Is it worth getting an astro modded DSLR?

[StuartT]

I have been using an un-modified EOS 750D so far in my first attempts at imaging (both at the prime focus of my telescope and with my various telephoto lenses), but I'd like to capture more of the H alpha signal.

I realise that the ultimate choice is to use a mono astro camera with filters, but if I am sticking with colour for the time being would I be better off going with a modified DSLR or a colour astro camera? I'd prefer to leave my current DSLR unmodified (so I can use it for non-astro), so the choice I am trying to make is whether I'd be better off getting a new astro-modded DSLR or a colour astro camera?

I guess the main advantage of the latter is to have cooling to reduce noise.

Thanks 

Edited June 28, 2021 by StuartT

[The Lazy Astronomer]

I think this is going to come down purely to cost.

You will get more sensor for your money with a DSLR for sure, but if you're buying specifically for astro, a cooled astro cam may well be the better investment.

If you could find a good second-hand modded DSLR, you probably wouldn't lose any money on resale if you did decide to upgrade again in the near(ish) future.

[bottletopburly]

 No save your money for an dedicated Astro camera , all depends on funds and how long you look at getting a Astro camera funds would be better off saved for that purchase IMO .

[StuartT]

Right. This was where my thinking was going actually, so thanks.

I am already learning the ropes w my DSLR, so I guess the logical next stage would be a proper astro camera.

so.. the next question would be which one? I’m prepared to spend up to £1000

[Chefgage]

19 minutes ago, StuartT said:

Right. This was where my thinking was going actually, so thanks.

I am already learning the ropes w my DSLR, so I guess the logical next stage would be a proper astro camera.

so.. the next question would be which one? I’m prepared to spend up to £1000

My quick two pence on this is you have stated you would like to keep your DSLR for non-astro work. I had my DSLR modified and while I am very happy with the result in the amount of Ha data I can see I kind of wish I had just waited a bit and saved for a dedicated camera. The reason being there is times I would also like to use my DSLR for non-astro although I suppose I could still do that with a clip in filter.

[Sabalias]

I was in the same position recently, but my budget was significantly lower so I plumped for the modded DSLR. Eventually I hope to be able to upgrade to a dedicated astrocam. In your position I think I'd be checking to see what might be available second hand, as a rule it seems people really look after their astronomy gear and you can get some excellent deals so you £1000 could go far. Otherwise, apply the tech-buying rule of thumb - buy the best you can afford?

Stu

[michael.h.f.wilkinson]

I got a modded Canon EOS 550D for just 200 euro, and that gives really nice results.

I also tried my ASI183MC planetary and lunar camera for DSOs, which is more sensitive, but has a much smaller sensor

I have since moved to a monochrome, cooled camera (ASI183MM-Pro) which is better still.

Note, this was just under 2 h of data, so very little to work with

There are several cooled cameras within your budget, so you could go for a dedicated astro camera

[StuartT]

2 hours ago, michael.h.f.wilkinson said:

There are several cooled cameras within your budget, so you could go for a dedicated astro camera

Thanks. Any particular recommendations? I hear ZWO are very good (the best, even?)

[michael.h.f.wilkinson]

6 minutes ago, StuartT said:

Thanks. Any particular recommendations? I hear ZWO are very good (the best, even?)

ZWO is certainly good value for money. I have only had one cooled camera which I chose mainly based on the fact that it was going cheap second-hand, and matched the colour version I already had in resolution and sensor size. I was originally going to go for an ASI294MM-Pro, but when the offer came up, I jumped on it

[Clarkey]

4 hours ago, StuartT said:

Thanks. Any particular recommendations? I hear ZWO are very good (the best, even?)

I have a mono camera, but if I was in the market for a OSC with your budget I would definitely be looking at the ASI294. In my opinion it is probably the best overall value for money.

[StuartT]

8 hours ago, Clarkey said:

I have a mono camera, but if I was in the market for a OSC with your budget I would definitely be looking at the ASI294. In my opinion it is probably the best overall value for money.

Thanks. Can anyone point me to a good summary of how it's different using an astro camera like this, compared to using a DSLR? Do you still set the exposure length, the ISO etc just as you would when shooting with a DSLR? Does it generate the same type of image files etc? Do you still shoot lights, darks, flats etc?

[The Lazy Astronomer]

45 minutes ago, StuartT said:

Thanks. Can anyone point me to a good summary of how it's different using an astro camera like this, compared to using a DSLR? Do you still set the exposure length, the ISO etc just as you would when shooting with a DSLR? Does it generate the same type of image files etc? Do you still shoot lights, darks, flats etc?

Answers in order: yes, yes, no, yes, yes, yes.

With a bit more detail: you'll need a laptop or a mini PC with appropriate drivers and software to control the camera. Plenty of freely available software for this - my choice is N.I.N.A.

Getting the software and the drivers initially set up can be a little faffy, but once all installed and configured there's no need to do it again. If you run into issues there, the people on this forum will be able to provide solutions.

Exposure lengths can be set to basically whatever you want (from memory, ZWO cameras can be set anywhere from 32 microseconds up to 2000 seconds). 

ISO is replaced with 'gain', but it's basically the same thing. The camera manufacturer should provide details on various aspects of the performance at different gain values; you can use that to help you decide what gain to use (you can also run your own sensor analysis in Sharpcap, should you so desire).

The standard file format for astro cams is FITS, all the stacking software will handle FITS files, you may need to download a FITS viewer program to look at the individual images outside of the capture or stacking software (again, loads freely available on the web - I use ZWO's one).

All the usual calibration frames will still be required: at a minimum, darks and flats, ideally flat darks as well. The advantage of set point cooling on an astro cam means you can build a darks library to reuse many times, negating the need to take darks every session, provided you stick to the same camera settings.

Advice here would be pick a temperature, pick a gain, take a load of darks for the various exposure times you normally use, and then stick to those settings for all of your imaging. Obviously you can just shoot some more darks whenever if you wanted to use different exposure lengths to what you already had darks for.

Wow, that became a looong post!!

[Sabalias]

Quote

With a bit more detail: you'll need a laptop or a mini PC with appropriate drivers and software to control the camera. Plenty of freely available software for this - my choice is N.I.N.A.

This is the way to go. Though I use a Canon I also use an Astroberry and I can tell you that you have all the controls you need through that for a ZWO CCD. I do have a ZWO guide cam and have used the software that came with the camera to test it using my PC but the astroberry option works very well indeed once you have it set up. I think most people who go down the ZWO ASIAir or Astroberry route do so to provide the control functions remotely; I believe that the same level of control can be gained by plugging your hardware direct into a laptop but it's probably a bit less mobile. Note that my understanding is a bit limited as I've not had a chance to use the setup in anger yet.

Hope it all works out

Stu

Edited June 30, 2021 by Sabalias

[Clarkey]

5 hours ago, The Lazy Astronomer said:

The advantage of set point cooling on an astro cam means you can build a darks library to reuse many times, negating the need to take darks every session, provided you stick to the same camera settings.

This is the main advantage of set point cooling. You can create a darks library and to have to waste imaging time creating darks. Also, if you are like me an need some sleep, you can take your flats / flat darks prior to imaging and set everything going and go to bed!

 

5 hours ago, The Lazy Astronomer said:

pick a gain

There is a large drop in noise at a gain of 100 so this is probably a good starting point.

[StuartT]

this is all super helpful! Thanks. I am going to copy and paste your answers into a crib sheet so I have them to hand 😀

I already run things from my laptop in any case (using APT and stellarium), scope control and plate solving, so don't need to learn that at least. 

@Clarkey as for 'going to bed' I could never do that. I'd be too worried about it starting to rain and then waking up to thousands of quids worth of destroyed gear!

Edited June 30, 2021 by StuartT

[Stuf1978]

1 hour ago, StuartT said:

this is all super helpful! Thanks. I am going to copy and paste your answers into a crib sheet so I have them to hand 😀

I already run things from my laptop in any case (using APT and stellarium), scope control and plate solving, so don't need to learn that at least. 

@Clarkey as for 'going to bed' I could never do that. I'd be too worried about it starting to rain and then waking up to thousands of quids worth of destroyed gear!

I made the jump to a dedicated astro cam (ZWO ASI 294MC Pro) from a modded dslr that I had been using through APT/Stellarium/EQMOD and it's was pretty painless. Downloaded the necessary drivers for the new camera and it all worked like before with the dslr, albeit the slightly different interface in APT for the cooled CMOS. 

Being able to create a darks library and the massive improvement in noise levels is a massive win win   

Edited June 30, 2021 by Stuf1978

[Clarkey]

6 hours ago, StuartT said:

I could never do that. I'd be too worried about it starting to rain and then waking up to thousands of quids worth of destroyed gear!

I understand this - it is my worse fear too. I do use a rain app called 'rain alarm' which uses rain radar to alarm. It seems pretty good but I only leave the kit outside if there is no rain forecast as well.

[nfotis]

I wouldn't invest in a new dSLR and conversion myself, as the cost starts approaching a cooled camera. Maybe if someone sold a used modified camera instead.

ZWO and QHY are the bigger brands known in astro cameras in recent years, but there others like Touptek/RisingCam and old CCD-era companies like Atik, Moravian etc.

It's been my understanding that having separate cameras for planetary imaging (non cooled) and deep sky objects (cooled) is ideal. For planetary imaging, the IMX462 and IMX464 sensors are considered among the best. For cooled cameras, it's color or monochrome sensors (and filters) and sensor size which separate the expensive from very expensive to obscenely expensive.

For color cooled cameras, the IMX533 and IMX571 sensors are quite popular and latest technology (no amp glow, etc.). For monochrome, the IMX294m (really IMX492) offers two different resolutions, and the IMX571 mono is wonderful. There are also full frame sensors, but these are pricey beasts and require experience in getting the most out of them (large image circle, careful tilt checking/correction, huge image files to process, etc.)

N.F.

 

[dark knight]

Just a thought but what telescope are you using?  as I had this same conundrum a while back, I ended up getting a Canon 6d dslr as I wanted a full frame sensor for my esprit 120 Pro ed, this was a much cheaper alternative  than buying a osc full frame. The canon does have fairly good ha response without being modded, after modding it is outstanding. There is an online calculator  which will help you match sensor size to your telescope.

 

[StuartT]

25 minutes ago, dark knight said:

Just a thought but what telescope are you using?  as I had this same conundrum a while back, I ended up getting a Canon 6d dslr as I wanted a full frame sensor for my esprit 120 Pro ed, this was a much cheaper alternative  than buying a osc full frame. The canon does have fairly good ha response without being modded, after modding it is outstanding. There is an online calculator  which will help you match sensor size to your telescope.

 

My gear is all in my signature 😉 After the advice here, I took the plunge and bought a ZWO. Not yet had first light tho.

But I have a new scope arriving any day now (SUPER excited) - Esprit 150ED

Edited July 8, 2021 by StuartT

[dark knight]

Omg Stuart you will love it,  the esprit is awesome,  mine had a moonlite focuser on it when I bought it second hand so don't know much about the sw focuser fitted to yours but the optics are fantastic, suppose that means months of clouds now then 

[StuartT]

32 minutes ago, dark knight said:

Omg Stuart you will love it,  the esprit is awesome,  mine had a moonlite focuser on it when I bought it second hand so don't know much about the sw focuser fitted to yours but the optics are fantastic, suppose that means months of clouds now then 

I'd ordered a Moonlite for my SCT but Rother had to cancel the order after several weeks because Moonlite have inexplicably stopped making them (and now add a motor for some reason) without bothering to mention this to their retailers! Most annoying.

[The Lazy Astronomer]

2 hours ago, StuartT said:

But I have a new scope arriving any day now (SUPER excited) - Esprit 150ED

Now that's a serious purchase! You will not be disappointed, l took delivery of the 100 a couple of months ago and it is fantastic - I firmly believe the Esprits really punch above their weight. 👍

A note on the weight though: I was really surprised how hefty the tube was for mine - I know all the weights and dimensions are available online, but still it was a bit of a shock just how big it actually was - I can only imagine how much of a beast the 150 must be!!

P.s. the stock focuser is more than capable too.

Edited July 8, 2021 by The Lazy Astronomer

[johninderby]

40 minutes ago, StuartT said:

I'd ordered a Moonlite for my SCT but Rother had to cancel the order after several weeks because Moonlite have inexplicably stopped making them (and now add a motor for some reason) without bothering to mention this to their retailers! Most annoying.

Moonlite posted this on CN

“All manual focusers are being phased out; only automated focusers will be produced. All our new focuser products in development are automated for 2021. However, changes are being made early due to severe supply chain issues with raw material and components not being available. We only have the resources to manufacture our automated versions currently. We have started to update the web page with our new models as they are completed. All of the old manual versions are being removed from the web site as it is updated.” - Ron Newman

[StuartT]

11 hours ago, The Lazy Astronomer said:

Now that's a serious purchase! You will not be disappointed, l took delivery of the 100 a couple of months ago and it is fantastic - I firmly believe the Esprits really punch above their weight. 👍

A note on the weight though: I was really surprised how hefty the tube was for mine - I know all the weights and dimensions are available online, but still it was a bit of a shock just how big it actually was - I can only imagine how much of a beast the 150 must be!!

P.s. the stock focuser is more than capable too.

Yes, the 150 weighs in at a hefty 15kg! Looking forward to trying it out once we get proper nighttime back next month 🙂

Great to hear you are pleased with your Esprit!

 

11 hours ago, johninderby said:

Moonlite posted this on CN

“All manual focusers are being phased out; only automated focusers will be produced. All our new focuser products in development are automated for 2021. However, changes are being made early due to severe supply chain issues with raw material and components not being available. We only have the resources to manufacture our automated versions currently. We have started to update the web page with our new models as they are completed. All of the old manual versions are being removed from the web site as it is updated.” - Ron Newman

Thanks. Unfortunately the automated ones are twice the price! I'm not really sure it's worth it for my old SCT

 

Edited July 9, 2021 by StuartT