Milesy303

13 minutes ago, scotty38 said:

Nice setup. Just curious if you considered the QHY equivalent? Reason I ask is that is on my list together with their bolt on filterwheel.... If you are planning on using more than 1 filter then I would get a filterwheel for sure. I have the ZWO 294MC and use 1.25" filters and have not seen any real issues, what slight vignetting that is there calibrates out with flats.

I got a good deal with an ex demo 115  

thank you for help with the filters 

On 09/02/2022 at 12:39, vlaiv said:

Here is the thing - you can't zoom in indefinitely as there is limit imposed by optics, atmosphere and mount.

Most galaxies are smaller than M101 you imaged and that one is 22 arc minutes in diameter.

With something like 1"/px - being absolute maximum in realistic resolution in amateur conditions - that would make M101 be 22 * 60 / 1"/px = 1320px

Even at max zoom level (if you are able to image at that resolution and still make sharp image) - you will need to crop your sensor if you are using something like DSLR with ~5000px in width.

I would say that good working resolution until you really hone your imaging / technical skills is about 1.5"/px - that would make M101 - only 880px in diameter.

Not sure if that would satisfy you (it is about x4 more zoomed in than above image of M101 you posted - but I guess that one was resized down).

To realistically get 1.5"/px - you will need 6" of aperture and depending on selected camera - different focal lengths:

3.3um pixel size - 900mm of focal length with super pixel debayering

3.75um pixel size - 500mm of focal length (that would make setup ~F/3.2 - so not really option), or 1000mm with super pixel debayering

4.65um pixel size - 650mm of focal length (in this case - maybe go with 130pds?) or fast F/4 150mm newtonian. Alternative is to go with F/8-F/9 150mm scope for ~1300mm of focal length and use super pixel debayering.

If aiming for this resolution with smaller scope - I would choose F/9 RC scope + 294 camera. Big warning - people have trouble collimating these scopes and many have given up on them. It is not easy instrument to work with for some people. Camera is also sensitive on calibration - most notably flat frames. I've seen many people report problems if they use flat assistant on APT. There were also thread about this camera saturating "early" - around 50000ADU with some gain settings - which again causes problems with flats if one is not mindful about that (and things that standard 65K is saturation point).

 

Thank you for all the great advice @vlaiv - I went a step further and chose the 115M camera, which by all I read is the mono version of the 294.

I have created a new thread for some advice on filters and mounting them.

Thank you to everyone else to helped me make a decision, it is much appreciated.

Hi all,

I have chosen to go with mono (please dont try convert me to OSC, I have made the choice and willing to roll with it just now haha)

I have went for an Altair 115m hypercam to use with my WO GT81. 

Does anyone know if I will be able to use 1.25" filters with this? and If I can will I be able to use them in a drawer or wheel in terms of backspacing etc?

Any help greatly appreciated 

On 07/02/2022 at 17:35, Adam J said:

But to bring it back onto topic I would say that the conclusion for me is get the IMX533, because: 1) Its back illuminated and the 269 is not, 2) You really dont need to go to 3.3um pixels as per the above discussion, 3) Although the 294 is perhaps the best match to a longer focal length refractor 700mm or so, I dont like the way many have issues with calibration when using duel narrow band filters. 4) The OP says he wants to image smaller targets, so the size difference between the two sensors is probably not a factor. 

 

Actually ill amend that and say get the 533 mono when it comes out lol. That way you can get a smaller scope for the same sampling, but OP may not like the idea of mono...., 

Mono I like in theory but I’m limited in budget and can only afford a camera just now. So I invest in a camera and don’t use it until i have the filters and wheel and eaf, and by the time next season comes and I unbox there will be a new camera I wish I had invested in. 

Or I just bank the money and write off the rest of the season and don’t do any imaging. End up with car troubles or my boiler breaks and I need to spend the money and in one years time I’ll be back writing the same post again haha  

So really I don’t want to hold off and just make the best purchase I can, even if it’s not best paired with my scope for a few months and then after the summer I’ll get a longer focal length. I don’t plan on staying with the GT81 so I don’t want to match it  

21 hours ago, vlaiv said:

I worry about that all the time

Do you have any idea of what sort of working resolution you want to achieve?

Hi @vlaiv - I will be honest I am not sure exactly how to answer. When I said resolution I just implied the only resolution I know is what I have had with my DSLR.

I want to go to a longer focal length to get better shots of things like the pinwheel, bodes, owl nebula etc I have managed to get a lot of these already, but require big crops, and then lots of processing. noise reduction and deconvolution etc. 

Now I just want to be able to produce better pictures and move onto the next stage of my journey 

Chris 

25 minutes ago, Adam J said:

ASI533mc pro is the answer in my opinion. After that the ASI294mc Pro but its a little trickier to calibrate, there are a few long threads on SGL covering this topic. 

I don't like what i see from the 269 as there seems to be allot of walking noise in most of the images i see. Guiding and dithering would be essential in my opinion. 

Adam 

I am looking at Altair, the 533 seems quite a bit cheaper than the 269 and the 294. I assumed it was less of a camera.

29 minutes ago, smudgeball said:

Hi, I've used my 269 with a Megrez 72 (current) and GT102 (currently stored)

I agree that all the online calcs and "seeing" etc can be too much.

I also think the numbers you get are based on ideal conditions (what are they ?)

Certainly the 269 gives very clean subs, I do calibrate but mostly for the dusty obsy I have 🙂

Neil

Thanks Neil, how did it serve up with the GT102? Do you take darks?

Hi all.

I’m currently looking at both sensors to use with my GT81 scope for a few months but want to go to a longer focal length for after the summer. I have been looking at the same targets at the same resolution for quite a few years with my DSLR and my primary objective is getting into smaller targets and more detail.

With the 269 I’ll be over sampled when I go to the longer focal length but there is no amp glow to deal with.

The 294 seems an older technology but maybe bet better suited to upgrading after the summer ?

To be used under "uk seeing" which I think might be "ok"

My head hurts with all the sampling and seeing.

Chris

Hey folks, so I am currently using a GT81 with a 0.8 reducer, and my future plan is to get a RASA8.

I am looking at the altair astro models, but I need to admit I am not totally clued up on the specifics of sampling, and pixels etc. I know the rough idea but not enough to make an expensive decision yet. I am currently looking at the 183, 269 or 294 models.

Are any of them suited to what I am doing, to what I plan with the RASA8 on doing under fairly suburban skies?

(Ignoring the colour/mono question for the moment)

Many thanks

Chris

Not much more will pay for a decent quality 8 port powered hub. 

i already run my pi from a good power supply. I’m not massively fussed on having a one stop shop 

maybe I should just get a lynx astro unit with Dslr and dew heaters 

I’m in a dilemma to get the Pegasus power box advance or the power box mini and a separate powered usb hub. 
 

it seems like an awful lot more for only a few USB ports that would be better spent on a recent usb hub. 
 

any thoughts?

At the moment I have the following setup. 

WO GT81, EQ6-R, Nikon D5500

and I’m in the process of getting set up with stellarmate so I can utilise dithering and guiding mainly more than capturing but that helps.  

I’d love a WO FLT132 but that’s way out my budget sadly at the moment. 

I’m basically imaging what I can with the scope I have, including smaller targets that I’ve cropped like Bodes, Whirlpool etc. 

I have about £1000ish to spend and my thoughts were to a new camera. 

My biggest pain points here in Scotland for the last two seasons has been 

1. Taking darks, it seriously hampers my very little imaging time I get. So something like a cooled camera like the 1600 or 183 hyper cam seemed appealing  

2. I miss so much imaging time during the moon and it’ll only be a few months until twilight creeps back again for the summer. I’ve only managed to image three times since October...... so going mono on the above cameras seems like a pretty good idea. 

Someone else also suggested the 183c with a triband filter  

All I want is to give me a bit of a boost in productivity with so little imaging time  

greatly appreciated of any responses  

many thanks 

chris