Equipment suggestions for live / near live imaging

[London_David]

Hi All,

I'm new here and this is my first post…

I’m looking to purchase an observing/imaging set up and looking for advice. I want to get:

• OTA
• Mount
• Camera

Also, some light pollution filter(s), and maybe some eye pieces, focal reducer. Other suggestions welcome.

Here is my thinking…

I want to see DSO’s and I like observing the moon. But DSO’s more than anything else. 
This is primary a set up for live or close to live EAA viewing, for me I’m thinking 1/4 second refresh or up to 10 second exposures with autostacking. That means a fast scope.
Occasionally I'll be do direct visual, but less important to me. 
I have no space, so it can’t be a big scope, and huge mount. 150mm reflector is upper limit, 130mm is probably more practical. 80mm refractor. 5”/6" SCT, Mak etc. Light as possible. 
I need to cut through light pollution.
I don’t care so much about super pretty images, I just want to be able to see things. Later I may upgrade to competing with Hubble, but not now.

I’ve done a bit of research and come up with the following shortlist…

OTA

• SkyWatcher Explorer 150PDS
• SkyWatcher Explorer 130PDS
• Altair Astro 70ED-R
• Celestron NexStar 130SLT
• Orion Starblast 6i Intelliscope
• Bresser NT150S/750
• Meade StarNavigator 130mm f7.7

Mount (if not in the package)
SkyWatcher Star Discovery AZ Goto.
It’s cheap and should take the 130pds no problem and be okay with the 150pds 
I’m planning on doing less than 30s exposures for the foreseeable future. Ideally less than 10s exposures.
I like the ability to push to while keeping track of mount orientation on this. 
EQ3 Pro (the most obvious choice, I suspect)
Since I will might advance to trying longer exposures (especially with my old DSLR cameras, but I'm not into that right now).
Downside is that it looks big and heavy

Camera

• Atik Infinity
• Sony A7s
• Starlight Xpress Ultrastar or Lodestar X2
• Malincam Xtreme
• ZWO ASI224
• GSTAR EX3

Something else for live viewing I don’t know of…?

Budget wise around £1500 for this trio of base equipment feels kind of acceptable. I know I need accessories on top of that. Maybe I need to re-assess the base budget. It is flexible. 

And now for the long version…

Living in London Zone 2 I have always assumed I wouldn’t be able to see any DSO with a telescope. However, recently was shown some videos and short exposure images from similar heavy light polluted areas which seemed acceptable to me. Maybe it isn’t a lost cause…

I want a set up for augmented viewing, not a tool for feeding photoshop and post processing — I do enough of that professionally. Imaging software and tech doesn't scare me since I deal with this stuff day to day. I just don't want photoshop to be the main focus of my astronomy time. I may get into that at some point later, but for now I want to see things live or near live. For me that means somewhere between video at 25fps to watching 10s exposure autostack. Ideally, I’m thinking I want something that can show me some basic stuff - even if noisy - with a 0.25s to 5s exposure time. 

This is a first set up for me, though I have put in some hours my Dad’s 8” SCT. I’d say I’m a beginner at astronomy, but I know photo and video tech really well. Previously I have worked as a cinematographer, so I know cameras, digital cameras, stacking, colour grading, computer systems, image processing and all that stuff very well (though the shift in perspective for astrophotography has created some holes I might not realize…). ISOs f-stops focal length exposure, gain etc are second nature, comparing cameras using quantum efficiency and readout noise to gauge what that translates to on screen, not so much. 

If my questions seem technical but at the same time ignorant of basic practicalities — now you know why! 

My thinking is that if I want something good for photography that means fast and as big as possible. This imaging idea orignally took me down the route of refractor. The refractor also has the advantage of being small something like the Altair Astro E80ED-R. However, at f7 I was calculating that the exposures for live or near live viewing would be way off for what I want. That put me onto an imaging newtonian and I read a recommendation for the Skywatcher 130mmPDS f5. Just how much crisper/better is a refractor vs an imaging newtonian?

Also — my apartment is small — so a 150mm aperture tube is as big as I can go, ideally smaller. Mostly this will be used in Zone 2 London on any clear evenings we get. I want it to be practical to just get the thing pointed at the sky for a few hours. Hence the Starblast Dob as an option on that short list. Or the Meade 130mm. I suspect they will be too big a sacrifice in terms of performance, but then again, maybe not — maybe they’re practical with an GSTAR or Atik or something. I don't know and find it difficult to compare performance.

I kind of don’t want a huge equatorial mount. The EQ3 is as big as I can go (probably too big actually, but...). Really I want smaller, though I understand that could be unrealistic.  An AltAz could be work since I’m used to those with the SCT and they’re smaller. It has to be go to. I’ve done enough with the 8” SCT to know I want a goto — especially for the DSO stuff. Also, I have crazy thoughts about using a cinema fluid head tripod I have that I know could hold the weight of the OTA. So I’m entertaining short term thoughts of a non-motorized low performance solution with that… It should be good for exposures under 10s. Maybe.   

I definitely want to see/image/explore DSO’s. That’s what has always got me most excited. So far I’ve shot tiny purple smudges of Orion with a f1.8 55mm and no tracker (though not in London). I roughly calculated that to get a good look at the Orion nebula (which will no doubt be the first target I try) for a single frame needs something like 25s at f7 at ISO 6400. However, 25s exposures are much higher than I’d like for this set up. I may want to get into that kind of imaging later, but not now. This set up is so that I can see stuff in the sky from light polluted London, not so that I can make pictures to rival NASA.

That led me to the A7s. A camera I already know. The high ISO live view on that for me is quite spectacular. Never tried it on a telescope though. To give you my noise expectations, I find the A7s at ISO128000 is pretty satisfactory and good enough for viewing. At ISO204800 it is still just about okay, but by 409600 too noisy. I calculated some other DSO’s for single frames (my maths may be off…) but to get a decent Lagoon and Triffid viewing frame should easily be possible for the A7s under 10s. Maybe, maybe not noisy -- but either way pretty cool for faint objects. And as I said — what I really want to do is see stuff. I’d also expect to autostack with DSS and Astro-toaster. I have a 60d already so I’m setting up to test that workflow before I buy anything.

All of those numbers may turn out to be way off for London light pollution. It probably is. It’s obviously dependent on seeing and other conditions. Which made me think… maybe the A7s is too dependent on seeing for the light pollution of London. What about the Atik Infinity? I like the look of the software and the live stacking looks great. If it's designed for this shouldn't it be better?

Just how do some of these CCD’s compare to a super sensitive camera like the A7s. I asked an astro imaging shop rep that question and they were very dismissive and condescending. Before telling me something about DSLR’s that I know to be untrue. So I have no faith in his answers (and I won't be buying from him). Either way -- I’m still in the dark… My own back of envelope reverse engineer calculations suggest to me that you could rate the Atik Infinity at ISO 6400 and expect to get low noise. But that is a speculative guess and I have no idea how to compare to anything else. Nor what happens if you crank up gain etc.

My budget is process based: I’m aware that I could easily drop a lot of money on astronomy equipment that could sit in a cupboard rarely used. It wouldn’t be the first time I’ve done that with on camera equipment. If I was to get amazing results, maybe I’d spend more, then again there is a part of me that thinks, just buy a cheap 4/5 inch tube so it can fit in a cupboard nicely, and I can stick my existing Canon 60D to occasionally experiment (I suspect that would just frustrate me though). I’m wary of overspending but feel more constrained what it is worth buying when there is so much light pollution, along with the physical size of any equipment.

Which takes me back to the OTA. The Skywatcher Explorer 130/150PDS has kept jumping out at me. It was one of the first scopes that I came across that seemed to fit a lot of what I thought I was looking for. It was then recommended in two separate books I picked up, plus I’ve seen a lot of good stuff in the forums about the 130mm version. I’m just assuming that for what I want in terms of light collection the 150mm is better 33% might not be much for visual as it is less than half a magnitude but it could mean a lot in imaging if it is reducing exposure times by 33%. Or maybe not. I have no experience in this. Are there other OTA’s that would work as well or better for what I’m looking for? A cheaper scope and a more expensive imager? A more expensive scope and a cheaper imager? I don’t know!

Any filter or eyepiece recommendations for the OTA are also welcome…

And maybe I’m missing some other basic things too -- I’m definitely open to other suggestions! As I said it's all pretty new to me!

Thanks!

[Martin Meredith]

Hi David

Welcome to the forum!

It might be worth reposting in the video section. There are lots of us doing the kind of thing you're proposing and you're sure to get some answers.

Martin

 

[laser_jock99]

For instantaneous DSO imaging the Lodestar x2 cameras are quite good (and also double up as exceptional autoguiders).

Here's a 'stack' of 3x 5 second exposures of M51 with a Lodestar x2 mono through my 10" F4 Newtonian- with a full moon in the sky.

 

 

It is remarkable what can be achieved from London if you take the right approach with the right equipment. Check out Nytecam (Maurice Gavin's) website

http://home.freeuk.com/m.gavin/cnlinks.html

Instead of targeting the widefield objects better suited to darker skies Maurice uses a longer focal length 12" SCT and sensitive Lodestar cameras to target smaller objects like galaxies, planetary nebulae, star clusters, super novae and distant quasars most of us never even try to look for.

 

 

[iapa]

52 minutes ago, London_David said:

 

• OTA
  •  
  •  
  •  
  • Celestron NexStar 130SLT
  •  
  •  
  •  

 

My tu'ppence worth..... others may have, and will express, contrary views.

My first was an SLT 130.

• Good optics for the price.
• Mount is a bit light, so, a fair bit of vibration after touching it (12-12sec) - a few lines of water in a bag suspended from the tray does help:)
• Suffered from movement when anything more than a very light breeze - sand in tripod legs helped there.
• Focuser - I never managed to get that smoothly moving.
• As a starter, for observing, I'd be happy to use this. For imaging, I'd not be as keen now as I was 3 yrs ago.
• Collimation was no more difficult than the reflectors really.

PS my best, to date, of M42 was a Nikon D90 with 300mm lends on a tripod

DSLRs do get quite warm which introduces some noise in parts of the image nearest the warmer parts of the body. This can removed by taking 'darks'. (there are other ways to reduce noise using flats as lights and removing bias - haven't got my head around that yet :))

I upgraded to an AVX mount, and results on the 130SLT OTA were very satisfactory to me.

PSSounds like you can give suggestions on post processing with PS tho'  

[London_David]

2 hours ago, laser_jock99 said:

For instantaneous DSO imaging the Lodestar x2 cameras are quite good (and also double up as exceptional autoguiders).

Here's a 'stack' of 3x 5 second exposures of M51 with a Lodestar x2 mono through my 10" F4 Newtonian- with a full moon in the sky.

 

 

It is remarkable what can be achieved from London if you take the right approach with the right equipment. Check out Nytecam (Maurice Gavin's) website

http://home.freeuk.com/m.gavin/cnlinks.html

Instead of targeting the widefield objects better suited to darker skies Maurice uses a longer focal length 12" SCT and sensitive Lodestar cameras to target smaller objects like galaxies, planetary nebulae, star clusters, super novae and distant quasars most of us never even try to look for.

 

 

Thats really interesting - I saw Nytecam's stuff but didn't think about the fact he was looking at small objects. A 12" SCT is out of the question for me, but that kind of knocks my assumption that I need a fast f5 telescope. Those objects are really interesting to me though. A 6" SCT would be on my size limit. I'd also be worried that the subframes would try my patience and light pollution would cause issues. I'll have a look closer at Nytecam's work. Thanks!

 

[cletrac1922]

Hi David

 

I have a Skywatcher ED80 on a EQ5 mount, and find works well. Still venturing into astrophotography, using a Canon 600 DSR.

[rml63]

David,

I  am  in the same boat as you are and I was thinking of purchasing the Ioptron AZ Mount Pro and the Mallincam Universe.  I already have the SW BKP 130 DS which has a well built 2" focuser.  I am looking forward to getting started in EAA, best of luck.

 

Mike