SXV M25C or Atik 4000 One Shot Colour

[bazza]

I'm thinking of a One Shot Colour camera to go initially, with my WO Zenithstar ED80.

In the future, I'd like to upgrade this scope to a triplet APO refractor of some sort.

Not exactly the same format camera, but close.

I thought about including the QHY8 in this, but as the camera is going to be kept outside in a permenent set up 24/7, I haven't, as I've heard of condensation problems to the QHY8 when left outside?

Just wondered if anyone had any thoughts or advice or comments on either camera.

I know Steve (steppenwolf) has the M25C and produces some spetacular images with it.

Barry.

[steppenwolf]

Hi Barry, I am very pleased with my M25C, it is a finely engineered camera and although I did have some teething problems with it, these were easily resolved and the after-sales service from Starlight Xpress is exemplary.

I would buy the camera again without hesitation (actually, it was a surprise present from my wife Jane - but that is another story!!).

[Ben Ritchie]

What about the QHY8 pro version that's out soon? Condensation shouldn't be an issue with that.

Worth being aware that the Kodak chip in the Atik is significantly noisier than the Sony chip in the QHY/M25C

[bazza]

Ben,

I was aware of the QHY8Pro, but have no idea when it's expected to enter the market.

Will it be significantly more than the QHY8?

The price of the QHY8 is very tempting though.

Thanks for the heads up on the Kodak chip of the Atik.

I also understand that the gain and offset are adjustable on the QHY8? Why?

What would be the advantage of this?

This sounds like something I could do without - I normally have enough problems to contend with in the Obs when imaging!! Without introducing more complications!! (Tongue in cheek!)

Barry.

[SteveL]

Gain and Offset is something you change *ONCE* then leave alone most of the time. Gain is equiv to ISO speed for DSLRs. Offset allow you to ensure that the blackets/darkest pixel on the image is above zero. The reason for this is that if anything in the image is completel;y black, you have almost certainly lost some data. Making "black" into "dark grey" means that everything you capture is in the data.

For the QHY8 and Maxim drivers, I use 50% gain and 120 offset, and have done since the very first day I got the camera... never touched it since.

[Ben Ritchie]

I've just been trying to figure out the gain/offset for the QHY8 ... I think that the amount of information online makes it seem more confusing than it probably is. As Steve says it's something you do once and then forget. I'm still trying to figure it out though, as I seem to have some zero-value pixels regardless of the offset value (most instructions say keep increasing it until the minimum pixel value is just above zero, but that doesn't work if one pixel never goes up).

I was aware of the QHY8Pro, but have no idea when it's expected to enter the market.

Quite soon, I think. Main benefit appears to be for hyperstar users, but the sealed design may be useful too. There's also a standard QHY8 version with two air sockets to make it easy to flush with dry air before use to prevent misting.

[bern]

To make things easier I test every QHY8 before despatch and suggest optimal settings for gain and offset, usually 0% - 10% gain and around 115 offset.

This is a useful discussion of the underlying principles:

http://www.stark-labs.com/blog/files/GainAndOffset.php

bern

PS I'll try to get a meaningful ETA for the QHY8 Pro

[NickH]

Both is good

Having used the 4021, I am about to order one (and some other Atiks for a project I am involved with)..we also (our astro soc) have a 25C, and for one shot, it's a cracker too..