Help check my setup before I buy

[deanchapman2705]

Hi,

I started deep sky astrophotography a few years ago now and still feel fairly new to this very complex hobby (although with the UK weather, that's probably only a couple of weeks worth of actual experience 😂) and have spent the past year or so looking at upgrading my whole setup, and hope that those with more experience can see if it all sounds ok and that nothing clashes with each other or if you think that something else would work better etc. (I currently own everything I need for the autoguiding side of things)

 

Here's what I have come up with:

Scope: Explore Scientific ED APO 102mm Carbon (FL: 714mm - FR: F/7)

Flattener: TS 2" 0.8x Reducer / Flattener for 100-102mm f/7 Refractors (as recommended by Astrobackyard)

Mount: iOptron GEM28 (1.75" LiteRoc Tripod + iPolar)

Camera: ZWO ASI 294MM-PRO (2x2 4.6um or 1x1 2.3um)

NB Filters: Baader Narrow Band Filter Set - CMOS Optimised (1.25" Ha, Oiii, Sii - 6.5nm)

FW: ZWO Mini EFW

Extras: ZWO ASIAIR Plus - ZWO EAF - some sort of portable power supply (12v 5a)

 

Specs:

Scope - FL: 714mm @f/7 (571mm @f/5.6 with 0.8x flattener/reducer) Triplet APO FCD-100 glass

Camera - M4/3 Sensor - 11.7MP, 4.63um, 14 bit, RN: 1.26e, FW: 66K, QE: 90% (2x2 bin as standard) for 102mm scope  - or -  47MP, 2.3um, 12 bit, RN: 2.7e, FW: 14K, QE: 90% (un-binned) for small refractor/lens.

Mount - Max Payload: 12.7kg (roughly 10kg for AP as advised by FLO) - scope with all attachments etc. comes to roughly 5.5kg

 

Why?:

Scope - I chose the scope as I love the quality to price ratio and it's wide FOV - the extra £200 for the carbon I think is a good to have with the much reduced total weight of 3.3kg! (which is handy for the lower payload mount) and it looks cool of course 😁

Flattener - I'm not sure on the flattener, there doesn't seem to be one designed specifically for the scope that's not ridiculously priced - Astrobackyard used this one when he had the same scope.

Mount - I like the light weight/portability of it with it only weighing 4.5kg and can still take a large payload considering (also plenty of payload for scope/attachments).

Camera - I chose this as I like the ability to be able to switch bin modes - the bigger 4.63um pixel size for the 102mm scope and smaller 2.3um for my WO Z61 and Samyang 135mm lens. It's almost like having two cameras.

FW - The small filter wheel was due to only using 3x 1.25" NB filters (colour with Sony A7iii for now) and for the Samyang lens it would be better with a smaller setup.

 

I think that's everything... as you can see, this is quite a lot of money to be spending so that's why it would help me if someone with much more experience could check before I buy everything to put my mind at rest!

Thanks,

Dean

[Catanonia]

Dew heaters ?

Finder scope and camera ?  (if imaging)

 

[scotty38]

I know you said why but if there is any chance you will consider LRGB  at any time then it might make sense to go with the 8x1.25" filterwheel.

I'd also search for Cuiv's video on filters just in case it makes you consider other brands. Better to think about it now.....

Edited January 27, 2022 by scotty38

[deanchapman2705]

1 hour ago, Catanonia said:

Dew heaters ?

Finder scope and camera ?  (if imaging)

 

Yes, I have a dew heater on my current setup as well as finder scope and autoguiding which I will transfer over.

Thanks!

[deanchapman2705]

14 minutes ago, scotty38 said:

I know you said why but if there is any chance you will consider LRGB  at any time then it might make sense to go with the 8x1.25" filterwheel.

I'd also search for Cuiv's video on filters just in case it makes you consider other brands. Better to think about it now.....

For the LRGB side of things, I doubt I will be shooting colour very often (maybe a couple of times a year for M31 & M43 etc.) and like I said, I will probably just use my Sony A7iii like how I do with my current setup. I can always upgrade later if needed to be fair.

I shall watch his video then 👍 there seems to be a lot of good qualities from Baader's latest filters that people usually have issues with other filters like halos, reflections etc. -

Also, with this being the first time shooting NB, I'm can go with the cheaper and broader 6.5nm filters (as I believe it's easier to see the subject when lining it up etc.) hoping to upgrade to higher quality 3nm filters in the future. So just didn't want to spend too much when starting out I guess.

Thanks for the advice!

[scotty38]

1 hour ago, deanchapman2705 said:

Also, with this being the first time shooting NB, I'm can go with the cheaper and broader 6.5nm filters (as I believe it's easier to see the subject when lining it up etc.) hoping to upgrade to higher quality 3nm filters in the future. So just didn't want to spend too much when starting out I guess.

With this type of setup, especially with the filter wheel, you can easily frame, focus etc with no filter at all if you wish so for the actual imaging buy the filters you want as it won't impact your ability to do those things.

Edited January 27, 2022 by scotty38

[ollypenrice]

22 minutes ago, scotty38 said:

With this type of setup, especially with the filter wheel, you can easily frame, focus etc with no filter at all if you wish so for the actual imaging buy the filters you want as it won't impact your ability to do those things.

Not sure about this. Some objects won't show at all in anything but one NB filter.

I don't find that it's easier to make out objects in my 7nm Ha than my 3nm. Nor is the broader bandpass faster. Rather the opposite, in fact.

Personally I'm wary of iOptron. We had a new one arrive here recently, dead on arrival with a circuit board fault. No new boards available. Later, one was supplied but the wrong one. The right one was still not available.  The owner went for a full refund. My feeling is that they knock out too many new products, using the customers as beta testers. Compare this with the long production runs and minor improvements in the Skywatcher business model. What will the iOptron spares situation be in five years?  This is just my personal feeling and I'm sure there are plenty of happy iOptron customers.

Olly

[gorann]

I would also stear away from the ASI294MM. It is the old generation of CMOS with amp glow and has some issues. Maybe @wimvb can chip in here.

[scotty38]

1 hour ago, ollypenrice said:

Not sure about this. Some objects won't show at all in anything but one NB filter.

I don't find that it's easier to make out objects in my 7nm Ha than my 3nm. Nor is the broader bandpass faster. Rather the opposite, in fact.

 

He was considering using 6.5nm filters vs 3nm for ease of focusing etc so all I was saying is with this level of automation there is no need as he can focus, frame, plate solve just fine with 3nm filters, plenty of folk already do. My point was with an EFW even if he did need "no filter" he can automate its selection, something that's a lot more difficult with no filterwheel and swapping them out individually.

[wimvb]

1 hour ago, gorann said:

I would also stear away from the ASI294MM. It is the old generation of CMOS with amp glow and has some issues. Maybe @wimvb can chip in here.

The ASI294 does have amp glow but it calibrates out fine. Otoh, if you have the option to get a cmos without amp glow, go for it.

@deanchapman2705: Having the possibility to switch bin states may seem appealing, but there are some major caveats to this. If you look on the ZWO web site, you'll discover that the ASI294 specs for the bin 1 state are not even close to the standard bin 2 state. So, you'll probably end up having to capture more subs to get good masters. And you'll need to do that with 4 times larger image files. So, you'll need the hard drive space and RAM to handle those larger files. I'm also not sure that even with the WO61 you'll see that much more detail in bin 1 than in bin 2.

Edited January 27, 2022 by wimvb

[Padraic M]

There's logic in getting the 8-position EFW. Certain DSOs respond better in broadband than narrowband, and for $100 extra you get the space to fit a set of RGB filters if you want. You will need a Lum/UVIR filter anyway, even with a narrowband filter set so it will be at a minimum LHaSiiOiii. Use the Lum filter for platesolving as trying to do that through a Ha filter is a PITA with longer exposure times. Lum is also faster for initial focusing (or with parfocal filters, or if you use filter offsets). 

I would also recommend the 3.5nm filter set from day one. If you want to spread the spend, just get Ha to start with and save for the others!

Re camera - I'm interested in what people would recommend as an alternative to the 294mm. I use the 1600mm which I know is a real favourite and a workhorse but seems to be considered a little dated these days.

I love the Prima Luce Lab Sesto Senso focuser. I can't compare with the ZWO but have heard about issues with backlash etc. and the PLL doesn't need any bracket to mount to the scope - it just clamps onto the fine focus shaft. Of course, the ASIAir is a walled garden so probably doesn't support the PLL focuser. For me, that's a good reason not to get an ASIAir (I hate walled gardens!). I use the MeLE Quieter2 mini PC with all the usual Windows capture software loaded and it works very well. For USB and Power distribution I use a Pocket Powerbox Advance. Will the ASIAir control your Sony DSLR? 

Finally, don't under-spec your PSU as under-volting causes all kinds of weird issues. Many 12V supplies can't regulate the voltage at 12V when under even moderate load. I'd look at a 13.8V 6-8A PSU.

[wimvb]

14 minutes ago, Padraic M said:

Re camera - I'm interested in what people would recommend as an alternative to the 294mm. I use the 1600mm which I know is a real favourite and a workhorse but seems to be considered a little dated these days.

There is no 4/3 alternative that I know of. You'd have to invest in the next size up, the 2600MM which is APS-C. The ZWO model is expensive, so to keep the price down, you have to get the RisingCam version or something similar. You'd still spend a fair bit more than what the 294 costs.