Advice appreciated re: future imaging set-up

[Lee_P]

Hi SGL folks, I’m hoping to get some thoughts on a future imaging set-up.

I’ve done astro imaging before, with an 80ED, ASI1600 mono plus filters, and an HEQ5. I recently sold most of the kit (but kept the HEQ5), as a new baby has left me precious little free time! I do miss the hobby though, and am contemplating a return – maybe this winter.

I’d be imaging from my garden in the centre of Bristol (i.e. terrible light pollution). My goal is to be able to set everything up with a minimum of fuss (say 20 mins max), and get some decent data to play with over the course of a night. I like nebulae and star clusters – not so fussed about planets. I’d also like any new kit to allow me to produce images as least as good – and hopefully better – than I was taking before. See here for examples. My budget will depend on how well my Covid-impacted work recovers, but I’m aiming for around the £3k mark. I'm not looking to win Astrophotographer of the Year; I want something that's fun and (relatively) simple. I reckon I’ve two big questions that need answering: OTA and camera. (I’ll be using my HEQ5).

OTA
I like short-tube refractors, and I’m leaning towards the William Optics 61 or maybe 73. I find relatively wide angles to be quite forgiving (i.e. easier to take photos with!) and they suit my target preferences.

However, there’s another option… I’m a professional photographer, and so could use my Nikon lenses. In particular, I may be getting the new 70-200 2.8 Z lens in the future. I do balk slightly at the thought of going down the lens rather than ‘scope route though, for a few reasons. I worry that the focal length might be a bit too short; that the lenses aren't made for astro work like telescopes are; automated autofocussing throughout the night is tricky (not keen on DIY options); not sure how I’d physically couple accessories such as a guidescope; and I’d worry about leaving the lens out in my garden all night when I might need it for paid work the next day. With a dedicated telescope I could just keep the camera permanently attached, which would also be easier. Some days I think I'm mad to consider a telescope as I have lenses; but the next day I'll think that a dedicated telescope is obviously the way to go!

Camera
Being in a city centre, using my unmodded Nikon camera is a no-go. I’d like to go cooled CMOS. I like ZWO cameras, plus am thinking of getting the ASIAIR Pro to make everything easier. Now comes a biggy… although I got good use out of my mono CMOS and filters, it was a bit of a faff dealing with all the different filters, matching calibration frames, and then the processing afterwards. I was capable of doing it, but I’d prefer something simpler. Now I’m hearing about filters such as the Optolong L-eXtreme and L-eNhance, and am wondering if one of those coupled with, say an ZWO ASI 294MC-PRO or perhaps an 2600MC-PRO could be a winning combo. Just to stress, I understand that all things being equal, mono plus filters would be better, but ease of use and consequently fun factor are critical here! But would I be able to take better photos than I was previously?

 

That’s a splurge of my current ideas. Any and all thoughts would be appreciated, and I’m definitely open to being challenged on any assumptions I may have made that you have a different viewpoint on.

Thanks!

-Lee

Edited September 2, 2020 by Lee_P

[Starflyer]

My first thought would be to put a pier in your garden, attach your mount to it and get polar alignment dialed in. Leave the mount out and just throw a decent cover over it when not in use.

This will cut down on your set up time considerably and allow you to get going quickly. 

[Lee_P]

12 hours ago, Starflyer said:

My first thought would be to put a pier in your garden, attach your mount to it and get polar alignment dialed in. Leave the mount out and just throw a decent cover over it when not in use.

This will cut down on your set up time considerably and allow you to get going quickly. 

Thanks, that's a good idea and is something I'll consider!

[Starflyer]

Here's mine, I went a step further and ran a 12v supply from the shed, it makes setting up a breeze.



[jimjam11]

2 hours ago, Starflyer said:

Here's mine, I went a step further and ran a 12v supply from the shed, it makes setting up a breeze.



Looks good. 

What cable did you use for the 12v run, how long is it and what is the voltage drop like?

[Starflyer]

I can't find the receipt email, but from memory it was armoured twin with 10mm cores. The run is only around 6m and there's no noticeable voltage drop, there must be some but it shows the same on the pier display as the battery display.

I have it connected up to a 110Ah leisure battery and that's kept topped up by two solar panels (I have no mains power in the shed).  Even in the depths of the UK winter, imaging for six to eight hours a few nights a week it hasnt dropped below 12v

[Lee_P]

Any thoughts from the SGL Hive Mind on my other questions? Would love to hear more opinions! Particularly keen to know informed opinions on the Optolong filters. Thanks!

[kens]

Just to give you food for thought... The most important piece of kit for imaging, especially for DSOs, is the mount. Opinions vary, but I would think that the mount would take up at around half the budget of your kit overall. Looking at your budget , you would appear to be underdone with an EQ5 mount. Many would consider the HEQ5 as a sensible minimum. Most of the frustrations with imaging stem from the mount so if you are after something that is simple and fun you should consider your choice of mount.

[Lee_P]

2 hours ago, kens said:

Just to give you food for thought... The most important piece of kit for imaging, especially for DSOs, is the mount. Opinions vary, but I would think that the mount would take up at around half the budget of your kit overall. Looking at your budget , you would appear to be underdone with an EQ5 mount. Many would consider the HEQ5 as a sensible minimum. Most of the frustrations with imaging stem from the mount so if you are after something that is simple and fun you should consider your choice of mount.

Thanks Ken, I realise that I wrote EQ5 whereas I actually have an HEQ5. I'll edit the original post. I bought the mount from SGL's very own Skipper Billy, and it's proved itself to be very reliable and steady as a rock with my previous set-up, which was heavier and had a longer focal-length that what I'm considering next. So it should be a-ok.

[DaveS]

If you really want to go OSC and if it must be ZWO for the ASIair then I'd eschew the 294 for the new generation ASI 2600 which has zero amp glow and 16 bit ADC, as well as being a fair bit bigger. I think my preference would be for the QHY version, but of course, it won't work with the ASIair.

I can't answer directly about the various dual and tri band filters as I'm strictly mono, but given your LP, the narrower the better. ZWO do a 54mm filter holder which it might be worth getting, it's available from FLO.

[carastro]

If you are keen on using lenses but worried about using the workday lens outside at night, why not consider getting a lens for AP. 

I bought myself a Samyang 135mm F2 lens a few months ago after struggling for years to get decent images with a camera lens, and it's every bit as excellent as every-one claims.  Of course it does depend on what camera you put on it and I can't comment on the CMOS cameras as I have only CCD cameras.

Carole 

Edited September 2, 2020 by carastro

[Lee_P]

7 hours ago, DaveS said:

If you really want to go OSC and if it must be ZWO for the ASIair then I'd eschew the 294 for the new generation ASI 2600 which has zero amp glow and 16 bit ADC, as well as being a fair bit bigger. I think my preference would be for the QHY version, but of course, it won't work with the ASIair.

I can't answer directly about the various dual and tri band filters as I'm strictly mono, but given your LP, the narrower the better. ZWO do a 54mm filter holder which it might be worth getting, it's available from FLO.

Thanks, that's really useful to know. Regarding the filter holder, they seem to be in-built into the flatteners; is the benefit of the separate filter holder that it allows easy switching? I expect I'd leave the filter in all the time, but maybe it wouldn't pan out that way.

[Lee_P]

7 hours ago, carastro said:

If you are keen on using lenses but worried about using the workday lens outside at night, why not consider getting a lens for AP. 

I bought myself a Samyang 135mm F2 lens a few months ago after struggling for years to get decent images with a camera lens, and it's every bit as excellent as every-one claims.  Of course it does depend on what camera you put on it and I can't comment on the CMOS cameras as I have only CCD cameras.

Carole 

Yes, that could be an option. Thanks for the suggestion. How do you deal with focussing the lens -- do you have that automated in any way? 

[DaveS]

4 minutes ago, Lee_P said:

Thanks, that's really useful to know. Regarding the filter holder, they seem to be in-built into the flatteners; is the benefit of the separate filter holder that it allows easy switching? I expect I'd leave the filter in all the time, but maybe it wouldn't pan out that way.

I would go for the filter holder, as it gives you the option of easily switching between a dual / tri band nebula type filter or a more broad band LP filter for clusters or galaxies. Incidentally the flatteners and reduces I use don't have a filter thread on them, so don't count on one being present.

Looking at various options, I see that IDAS do some interesting dual band filters with [OIII] / H-alpha, and [OIII] / [SII], but they need a further UV / IR blocking filter, so *two* holders, argh!

There is also a Crazy Expensive ultra-narrow quad band filter, but I don't really see the point.

[TerryMcK]

Wow that filter is expensive and I too don’t see the point.

[carastro]

Quote

How do you deal with focussing the lens -- do you have that automated in any way? 

I did buy a microfocusser to go with the Astrokraken mounting rings, it is manual but allows for fine focussing.  But I have found that the focusser ring is rather stiff when inside the mounting rings and unlikley to shift so i stopped using it.  So focuss is done manually with a Bahtinov mask.   I think some people have motorised their Samyang lens. 

Carole 

[Lee_P]

Carole's got me enthused about the lens route! The Samyang 135mm looks great (I spent hours looking through the epic forum thread), but if I could overcome my concerns about using my current lenses -- perhaps not by using particular ones that I might need for a shoot the following day -- then perhaps I could just use my existing collection, inc. 50mm f1.8 and 70-200 f2.8. With that in mind, two questions about lens set-ups, if I may:

* Considering I'd like to use a cooled astrocam, lens, guidescope, red dot finder, ASiair to control it... what's the best way of physically coupling all that kit to my HEQ5? I've seen some 3D printed options (Astro Kraken et al) but they seem bespoke for specific lenses. I'm imagining something something attached to the mount as a base, then this holder to attach camera. Then perhaps the guidescope next to the camera / lens, and the ASisiar at the back. Maybe a tube ring attached to the base plate, going around the lens, allowing for a red dot finder on top... I'm sure minds wiser than mine can suggest something better. Plus I'm not sure how to prevent any kind of sag in the image train if a heavy lens is used...

Edit: maybe something like this? https://www.firstlightoptics.com/dovetails-saddles-clamps/primaluce-lab-side-by-side-240mm-plus-vixen-bar-with-dual-fit-clamps.html

* I don't have a firm grasp on the importance of matching imaging sensor to lens. I was veering toward the ASI 2600, but according to CCD Suitability, that's best for focal lengths around 400mm -- longer than what I'm looking at. So is that camera a no-go with these lenses? Or is it not really critical?

Thanks again to everyone that's helped me so far  

 

Edited September 3, 2020 by Lee_P

[DaveS]

With the very wide field you will get from camera lenses I wouldn't get too hung up on the "/p figure, afterall you get the same sort of figures from using a DSLR.

I would be careful about mounting heavy lenses on a camera with no other support, the couplings are designed for putting the camera on a telescope, not the other way round. Pity you're Nikon else This might be an option, though I think you may be able to get a Nikon / Canon adaptor.

[Lee_P]

24 minutes ago, DaveS said:

With the very wide field you will get from camera lenses I wouldn't get too hung up on the "/p figure, afterall you get the same sort of figures from using a DSLR.

That's good, I was beginning to wonder exactly which camera *would* be suitable...

 

25 minutes ago, DaveS said:

I would be careful about mounting heavy lenses on a camera with no other support, the couplings are designed for putting the camera on a telescope, not the other way round. Pity you're Nikon else This might be an option, though I think you may be able to get a Nikon / Canon adaptor.

Yes, very wise. The only really heavy lens I'd be using is the 70-200 2.8, which has its own foot and tripod attachment, so I guess that would attach to the mount rather than the camera. Assuming there's a simple way to do that. Canon does seem to be much better catered for than Nikon, astro-wise -- and the fact that I'll be mostly using Nikon Z lenses narrows my attachment options further.

Actually, that's a question for anyone in the know: what would I need to attach a Nikon Z lens to a camera like the ASI2600, plus fitting a 2" filter in the image train?

[DaveS]

Ah, Nikon Z-mount. Sorry, my knowledge runs out there, I thought you might be Nikon "F", for which adaptors are available.