CCD advice 383 vs 414

[steviemac500]

Hi all,

I was after a bigger chip size for CCD imaging than my current 414EX which I love so I bought a second hand 383L+ at a very reasonable price thinking it would be perfect. However, after a bit more research, I'm starting to be a bit concerned about its suitability. I have 1.25" filters which I run on the Zagyl 5 pos wheel and I don't know if they can be used properly, there seems to be conflicting evidence. I can't really afford a new 2" set or a new wheel either. The mount will be an NEQ6 Pro which I am in the process of upgrading to so I'm not concerned about weight. I'm also a little worried about the flats and the mechanical shutter on the 383 causing issues. I have to sell the 414 to pay for the 383 but if I've made the wrong choice, I'll sell on the 383 but I just don't know!!!!! I do find the 414 very easy to use but the FOV is really restrictive.

If anyone can offer some advice either way, I would be very appreciative.

Thanks,

[swag72]

There are conflicting thoughts about whether the 1.25" filter can be used with the KAF8300 chip with a separate filter wheel (they work just fine with an integrated wheel such as on a QSI or Moravian) - I would say give it a try. You have the kit already by your post, so experiment and see what you think. You WILL need flats for sure. but it may be that the flats take out any vignette and that the filters will work OK. If you try it and is works then great! If not then the decision has been made for you

The mechanical shutter only means that you will need to take flats of a sufficiently long exposure so that the shutter doesn't get in the way...... I think about 2-3s is recommended. To that end you will need to have a way of dimming down your flats light source so that you don't take flats at a quicker exposure. That could be something as simple as a T shirt over the end of your scope for example.

Yes there may be new things to learn with the 383 - Such as ensuring that you get good flats that work well - But there are many happy people out there with the same chip that produce great photos. If you want a bigger chip than the Sony offerings, specifically want a CCD chip (not a CMOS), and can't afford a second mortgage on the BIIIIIIGGGG chips out there, then the KAF8300 is the only way to go at the present time in my opinion.

In summary - Experimentation is the name of the game! Whether your filters will work depends on so many different issues that it would be almost impossible to say for definite either way. Even if someone has the same camera and filter wheel setup for example, your telescope speed will also come into play...... 

Hope that helps, but probably wasn't the simple yes / no you were hoping for  

[SkyBound]

I have the 383 with SX filter wheel, and I use 36mm unmounted filters, as it stops any vignetting, I think you can get away with 1.25" but with a bit of vignetting in the corners but I guess darks and flats will sort that..

[Rush]

Dont worry, it works fine with 1,25". I have tried with Atik 1.25 filter wheels, vignetting is a mild issue , can be corrected and flats increase somwhere in between 4 and 5 seconds depending on the light source. Orelse till the shutter shadow disappears. Well, it was working good for me. I do agree with the with the advices mentioned above from other mates.

CS

Rush

[ollypenrice]

You need flats anyway so what's the big deal? I use 2 inch mounted filters with one full frame Atik CCD and 2 inch unmounted with another. I think Atik say you must use unmounted to avoid vignetting on these big chips. I find that at F5 both vignette, the mounted more than the unmounted, but once flats are applied the difference is precisely zero. At F7 the two inch mounted hardly vignette at all. So I suspect that, with flats, you'll be fine. Just don't put any spacers between wheel and camera. Keep them as close as possible - and shoot flats.

Olly

[steviemac500]

Thank you everyone.