Atik Horizon II or ASI 1600MM or...

[fwm891]

I have a RASA 8 inch and use an ASI 294 MC Pro OSC cooled camera on it. I'm thinking about a mono camera of similar 4/3rds format. The ASI1600MM has the same back focus as the 294MCP simplifying a camera change over. The Atik has a 13mm back focus requiring a shorter extension tube to meet the back focus requirements of the RASA 8 (25mm BF) so not a real problem as the camera + it's short extension can be swapped together.

My real dilemma is not knowing either the 1600MM or the Horizon II. I really like my ASI-294MCP, but I've owned an Atik 383L mono and really liked that so both manufacturers have my confidence.

I image DSO's almost exclusively, never tried EAA and not particularly interested in planetary, solar or lunar imaging.

If anyone has experience of these (one or both) I'd like your thoughts/comments please.

Keep Safe

[andrew s]

If you Google "Christian Buil spectroscopy" he does a comparison which should help you even though it's the older Atik Horizon.

Regards Andrew 

[fwm891]

2 hours ago, andrew s said:

If you Google "Christian Buil spectroscopy" he does a comparison which should help you even though it's the older Atik Horizon.

Regards Andrew 

Thanks @andrew s for that prompt to Christian Buil's site. Cameras are almost identical, just little things ZWO and Atik have tailored to their markets. One thing I hadn't realised is that the Atik Horizon has to be powered to be used unlike the ASI1600MM Pro which (like the ASI294MC Pro) can be used via USB cable only although there's no cooler operation. I've certainly used that feature with the 294. Some features of the 1600MM Pro can't be accessed via Ascom whereas the Horizon can. All a bit swings-n-roundabouts...

Edited June 3, 2020 by fwm891
text added

[andrew s]

I would check what the latest Ascom can do with the asi as it may well have changed.

Regards Andrew 

[david_taurus83]

1 hour ago, fwm891 said:

Some features of the 1600MM Pro can't be accessed via Ascom whereas the Horizon can. All a bit swings-n-roundabouts...

Which features are you talking about?

Originally I wanted the Atik mainly because of the UK customer service and the reputation they have for quality but I was swayed by the cheaper ZWO which comes with all the adapters you need. Rarely hear about issues with the ASI1600 anyway. I assume your aware of the microlensing issue of this sensor which will affect both Atik and ZWO versions.

[fwm891]

2 hours ago, david_taurus83 said:

Which features are you talking about?

Originally I wanted the Atik mainly because of the UK customer service and the reputation they have for quality but I was swayed by the cheaper ZWO which comes with all the adapters you need. Rarely hear about issues with the ASI1600 anyway. I assume your aware of the microlensing issue of this sensor which will affect both Atik and ZWO versions.

The comparison: http://www.astrosurf.com/buil/atik_vs_zwo/

As for the ASI1600MM Pro coming with all the adapters I need - they are all surplus, I can't use any of them because the back focus on the RASA 8 at 25mm wont allow it. I like the 1600 because it has the same 6.5mm BFD as my 294MC so I can make a simple change over of the cameras. However it would be quite a simple task to turn up a short custom spacer to match the Horizons 13mm BFD with 42 x 0.75mm opposing threads.

[Adam J]

Honestly the reason I went with the ASI1600mm pro and not the horizon was the ability to use 1.25 inch filter on the ASI1600mm pro, but if I was using a fast scope like the RASA I would go with the Horizon for the UK service because you will need 36mm filter in either case. So I say Horizon in this instance.

Adam

[david_taurus83]

2 hours ago, fwm891 said:

The comparison: http://www.astrosurf.com/buil/atik_vs_zwo/

 

Are you referring to the apparent inability to control offset? In the drop down box that says unity gain is also the option to select custom. Once selected, the offset slider becomes available. AFAIR anyway🤔

[knobby]

Possibly a dumb observation but surely you can't just put the 1600 in place of the 294, you'll need a filter holder of some sort or are you just going sole mono ?

[fwm891]

12 hours ago, knobby said:

Possibly a dumb observation but surely you can't just put the 1600 in place of the 294, you'll need a filter holder of some sort or are you just going sole mono ?

I have a Baader filter draw enabling me to manually change 2" filters. That wouldn't be an option with the Horizon. But I'm not giving up on the Atik yet. I'm trying to see if I can make the short extension tube for the Atik able to take filters but it's going to be really tight.

Edited June 4, 2020 by fwm891
text added

[fwm891]

Initial thoughts on a filter draw. Filters would need to be removed from screw mounts to allow a thin enough tray/holder to be used but definitely looks promising.

Side view attached showing front end of the Horizon II (drg from Atik website). Black rectangle shows the CMOS chip, red rectangle - a filter. Grey areas show the approximate cross section of the adapter. The adapter would be in two halves to allow machining of the filter tray registration slot... TBC.

[Adam J]

So the backfocus on a rasa is only 25mm? Then how do people use a DSLR with one?

[Dinglem]

27 minutes ago, Adam J said:

So the backfocus on a rasa is only 25mm? Then how do people use a DSLR with one?

They don't it's a RASA 8" the camera would cover most of the aperture

[Dinglem]

i got this off FLO's site for thr RASA 8"

Built for Today's Cameras

Unlike the larger RASAs, the 8" model is not suitable for use with DSLR cameras. Instead it has been optimised for use with cameras that have sensors with a diagonal size ~22mm, which gives an image circle of 3.15°. This makes it an excellent choice for use with today's highly popular CMOS deep sky cameras, such as the ASI183 & ASI1600 series from ZWO. Starlight Xpress' compact CCD cameras also work very well. And whilst ~22mm diagonal is optimal the RASA 8 can also be used with larger sensors up to 32mm diagonal, including the APS-C sized sensors used in many mirrorless cameras, though some compromise must be expected at the image periphery. Celestron advise camera bodies should be less than ~100mm / 4" in diameter. 

[Adam J]

Sounds like they have designed a telecsope for ZWO cameras only as anything with greater back focus will be difficult to use as per this example.