions allow!

Look forward to seeing some of your images once you get some processing done.

[Pete Presland]

very good image, processing looks fine to me.

[U Cyg]

Great image Jake, well done!

Angie