Upgrade from SXV-H9 to SXV-H16?

[Dangerous-Dave]

Hi gang, I have been using an SXV-H9 for about 18 months now and come to the conclusion I "need" more megapixels! I have found myself using Pentax medium format lenses in an attempt to get the focal length short enough to fit my favourite targets onto the 285 chip and, while I have been pleasantly surprised with the quality of these lenses, being achromatic they aren't particularly suited to LRGB work. Ranging in aperture between 33.75mm (for the 135mm/f4) and 75mm (300mm/f4), they also lack somewhat in the light-grab department and I am finding some of my exposure lengths quite high with the shorter lenses, eg 20 minutes for Ha shots of Cederblad 214 with the 135mm/f4.

Being a man of modest means, and other financial commitments, I would like to upgrade to something bigger but with minimum of fuss and outlay. I have a range of SX accessories already - ie a fully populated SX 7x1.25"filter wheel, SXV guide head and SX slimline OAG - and have found Terry Platt's customer service superb, above and beyond the call of duty, so would like to stick with that company if possible.

A common "upgrade route" seems to be to move from the H9 to the H16. Looking at Starlight Xpress's website, the Kodak4021M used in the H16 appears to be inferior to the Sony ICX285AL in every way (apart from size) but the H16 is cooled to 40 degrees below ambient, whereas the H9 is cooled to 30 degrees below ambient - does this compensate for the higher dark current, read noise and lower QE? Also, am I right in thinking the H16 is still small enough to be used with 1.25" filters without vignetting?

I would be interested to hear from anyone (Psjshep?) who has gone down this route and how they felt the two cameras compared.

cheers!

(also posted on UKAI)

[ollypenrice]

Greetings, Dave,

My rather parallel route might be of interest. I went from Atik 16HR to Atik 4000(s), the plural because I have OSC and mono...

On the Atik 4000s with an 18mm chip distance on the camera only you are okay with 1.25 filters. No issues at all. I have a 19mm deep filterwheel.

The first thing you notice is that darks are no longer an option. You need them, but with set point cooling this is a non-issue. Just knock out a set at realistic temeratures. I go for -20 because I can usually achieve this in summer and very easily in winter. I can't say that running at -15 made any great difference so I have not done a set of -30 darks for the winter. I think you can get too hung up on all this stuff.

I dare say the chip is a little less sensitive than the 285 but in just getting on with imaging I have entirely forgotten about this and can't say I am aware of any real difference. I haven't looked carefully but then I have felt no need to do so...

The extra space on the chip is an absolute glory, a dream, with whole new vistas opening up. As a narrowband man I'm sure you would never look back.

My stuff is here, the 4000 images are in the majority and date from later on when I had more of an idea what I was doing but the oblong chip shape reveals the earlier 16HR pictures.

ollypenrice's Photos

I would say, do it. That is based on Atik experience. I think Rob Hodgkinson (RobH) knows both Starlights very well and would advise on his experiences.

Olly

[harry page]

HI

I have a sxvf m25 with the sony chip and very quiet it is , like your H9.

I wanted a mono camera to go with it and I brought a H16 and very happy with it I was .

The chip is more noisy than A sony and takes a little learning , but all I did was dither my images and a good sigma stack all was fine

I must say I never used any darks at all , never ever , I say I was happy because I have just sold it to mr blueastra who has just started with it , hope he will kick in and pass comment;)

I have upgraded to a h35 which is a bit more noisey than a H16 , but I have faith in SX

Regards Harry

[Dangerous-Dave]

Thanks guys.

I don't think the H16 does set point cooling Olly - appears to be ambient minus 40 according to SX's website:

"Cooling system: Regulated constant current cooling supply with two stage thermoelectric cooler to give a CCD temperature of approximately -40C below ambient."

Hopefully Rob will chip in too.

[harry page]

Hi

the sxvr has regulated cooling

More help if you want to use darks , but As I said before I never did

Harry

[Dangerous-Dave]

Hi

the sxvr has regulated cooling

More help if you want to use darks , but As I said before I never did

Harry

Ah, many thanks Harry! I prefer not to take darks either, I find them a bit of a waste of imaging time!

How does set point cooling work? Is there an optimum temperature for setting the CCD to (say -30 C?), capture a set of darks at that, and always work at that temperature?

[harry page]

Hi

Yep you got it , you are not supposed to run it at max so you can adapt to varying temperatures

Harry

Ah, many thanks Harry! I prefer not to take darks either, I find them a bit of a waste of imaging time!

How does set point cooling work? Is there an optimum temperature for setting the CCD to (say -30 C?), capture a set of darks at that, and always work at that temperature?

[ollypenrice]

Set point is a doddle. Pick the lowest temp you can regularly reach (lower for you than for me in the summer!!) and shoot a set of darks from which to make a master. You do it in the daytime, no need to waste imaging time. Once it is done it is done. Maybe redo them every six months. It is no hassle at all.

Olly

[BlueAstra]

Mr BlueAstra here. I have Harry's old H16 and I'm quite happy with it. I only have a Ha filter at the moment, still waiting for my SX filter wheel and SX OAG. I've gone for the 2" filter route (baader LRGB) to try and future proof the kit to some extent in case I eventually go for one of the big chips. I've taken some initial shots up to 600s with my Meade 5000, and they are my best so far. Of course, my processing is still wanting, but I'm pleased with he images. None of them used darks. The difference between the H16 and my 1000d is a revelation, since this is my first dedicated CCD astro camera. Its the older F version, so I think just runs at ambiant-40C, and dosen't have the setpoint cooling of the newer version. I was used to the FOV of the 1000d, and didn't want to reduce it too much. To be honest, I was going for an H9 before the H16 became available. I've also recently taken some 600s darks for future use.

[Dangerous-Dave]

Thanks again.

Think I'm going to go for it, if I can find a suitably priced second hand model!