Best Arcsec per pixel camera for 8" F5 scope?

[Poita (Peter)]

I've run with and without darks with the QHY8, and stopped doing darks as they really weren't necessary, there just wasn't any discernable difference in the photos I was taking. YMMV.

I agree that a temp controlled newer model would be nice, but it can easily run to twice the money, and that extra $800 or more might get more bang for buck on other items.

[Poita (Peter)]

The camera is now in Chris's (giant) hands, so we now all await your images Chris

[Hagar (Doug)]

Originally Posted by Poita

I've run with and without darks with the QHY8, and stopped doing darks as they really weren't necessary, there just wasn't any discernable difference in the photos I was taking. YMMV.

I agree that a temp controlled newer model would be nice, but it can easily run to twice the money, and that extra $800 or more might get more bang for buck on other items.

You have to have had a quite wonderful camera Peter. Either that or the darks you were using were, well, useless. Any camera will benefit from the use of good dark frames, be it for the removal of hot pixels or just read noise and electronic noise.
I ued a QHY8 for many years and although the Sony chip had a very low inherant noise level it did have some noise which darks went a long way to removing.
Noise is best viewed at full frame size and look less of a problem when images are resized but usually becomes very evident when the image is cropped and resized.

I wish Chris well with the camera but can assure both of you that temprature control was the biggest step up the QHY range of cameras has experienced. It makes image control and calibration a real breeze and in my opinion probably the only reason to ditch a QHY8.

[Poita (Peter)]

I may have been lucky, I had no hot pixels, and do most of my work at 1:1 and just didn't get an issue. I don't see any amp glow either, I make sure the amp is switched off in the software and that seems to do the job.
With the hyperstar I'm no longer doing really long exposures anymore either.
If darks are required then making a library of dark frames would be enough in most cases if required to get rid of read noise or other noise if you experience any on particular targets.

Of course flats and bias frames are another story.

The Quantix 6303 though is another beast altogether my god that thing is useless without a set of darks.

[Screwdriverone (Chris)]

Originally Posted by Poita

The camera is now in Chris's (giant) hands, so we now all await your images Chris

Ha, it was great to meet you and your family Peter...and Happy Birthday for today ( I will find the HB thread in a minute)!

I had an "interesting" night last night, VERY tired from 9 hours in the car after the wife decided to give me some errands to do before we got home from the drive, at least Anthony has only 4 hours left of his 120 now, which is good.

After dinner and frustrating driver install/uninstall/install/uninstall......I lost patience and asked here on IIS (D'oh) and got the CCDCAP, EZCAP and Nebulosity all connecting to the camera, so I could try out which one is best for me.

I would have to say, it seems Nebulosity is easiest, then CCDCap followed by EZcap. Trouble is, I wasnt going to buy a licence to save without the jailbars on the image, so I simply didnt use it for capture apart from testing if I was on target.

My alignment was woeful as PHD was constantly correcting, so I spent easily 2 hours playing with it with the assistance of Trevor's (tlgerdes) excellent tutorial on how to use PHD to drift align. YAY for me, I had NO discernable drift at ALL after this, even with sidereal tracking OFF. I know this because I took a test shot of 120 secs, then went back to PHD and went "woops, forgot to guide!".....man.....

Anyway, out from about 10pm right up till about 3am, skies clear all that time, me playing with drifting, camera was humming away, tried every capture program, played with gain and offset, slewing around waiting for M20 to get to the same height as the last DSLR debacle....

In the end, I THINK I captured about 5 x 2 min subs of M20, tried for M104 before the drift correction as it was woeful, didnt get much there as the software and I are from different planets it seems.......

NOW, I am back to where I was before with the data problem of RAW/FITS.......

I have tried stacking with DSS, applying the QHY8 bayer settings and used AHD, bilinear, drizzle et al.....same issue!

It confounds me and also disappoints me somewhat to think this is so difficult for someone like me who is quite techical, works in telecommunications and computers and aint no dummy....

Tutorials are hard to come by.....going by eye/feel seems to be unreproducable and my frustration level climbs with each attempt at getting data/colour/results out of what is essentially a SUPER light bucket camera compared to my hotplate of a DSLR....

I dont know if the next two weeks with Peter's QHY8 are going to have many rain free days, but if initial impressions are anything to go by, it seems that guiding/capturing is OK for me, but then it all turns to a word starting with S and ending in HIT......

The main frustration I have I think is impatience.....here I have a COOLED Astro CCD and when I take say a 2-5 min sub, I expect to SEE something jump out at me on the screen. To simply see a faded blob where M20 should be on the FITS reproduction, that then needs to be stretched, stacked, debayered, calibrated, corrected and then processed before I can determine if all this time and money is worth it.....just seems a little crazy!

Im surely not the only one who has felt hamstrung by this feeling of inadequacy when using moderately good equipment and finding it a minefield of options, black magic and blind faith to be able to get a nice astrophoto produced?????

I may have talked myself into sticking with the DSLR just purely from the simplicity of it all, put it back to JPG capture and take some darks, stack these cruddy 8 bit compressed subs and maybe make a light box and a copper cool box for the camera and perhaps buy a Hutech NDAS LPS filter for it for the skyglow and save myself at least $1000 or more and retain a shred of what sanity is left.....?

Sorry I havent any better news, especially with such a nice camera in my posession, with upcoming rain and it seems an insurmountable roadblock of knowledge peeing me off at the moment, I doubt any good images are pending.....

Apologies for yet another whinge encrusted sobfest of how useless I feel about this all, but it helps somewhat to vent this frustration as the wife just stares at me and says, "fine, I dont want to hear about it anymore"

Anyway, back to surfing the web for "how to process FITS files into COLOUR without having to stand on your head, reach around under your leg and press CTRL - 9 while simultaneously hopping on one foot and then passing it into 46 OTHER programs to tweak 0.00001 percent of a HIDDEN application setting with no real proper help file to output it into a different format to load into another program to start all over again with a washed out pathetic excuse for an image to find I have done it ALL wrong because I forgot to carry the 1 or press a check box on screen 72 of step 1,362!!!!!!!!!"

Jeez Louise!!!!!!!!!

Chris

Edit: Oh, dear...I may have said that all out loud......woops......

[RobF (Rob)]

Don't stress Chris - a FITS image does look a bit unexciting on the screen compared to a DSLR purely because of all the extra dynamic range. Once cal'd, stretched etc there's generally a lot more to see though. Realise your keen to put the loan camera through it's paces, but it takes time to get it all together (assuming some of us have ever actually "got it all together" )

[Screwdriverone (Chris)]

Thanks Rob,

Yeah, I know its all technically better, but it honestly feels like going backward to go forward.

And dont get me started on some of these so called "capture programs".....I must have perhaps 10 of them on my PC clogging the place up, maybe 80% of them are just useless to use, no instructions, no real help files, nothing to sort of point you in the right direction. Its like there is an assumed knowledge of what you need to do to fix something or get good results.

I know that there is a level of knowledge and understanding required to be able to get good results, but with each new step I take or improvement I make, it seems to shine a spotlight on all the other CRAP bits that were previously in the shadows.....for example....I fix the MPCC problem with my DSLR, NOW I have a massive vignetting problem, I need a light box to fix that, in the meantime, my raw files are full of hot pixels and heat noise, need a cool box to fix that, or a cooled CCD. I borrow a cooled CCD, expect things to JUMP out at me compared to a DSLR, nope, not gunna happen, I need to go to FITS tutorial camp for 2 weeks to understand how to calibrate them and debayer them and then stack them properly and then combine them with darks (oops, didnt do any) and flats (oops, no light box) and bias (oops, dumb ass me doesnt know how to do these - MORE reading) and dark-flat-bias-light-combination master-garbage-superflats with stretched histograms!!!!

But before I do that, I need to use a crappy capture program with 4 settings, doesnt save, locks up, doesnt explain itself and was probably written by the last guy who got the cranks with the previously bad program and decided to write his own to make HIS life easier and he simply forgot to attach an instruction manual.

I mean, I respect those who produce amazing images and have the knowledge, skills and patience to do all this and throw endless wads of cash at a problem (it seems) to get better results, but it astounds me as to just how ridiculously complicated and never ending it all seems to be....

I mean, case in point.... I searched for FITS viewer, got a hit from NASA of all places, talking about a FITS Liberator for Hubble generated data. I thought, GREAT! now I can see the FITS files in all their glory, load it up, NO NO NO NO NO!!!!! I see a bayer matrix all over the screen, NO WAY to apply the RGBG or RGGB or BGGR or BRGR or GBRR or GRRBUFHBSDFBDSF friggin matrix to the stupid picture and 1.9 Million combinations of logx/sinr/logqx/sqrt crap that only means something to rocket scientists....!!!!

I am SO sick of downloading (and then uninstalling)software to try and SEE what data there is to SEE, that my ADD/REMOVE programs icon has filed a restraining order against me!

Grumble grumble grumble.....some more......

Chris

[alistairsam]

Chris,

i"ll keep it simple
since you're just testing the qhy8, i'll suggest the following
use ezcap in win7, big plus is you dont need to debayer, you can see the colour image straight away, and the even save it as bmp to test stack in dss.
what I do is get my alignment, guiding sorted out, then save each exposure as bmp and fits. the bmp is 24 bit colour so no debayer necessary, then i play around with gimp with just one frame to see how much detail has been captured, and then if there is potential, i use the fits and dss.

you'll see the big advantage with the cooled ccd when you realize there is almost no noise, you dont need to bother with darks or dithering and you can stretch the image a lot more than the dslr since its 16 bit.
the live preview is a real neat feature like live view. just set the exposure to 400ms or so.
use a dew strap around the nosepiece and the mpcc spacer and the glass wont fog up
just tackle one issue at a time systematically. it does need some patience but is well worth it.
get the gain and offset value with the bias frame. I use 2 and 125.
I've just started with the camera as well and with mine being F4, its a lot more &%%$^#,.
the more i use it, the more i like this camera.
all my software issues were fixed by moving to win7.
good luck.
edit, in ezcap, remember to hit the auto button below the histogram and use x8 or x16 oversampling.

[Screwdriverone (Chris)]

Hi Alistairsam,

Thanks for the tips, I only have XP on my astro laptop, however, I can use my Win 7 work laptop which I have been using as it has an SSD and 4GB of Ram for processing.

I will try the gain and offset setting too, I have found wildly varying user settings on the net for these, so thanks.

The MPCC doesnt work as I dont have the correct spacing for it and the coma is worse, anything I get I will simply crop or use startools repair to dodgy the stars back into shape.

As you said, its only a test, so these tips will hopefully help.

Thanks

Chris

[alistairsam]

Hi,
yes I was swearing black and blue with xp, lot more stable with win7.
I'd suggest using your guidecam in your main scope while drift aligning with phd first or you could use the trial version of alignmaster. atleast that's what I plan to do when these clouds clear.
ezcap although a bit archaic, is pretty easy and does the job if you want to see what it looks like. you can choose the focusing area by moving the box around in the preview, and then use live in the focusing secn. you'll have to set 400ms or so and click that auto else you won't see anything.
you could use high speed readout, but apparently that introduces a bit of noise.
you could use a 5 or 10 sec preview to get your target framing correct, and then do your 3 or 5 min image, and save each as bmp and fits.

Also, if you use DSS, you don't need to debayer each image. there is a setting in DSS where you specify QHY8 as the imaging camera and it chooses the correct debayer pattern. just import the fits files and convert them to lights. clicking each also brings up the preview.
once stacked, you can choose save as TIF and then play with the TIF. so no need to fiddle around with the FITS files either.
you mentioned you don't use a spacer and mpcc, but once you have the camera running say for 20mins or so, i'd suggest removing it out of the focuser keeping it powered just to see if there's condensation in the UV/IR nosepiece. if there's none, then you don't have to worry about it. else just use a dew strap around it.

let us know how it goes.

[Poita (Peter)]

I'd give Nebulosity another look.
There are some great tutorials and documentation, which as you say, is unusual!

http://www.stark-labs.com/movies/Capture_Full.html

The nice thing in Nebulosity is that the images *do* jump out at you, as there is an auto black/white point setting (auto scale) in the preview screen (doesn't affect final image) that lets you see what you got.

The capture part is all explained really well in the video above, along with multiple exposures etc.

Then for post processing basics:
http://www.stark-labs.com/help/nebul...cHowTo_v1b.pdf

There are even the fits files on this page to practice with, so you can have a go before imaging again.
http://www.stark-labs.com/help/nebul...tutorials.html

Anice walkthrough of pre-processing is here:
http://www.stark-labs.com/help/nebul...rough_comp.pdf

and the detailed version is here:
http://www.stark-labs.com/help/nebul...sing_HowTo.pdf

BTW, for that camera the gain is 1 and the offset is 111 in Nebulosity.

[Poita (Peter)]

Oh, and check your PMs

[Screwdriverone (Chris)]

Peter's QHY8 has a heater incorporated into the main window which I think he fitted himself, so no problem with dew there.

It seems like I am doing the right thing as what you are suggesting is what I am doing already, might take another look.

Thanks Peter, I will use these settings and do some reading while the rain pours down this week....typical!

Cheers

Chris

[Poita (Peter)]

To add to your reading:
http://www.astro-imaging.com/Tutorial/LRGB.html
It is for LRGB, but the stretching part will be of use conceptually.

http://www.mistisoftware.com/astronomy/index_fits.htm
This page has a bunch of fits files ready for processing practice, and has a tutorial for the M8 data as well.

[Poita (Peter)]

I had a truly stunning night here last night, seeing was better than it has been in years, so without the QHY8, I thought, good excuse to do some planetary.
The view on the chip was great, but I was so excited I recorded the DBK colour signal as mono. Didn't realise until my session was nearly over and Saturn was about to disappear behind the trees.

ARRRGGGHHHH!

Hope you get some nights like this in Sydney soon.

Weather-wise, not frustration-wise that is!

[Screwdriverone (Chris)]

Hey Peter,

Sorry you didnt have the QHY8. I DID use it last night as it was clear and calm and nice temp outside, so hopefully that makes up for something....

I noticed a few dust bunnies ( I used my lens pen brush but they are still there) and my vignetting is horrible, but the point is I got some nice subs with Nebulosity (6 x 5 mins) of M83 as well as some M104 with the QHY8.

I even had time to swap out the QHY8 to try my DSLR on M83 as a direct comparison of sub time and hopefully if I can figure out how to process both sets, can put a side by side comparo together on M83 to see the difference.

Guiding was pretty spot on again, so I was quite happy to go long with the QHY with your recommended gain =1 and offset = 111. The data on first inspection in Neb 3 seemed MUCH better than the first effort.

Depending on my blood pressure level for processing, I might FTP the files somewhere and let others have a go at it so I can get an impartial and proper process on my data to help me decide if its all worth the expense or not.

I would have to say though, once I knew what I was doing in capture land, it was a doddle to get lots of subs, the only downside that it was a school night and had to pack up early around 11:30.

I got a good 4 hours of play time in though, so it gave me time to quadruple check my drift alignment technique and play with both cameras, so it was a productive night.

Now its just a matter of heads down, bums up for processing.

Wish me luck

Cheers

Chris

[Poita (Peter)]

That sounds like a good idea.
You could sign up for dropbox, makes it easy to share those big files.
If you sign up with this link, you get an extra 250MB of space, and so do I.
http://db.tt/vdYmCvw4
It is free and you get 2GB as standard, and is very easy to use, you put the files into the shared folder and they automatically synch, and you can send the link to anyone. It is how I have been sharing the planetary captures in the beginners section.

I'm really keen to see how it compares.

You may have to take the front off and clean the sensor glass directly.

From the poorly written manual

QHY8 is designed to allow user clean the CCD sensor in easy way. QHY8 has a IR or AR optic windows. Please unscrew it . Then you can clean the CCD surface. The QHY8 CCD surface has no coating. It is very easy to clean. You can use the alcohols and lens paper. Clean the CCD carefully. After cleaning CCD. Please wait all liquid dry. Screw on the optic windows and dry the camera according the method in above description.
Of course it is a difficult thing to get zero dust. For small dust we suggest use flat field calibration to remove it.

https://www.google.com.au/search?q=c...ient=firefox-a

[RobF (Rob)]

You do need some decent software to make the most of a CCD Chris. Plenty of options and choices to make of course.

[gregbradley]

I saw an SBIG ST8300 on Astromart for about $1300 or so recently.

That may be worth looking at too. The 8300 chip is very popular as it is a good all round performer and particularly clean and defect free.

Greg.

[Screwdriverone (Chris)]

Originally Posted by RobF

You do need some decent software to make the most of a CCD Chris. Plenty of options and choices to make of course.

Hey Rob - yep, and some processing skills would be nice too, thats what I am up to now, trying to process....

Originally Posted by gregbradley

I saw an SBIG ST8300 on Astromart for about $1300 or so recently.

That may be worth looking at too. The 8300 chip is very popular as it is a good all round performer and particularly clean and defect free.

Greg.

Hmmm, thanks Greg, a good tip, I will keep an eye on that one as well as Astromart in general.

Cheers

Chris