Rambling camera thoughts.

[Endolf]

Currently using an 8" f5 (TS Optics Photon), I'm also thinking for nebula season of getting an Esprit 100, maybe with a .75 reducer for really large nebula. Currently looking to replace my unmodified Canon 600D with an astro camera. In theory I'm in Bortle 6 skies, but 2 of my aspects look over cities....

I'm torn between the ASI294MC Pro and the ASI1600MM Pro, with both cameras one scope or the other falls out of the ideal range of pixel scale, but I can't afford both, so need to compromise. With the ASI1600 I was thinking one of the bundles with ZWO filter wheel and LRGB + Ha/SII/OIII filters, so narrow and broadband covered. For the ASI294 I'd need a filter drawer and then probably the IDAS LPS D2 (currently have the EOS version) for broadband and the IDAS LPS NB1 for narrowband.

I like the idea of the ASI1600, being able to process each channel, faster per image and full res per filter. Given the UK weather, I'm drawn to OSC and being able to get a complete image in a night or 2.

So far I have done a bunch of googling and looking at specifications, does anyone who have 1 or both of these cameras have any useful input?, e.g. does using the 294 for multi band narrow band filter mean the exposures need to be so long you have to use multiple nights anyway, or that the shorter exposure times on the 1600 means you can get 4 filters shot in a few hours?, or alternatives to look at given my site/scopes?

Thanks

[Gina]

A mono camera is definitely better than a colour one for astro imaging but costs more because you need filters and a filter wheel.  I have the ASI1600MM-Cool and very pleased with it.

You need a cooled version too for deep sky objects.

Edited April 30, 2020 by Gina

[Endolf]

Yup, not looking at anything that isn't cooled

[Knight of Clear Skies]

I think you'd be better off going down the mono route. While I understand the attraction OSC in UK weather there are ways of mitigating interrupted sessions. Depending on the target I'll shoot a fair bit of Ha or Lum first so I have something in the can (I like mono images). After that I mix up the imaging plan so I don't have too much of an imbalance. Of the colours I always shoot green last as a green channel can be synthesised from red and blue if necessary. Ultimately, a mono camera gathers data more quickly and makes better use of the imaging opportunities we have.

The 1600MM cool is a very flexible camera. Last time I used it on a scope I shot this with 30 second unguided subs. The low read noise makes this possible, so you don't have to ditch a 5 or 10 minute sub if a wisp of cloud rolls in.

9 hours ago, Endolf said:

e.g. does using the 294 for multi band narrow band filter mean the exposures need to be so long you have to use multiple nights anyway, or that the shorter exposure times on the 1600 means you can get 4 filters shot in a few hours?, or alternatives to look at given my site/scopes?

Shooting Ha on a colour camera is very worthwhile but you are losing 3/4th of your signal. I recommend using Ha filters with modded DSLRs as isolating the nebulosity from the background makes a big difference, even from a dark site (this is IC1396 with a DSLR). However, a specialist OSC camera + Ha isn't really cost or time effective.

[ollypenrice]

All things being equal, mono is faster. During the luminance phase of the capture you are obtaining the red, green and blue light simultaneously on every pixel and this is not possible with an OSC. Also you are likely to want Ha for many nebulae and an OSC works on only one pixel in four with this filter. Finally this efficient capture of Ha can be done on moonlit nights. As evidence of the speed of a mono camera I made up this Heart Nebula image. I do have a better Heart image but this just used 2 hours' data, 2x30 minutes Ha and 2x10 minutes each in R,G and B. The CMOS cameras which interest you would be faster than the CCD I used here.

Olly

 

 

Edited May 1, 2020 by ollypenrice
Typo

[scitmon]

1 hour ago, Knight of Clear Skies said:

The 1600MM cool is a very flexible camera. Last time I used it on a scope I shot this with 30 second unguided subs. The low read noise makes this possible, so you don't have to ditch a 5 or 10 minute sub if a wisp of cloud rolls in.

How often (if ever) have you run into the micro lens diffraction pattern issue?  This is something that really puts me off the 1600MM.

[Knight of Clear Skies]

4 minutes ago, scitmon said:

How often (if ever) have you run into the micro lens diffraction pattern issue?

Haven't come across it, I had to google it. I've not used my 1600mm cool a great deal with really bright stars in frame. I also rarely use guiding so my targets tend to drift a little, possibly this movement plus a sigma-clip when stacking would help reduce this effect.

[Knight of Clear Skies]

I've just bookmarked this post which has some tips on reducing the effect, in case I ever come across it.

[Gina]

I think I may have seen it once but it could have been something else.  I have taken thousands of images with my two ASI1600MM-Cool cameras.  I too only knew of it from other posts.

[Endolf]

Thank you for the replies, the ASI1600 (cooled) is looking likely then.... I guess the next question then is which filter wheel to go for, they do 3 bundles with 1.25", 31mm and 36mm filters....
I understand the zwo filters have improved, so I'm tempted with a bundle with 7 filters, LRGB + Ha/SII/OIII....