Guide Camera set up - just to double check

[Rustang]

By the end of the year I would like to be guiding so I'm slowly sorting out what I need (baby steps!). I have been doing my research, nearly gave up again just reading about what I need!, is nothing easy in this hobby!? 😄 My scope SW 130PDS - 650FL, camera Nikon D750 and Canon Modified 600D, mount HEQ5 Pro. Ive brought Adam's Altar Astro 60mm guide scope so I'm now looking at cameras. I have read that mono is better so I'm looking at (to keep costs down) the ZWO ASI120mm and the S model!. Looking at the specs and whats compatible, I believe the following calculations will give my the correct set up:

So Canon APS 4.3 x 206 / 650 (scope FL) = 1.36 APS

Nikon  5.97 x 206 / 650 =1.89 APS

ZW0 guide cam APS 3.75 x 206 / 225 (Astro guide scope FL) = 3.4 APS

 

Guiding ratio = Cannon 3.4 / 1.36 = 2.5

Nikon 3.4 / 1.89 = 1.79

I believe a maximum ration of 4.1 is suggested so these calculations fall well in regards to this?

Also, apart from the USB port, size and weight extra are there any other differences to consider between the ZWO ASI120mm and the S model,  for me the USB 3 port would be better.

I will also be looking into this but for a beginner and to keep frustrations down, what would be the best/easiest software to use to start guiding?

 

Cheers

 

Russ

 

[Aramcheck]

For guiding software, I'd give PHD2 a go. Dylan O'Donnell's video on "Push Here Dummy" is pretty much all I needed to follow: https://youtu.be/Mt0luBLaHDw

I've been using a ZWO ASI120mm with a SW 9x50 finderscope, which was my cheapest option to get started. Can't comment on the "S" variant....

Cheers
Ivor

[rnobleeddy]

Mono is better but from my research, and (albeit) limited experience the colour version will perform perfectly well. I use a ZWO ASI120MC-S with a SW 9x50 finderscope and the camera is working well for guiding. I made this choice because I'd like to use it for planetary imaging without filters.

[rnobleeddy]

Also something I didn't spot (but got lucky with) is that the USB 3.0 version of the camera works well with linux but a lot of people had issues with the USB 2.0 version. That may not be important for you, but I found the astroberry software for Raspberry Pi to be a  really easy starting point, rather than having to have a laptop plugged in.

[x6gas]

The QHY5L II is also a popular choice and for reasons I've neve understood the colour version is cheaper than the mono...

[endless-sky]

+1 for the Astroberry tip! I have been using it since April and in one or two months I should get my new refractor for imaging and the autoguiding setup (guide scope plus guide camera). I have been reading about all sorts of problems with the 120MM Mini version and Raspberry. Apparently the QHY5L-II is not doing any better, plenty of issues there, too. So I ultimately decided to go with the ASI 224 MC, a little more costly, but it can double as planetary camera as well.

As for why color versions of the same camera models are less expensive, I used to wonder this, too. Then I read an explanation that made very good sense: the astrocameras "borrow" the same mass produced sensors that are generally used for everyday cameras. These sensors are mostly color (who wants a black and white only camera for everyday use - expecially when exposure times are so fast and converting color to black and white is merely a click away in post-processing?). Therefore, the cost of the mass produced color sensors - higher in supply - is lower than the cost of rarer monochromatic sensors - lower in supply - that have to be made specifically for the astrocameras. This explanation made sense to me when I read it, so I agree with it.

[TerryMcK]

The ZWO ASI120MM mini is an excellent choice for a guide camera and this black and white version is really sensitive.

Edited June 27, 2020 by TerryMcK

[Rustang]

Thanks guys for all the info. Just to check, are my above calculations correct? I shall look into all suggested options 👍

Edited June 27, 2020 by Rustang

[edarter]

Using a ASI 120MM mini with a sw st80 as my guiding setup without issues on my sw130pds and Canon 600d. 

[rickwayne]

Definitely go with the S model. It's been awhile but I'm not at all sure the USB problems were limited to Linux. And you may as well have the faster download available -- who knows, you might be imaging planets one day and want to shoot video.

I don't have a basis for comparison since I've only ever had one guide camera, but the MC seems to do fine. I've had a couple nights where I was getting 0.6" RMS on my CEM-25P with it, though habitually I see more like 1.2".