another camera choice question

[Anthonyexmouth]

ok 

1. are the zwo and altair x183 variants the same camera or are there differences?

2. is the asi1600 worth the additional £350 over the 183? am i right in thinking its a more versatile camera? it'll be going on an ed80 to start and both look suitable. 

[vlaiv]

1. Can't be sure, but probably so - look at sensor specs for each - if it's the same sensor - there should not be much differences to camera except for extras (like cooling performance, driver support, quality of build, etc).

2. Looking by the imaging surface, we have following: ASI183 - 116.16 mm2 vs ASI1600 237.18mm2 - that is over 100% increase.

I would not take sensor surface as being primary consideration for selecting particular model, but if otherwise on equal footing - both can be properly matched with given scope - then larger sensor is certainly worth more money, and in this case having more than 100% surface justifies larger cost of camera. I would not expect it to cost twice as much, therefore one can argue that 40% ish percent increase in cost is worth it.

Ideally, you want combination of the two - low read noise of 1600, QE and pixel size of 183, size of 1600, ... you get what I mean

[Anthonyexmouth]

yeah i kinda get it, just makes the choice so much harder. just getting nervous with the credit card. b/day today so thinking about using that as an excuse to treat myself but the prospect of a few more weeks of crappy weather is swaying me to hold off.

[vlaiv]

Happy B/day then!

 

[Anthonyexmouth]

5 minutes ago, vlaiv said:

Happy B/day then!

 

Thank you. where's my clear skies i asked for? only asked for 1 thing. 

[Demonperformer]

I swapped a 1600mm for a pair of 183s at the end of last year. I haven't regretted the move. All used with a star71.

[Anthonyexmouth]

4 minutes ago, Demonperformer said:

I swapped a 1600mm for a pair of 183s at the end of last year. I haven't regretted the move. All used with a star71.

what made you make the swap?

[Rush]

Happy birthday ,

The day s urs:) so hardly u can make a wrong choice?.

FOV of 4/3 rd  is by far greater than than Alt -? 183 series i guess.

Well , if u r comming from  DSLR path, 1600 is the right choice.

Its worth every cent  U invest in a bigger sensor no matter which optics U want to use., apart from planetary stuff.

Cheers and a nice bday,

Rush

 

[Demonperformer]

8 minutes ago, Anthonyexmouth said:

what made you make the swap?

I'm not sure my reasoning was particularly scientific. I was after a matching pair to make combining results easier and the 1600MC (which may well have been my first choice) became unavailable. The 183 has smaller pixels and a bigger chip and has a higher QE in the near UV (NeIII is 386.9nm) all of which I considered to be a positive.

[Anthonyexmouth]

3 minutes ago, Demonperformer said:

I'm not sure my reasoning was particularly scientific. I was after a matching pair to make combining results easier and the 1600MC (which may well have been my first choice) became unavailable. The 183 has smaller pixels and a bigger chip and has a higher QE in the near UV (NeIII is 386.9nm) all of which I considered to be a positive.

it has a bigger chip? can you set the temp on both of these?

[Demonperformer]

Sorry, got that backwards ... it has more pixels. With an ED80 (without reducer/flattener), the 183 gives you 78.9' * 52.7' @0.86"/px, the 1600 gives you 101.2' * 76.5' @1.3"/px, so the 183 gives you greater resolution.

Yes, all the zwo cameras I have owned have fixed-point cooling and they have all been quite speedy about reaching it.

[Anthonyexmouth]

does the smaller sensor also mean being able to use smaller and hence cheaper filters? 

[vlaiv]

Just now, Anthonyexmouth said:

does the smaller sensor also mean being able to use smaller and hence cheaper filters? 

In general yes. You can still use 1.25" filters with ASI1600, but those need to be mounted fairly close to avoid excessive vignetting. You won't have such issues with 183.

One drawback of mounting filters close are those annoying reflections. You probably get the same reflections with filters mounted further away, but because of their distance - light gets defocused more and reflection gets spread over more pixels - and that makes if much fainter - it goes unseen in the images.

[Anthonyexmouth]

3 minutes ago, vlaiv said:

In general yes. You can still use 1.25" filters with ASI1600, but those need to be mounted fairly close to avoid excessive vignetting. You won't have such issues with 183.

One drawback of mounting filters close are those annoying reflections. You probably get the same reflections with filters mounted further away, but because of their distance - light gets defocused more and reflection gets spread over more pixels - and that makes if much fainter - it goes unseen in the images.

so for long term investment, would buying 36mm filters as and when money allows be a better option?

[vlaiv]

3 minutes ago, Anthonyexmouth said:

so for long term investment, would buying 36mm filters as and when money allows be a better option?

I guess it would. I'm using 1.25" filters with ASI1600 on both my scopes. I have solution that mounts filters really close to sensor - filter drawer, and so far, for my needs, it has worked. I do get reflections in NB - here is OIII example:

but those are fairly mild in comparison to some that I've seen.

ASI1600 gets those in some cases due to microlenses and lack of AR coating on sensor it self (so it's been reported). Don't know if ASI183 gets those - I've not heard of the case yet. Some people claim that you will get those with ASI1600 regardless of filter used, but I think it needs to be just right combination of spacing, filters and scope F/ratio to produce them in certain measure (sometimes it's less, sometimes it's more - I've seen couple really strong examples).

[Anthonyexmouth]

2 minutes ago, vlaiv said:

I guess it would. I'm using 1.25" filters with ASI1600 on both my scopes. I have solution that mounts filters really close to sensor - filter drawer, and so far, for my needs, it has worked. I do get reflections in NB - here is OIII example:

but those are fairly mild in comparison to some that I've seen.

ASI1600 gets those in some cases due to microlenses and lack of AR coating on sensor it self (so it's been reported). Don't know if ASI183 gets those - I've not heard of the case yet. Some people claim that you will get those with ASI1600 regardless of filter used, but I think it needs to be just right combination of spacing, filters and scope F/ratio to produce them in certain measure (sometimes it's less, sometimes it's more - I've seen couple really strong examples).

is there anything in the 1600 specific filters or is it just marketing? i see the 183 from altair charge extra for AR but the ZWO says its standard. 

[Demonperformer]

6 minutes ago, vlaiv said:

Don't know if ASI183 gets those

I use a 1.25" filter with the mono, using the adapter and I screw this in as far as it will go. Curiously, the halos seem to be worse on fainter stars, the brighter ones seem better. Maybe I will try not screwing it in so far to increase the distance.

I use a 2" with the osc which is at the end of the extension tubes (the end that screws into the scope) so no problem.

[vlaiv]

22 minutes ago, Anthonyexmouth said:

is there anything in the 1600 specific filters or is it just marketing? i see the 183 from altair charge extra for AR but the ZWO says its standard. 

I don't know anything about those filters, I use Baader ones. There are two different sensor covers in ASI1600 - one that seals sensor chamber and is facing outside of the camera - that one is AR coated. There is also a layer of protective material that sits on top of actual pixels and silicon. That one is supposedly not AR coated - it's that way straight out of Panasonic factory and one would need to take sensor "apart" to do anything with it (probably damaging chip and it will certainly void warranty).

Size of reflections suggest that culprit is this chip cover window rather than chamber window. Dust on chamber window produces larger shadows.

[Adam J]

3 hours ago, Demonperformer said:

I swapped a 1600mm for a pair of 183s at the end of last year. I haven't regretted the move. All used with a star71.

That makes sense at that focal length, not universally a good idea though.

[Adam J]

2 hours ago, Demonperformer said:

Sorry, got that backwards ... it has more pixels. With an ED80 (without reducer/flattener), the 183 gives you 78.9' * 52.7' @0.86"/px, the 1600 gives you 101.2' * 76.5' @1.3"/px, so the 183 gives you greater resolution.

Yes, all the zwo cameras I have owned have fixed-point cooling and they have all been quite speedy about reaching it.

Am 80mm has a Dawson limit of about 1.6arcseconds / pixel so you will see no difference in resolved detail between the two cameras as they are both over sampling the available optical resolution. 

For me the choice is a larger more sensitive Vs a smaller less sensitive sensor (183) that does not suffer from microlensing diffraction  patterns like the ASI1600mm pro. Also it costs less. 

[Anthonyexmouth]

2 hours ago, vlaiv said:

I guess it would. I'm using 1.25" filters with ASI1600 on both my scopes. I have solution that mounts filters really close to sensor - filter drawer, and so far, for my needs, it has worked. I do get reflections in NB - here is OIII example:

but those are fairly mild in comparison to some that I've seen.

ASI1600 gets those in some cases due to microlenses and lack of AR coating on sensor it self (so it's been reported). Don't know if ASI183 gets those - I've not heard of the case yet. Some people claim that you will get those with ASI1600 regardless of filter used, but I think it needs to be just right combination of spacing, filters and scope F/ratio to produce them in certain measure (sometimes it's less, sometimes it's more - I've seen couple really strong examples).

whats your reason for using a filter drawer instead of a wheel? 

[vlaiv]

1 hour ago, Anthonyexmouth said:

whats your reason for using a filter drawer instead of a wheel? 

Multiple things put together

Shorter optical path at 10mm, can be mounted closer to sensor - 1.25" / vignetting thing. Was cheaper option a the time. Due to stronger LP I don't really change multiple filters due to course of the night, so in reality, I could have done without it completely, but its handy thing for both 1.25" and 2" filters.

[Anthonyexmouth]

been looking at drawers, some are blooming expensive, what one did you go for?

[vlaiv]

I went with this one:

https://www.teleskop-express.de/shop/product_info.php/info/p3979_TS-Optics-Filter-Quick-Changer-for-2--filters---M48x0-75-mount---length-15-mm.html

Actually that one is M48 thread, I have one with T2 - which does not seem to be listed any more. I said 10mm optical path, but it looks like I was wrong - it's 15mm.

It looks like they now have different version, a bit longer and a bit thicker at 18mm optical path - this one comes in T2 variant as well - looks the same but a bit thicker, I believe drawers are compatible

https://www.teleskop-express.de/shop/product_info.php/info/p10474_TS-Optics-T2-Filter-Changer---strengthened-Design.html

There are few more models - like one for 36mm unmounted filters - that one is really short at 10mm

 

 

 

 

[Demonperformer]

Not considered one of those before, but looks like it could be a lot simpler than the wheel - particularly when trying to achieve backwards/forwards balance with the small frac ... €140 + postage ... maybe ...