Atik 420 Mono - experiences, opinions, options?

[jusasi]

Greetings fellow stargazers, I'm looking for an affordable camera for DSO imaging and this camera caught my attention. On paper it looks pretty good for its price. Does anyone here have some experience with this camera? Also I'd love to get some input from you experts here whether you own the camera or not. I'm trying to find a decent camera at the ~1000€ price point (filter wheel & filters not included).

For a little background information I currently have the following base equipment:

- C9.25 SCT

- Focal reducer f/6.3

- Advanced VX mount

- Canon EOS 1100D

I had to get the reducer to get good full images of the Moon and to be able to capture bigger DSOs, although Andromeda is still to large to fit into one frame it seems.

I've been using my old DSLR for everything so far and it was good for entry level photography but now I yearn for more.

Also planning to get an autoguider (looking at the Orion auto-guider package, including AC 80/400 OTA) as any attempt to cross the 30s exposure time seems more or less futile.

Additionally I'll maybe get ASI120MC for planetary work - I hear it's good for that and hassle free with the color version and doesn't cost too much.

I'm fairly new to this hobby, just been at it for a few months so I'm still a bit wet behind the ears - so please point out if I'm doing something wrong or wasting money into something I shouldn't

This is an expensive hobby but hey, you spend on what you feel is important, right?

[ollypenrice]

Two obvious drawbacks for you with the 420. 1) The chip is very small so at your focal length, even reduced, your field of view will be tiny. 2) the small pixels will give you an unreachable resolution if used unbinned. Using http://www.12dstring.me.uk/fov.htmwe get 0.67 arcsecs per pixel unbinned and 1.3 arcsecs per pixel binned. The former would need both very high order guiding and excellent seeing to be at all realistic as an objective. Even binned you're below the more tolerant and relaxing 2"PP favoured by many UK imagers. Your field would be a cramped 18x13 arcminutes.

If you went for the Atik 314L you'd get a more useful and workable 23x17 arcmins and 1.96 "PP in bin 2. The field will still be tiny but that's the problem with long focal lengths.

In any event it's important to go for mono so you can bin your pixels 2x2 to get a reasonable pixel scale.

What about a second hand 383 to get a more reasonable chip size on budget?

Olly

[jusasi]

Man, that site is pure gold!

I had a thought now: if I bought the ST80 guide scope, for use with my C9.25 and then a smaller guide scope for the ST80 itself... and then an Atik 314L+ camera to be used by both the ST80 and the C9.25. I could then use the ST80 for imaging large DSOs like Andromeda and when I'd like to hunt small targets and planets I could use the heavy gear for that. The 314 looks like a nice compromise that could be used by both scopes. Would need to throw in more bucks but this started to look like an interesting option. I can see the benefits of getting a shorter focal length and the wide field of view.

What do you think?

[Chris]

Man, that site is pure gold!

I had a thought now: if I bought the ST80 guide scope, for use with my C9.25 and then a smaller guide scope for the ST80 itself... and then an Atik 314L+ camera to be used by both the ST80 and the C9.25. I could then use the ST80 for imaging large DSOs like Andromeda and when I'd like to hunt small targets and planets I could use the heavy gear for that. The 314 looks like a nice compromise that could be used by both scopes. Would need to throw in more bucks but this started to look like an interesting option. I can see the benefits of getting a shorter focal length and the wide field of view.

What do you think?

I was going to suggest something similar although instead of an ST80 I was going to suggest a small ED refractor.

Unless you're going to only do pure narrow band imaging, the ST80 will show very bloated stars due to chromatic aberration (CA), also the focuser on an ST80 is very basic and course which would cause problems for both getting and maintaining focus. 

As you are fairly new to deep sky imaging I think a long focal length scope like the C9.25 (even with reducer) is probably not the easiest path for you. The C9.25 has a long focal length, even when reduced it's something like 1500mm!

Imaging holding a 1500mm stick out in front of you and seeing how much the end of the stick wobbles, quite a lot right! If you held a much shorter 400mm (small ED refractor focal length) stick out in front of you it would wobble much less. This is how focal length effects tracking accuracy, it's much easier to accurately track with the stars at shorter focal lengths, piggy backing a small light ED refractor on your C9.25 would allow this, you can even use the C9.25 to guide the short refractor!

The Atik 420 would work much better with a short ED refractor, but a 314L would be even better still, chunky pixels are more sensitive and have better well depth. There is no point in having higher resolution than your seeing allows.  

[jusasi]

I was going to suggest something similar although instead of an ST80 I was going to suggest a small ED refractor.

Unless you're going to only do pure narrow band imaging, the ST80 will show very bloated stars due to chromatic aberration (CA), also the focuser on an ST80 is very basic and course which would cause problems for both getting and maintaining focus. 

As you are fairly new to deep sky imaging I think a long focal length scope like the C9.25 (even with reducer) is probably not the easiest path for you. The C9.25 has a long focal length, even when reduced it's something like 1500mm!

Imaging holding a 1500mm stick out in front of you and seeing how much the end of the stick wobbles, quite a lot right! If you held a much shorter 400mm (small ED refractor focal length) stick out in front of you it would wobble much less. This is how focal length effects tracking accuracy, it's much easier to accurately track with the stars at shorter focal lengths, piggy backing a small light ED refractor on your C9.25 would allow this, you can even use the C9.25 to guide the short refractor!

The Atik 420 would work much better with a short ED refractor, but a 314L would be even better still, chunky pixels are more sensitive and have better well depth. There is no point in having higher resolution than your seeing allows.  

Good point on the ST80, I've been googling images taken with it and I'm not impressed. Any good suggestions for a good short refractor?

The cost of all this is really starting to kill me though.

[Chris]

https://www.altairastro.com/lightwave-66mm-f6-ed-r-refractor-with-dual-speed-r-p-focuser-alu-case.html

http://www.teleskop-express.de/shop/product_info.php/info/p1151_TS-INED-70-mm-f-6-Refraktor-Reiseapo---Carbon-Tubus---2--Crayford-Auszug.html

http://www.firstlightoptics.com/william-optics/william-optics-zenithstar-zs71-ed-2013.html

Just a few examples above, so you're looking at about 300-450 pounds for a brand new small ED scope. You can pick them up on the second hand market for around 200. 

Another option would be to use your mount with the C9.25 for visual and planetary imaging, but swap the optical tube for something like below for deep sky imaging:

http://www.firstlightoptics.com/reflectors/skywatcher-explorer-130p-ds-ota.html

The 130pds is by far the best value imaging scope on the market if you ask me, this would leave you plenty for a CCD and if you keep the chip fairly small you've get away wihout needing a coma corrector, but even they are only 97 pounds if you want to use a large format chip.

Take a look at the images taken with the 130pds:

http://stargazerslounge.com/topic/210593-imaging-with-the-130pds/page-1

[jusasi]

I've been looking at the options now and I'll probably go with the TS INED 70mm scope Chris linked. Also I've decided to get the Atik 414EX as it's 60% more sensitive than the 314L+ and the price difference isn't that big. Now I just need to figure out which set of filters to get but things are locking into place now.

The FOV calculator gives a pleasant field of view.

F ratio: Focal Length: Field of view: Resolution:   f6 420mm 1.22° x 0.92° 3.17"/pixel

Unless someone comes and tells me I'm making a terrible mistake I'll probably go with this setup

I really appreciate all the help and expertise on these forums!

[Chris]

I think you'll be very happy, great choice